cover2 3 2002 - dfg · silke hamann, astrid karl ... dr. rembert unterstell, ursula...

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rman

2/2003 Life under the “Cold Skin” The Unemployedand the Solidarity Fungi and Plants Become Partners under Stress On the Rise and Fall of theTown of Xkipché The Fire Salamander

Magazine of the Deutsche Forschungsgemeinschaft

Germ_res_cover_2_03 26.11.2003 11:32 Uhr Seite 2

german research 2/2003

In this Issue

Tracking Down Mayan CultureThe Mexican peninsula of Yucatan is abundant in evi-dence of the Mayan culturehewn in stone. At the Xkipchésite archaeologists have discov-ered that the Mayan people evi-dently abandoned their housesand palaces before their demise.Was warlike conflict responsi-ble, or was it perhaps due to anextended period of drought last-ing several years? Archaeolo-gists are searching for clues.Page 4

In Focus: Mass Unemploy-mentWhat is the real situation when itcomes to solidarity with the un-employed in Germany? A surveyof people in employment showsthat even when times are toughthe public support for social wel-fare benefit payments such asunemployment benefit, unem-ployment assistance and publicassistance is strong, whereas theindividual benefit payments arejudged very differently by therespondents. Page 11

A Partnership between Fungi and PlantsOver 80 percent of all plants livein symbiosis with mycorrhizalfungi. The fine threads of thefungi can penetrate the soil fur-ther and more efficiently thanthe plant’s roots. The molecularbasis for this remarkable bio-coenosis is the focus of one of theDFG’s Priority Programmes.Page 20


Expeditions into the Arctic Pack Ice

Two researchers are set down on the ice in a pod hanging from the crane on the research vessel “Polarstern”. This method is particularly advisable on thin ice, sinceice cores can be drilled directly from the pod.(Page 26) Cover photo: Michael Spindler

Commentary

Ursula PetersProspects for a Living Community . . . . . . . . . . . . . . . . . . . . . . . p. 2

Arts and Humanities

Hanns J. Premm, Michael Vallo, Iken PaapOn the Rise and Fall of the Town of Xkipché . . . . . . . . . . . . . . p. 4

Heike Wolf, Frank M. Spinath, Alois AngleitnerSimilar and Yet Still Different? . . . . . . . . . . . . . . . . . . . . . . . . . . p. 8

Silke Hamann, Astrid KarlThe Unemployed and the Question of Solidarity . . . . . . . . . p. 11

Life Sciences

Sebastian Steinfartz, Diethard TautzThe Fire Salamander: Source for New Species . . . . . . . . . . . p. 14

Wolfram Kutsch, Sebastian Berger, Hanno FischerStudying the Curved Flight Pattern of Locusts . . . . . . . . . . . p. 17

Hermann Bothe, Ulrich HildebrandtFungi and Plants Become Partners under Stress . . . . . . . . . . p. 20

Natural Sciences

Andreas Greiner, Martin Steinhart, Joachim H. Wendorff, Ralf WehrspohnA Gossamer Veil – News from the Nanoworld . . . . . . . . . . . p. 23

Michael Spindler, Rolf GradingerLife under the “Cold Skin” . . . . . . . . . . . . . . . . . . . . . . . . . . . . p. 26

Impressum

german research is published by the Deutsche Forschungsgemeinschaft (DFG; Ger-man Research Foundation); Editorial staff: Dieter Hüsken (editor-in-chief and design),Dr. Rembert Unterstell, Ursula Borcherdt-Allmendinger, Angela Kügler-Seifert; English Consultant: Nicholas Naughton BDÜ, Translation: SciTech CommunicationsGmbH, Heidelberg; Publisher: WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim(Germany), P.O. Box 10 11 61, D-69451 Weinheim; Annual Subscription price 2004:€ 44.00 (Europe) US $ 48.00 (all other countries) including postage and handlingcharges. Printed by: Bonner Universitäts-Buchdruckerei; Address of editorial staff: Deutsche Forschungsgemeinschaft, Public Relations, Kennedyallee 40, D-53175 Bonn; E-mail: [email protected]; printed on chlorine-free bleached paper with 50% recycling fibres. ISSN 0172-1526

German_research_2_03 01.12.2003 10:17 Uhr Seite 1

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If the academic debates in the re-view and readers’ letters sectionsof newspapers in recent years are

to be believed, the humanities are inan awkward position. It is not justthat they feel marginalised in publicdiscussion. Mutual decision-mak-ing between politics and universi-ties is also putting them under pres-sure: the abolition of entire coursesof study and reduction in their re-sources, together with an increasingnumber of students and overload-quotas in other areas, leave hardlyany time for research; the newFramework Act for Higher Educa-tion, which includes the abolition ofthe “Habilitation”, the introductionof junior professorships and newtenure regulations, none of whichsufficiently accommodates the spe-cific careers in the humanities; theintra-university distribution of bud-getary funds according to parame-ters which, due to their dispropor-tionate provision for third-partyfunds in cooperative associationsand areas of distinction, also put thehumanities at a disadvantage. Andfinally the Deutsche Forschungsge-meinschaft (DFG, German ResearchFoundation): with its funding instru-ments and its programmes foryoung researchers it seems to be ac-celerating the decline of the human-ities, or at least not be slowing itdown.

This nightmare scenario, howev-er, represents only one side of thecoin. There is an entirely differentone. Due to the not unproblematicassumption of the cultural-theoreti-cal “renewal” that has been takingplace on a broad basis and in almostall disciplines ever since the 1980s,the humanities in particular havebeen involved in an intensive, attimes bitter, but all the more fruitfuldiscussion about their practical aswell as methodological bases. Inmany areas, this discussion has ledto a thrust, embracing hitherto over-looked areas, leading to new ques-tions and to disciplinary expansion.At the same time, however, it hascaused each individual discipline toposition itself historically within thespectrum of disciplines, by extend-ing into the other great academicareas, and thus achieved, especiallyin Germany, a high standard of his-

Commentary

torical reconstruction, theoreticalself-reflection and a practical redef-inition of the disciplines.

The results of this interdiscipli-nary, public discussion concerningthe humanities and their cultural-theoretical basis are obvious: a highdegree of internationalisation of theindividual disciplines and at thesame time an increasing internation-al dissemination through its recon-structive return to the diversity ofcultural-theoretical theory-building,which characterised discussions in

The humanities are thus an ex-tremely lively community conduct-ing discussions on the fundamentalissues of individual disciplines dur-ing teaching as well as in research,internally as well as in public, andthus shaping to a considerable ex-tent the current discussion aboutmodern culture.

There are nonetheless problemsthat the Deutsche Forschungsge-meinschaft should pay particularattention to. This is not abouthedge clauses which the humani-

Germany during the early 20th cen-tury; attractive university teaching,since students are confronted fromthe outset with fundamental ques-tions about their disciplines; richprogrammatic research activitiesthat take place not so much in estab-lished specialist journals but ratherin interdisciplinary joint works, an-thologies and conference proceed-ings and are mainly carried forwardby young researchers; and finally,radical changes concerning theintra-disciplinary structure by intro-ducing new courses of study.

ties certainly do not need. Formany years, they have retainedtheir percentage of the DFG fund-ing volume (with a slight increasecompared with the natural sci-ences), and in some areas, such asthe interdisciplinary promotion ofyoung researchers in the ResearchTraining Groups, they have evenbeen particularly successful. Theproblem is on a completely differ-ent plane to the percentages, how-ever. Far more, as has been demon-strated by an internal survey con-ducted by the DFG, it is the age

Prospects for a Living Community

The humanities demand flexible funding instruments – special

requirements must be accommodated

Prof. Ursula Peters


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may not be significantly older thantheir colleagues when they are ap-pointed. It is clear, however, that inthe majority of humanist disciplinesthe long qualification phase and thecorrespondingly high age of youngresearchers in individual cases isnot regarded as a drawback. On thecontrary: in many cultural and his-torical disciplines, in-depth famil-iarisation with foreign cultures andlanguages determines the youngacademics’ standard and thereforealso their qualification planningprocess. This should perhaps be

searchers, by Individual Grants Pro-grammes, Research Fellowships,the second stage of the Emmy Noe-ther Programme, and Printing Sub-sidy. For established university lec-turers, funding for individual re-search includes Sabbaticals. So farthis type of funding has tended to beseen as an exception and therefore,despite the demand for it, has notbeen utilised enough. An expansionof this funding instrument by in-cluding Sabbaticals in the normalproposal for a Research Grant wouldthus be of great benefit for individ-

factor for qualification of young re-searchers, individual research inprojects aiming at publishing amonograph, as well as the magni-tude of cooperative processes.

The bitter reaction, mainly by re-searchers in the humanities, to thetenure regulations of the newFramework Act for Higher Educa-tion shows that in this communityage plays a different role during thequalification phase and at the timeof appointment than in the otherareas of academic life. Humanists

taken into account more than beforewhen discussing the funding ofyoung researchers on all levels, in-cluding the programmes of excel-lence.

The monograph, the result of in-dividual research, is and in manybranches of the humanities will, forgood reason, remain the most respected way of doing research.For this reason, the DeutscheForschungsgemeinschaft promotesindividual research in all stages, es-pecially in the case of young re-

ual research, which is so prestigiouswithin the humanities. In return,young researchers would be able togain the necessary qualifications foran appointment by carrying out re-placement teaching.

Alarge part of research in thehumanities, too, consists ofcooperative associations. The

Deutsche Forschungsgemeinschaftaccommodates this with a specialbudgetary sector for long-term pro-jects in the humanities for the jointreconstruction and safeguarding ofhuge stocks of knowledge. The in-creasingly successful establishmentof the Collaborative Research Cen-tres also demonstrates an interest incooperation. In the context of“structural formation”, it has beentried to increase the critical massthrough large Collaborative Re-search Centres and above allthrough the DFG Research Centrewhich is so successful in other aca-demic areas. However, due to theheterogeneity of the range of disci-plines, the humanities find theirown natural limits and can there-fore not easily join together in largeassociations. For the humanities,the (distributed) Research Unit, dueto its flexibility, appears to be a par-ticularly suitable instrument of co-operative research funding. TheDeutsche Forschungsgemeinschaftmust explain to its member organi-sations (the universities) that notonly DFG Research Centres andlarge Collaborative Research Cen-tres contribute to their image, butalso small formations that are inter-linked with research groups ofother universities. The humanitieswould benefit a great deal.

Prof. Ursula Peters

Ursula Peters, Professor for Older GermanLanguage and Literature at the University ofCologne is Vice-President of the DeutscheForschungsgemeinschaft. The DFG’s Execu-tive Committee consists of the President andeight Vice-Presidents as well as the Chair-man of the Stifterverband für die DeutscheWissenschaft (Donor´s Association for thePromotion of Science and Humanities in Ger-many).


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The hilly region of Puuc, whichlies to the north-west of theYucatan Peninsular in Mexi-

co, is richly endowed with residualsettlements of the classical Mayaculture. One area of almost impen-etrable bush contains many re-markably well preserved remainsof their numerous villages andtowns, comprising hundreds oflarge stone build-ings and palaceswhich the Mayaabandoned soprecipitately wellover a millenni-um ago. In addi-tion to the largetowns, such asUxmal, Sayil andOxkintok, whichin their heydayaround 800 A.D. had up to 30,000inhabitants, thissparsely populat-ed area also heldaround 200 to 250smaller and larger settlements,most of which have yet to be ex-plored.

The archaeological site ofXkipché, located not ten kilometresdistant from the Maya town ofUxmal, lies in the heart of the zoneknown as Puuc, with its characteris-tically closely packed karst cockpitsrising to heights of over 100 metresand broad, gently rolling, valleys.Here, too, despite the uncertain andproblematical water supply provid-ed to the settlements from subter-ranean cisterns with capacities of upto 40,000 litres, the Mayas succeed-

ed in creating the prerequisites fordense settlement.

The prevailing opinion amongstresearchers is that these villagesand towns came into being around600 A.D., and that after a rapid riseand just a brief heyday, they wereabandoned again around 1000 A.D.The details of this process, and thefactors which contributed to the

historical events is the accurate de-termination of their chronologicalsuccession, our first priority was toelucidate the temporal develop-ment of the site at Xkipché. In thePuuc area, in addition to the succes-sion of its architectural styles, thisso-called chronology rests primarilyon the cross-dating of ceramic arte-facts and their inscriptions with

those found in theclassical centresof the Maya cul-ture lying far tothe south.

Thus within the framework of this chronologi-cal investigation,the first series of excavationsbetween 1991and 1997 was devoted to thelargest buildingin Xkipché – apalace complex.This, with two

storeys and over 48, mostly well pre-served, rooms, is one of the largestedifices in the entire region. At thesame time a complete survey of thevisible architectural remains andadditional excavations in individualsections of the settlement area werealso undertaken. Subsequent as-sessment of the finds made duringthese excavations produced the dif-ferentiated picture of the townwhich we had hoped for.

As a result of these latest excava-tions we can now assume that thesettlement of the entire Puuc regionbegan much earlier. The first re-

Arts and Humanities

On the Rise and Fall of the Town of XkipchéMexico possesses abundant stone witnesses to the Maya culture. As Xkipché shows, the Mayas had abandoned their houses and palacesprior to their decline. Archaeologists examine the history

sudden vacating of this area of set-tlement, are still largely unknown.Hence one of the central aims of ourarchaeologists from Bonn and theirexcavations was to help find the an-swers to these questions. Since onevital prerequisite for any analysis of

On the trail of the Mayan culture: A roundaltar with a stele is exposed during thesystematic excavation of Xkipché. Right:The “Palace of Xkipché”. With its twostoreys and nearly fifty rooms, this was thelargest building in the town. The Mayasabandoned it before it had been properlycompleted.


5


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mains of settlements and the earlyceramics found in Xkipché datefrom the 1st century A.D., and thussome 400 years earlier than had pre-viously been believed. But it wasnot until the 8th century that Xkipchéexperienced a true boom. In thiscentury, as also over the following250 years, there is evidence of briskbuilding activity. Apart from thework on the great monumental edi-fices of the, most probably, aristo-cratic upper stratum of society, thisalso embraced the local religiouscentre and the comprehensive con-struction of houses for the commonpeople, too. Within a brief period oftime, not only did huge places of as-sembly and pyramids arise, butlarge numbers of minor sacrificialshrines and temples as well. Along-side imposing architectural re-

mains, evidence of wide-spreadtrade relations were also found ex-tending as far as the Guatemalanhighlands 1,000 kilometres away.Columns of porters carried valuablejade, swords made of obsidian – avolcanic glass, and tuff for ceramics,in particular, over distances of sev-eral hundred kilometres, or goodswere brought to the north of the Yu-catan Peninsula in small ships andrafts plying up and down theCaribbean coast. In all probability,the heyday of the Puuc regionended towards the end of the 10th

century or at the beginning of the11th. At this time, the Puuc settle-

ments were abandoned precipitate-ly by the aristocratic élite, and thena short time later by the rest of thepopulation, too. The palace com-plex in Xkipché furnishes particu-larly impressive evidence of theseprocesses in that the north façadeand the east wing of the first storeywere never completed. This factwas deduced from the worked doorposts and lintels left lying before theroof-high walls by the master-builders. Other parts of the buildingalso created the impression that theMayan master-builders had sud-denly abandoned the constructionsite in company with their gangs of

A monumental building from the heyday of the Mayas:

The palace complex in Sayil, some 20 kilometres from Xkipché. Pottery

and flint tools were the typical grave goods on the Yucatan Peninsula.


7

workers – some of whom had evenabandoned their tools. What actual-ly caused this monumental edificeto be abandoned, and the ensuingprobable evacuation of the wholetown, is still largely unexplained. Inaddition to the fragments of spear-points and axes which have beenfound, suggesting that fighting hadtaken place, there are also indica-tions of a change in climate occur-ring towards the end of the 9th cen-tury. This, taken in conjunction withover-exploitation of the natural re-sources through the traditional sys-tem of agriculture based on forest

clearance, also played an importantrole. For in an area lacking any sur-face waters, where survival duringthe annual dry season is dependenton precipitation stored during therainy one, any extended years ofdrought can have a catastrophic ef-fect, something which might ac-count for the complete abandon-ment of this once densely populatedarea.

Building on these results, in early2000 a start was made on the con-ception of a fresh archaeological re-search project. Supplementing ourexcavations to date, which had been

mainly concerned with architecturalstyles, we now turned our attentionto questions affecting the laterstages of the settlement of the Puucregion and to the conditions of life ofthe common peasant populace im-mediately prior to the abandonmentof the Xkipché site.

A t the beginning of our four-month series of excavations in Mexico in 2002 efforts

were concentrated on a special typeof c-shaped building which had alsobeen found at other archaeologicalsites in the region and which, ac-cording to the latest state of re-search, was known to have occurredvery late in the table of chronologi-cal development. In Xkipché a massof such buildings is to be found closeto the largest pyramid. Most of these

The great pyramid in Chichén Itzá bearswitness to the intensive building activity of the Mayas in the 9th and 10th centuriesA.D. Archaeologists discovered historicarchitectural remains in a burial ground in Xkipché.


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Over the centuries, the phe-nomenon of twin birth hasexerted a fascination for

poets, philosophers and re-searchers. But systematic compar-isons of monozygotic (MZ) and dizy-gotic (DZ) twin pairs only beganwith Sir Francis Galton in the late19th century. Since then, the twinmethod has developed into one ofthe standard methods of behaviour-al genetic research. The major aimof this kind of research is to answerquestions about the causes of indi-vidual differences in a psychologi-cal trait of interest and to decom-pose this interindividual varianceinto its genetic and environmentalparts. Monozygotic and dizygotictwins are of such interest for behav-ioural genetic research because ofthe differences in their genetic simi-larity. MZ twin pairs are geneticallyidentical, while DZ twin pairs shareon average only half of theirgenome, that is they are as similaras “normal” siblings. In cases whereMZ twin pairs exhibit greater simi-larity in a particular trait than DZtwin pairs genetic effects have im-portant influences on individual dif-ferences in this trait.

One of the basic assumptions forsuch a conclusion is the so-called“equal environment assumption”which states that the environmentalinfluences on a specific trait are thesame for MZ and DZ twin pairs. Thecorrectness of this assumption hasbeen confirmed for a large numberof psychological traits. By compar-ing the similarity of MZ and DZ twinpairs regarding a psychologicaltrait, genetic and environmental in-fluences on this traits can be esti-

mated. The portion of observabledifferences between individualsproduced by the overall effect ofspecific genes is referred to as “ad-ditive genetic variance”. The“shared environment” covers envi-ronmental influences which con-tribute to the similarity of individu-als who grow up together, such asthe family home surroundings ortheir socio-economic status. Influ-ences, in contrast, which help to cre-ate differences between individualsgrowing up together are denoted as“specific environment”. This might,for instance, include differentfriends or occupations.

Earlier behaviour genetic studiesconcordantly found that the sharedenvironment is less important while,on the other hand, the specific envi-ronment has considerable influenceon psychological traits. A multitudeof studies in the field of personalityresearch suggest that around 40 percent of the differences in personalitytraits can be explained by additivegenetic effects, and around 60 percent by the influences exerted bythe specific environment. Althoughthe estimation of the amount of indi-vidual differences due to geneticand environmental influences is relatively simple, the identificiationof environmental influences is moredifficult. Hence some authors con-clude that children are chiefly so-cialised by their peer group and notby their parents, whereas otherspoint to inadequacies in the methodof investigation, which involvesmost of the results from behaviourgenetic studies of personality beingderived from questionnaire data,and especially self-reports. How-

buildings, which are built on a plat-form, face to the east. The side-wallscomprise only a low base wall, intowhich wooden posts had been in-serted, probably to be combinedwith wattle sections interlaced withtwigs and clay to form the actualwalls of the building. The roof,rather like the traditional buildingsstill in use today, was made of hollyleaves laid in thick layers andthatched onto the wooden roof con-struction. In the course of these ex-cavations a number of interestingdiscoveries were made regardingthe chronology of the buildingsunder investigation. Of all the build-ings we had examined at this site sofar, these were the latest to be built,as although they are seated on olderprevious buildings, they exhibit nosigns of any subsequently superim-posed structures. Characteristic ofthese buildings is their constructionusing stones from earlier structures,and in this context wide use wasmade for these c-shaped buildingsof the exceptionally well workedstones removed from the façades ofearlier stone structures. The simple,and sometimes provisional, charac-ter of the buildings investigated isalso reflected in the way in which of-ferings had been deposited. Plainwater vessels – some of them brokenor damaged after long use – hadbeen placed on the platform of oneof the altars in the neighbourhood.No traces of their contents have sur-vived, but they probably held foodor drink. Taken in conjunction withother finds, this would indicate thatthe economic situation had entereda period of clear decline towards theend of the 10th century, which couldhave resulted from the marked in-crease in the population up to thebeginning of the 10th century, thecreeping exhaustion of the areaunder cultivation, and a simultane-ous change in the climate. Deterio-ration in the food situation then ap-pears to have led to fighting over itsdistribution between the individualsettlements, and finally to a com-plete regional collapse.

Prof. Hanns J. Prem Dr. Michael ValloDr. Iken PaapUniversität Bonn

Similar and Yet Still Different?Do the predisposition of our genes or the influencefrom our environment influence human behaviour? A study of twins provides new information

Arts and Humanities


9

ever, if traits of interest were exclu-sively assessed by self-reports thiswould make it harder to judge thevalue of these assessments, sincepossible distortions in perception, orother disturbing influences, wouldbe difficult to check out.

Consequently, in a behaviouralgenetic study on personality at the

University of Bielefeld in 1995, peerreports of personality were includedas an additional source of informa-tion. The results confirmed thoseobtained from self-report studies.Moreover, this study also indicatesthat the effects of genetic and envi-ronmental influences on personalityare largely the same, regardless of

the source of information (self- orpeer reports). As a model frame-work for personality description theso-called five factor model (FFM)was employed, an approach to de-scribing the structure of personality.The five factors are traditionallycalled extraversion, neuroticism,openness to experiences, agree-ableness, and conscientiousness.An extraverted person is generallysociable, active and communicative,a neurotic person is nervous, unsureof himself, apprehensive, and tendsto emotional instability. Opennessto experiences characterises peoplewho welcome change, are eager tolearn, creative, and have broad cul-tural interests. Agreeable peoplemay be described as selfless, sym-pathetic, understanding and wellmeaning. The factor conscientious-

ness relates to someone who istidy, reliable, hard-workingand disciplined.

This model was also em-ployed for the German Ob-

servational Study of AdultTwins (GOSAT). The aim of thisresearch project was to investi-gate the significance of the fami-ly (shared) environment for indi-vidual differences in personalitytraits. In addition to this, an ap-proach was implemented for theGOSAT which embraced acombination of objective tests,behaviour observations and in-terviews. Within the GOSAT, 300 same-

sex twin pairs aged between 18and 70 were invited to Bielefeldfor one day. Previously, each of them worked on a set ofquestionnaires, rating their self-perceived personality and theirpersonality as rated by twopeers each, so that it was possi-ble to compare our day-long ob-servations with the results ob-tained from these question-naires. The tasks were designed

to create situations suitable for theobservation of personality-relevant

Where is the difference? Monozygotic and dizygotic twins are of such interest to behavioural genetic research because of their different genetic similarity.


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behaviour. Most of the time twinand co-twin worked independentlyon the various tasks and were at-tended by different experimentersin order to avoid any cross-influenc-ing of the results.

In addition to recording intelli-gence and temperament traits,priority was afforded to observa-

tional data gained from unobtrusivebehaviour counts on the one hand,and open video recordings on theothers. The experimenters and theirconfederates, who had been intro-duced to the twins as randomly se-lected students of the University ofBielefeld, observed them in varioussituations over the course of theday, recording such details as thenumbers of comments made orquestions asked. The twins werevideotaped in 15 of the varioustasks, for example introducingthemselves in front of runningvideo cameras, building a papertower of maximum height and sta-bility, or demonstrating as manyuses for a brick as they could thinkof. Seven of these 15 situations

were conducted in interaction withthe confederate. Thus for instance,one task involved phoning a femaleneighbour at 11.00 pm and per-suading her to turn her (very loud)music down. Another, completed inthe absence of the experimenter,involved a ten-minute conversationabout partialities and hobbies. At alater stage of the project, thesevideotaped situations were rated byindependent judges regarding thetwins’ personality. These judg-ments were made on the basis of 35personality scales representing thefive-factor model. Additional scaleswere also employed to assess theattracitiveness and sympathy oftwins. In each situation, differentpanels of four independent judgesrated the personality of one twinsibling on the basis of the video-taped behaviour. In order to ex-clude any possible influences aris-ing from comparative judgements,different panels of judges ratedtwins and co-twins. Making theseassessments, the situations could beviewed either individually or as awhole. Aggregations of the person-ality ratings made in all the situa-tions produced a reliable evalua-tion of the genetic and environmen-tal influences. These ratings werebased on a total of sixty judges pertwin and a broad range of behav-iours from different situations. Itemerged that the differences (vari-ance) over all the personality traits

could be explained to 42 per cent byadditive genetic influences, to 18per cent by influences from theshared environment and to 35 percent by influences from the specificenvironment. A minor part of thevariance – six per cent – was attrib-utable to unreliability of the mea-surement. Hence in observationalstudies, factors linked to the sharedenvironment proved to be ofgreater significance than in ques-tionnaire studies. Evaluation of theunobtrusive behaviour counts,moreover, revealed that genetic in-fluences at the personality-traitlevel were especially marked whenspecific behaviours were aggregat-ed over a variety of situations. Incontrast to this, no genetic influ-ences were detected when specificbehaviours were examined withinindividual situations. This con-firmed what had been expected,namely that although behaviouraltendencies are anchored in thegenes, specific behaviours are not.

In 1999, a study was initiated at theUniversity of Bielefeld with theaim of detecting specific environ-

mental factors which influence per-sonality traits. In addition to collect-ing data from questionnaires on ge-netic and environmental influences,the study comprises new questionsrelating to goals in life, life eventsand attitudes. Apart from the datacollected in this way, the video-taped behaviour in the various situ-ations will likewise offer many op-portunities for addressing furtherquestions. In this manner, for exam-ple, objective observations of theoccurrence and incidence of specificbehaviour will be possible, enablingcomparisons of twins and co-twinsto be made. Systematic comparisonswill furnish information about thesignificance of genetic and environ-mental influences on detailed be-havioural styles. In the case of tem-perament research, too, observa-tions of motor behavioural compo-nents will provide a supplementarymethod to questionnaires.

Dipl.-Psych. Heike WolfDr. Frank M. SpinathProf. Alois AngleitnerUniversität Bielefeld

A special kind of twin reunion: For the German Observational Study of Adult Twins over 300 same-sex pairs of twins aged between 18 and 70 were each invited to attend the Universityof Bielefeld for a day.


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How willing are those in workto support the unemployed?How do those in work assess

social welfare benefits such as un-employment benefit, unemploy-ment assistance and public assis-tance? Do people have solidaritywith the unemployed in view of therampant mass unemployment in our society? Researchers at theMannheimer Zentrum für Europäi-sche Sozialforschung (MannheimCentre for European Social Re-search) have investigated these andsimilar questions. In the context ofthe public discussion about the sus-tainability of social security systemsthey examined to what extent bene-fits to the unemployed are accepted.In a number of detailed interviews,they mainly asked people abouttheir attitudes who, through payingtaxes, contribute to the social secu-rity system: people in work whohave long-term, well-paid, secure,or well-qualified jobs. Closest atten-tion was paid to the positive andnegative assessments of social secu-rity benefits (unemployment bene-fit, unemployment assistance, andassistance to cover living expenses –referred to here as public assis-tance).

Contrary to the widespread opin-ion in public discussions, the empir-ical results show that people in workstrongly support all three types ofbenefits, although they argued for itin many different ways. Most of theinterviewees support the aim of thesocial security benefits for the un-employed (preservation of statusand livelihood) as well as the associ-ated moral concepts of solidarity

and justice. People generally ap-prove of the redistribution impactthat is associated with the benefitsfrom those in work to the unem-ployed.

On the other hand, the benefitsare judged in many different ways,and approval is often qualified. Crit-ical statements, however, neverlead to a complete rejection of thesocial security system, they merelyput the essentially positive judge-ments into perspective. The reser-vations refer only to some aspects(such as types of means tests), unde-sirable side-effects (“abuse of bene-fits”, condemnation of the recipientsof benefits) or to groups of recipientsdeemed “undeserving”. The great-est reservations concern certaingroups of recipients who are as-sumed to abuse the social security

system. This suspicion grows withthe length of unemployment. Whatis the reason for the generally posi-tive assessment of all three types ofbenefits? A central point was thatthe interviewees whose own risk ofunemployment is relatively low be-lieve that unemployment can inprinciple happen to anyone. Ac-cording to the interviewees, loss ofemployment or rapid success in jobseeking does not solely depend onpersonal behaviour and commit-

The Unemployed and theQuestion of SolidarityRampant mass unemployment and the discussion about the future of social securityraises many questions. A study examines to what extent social welfare benefits areaccepted amongst the population

How much solidarity do people in Germanyfeel with the unemployed? One studyshows that even in times of crisis people in work strongly agree with welfarebenefits such as unemployment benefit,unemployment assistance and publicassistance.

Arts and Humanities


12


ment. Rather, today’s mass unem-ployment is seen to have structuralreasons. An individual’s scope foraction is seen as limited.

The interviewees describe theconsequences of possible unem-ployment as very threatening. Theyassociate job loss with an often sud-den and drastic loss of income. Theindividuals themselves should nothave to bear the financial losses andshortages caused by unemploy-ment. Even if, in the favourablecase, there are savings, these canbridge only a short period of unem-ployment. Safeguarding the stan-dard of living and livelihood mustinstead be guaranteed through thesocial support systems. A reductionin benefits is therefore largely op-posed, as this is seen to endangersocial cohesion. Poverty, exclusionand criminality are expected to in-crease and there is a fear of politicalradicalisation.

Depending onthe system, how-ever, the readi-ness to contributeis argued for indifferent ways.The intervieweesare aware of thedifferently con-structed socialsecurity systemsand the related burdens, and judgethem according to the “appropri-ate” logic and values. The per-ceived purpose of the social securitysystems proved to be of particularimportance. Justice of equity andjustice of need as well as self-inter-est in the benefits played an impor-tant role in the assessments.

How do the interviewees assessthe individual social security bene-fits? The unemployment benefit,which is an insurance payout andpresupposes gainful employmentfor at least one year, is regarded as abenefit that serves to secure thestandard of living and to protect itsrecipients from unexpected socialdecline. The idea of justice of equitythat is linked to the insurance prin-ciple (the unemployed receive ben-efits depending on the amount pre-viously paid in) is approved of. Theinterviewees support the idea thatthere is a jointly financed fund and

that each insurance contributor isentitled to benefits in the event ofharm on the basis of previously paidcontributions.

By way of explanation, the inter-viewees often fall back on ideas ofmutual aid. As a reason for thereadiness to support others withtheir contributions, the intervieweesfelt that they may one day profitfrom the benefits to the unemployedthemselves. Self-interest thus playsa role when assessing social securitysystems based on the idea of soli-darity.

Unemployment assistance, whichfollows after unemployment ben-efit, serves two purposes. On theone hand, like unemployment ben-efit, it is designed to maintain a cer-tain social status. The regulations ofthe insurance logic such as theneed for advance payments are as-sessed positively. On the otherhand, unemployment assistance,

which is lowerthan unemploy-ment benefit, isintended to in-crease the in-centive to workin order to pre-vent long-termunemployment.Many believethat despite the

difficult labour market it is possibleto find work whilst receiving unem-ployment benefit or assistance.Most of the interviewees mistakenlybelieve that unemployment assis-tance is, like unemployment bene-fit, a temporary benefit and is mere-ly a transition to the temporally un-limited public assistance. If the un-employed person does not find a jobwhile receiving unemploymentbenefit or assistance, the interview-ees believe that an almost in-escapable descent into public assis-tance follows.

The interviewees regard the safe-guarding of the standard of living asa basic requirement of unemploy-ment assistance. Pragmatic argu-ments, however, are also important;in the case of long-term unemploy-ment, financing problems are ex-pected. Arguments of a “punitivejustice” are put forward to defendthe relatively low benefits when

Reductions in socialbenefits are largelyopposed as these arebelieved to endangersocial cohesion


13


those affected do not succeed infinding a job. The response was sim-ilar for the means test, which is re-jected when unemployment assis-tance is seen as an insurance bene-fit. The means test is approved of ifunemployment assistance movescloser to public assistance, or if workincentives, financing problems, orfamily-related allowances are givenspecial emphasis.

The interviewees regard the pub-lic assistance as the safeguarding ofthe livelihood of those unemployedpeople who are not entitled to unemploymentbenefit, such asschool-leavers.The intervieweesaccept that themoderate publicassistance shouldbe granted indef-initely, and thatprevious contri-butions shouldnot be a prerequiste since the exis-tence of a “final net” for those whoneed it is considered absolutely nec-essary. Although the intervieweesdo not believe that it is very likelythat they will ever need to receivepublic assistance, they do supportthe principle of justice of need.

They finance such welfare bene-fits and accept the associated redis-tribution effects because they be-lieve in the necessity of social soli-darity. If there were no such bene-fits, according to the interviewees,society would suffer great damage.Often, feelings of moral obligationare expressed. Such feelings ofobligation are often derived fromthe fact that they themselves havenot suffered unemployment andtherefore belong to the social groupthat is able to support the “weaker”or “less fortunate”. The unem-ployed are typically described withmuch empathy, as innocently in

need, “who are not able to work”.The support thus emerges from therecognition of people’s distress.However, social security benefitsare not accepted without reserva-tion. A general cut in social securitybenefits, though, is rejected by mostinterviewees. In view of the prevail-ing circumstances, however, cutsare seen as unavoidable. The reasonfor this is an increasing disparity be-tween the number of those in workand the great number of unem-ployed, which creates financingproblems.

Long-term unemployment is re-garded as a particular problem.Long-term receipt of benefits jeop-ardises the “balance” between con-tributions and benefits. The inter-viewees thus demand state mea-sures to combat long-term unem-ployment. On the other hand, theyexpect more commitment from theunemployed and a greater willing-

ness to accept re-strictions as wellas to make con-cessions when itcomes to accept-ing a new job. Asa “service in re-turn”, the long-term unem-ployed shouldwork in order to

take the load off the community. Other reservations are due to con-

siderable mistrust towards the re-cipients of benefits. Benefits areseen as sometimes being granted“too automatically”, without thequestion being investigated as towhether it was the recipients’ ownfault that they lost their job orwhether they are willing to work.The systems are therefore unable toexclude recipients who are them-selves to blame for their long-termunemployment or who take advan-tage of the insurance schemes. Thismistrust increases with the durationof unemployment and is thus direct-ed mostly against recipients of pub-lic assistance.

Dipl. Soz. Silke HamannDipl. Soz. Astrid KarlUniversität MannheimMannheimer Zentrum fürEuropäische Sozialforschung

Looking for work: Today, the young andthe elderly are affected. According to manyof those questioned, loss of employmentand success in the search for employment isnot merely a matter of personal behaviourand commitment, but rather is affected bystructural factors.

Society recognises theneeds of the unemployedbut expects morepersonal commitmentfrom the job seekers


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One of the central and most de-bated topics in evolutionarybiology is the question how

new species arise and how they areable to stay separated from eachother. Until very recently it has beenthe common view that new speciesarise through geographical isola-tion, e. g. through isolation by wa-tersheds, mountain massifs or in en-vironmental refugia during iceages. Such a geographic isolationprevents gene flow between theseparated populations and finally(normally after million of years) bothpopulations are not able to inter-breed and represent therefore newspecies. This process is called “al-lopatric speciation” and has domi-nated the species discussion dur-ing the last century. However,alternative concepts predictthat speciation can hap-pen under natural condi-tions even without geo-graphical separation – i.e. speciation can takeplace under “sympatricconditions”. In contrastto ”allopatric specia-tion”, which can be seenas a purely passive process,“sympatric speciation” is anactive process, mainly drivenby adaptation.

New theoretical models suggestthat intraspecific competition undersympatric conditions is the startingpoint for speciation, which thenleads to the formation of differentlyadapted subpopulations. Thesesubpopulations can only split intodifferent species if intermixing isprevented by “assortative mating”.

In this context “assortative mating”assumes that partners of the sameadaptation type prefer mating withtheir own type, and avoid matingwith other adapted types. Consider-ing these two factors, i. e. adapta-tion in combination with assortativemating, new species can form veryrapidly (within less than 100 gener-ations) without the long time postu-lated for geographic isolation mech-anisms. The process of adaptivespeciation can be expected to occurin newly colonized habitats, whereappropriate ecological niches arestill unoccupied.

In par-

allel with theprogress made atthe theoretical level,the experimental potential for in-vestigating splitting processes innatural systems has increasedtremendously. The comparison andanalysis of DNA sections which arelocated either in cell organells as

the mitochondrium or in the nucleuscan be used to trace differentiationand speciation. To investigate veryrecent splitting events, highly vari-able DNA markers are required.Tandemly repeated DNA stretcheswhich are located in the nucleus areknown as “microsatellites”. Mi-crosatellites can be used for „finger-printing“ individuals, thus making

it possible to test whether subpopu-lations under investigation still havegenetic exchange or have alreadyseparated from each other.

Some of the best documented ex-amples of sympatric speciation havebeen provided for cichlid speciesfound in crater lakes in Cameroon.A former Ph. D. student in the labo-ratory in Munich, Ulrich Schliewen,showed that in one of these lakes,the Barombi Mbo, several newspecies had formed under sympatricconditions from a single founderspecies. A project at the University

of Cologne has now

been launched toinvestigate the ap-plicability of thenew theoretical

concepts to terrestri-al natural systems, too. SebastianSteinfartz and Markus Weitere fo-cused on the ecology and evolutionof terrestrial fire salamanders, a ver-tebrate within the amphibia belong-ing to the order of caudates (Cauda-ta). Fire salamanders represent themost variable terrestrial vertebratesand have adapted to various differ-ent niches, and are thus an idealmodel system for studying adaptivespeciation. Its conspicious appear-ance has always attracted the inter-est of naturalists and collectors. Atleast five distinct species of fire sala-manders can be distinguished, and

Life Sciences

The Fire Salamander:Source for New SpeciesWhat you should know about the colourful fire salamanders: how a new species arises through adaptation to its environment is of general interest



up to fif-teen local

subspecies canbe found throughout its distri-bution area. In the course ofthe project, more thanforty populations, cover-ing the whole Europeandistribution area, were geneti-cally analysed. Interestingly,all morphologically distinguish-able subspecies were also geneti-cally different, suggesting that dif-ferentiation goes beyond the sub-specific level. Even within the lin-eage which currently colonizesMiddle Europe, interesting localadaptations can be detected. Thisreflects the pattern that is expectedfrom the theoretical models of adap-tive speciation, which assume thatafter the recolonization of openniches (as is the case after an iceage) conditions are ideal for newspecies to form under sympatricconditions. By carrying out an area-wide investigation of Germanyanalysing more than 50 populationsof fire salamanders, the researchteam under Professor Tautz tried toidentify a candidate population inwhich the splitting of differentlyadapted ecotypes could be studiedunder natural conditions. They did

indeed find a popula-tion near to Cologne

where such splitting is currently takingplace.

In comparison toother salamanders and

newts, the reproductivebehaviour of fire sala-

manders is quite complexand environmentally adapt-ed, i. e. reproductive behav-iour differs be-tween the various

habitats occupiedby fire salamanders. InCentral Europe and Ger-many fire salamanders are acharacter species of oldbroadleaf forests on low mountainranges such as the Harz Mountainsand the Black Forest. Normally thefemales deposit living larvae in oxy-gen-rich streams. Until metamor-phosis – the transition from theaquatic to the terrestrial habitat –the larvae are strictly confined towater. After their metamorphosis,the fire salamanders are strictly ter-restrial and need up to five years tobecome mature. Accordingly, mat-ing is performed on land. In someareas of Germany fire salamanderscan be also found in “atypical” flat-land habitats in which streams arerare. In such habitats the fire sala-manders have started to use stag-nant waters such as ponds andslopes for reproduction.However, the eco-logical conditionswith respect tooxygen content,temperature,food

avail-ability,

etc. differsharply be-

tween pondsand streams. Low

food availability, especial-ly when taken in combination witha high desiccation risk in ponds,creates unfavourable conditionsfor amphibian larvae in general.As a consequence, the fire sala-manders have to adapt to theseconditions. The degree of differen-tial adaptation to stream versuspond habitats was analysed underboth laboratory and natural condi-tions. Representative stream-breeding populations were there-fore studied in the Bergisches Landand the Eifel and compared topond-breeding populations in theVille near Cologne and Bonn. Theresults confirmed that the occupa-tion of stream and pond habitats

Impressive variety: The fire salamander, a member of the Caudata, embraces

numerous species and sub-species,augmented by regional and local variants. Left: A fire salamander from North-west Spain. Above: An example from the Pyrenees.

Right: An animal conspicuous by its striking colouration.


16


has already led to genetically fixedadaptations.

To test whether the adaptation tostream- and pond-breeding alsoleads to a splitting of these ecotypesunder sympatric conditions (as pre-dicted from the theoretical modeldiscussed above) an area had to befound in which both reproductivetypes occur in sympatry. The Kot-tenforst, near Bonn, is such an area.Ponds and streams are irregularlydistributed across the Kottenforstand are inhabited by fire salaman-der larvae. The current genetic andecological analyses suggest thatpond- and stream-breeding firesalamanders are indeed in theprocess of speciation.

To interpret genetic patterns interms of speciation it is necessary toknow as much as possible about thebehaviour of the organism under investigation. Therefore, factualknowledge regarding its move-ments, expansion and reproductivebehaviour are crucial. Under cap-tive breeding conditions, the malesperm of fire salamanders can bestored for several years by the fe-males and still be used for success-ful fertilisation of the eggs at a later

point in time. However, the extentto which such sperm storage andmultiple paternities occur alsounder natural conditions is an openquestion. Long-time sperm storageand multiple paternities do not onlyhave an impact on the populationstructure, but the analysis of multi-ple paternities will also permit con-clusions to be drawn regarding as-sortative mating, which is the keyfactor for keeping differently adapt-ed types apart. To study the migra-tory behaviour of individuals, so-called “transponders” were plantedunder the skin of more than onehundred individuals from a selectedfire salamander population. Thesetransponders comprise a small mag-netic coil, and enable individualscollected at later times to be un-equivocally re-identified. It was

thus possible to track the individu-als and to determine their move-ments over a period of more thanthree years. In parallel with this, itwas possible to test the offspring ofseveral individuals by microsatellitefingerprinting and to show thatsperm storage and multiple paterni-ties are indeed common in fire sala-manders, even under natural condi-tions.

The Salamander Project is still inits initial phase. Further research ef-fort will focus on the genetic analy-sis of recently diverged stream- andpond-types to obtain detailed datafor testing a speciation scenariounder sympatric conditions. Oncethe preliminary data have been ver-ified, detailed behavioural studiesand crossing experiments betweenboth ecological types will be used todetermine the genetic principles ofsympatric speciation. This studysuggests a shift in focus: speciationhas not necessarily to be studied intropical regions – new species arisein front of our doorstep.

Dr. Sebastian Steinfartz Prof. Diethard TautzUniversität zu Köln

In our latitudes, the fire salamander is a classical inhabitant of wooded hill-country. It deposits its larvae in oxygen-rich streams. Only the adult animals live permanently on land. In many regions the fire salamander may, notwithstanding, be found in flat areas with standing water.


17

The flight of birds and insects has always fascinated people. The locust’s ability to fly, and

especially that of the species mi-grating in large swarms – known asthe eighth Egyptian plague – hasalso been studied for more than 40years. Locusts fly for hours, not onlyin nature, but also in a wind tunnel.Their flight is not even impaired byattaching a load of up to 15 percentof their body weight on their backs.Due to the locusts’ load bearing ca-pacity and their size, measuring de-vices can be attached to their backsto study their flight motions.

We are using the locust to analysethe motor programme of free-flyinganimals. Studies of this type are partof the field of neuroethology, which

seeks to understand those processesin the nervous system that lead toparticular behaviour patterns in ani-mals and, especially, the move-ments of their limbs. Such investiga-tions are possible on entirely differ-ent levels, from the comparativelysimple swimming motions of jelly-fish to the complex movement se-quences of mammals. The actualgoal is to examine the links in thecentral nervous system includingthe brain. For example, an attempt isbeing made to find out how incom-ing nervous impulses are processedthere. But it is still not possible tospecifically image the activity of in-dividual neurones in their centralnervous network, even though theirfunction is already known.

Researchers have therefore turnedto the analysis of the activity ofmotor neurones, i.e. the nerve fibresthat transfer information from thecentral nervous system to the mus-cle and thus activate it. In movinganimals, motor neurones are diffi-cult to study. The muscle’s electricalactivity can, however, be recorded

Studying the CurvedFlight Pattern of LocustsUsing miniaturised remote data transmission, biologists examine the flight motions of free flying desert locusts and other insects. Computer-based video technology reconstructs behavioural sequences

Life Sciences

A flight room for studying the locust’scurved flight: The subject flies through adark corridor towards the light-colouredrear wall and then turns towards theopening on the right. Transmitters send the electrical activity of the individual wingmuscles to the two receivers on the ground.At the same time, two special videocameras record the flight manoeuvre.


18

ed from animals that were wired toelectronic devices. In the next step,the research team analysed theflight motions of free flying locusts.For this purpose, fully grown fe-males of the desert locust were fit-ted with the miniaturised transmit-ters. By means of double-channellead, the electrical activity of twomuscles could be recorded simul-

taneously. Thecentral questionwas: how does alocust co-ordi-nate its front andhind wings incurved flight?

To answer thisquestion, the re-search team builtan arena in

which locusts were induced to fly ina curve. For this purpose, they tookadvantage of the fact that most in-sects are attracted by light sources.A black corridor was therefore builtthat finished with a light-colouredwall. This screen was lit up from theoutside by a lamp located at the endof the right wall. When a locust isflying in the dark corridor, it firstflies straight towards the light-coloured screen. However, as soonas it flies beyond the end of the rightscreen, it sees the bright lamp to-wards the side and heads towards it,thereby flying in a curve. Its flight is

recorded by two high-frequencyvideo cameras. By means of

computer-based analysis, thefollowing parameters

can be deter-mined: ve-

locityand

by means of an electromyogram(EMG) and then conclusions may bedrawn from it regarding the use ofthe upstream motor neurones. Torecord the EMG of a locust, elec-trodes are implanted in its muscles.These electrodes are a mere 50 mi-crometres thin so that as little mus-cle tissue as possible is damaged.Potentials of a few hundred micro-volts are thus recorded and thenamplified in order to make them vis-ible on an oscillograph screen or aPC. In the next step for understand-ing the motor programme of locustflight, the electrical activity of the

muscle is related to wing motion, aprocess in which computer-basedvideo technology, such as high-fre-quency analysis, is employed. For-merly, motions had to be recon-structed by means of time-consum-ing filming procedures, but todaycomputer programmes allow for alargely automatic reconstruction ofthe behavioural sequence.

The initial studies of the flightmotor programme were based on ananalysis of stationary flight. For thispurpose, the animals were attachedto a holder and suspended in a windtunnel. The warmed airflow caused

the animals to continuously beattheir wings. Many important in-sights were gained by this method.However, since the locusts werefixed in the wind tunnel, they re-ceived no feedback on the effects oftheir wing motion in these experi-ments. This arrangement is calledan „open loop“ system whereas acomplete system is based on“closed loop“conditions. Thismeans that theanimals perceivethe effects oftheir movements.However, closedloop conditionsare only presentin free flight.

But how caninformation on the motor pro-gramme of a free flying animal beacquired? Transmitters for wirelessrecording of the wing muscles’ elec-trical activity must be developed,which enable the transmission ofthe EMG data over a certain dis-tance. For this purpose, advances inelectronic miniaturisation are used.Components have been developedthat are smaller than a millimetre insize and from them, a transmitterpowered by a button battery is as-sembled under a microscope. Thistransmitter, together with a homemade aerial, weighs no more thanabout 155 miligrammes.

To test the trans-mitter’s effective-ness, we placed up tofour transmitters ona Madagascan cock-roach and recordedthe activity of the in-dividual runningmuscles. The ani-mal, when fittedwith transmitters,ran through a 20-metre long base-ment area withoutany apparentimpairment.The EMGswere transmittedwithout prob-lems. Therecordingswere largely equivalentto those previously record-

Miniaturised transmittersare used for wirelessrecording of the electricalpotentials of flight motions


19

wings, which confirms the assump-tion that the hind wings provide themain propelling force for the flightwhile the front wings are responsi-ble for steering.

The electrical activity of strongflight muscles is then assigned tothese free flight wing motions. Wealready knew that locust wings aremoved by two groups of musclesthat oppose each other’s actions:one group is responsible for thedownbeat, the other for the up-stroke. By means of one representa-tive of each muscle group, it can bedemonstrated that their electrical

height of the flight as well as the lo-cust’s turns in various planes. In ad-dition, the track of each wing can bedisplayed. This provides the meansfor analysing how the animals con-trol their wing motions.

The analyses show that locustsmove their wings asymmetricallyduring curved flights. A similar ma-noeuvre is known from rowing. Tonavigate the boat around a curve,one side pulls more strongly on theoars than the other. The locusts flyaround a curve in a similar manner.On the outer side, the time for thedownbeat of the wings is somewhatlonger than on the inner side. Theouter wing is also pulled a bit fur-ther down than the inner wing. As aresult of the differential productionof force, the animal tilts towards theside and flies around in a curve.

The effect of the uneven wingmotion becomes apparent veryrapidly. We anticipated that move-ments would only show after one ortwo wing beats. However, theanalyses show that the body’s tiltingmotion is directly and temporallycoupled to the wing asymmetry.Furthermore, in curved flight thefront wings of the locust are ofgreater significance than the hind

The flight motions of a locust that isattached to a holder in the wind tunnel are

being studied. Left: A cockroach fitted with four miniature transmitters, button

batteries and tiny ring-shaped aerials. Theelectrical activity of its leg muscles is

transmitted without wires. Biologists alsostudy the free flight of desert locusts

in this manner.

The grasshopper’s flight motionsrelease electrical voltages. Theseare transmitted using miniaturisedwireless transmitters. This makesit possible to record the activityof two muscles simultaneously.On top the electrical discharge from the left front wing and underneath that of the right frontwing.

activity occurs ten milliseconds be-fore the two extreme positions. Inthat way, muscle movement trig-gered by the electrical activity canbe optimally used for the reversal ofthe movement direction.

We certainly do not yet under-stand the motor programme of a freeflying locust, but this study providesan experimental approach that al-lows further research on the co-ordi-nation of many different muscles ina wing beat. The miniaturised datatransmission system will also be ofspecial significance in the future.

Prof. Wolfram KutschDipl. Biol. Sebastian BergerUniversität KonstanzDr. Hanno FischerUniversity of Cambridge,United Kingdom


20

Symbiosis isthe interac-tion between

two species withbenefits for both.One widespreadand ecologicallyhighly significantsymbiosis is that ofplants and mycor-rhizal fungi. Over80 percent of allplants form a my-corrhiza (Greek:fungus root). Thefine threads offungi, called hy-phae, can pene-trate the soil moreextensively and ef-ficiently than plantroots. These hy-phae mobilisewater and nutrients and transferthem through the plant roots to theshoots and leaves. In turn, the fungireceive up to 20 percent of the or-ganic carbon formed by the plants.Only when plants have an opti-mized nutrient supply in the soilthey save these costs and do notenter into a mycorrhizal symbiosis.This partnership is formed under di-verse stress conditions, such as alack of nutrients, drought, heavymetal contamination or infection bypathogens. Due to the more efficientnutrient supply through fungal hy-phae, the plants become more resis-tant to these stress factors. The im-portance of mycorrhiza has onlybeen truly recognised in the lasttwenty years; today, it has become arather fashionable research area.

Several types of mycorrhizal sym-bioses are distinguished: In ec-totrophic mycorrhiza, fungal hy-phae grow as a mantle around plantroots while others extend far intothe soil to mobilise nutrients. Otherhyphae penetrate the outer cell lay-ers of roots and swell in the process.The nutrient exchange between thesymbiosis partners takes place atthese latter hyphae, which areknown as Hartig net. Characteristi-

Fungi and Plants BecomePartners under Stress80 percent of all higher plants live in an ecologically advantageous and effectivesymbiosis with mycorrhizal fungi. Investigations on the molecular basis of thissymbiosis are at the centre of a DFG Priority Programme

The common fly agaric (above), a native of coniferous forests, is a typical

ectomycorrhizal fungus. Right: In thearbuscular mycorrhiza, the most intensive

substance exchange between fungus and plant occurs in the arbuscules

(treelike structures).

Life Sciences



21

cally, in this type of mycorrhiza, thefungal hyphae do not penetrate thewalls of the plant cells. Ectotrophicmycorrhizal fungi are typical for ourdeciduous and coniferous trees.These mycorrhizal fungi are knownto everybody from their above-ground fruit bodies as commonmushrooms. Fruit bodies are formedfor the fungal propagation byspores. Typical examples for ecto-mycorrhizal fungi are the fly agar-ics, yellow Boletus and truffles.

In endotrophic mycorrhiza, thefungal hyphae penetrate the cellwalls of the plants, but, unlike path-ogenic fungi, they do not penetrate

the living part (the cytoplasm) of theplant cells. Orchids, for example,depend on mycorrhizal fungithroughout their life cycle. Theyhave very small seeds, whose nutri-ents are exhausted soon after ger-mination. If they were not nourishedby fungal hyphae at this earlygrowth stage, they would soon die.Orchids continue to need fungi fornutrition later in life, too. As notedbefore, an ideal nutrient supply sup-presses the formation of mycorrhiza.Since orchids can no longer livewithout fungi, they die when drymeadows are fertilised or when theorchids are transplanted from theirnatural habitat into garden soils richin nutrients. Similarly, plants of nu-trient-poor heaths and moors, suchas common heather, cranberry, bogrosemary, cowberry and cross-leaved heather, are examples forendomycorrhizae.

Far more common, however, isthe arbuscular mycorrhizal symbio-sis. With few exceptions, these fungicolonise almost all herbaceousplants and also many shrubs andtrees. Evidence of the presence offungi of this type in plants has beenfound in samples up to 460 million

years old. They always remain inthe soil and form structures such asextraradical (living outside the root)hyphae, spores for reproductionand, within the roots, intraradicalhyphae, usually vesicles for fat stor-age and the arbuscules (“littletrees” because of their shape, fromwhich this mycorrhiza takes itsname). The arbuscules are formedby strong branching of the fungalhyphae and are in turn enclosed bythe surrounding plant membrane.Intensive metabolic processes occurbetween the growing arbusculesand the periarbuscular membraneof the plant. Localization by meansof antibodies showed an increasedformation of some enzymes thatcatalyse the exchange of substancesbetween the partners. Arbusculeshave a life expectancy of about four-teen days and continuously formand collapse. Gene expressions inthe arbuscules and surroundingplant cells can readily be re-searched using modern molecularmethods.

It may appear surprising that ar-buscular mycorrhiza is not betterresearched but, both in pure and

applied research, studies on mycor-rhiza are faced with many difficul-ties. In the first place, no method hasbeen found so far to cultivate thefungi independently of the plant, sotheir propagation for laboratorypurposes is complicated. However,

the fungi can becultivated in thepresence of specialroot tissues fromcarrots or bacteriaof the genus Paeni-bacillus until theformation of newspores. Therefore,it only appears tobe a matter of timeuntil the sub-stances which thefungi require forgrowth are identi-fied. The fungi arenot divided intocells. A fungalspore has up to onethousand nuclei,whose gene com-position is proba-

Left: Spores of arbuscular mycorrhizalfungi. The zinc violet (below) can only thrive on heavy metal contaminated soils because it is colonised by mycorrhizal fungi.


22


bly not uniform. No sexual stages orchromosomes are known from ar-buscular mycorrhizal fungi. There-fore, we do not know how the ge-netic information varies from indi-vidual to individual or is passed on,or how one species is distinguishedfrom the next. Information fromgene sequences and the characteri-sation of the external spore shape

tures that can be systematically in-oculated with mycorrhizal fungi.Likewise, inoculation with my-corrhizal fungi increases the successrate of shoot propagation, for exam-ple, in poinsettias and grape vines.

Only a few plants and some ar-buscular mycorrhizal fungican live on heavy metal

heaps. It was shown that the zinc vi-olet, which occurs on such locationsin the Aachen-Liège area and inBlankenrode near Paderborn, canonly exist on heavy metal soil solelybecause of the mycorrhizal colo-nization. As a rule, the mycorrhizalcolonisation of the roots of the zincviolet increases in parallel with theheavy metal content of the soil. Afungus was isolated from the zinc vi-olet that transfers heavy metal resis-tance to plants. This could beshown, for example, with a Mediter-ranean lucerne species. When thisplant and many others are optimallyfertilised in greenhouse experi-ments, they can grow on heavymetal soils of most diverse composi-tion provided the pots are inoculat-ed with the fungus. Currently, re-search is underway to find outwhether isolated fungi of this typecan be used for replanting heavymetal contaminated soils and stabil-ising them against erosion. The po-tential usefulness could even behigher on saline soils. About eightpercent of the global soils are un-suitable for agriculture because oftheir high salt load. Studies on di-verse saline soils in Germany, TheNetherlands and Hungary showedthat many saltland plants form my-corrhizal symbioses and that Glo-mus geosporum is the most commonmycorrhizal fungus in these salinelocations. Currently, field experi-ments are in progress to determinewhether a mycorrhizal culture canconfer salt resistance to plants simi-larly as shown for heavy metal soils.At this time it is only a vision thatsoils in dry regions may one day beirrigated with seawater by system-atically planting these areas withmycorrhizal fungi.

Prof. Hermann BotheDr. Ulrich HildebrandtUniversität zu Köln

Comparative study on an alfalfa species(Medicago truncatula): When optimallyfertilised the plants grow in heavy metalsoils only if they have been inoculated withmycorrhizal fungi (upper photo). Those notcolonised by fungi develop very poorly(lower photo).

show that there are, infact, different species,but it is also revealedthat individual gene se-quences can deviate by5 to 10 percent fromeach other within indi-viduals. For all thesereasons, it is difficult toproduce mutants of thefungi or to alter theirmetabolism by meansof specific changes inindividual gene prod-ucts. Some plant fami-lies, such as the mus-tard and goosefoot fam-ilies, are not readilycolonised by mycor-rhizal fungi. However,recent research onBuckler mustard andpenny cresses (mem-bers of the mustardfamily) demonstratesthat the entire symbio-sis programme is pre-sent but that the fungalstructures are only oc-casionally formed in theplant roots. Consider-ing everything that hasbeen said, arbuscularmycorrhizal symbiosisis most certainly not aneasy research field.

Still, arbuscular myc-orrhiza is a subject inwhich pure and appliedresearch meet. With theaid of current molecularmethods, gene expres-

sion and protein formation in my-corrhizal and uncolonised controlplants can be compared and de-fined. These molecular approacheshave contributed to the identifica-tion of genes, proteins and signalsubstances with sometimes surpris-ing properties. It is also possible toproduce fungal material with a highand reproducible colonization po-tential as well as with sufficient pu-rity for inoculating plant cultures.This inoculation material is suitablefor diverse applications: It has beendemonstrated that plant pathogenicorganisms are repelled if the rootsare inoculated with mycorrhizalfungi as they start to grow. This par-ticularly applies to greenhouse cul-


23

Natural Sciences

Miniscule objects that are sosmall they cannot be seenby the naked eye or by

using an optical microscope are ofgreat technical significance. This isbecause it is becoming increasinglyevident that further reducing thesize of objects with dimensions inthe metre, millimetre or even mi-crometre range by one or more fac-tors of 1,000 to the nanometre rangeprovides a fascinating approach togenerating new functions and cre-ating new material properties. Herethe important factor is the chemicalstructure of nanosystems which arealso interesting in biology, sincenanoobjects have the same dimen-sions as viruses and enzymes.

The nanometre region is subjectto different laws than the world visi-ble to the naked eye. Semiconduc-tor devices, for example, may exhib-it radically different electronic andoptical properties when their spatialextent is reduced. Depending on theform of the reduced object, suchstructures are called quantum films,quantum wires or quantum dots.These structures are especially im-portant for optical information tech-nology. Even if the consequences ofa size reduction are not especiallyspectacular, they can still be techni-cally significant. In the case of fi-bres, for example, the ratio of sur-face area to unit mass increases dra-matically with the transition to

nanoscale dimensions. Typical ap-plications are found in filtering orcatalysis, which is the regulation ofa chemical reaction by a catalyst.

In the nanoworld, tube-like ob-jects play a special role. Carbonnanotubes constructed from graphite-like entities are currently stimulat-ing the imaginations of researchersthroughout the world. Such elon-gated objects lead to applications insensor technology, catalytic reac-tions, nanoelectronics and photon-ics (which uses light instead of elec-trons).

An essential objective of nano-technology is the development ofpreparation methods for nanoob-jects. Depending on the intendedapplication, such objects must be

made from polymers, metals, ce-ramics or glasses. The architectureof the object may be simple, as withsolid fibres or hollow fibres, or thearchitecture may have to be com-plex, as with multilayer structuresmade from several different materi-als. Finally, it may be necessary topurposefully arrange the objects ina hierarchic relationship in order tointegrate them into structural mem-bers.

Nanotubes are often producedusing a template process, with a va-riety of specific methods beingused. In the “tubes by fibre tem-plate” (TUFT) method, a very thinfilm of one or several wall materialsis first applied to endless nanofibres,after which the template fibres are

A Gossamer Veil –News from the NanoworldTube-like objects play a special role in the nanoworld. New preparation methods have been developed for making nanotubes. Such innovative procedures provide the basis for a multitude of technical applications

1 µmA miniscule template for producing nanotubes, with regularly ordered poresand a thin polymer wall (represented by

the white outlines).


24


removed. This yields endless nano-tubes.

Template fibres with dimensionsdown to a few nanometres, prefer-ably made from polymers, can beproduced in a very effective andcontrolled manner using the elec-trospinning process. With thisprocess, nanofibres are formedusing a very high electric potential.The material to be spun, in the formof a melt or a solution, is passedthrough a nozzle. The electric fieldproduces a charge, which causesthe material to form a fine jet that isaccelerated towards the counterelectrode. During this acceleration,the jet deforms, splits into multiplebranches – just like a lightning dis-charge –, and, finally, is depositedon the counter electrode. During thespinning process, the solvent evap-orates or the melt cools to a solidform. The fibres are deposited at aspeed of several metres per second,and individual fibres have lengthsof many metres. This process alsoallows extremely small metallic orceramic particles to be directly in-corporated into the fibres duringspinning, so that they can be intro-duced into the nanotubes in the fol-lowing step. The final result is anextremely fine web of fibres, whichcan be up to a square metre in size.This web may be so fine that it can-not be resolved by the naked eye oran optical microscope.

The second step of this processconsists of applying a wall material.This is done using a technicalprocess, such as vapour depositionor dipping, centrifuging or sprayingthe template fibres with a solution ofa polymer material. Metallic nano-tubes can be fabricated in this man-ner by applying a metallic coating,and nanotubes with complex struc-tures can be produced using severalcoating processes in a sequence. If atemplate fibre filled with extremelysmall metallic particles is used,nanowires with diameters of a fewnanometres can be produced in thismanner.

1 µm

200 nm

17 nm

For nanoelectronics, nanowires (above)with conductive metal cores and polymerinsulation are highly important. Right: An assembly of polymer nanotubes.


25


In the final step of this process,the template fibre is removed. Oneway to achieve this is to raise thetemperature of the material, in orderto decompose the polymer into easi-ly volatised building blocks. As analternative, the fibres can also be re-moved with a solvent or, with suit-able types of fibres, by using biolog-ical degradation.

For a large number of applica-tions, it is essential to obtain well-or-dered assemblies of nanotubes, andin some cases the nanotubes mustalso have well-defined lengths. Thisis very difficult to achieve with themethods described above, but it canbe achieved using a technique de-veloped only quite recently. Thistechnique is based on a phenome-non the theory of which is not yetfully understood. If a polymer melt(polymers are compounds formedfrom giant molecules) comes in con-tact with a surface having high sur-face energy, such as that of a metalor an inorganic semiconductor ma-terial, an extremely thin film, with athickness in the range of several tensof nanometres, quickly spreads overthe surface. Such a film is producedeven with highly viscous polymersystems. This spreading cannot re-sult from a conventional flowprocess, since it occurs much tooquickly. The concept is to utilise thisspontaneous process to producepolymer nanotubes. This is done bybringing a suitable template withcylindrical pores in contact with apolymer melt.The walls of thepores are sponta-neously coveredby a thin polymerfilm, which solid-ifies when thetemperature isreduced. Thenanotubes areobtained by re-moving the template material. Thistechnique can be used to fabricatenanotubes from commercially avail-able polymers, polymer alloys orpolymers with special additives,such particles of metallic, ceramic orsemiconductor materials, but it canalso be used to form metallic or ce-ramic nanotubes using polymer pre-cursors. Solids with high surface en-

ergies, including silicon and alu-minium oxide, are suitable for use astemplate materials. The special ad-vantage of these materials is that it ispossible to generate pores with quitea wide range of diameters using spe-cial electrochemical processes. It ispossible to obtain pore diameters of10 to 1,000 nanometres with con-stant pore crosssection and aspectratios of up to10,000 alongwith a high de-gree of regularityin the arrange-ment of thepores. Two dif-ferent techniqueshave been devel-oped for fillingthe pores: wet-ting the porous template using apolymer melt and wetting it using apolymer solution. Even with a vis-cous polymer melt, it only takes afew minutes for the pore walls to becovered with a film several 10-nanometres rich. A very surprisingresult is that even pores that are1,000 times deeper than their diame-ter are uniformly and completelywetted all the way to the base.

Well-ordered arrangements ofnanotubes with walls made frompolymers, such as biologically com-patible polymers, are interesting fora wide range of applications inbiosensor technology and bioana-lytics. In order to obtain isolated hol-low polymer fibres, the templates

are removedwithout damag-ing the polymers.This is doneusing an acid oralkaline solution.These methodshave proved tobe highly suit-able for use witha wide variety of

polymers for preparing regular arrays of hollow-fibre tubes withwell-defined outside diameters andaspect ratios. Without doubt, polyte-trafluoroethylene (Teflon), which istechnically extremely difficult toprocess, represents an extremecase, but it is possible to produceTeflon tubes in this manner withoutproblems. Since its original discov-

ery, this method has proven to besuitable for a wide variety of uses.For instance, if metal-organic com-pounds are added to the polymers,metallic tubes can be produced. Asa point in case palladium nanotubeswere prepared. To obtain a highersurface to volume ratio, which is ad-vantageous for various applications,the porosity or roughness of their

walls can be ad-justed. The ap-plications forsuch tubes arefound in catalyticprocesses andhydrogen stor-age for fuel cells.These nanoob-jects open theway to a wealth

of extremely varied applications.Currently, applications in photonicsare being intensively researched.(Photons are the elementary energyparticles of electromagnetic radia-tion.) For example, substances thatemit light when excited, such asmixtures of semiconductor quantumdot structures and polymers or purepolymers, can be introduced intothe porous template. The regularityof the arrangement and dimensionsof the pores allows the emissioncharacteristics of the luminousnanotubes to be tailored to meetspecific objectives. Due to the asso-ciated special effects, such struc-tures are called ‘photonic crystals’.Attention is also being focussed onusing nanotube arrays as bounde dsystems with well-defined forms,sizes and functions for separatinggases, liquids and particle suspen-sions. This could be useful for thetargeted encapsulation or release ofmedications by artificial viruses, orfor microreactors. Finally, nan-otubes are candidates for use ashigh-performance thermal insula-tion, for example in garments, or in ultra-light construction, wherenanotubes might be used for me-chanical reinforcement.

Prof. Andreas Greiner Dipl.-Chem. Martin Steinhart Prof. Joachim H. Wendorff Universität Marburg Dr. Ralf Wehrspohn Universität Paderborn

Nanotubes stimulate the imaginations of researchers – they openthe way to a wealth ofnew applications

Attention is focussedon using nanotubearrays for separatinggases, liquids andparticle suspensions


Seven million square kilometres of the surface of the Arctic Ocean are

permanently covered by ice. Only by usinga research ice-breaker like the “Polarstern”

can this barely accessible habitat be explored.


Natural Sciences

Life under the “Cold Skin”The Arctic sea ice is the habitat of an astonishing abundance ofplant and animal life. These biocenoses have a momentous impacton the polar ecosystem


28

Freezing cold, their continentscovered by massive ice caps,with ice floes to inhibit naviga-

tion – at first sight the polar oceansappear to be the very last placewhere life could exist.

Over 150 years ago, scientists hadalready observed that the “coldskin” of the Arctic Ocean, the seaice, supports life, and can assume abrown coloration from the abun-dance of microscopic diatoms exist-ing in it. For many decades, biologi-cal research in the Arctic was con-centrated on cataloguing the algaeinhabiting this ice, and especiallythe diatoms. Only in the last 20 to 30years have scientists begun to studythe ecological aspects of these or-ganisms in the ice.

The living conditions in the Arcticsea ice are unique. Whereas in theAntarctic the sea ice thaws almostcompletely in the course of the sum-mer, in Arctic regions at least sevenmillion square kilometres of theocean surface are permanently cov-ered by ice. Hence ice floes can

exist for periods of several years.Such differences between the twomarine regions have also engen-dered diversity in the colonisation oftheir ice. Even today, access to theArctic habitat is fraught with prob-lems. Its pack ice is not navigable bynormal shipping, and the extremeclimate complicates research in thewinter months.

The research undertaken by scien-tists from the Institute for Polar Ecolo-gy in Kiel began with an expeditionon the “Polarstern”, an ice-breakerdedicated to marine research, in thespring of 1988. Their studies were ini-tially concentrated upon the organ-isms in and under the sea ice, butwere later extended to include the in-terplay between the two habitats, iceand open water, too.

The working conditions for re-searchers in the two polar regionsvary radically. Whereas in theAntarctic, Adélie and Emperor pen-guins accompany the extraction ofthe drilling cores in the ice as in-quisitive visitors, in the Arctic, it is



29


voracious polar bears which turn upas interested visitors to pose a threatto human beings. For this reason,research in the north demands thepresence of specially trained sharp-shooters with loaded rifles on the iceto watch for approaching bears. Upto now, however, they have neverbeen called upon to intervene as thepolar bears have always been dis-covered in time and either driven offwith the aid of a helicopter, or thescientists have succeeded in retiringin good time to the “Polarstern”.The scent emanating from theirabandoned equipment was obvi-ously attractive to the bears, butluckily they soon lost interest.

Researchers, complete with theirequipment, have been set down on the iceto explore the pack ice. In the background,the “Polarstern” can be discerned in thecommonly occurring Arctic haze. Left: A diatom colony from the sea ice. Right: A predatory amphipod clings to theunderside of the ice with its hooked legs.


30


Equipped with power ice drillsand snow shovels, we had in themeanwhile collected ice and snowsamples from numerous stations formicroscopic examination either di-rectly on board ship in refrigeratedcontainers, or in our home laborato-ry. The vast majority of organismscontained in these samples mea-sured less than one millimetre. Ourstudies revealed that the Arctic seaice provides a habitat for a highly di-verse community embracing, in ad-dition to diatoms,also viruses, bac-teria, proto- andmetazoans suchas threadwormsand flatworms,and rotifers. Werealised that theice regions closein-shore and thesurfaces, in par-ticular, were distinguished by ahigh degree of biodiversity, and atthe same time, carbon production.

Our scientists made a specialstudy of the habitat formed in poolsof melt water. These only occur inthe sea ice in northern latitudes. Inthe summer, these pools can coverover half the surface of the ice floesand contain degrees of salinityranging from pure fresh water rightup to saline seawater. Even in thesefresh-water pools on the high seasunicellular organisms were to befound which had adapted to theirenvironment and defied winter tem-peratures below minus ten degreesCelsius and which, in summer, canreproduce within the space of just afew weeks.

The inside of the ice floes are per-manently inhabited by animalswhich crawl through the narrowmesh formed by the labyrinth ofminute brine channels. They con-sume bacteria, algae and other ani-mals. Their consumption has not yetbeen measured, as working on theice is exceptionally difficult in that

once the ice has melted, the habitatis destroyed and an artificial systemis created. Furthermore, minutefluctuations in temperature producesuch changes in the brine channelsthat much of the data published sofar regarding the natural conditionscan only be applied with reserva-tions. Surprisingly, the studies con-ducted aboard the “Polarstern” re-vealed that individual plant and an-imal protists were just as active attemperatures between minus two

and minus fourdegrees Celsiusas were relatedspecies in theTropics.

The many biological sub-stances (bio-mass) and theproductivity ofthe organisms

inhabiting the ice ensure a rich sup-ply of food, which is used by a multi-tude of diverse animal species, all ofwhich live along the ice-waterboundary layer. For studying theseregions, the scientists employedunder-ice video systems, whosecameras, measuring only a few cen-timetres in diameter, were loweredon long poles through holes drilledin the ice. This enabled us to docu-ment the structure of the undersideof ice floes and the occurrence ofplants and animals. We discoveredthat the habitat on the underside of

the sea ice was a highly structured,three-dimensional system of cracks,projections, holes and submergedfragments of the ice floe.

Various species of amphipod andsmall shrimps unique to the Arcticdwell here, most of which swimfrom the water at the underside ofthe ice to serve the ice. The animalworld under the ice occupies a cen-tral position in the polar food net-work as it forms the link betweenthe production of biomass in the iceon the one hand, and higher levelsin the food chain on the other. Theamphipods under the ice are fedupon by polar codfish, amongstother predators. These form the sta-ple diet of the seals which, in theirturn, serve the same purpose forpolar bears. Thus, in the end, eventhe polar bear is dependent uponthe minute organisms inhabitingthe Arctic brine channels.

When the peripheral ice begins tomelt, dramatic biological changestake place. Melting processes in thesea ice first affect the water layersbeneath and between the ice floes.Here layers of fresh water are creat-ed down to a depth of one metre.The biological processes directlyunder the ice or in openings be-tween the ice floes exhibit stark dif-ferences, which we were unable torecord from the conventional sam-ples on board our research ice-breaker. This was because the icereduces the light energy required

Using motor-driven drills, scientists can obtain ice cores 10 centimetres indiameter. Right: Polar organisms are

studied in a refrigerated container onboard the “Polarstern”.

Studies show that the Arctic sea ice offersa suitable habitat for an abundance ofplant and animal life


31


for carbon production. Should the“Polarstern” use its powerful bowthrusters or its stern propeller theselayers would be immediately de-stroyed. In spring, the reducedsalinity in the surface layer and themore powerful solar radiation leadto an enrichment with algae (phyto-plankton). So-called ice-marginalblooms occur, whose concentrationas a rule is higher than in openwater.

Modern remote sensing tech-niques have revealed thatthese superficial processes

influence the coloration of theocean, which explains why satelliteimages often show such a discol-oration of the ocean around theperimeter of the ice. These algalblooms around the edge of the iceare of vital importance to the life-cycles of many polar organisms.They are consumed by herbivorouszooplankton, and especially bycrustaceans, who use this rich nour-ishment for building up their re-serves of fat against the winter or forreproduction. This zooplankton, inits turn, forms the staple diet forhigher levels in the food chain.Hence large colonies of birds are tobe found in ice-edge regions closeto major stretches of open water. Inthe course of our expeditions wealso found that whales and sealstended to con-gregate alongthe periphery ofthe ice.

The Arctic seaice has long lostits purity as a natural habitat.Multitudinousstudies haveshown that an-thropogenic pollution, such asheavy metals, has been deposited inthe ice. Just what happens to thesesubstances when the ice melts, andwhere they go to, is not known,even though a portion does appearin high concentrations in the pelagicfood web. This is equally true of nat-ural deposits on the Arctic sea ice,which in places produce broadareas of “dirty” ice. These depositsoriginate from diverse sources, andmay enter the ice as wind-blown

dust or frozen pelagic sediments. Asa consequence, changes in the icecover of the polar regions will havea considerable effect on marine, bi-ological, sedimentological andchemical conditions. Current globalclimate models predict that thegreatest temperature changes willbe found in Arctic regions, where

they will cause adramatic reduc-tion in the thick-ness and extentof the Arcticpack-ice cover.Drastic changescan be expectedin regional icecover. Yet manyspecies of life in

the Arctic are dependent upon theexistence of perennial ice cover. So-called ice amphipods, which creeparound the underside of ice floes, forexample, are poor swimmers, andtheory has it that after the ice hasmelted, these sink to the ocean floorand die. Other species are depen-dent upon at least an annual icecover. Seals, for instance, spendmost of their lives on ice floes, usingthe pack ice as a nursery, restingplace and hunting ground. Hence,

looking at fundamental biologicalproductivity, in the case of the cen-tral Arctic, which has hitherto beenone of the most unproductive pelag-ic regions in the world, an increasein productivity can be expectedshould a change take place fromperennial to seasonal ice cover, withice-edge blooms also extendingfrom the coastal ice into the deep-water regions. In view of the pre-dicted and, in part, already record-ed, reactions of the Arctic sea-icecover to climatic changes, we arenow confronted with the task of esti-mating the order of magnitude ofthe biological consequences at alllevels from the cellular right up tothe all-embracing model.

Prof. Michael SpindlerUniversität KielProf. Rolf GradingerUniversity of Alaska, Fairbanks

Two scientists are being set down on the icein a gondola suspended from the researchvessel´s derrick. This method is especiallyrecommended for thin ice, as it enables icecores to be extracted by drilling directlyfrom the gondola, thus avoiding having totread on the ice itself.

Global climate changeswill result in dramaticreductions in the thickness and extent ofArctic pack ice cover


32


Authors’ AddressesProf. Hermann BotheDr. Ulrich HildebrandtBotanisches Institut, Universität zu Köln,Gyrhofstraße 15, D-509923 Köln

Dr. Hanno FischerDept. of Zoology,University of Cambridge, Downing Street,Cambridge CB23EJ, United Kingdom

Prof. Rolf GradingerInstitute of Marine Science, 231 Irving II,University of Alaska, Fairbanks, AK 99775-7220

Prof. Andreas GreinerDipl.-Chem. Martin SteinhartProf. Joachim H. WendorffInstitut für Physikalische Chemie, Kernchemie und Makromolekulare Chemie,Universität Marburg,Hans-Meerwein-Straße, D-35032 Marburg

Dipl. Soz. Silke HamannDipl. Soz Astrid KarlMannheimer Zentrum für Europäische Sozialforschung,Universität Mannheim, L7,1,D-68131 Mannheim

Prof. Wolfram KutschDipl. Biol. Sebastian BergerFachbereich Biologie, Universität Konstanz, D-78457 Konstanz

Prof. Ursula PetersInstitut für deutsche Sprache und Literatur, Universität zu Köln, Albertus-Magnus-Platz, D-50923 Köln

Prof. Hanns J. PremDr. Michael ValloDr. Iken PaapInstitut für Altamerikanistik und Ethnologie,Universität Bonn,Römerstraße 164, D-53117 Bonn

Prof. Michael SpindlerInstitut für Polarökologie, Universität Kiel,Wischhofstraße 1-3, D-24148 Kiel

Dr. Sebastian SteinfartzProf. Diethard TautzInstitut für Genetik, Abteilung für Evolutionsgenetik,Universität zu Köln,Weyertal 121, D-50931 Köln

Dr. Ralf WehrspohnLehrstuhl für Nanophotonische Materialien,Universität Paderborn,Warburger Straße 100, D-33098 Paderborn

Dipl.-Psych. Heike WolfDr. Frank M. SpinathProf. Alois AngleitnerFakultät für Psychologie und Sportwissenschaft,Universität Bielefeld,Universitätsstraße 25, D-33615 Bielefeld

Illustrations Querbach (p. 3), Prem (pp. 4, 5, 6, 7), ZEFA-Virgo (p. 9), Universität Bielefeld (p. 10),ZEFA-Kappelmeyer (p. 11), ZEFA-Anousch(p. 12/13), Steinfartz (pp. 14, 15, 16), Kutsch(pp. 17, 18, 19), Bothe (pp. 20, 21, 22), Wen-dorff (pp. 23, 24), Spindler (Cover, pp. 26/27,28/29, 31), Gradinger (pp. 28 b., 30 l.), Werner(p. 29 b.), Mumm (p. 30 r.), Oesch (back cover).

l. = left; r. = right; b. = below

The Deutsche ForschungsgemeinschaftThe Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) isthe central self-governing organisation responsible for promoting research inGermany. According to its statutes, the DFG serves all branches of science andthe humanities. The DFG supports and coordinates research projects in all scien-tific disciplines, in particular in the area of basic research through to applied research. Particular attention is paid to promoting young researchers. Every Ger-man scientist and academic is eligible to apply for DFG funding. Proposals aresubmitted to peer reviewers, who are elected by researchers in Germany in theirindividual subject areas every four years. The DFG distinguishes between the following programmes for research fund-ing: In the Individual Grants Programme, any researcher can apply for financialassistance for an individual research project. Priority Programmes allow re-searchers from various research institutions and laboratories to cooperate withinthe framework of a set topic or project for a defined period of time, each workingat his/her respective research institution. A Research Unit is a longer-term col-laboration between several researchers who generally work together on a re-search topic at a single location. In Central Research Facilities there is a particu-lar concentration of personnel and equipment that is required to provide scientif-ic and technical services. Collaborative Research Centres are long-term university research centres inwhich scientists and academics pursue ambitious joint interdisciplinary researchundertakings. They are generally established for a period of 12 years. In additionto the classic Collaborative Research Centres, which are concentrated at one lo-cation and open to all subject areas, the DFG also offers several programme vari-ations. Transregional Collaborative Research Centres allow various locations tocooperate on one topical focus. Cultural Studies Research Centres are designedto support the transition in the humanities to an integrated cultural studies para-digm. Transfer Units serve to transfer the findings of basic research produced bya Collaborative Research Centre into the realm of practical application by pro-moting cooperation between research institutes and users. Research Training Groups are university training programmes established for aspecific time period to support young researchers by actively involving them inresearch work. This focuses on a coherent, topically defined, research and studyprogramme. Research Training Groups are designed to promote the early inde-pendence of doctoral students and intensify international exchange. They areopen to international participants. In International Research Training Groups, ajointly structured doctoral programme is offered by German and foreign univer-sities. Other funding opportunities for qualified young researchers are offered by theHeisenberg Programme and the Emmy Noether Programme. Humanities Research Centres were created in the new federal states to improvethe existing research infrastructure. These centres have been established for aspecific time period and serve to promote interdisciplinary research. The DFG also funds and initiates measures to promote scientific libraries, equipscomputer centres with computing hardware, provides instrumentation for re-search purposes and conducts peer reviews on proposals submitted within theframework of the Hochschulbauförderungsgesetz, a legal act which provides formajor equipment and the construction of institutions of higher education in Ger-many. On an international level, the DFG has assumed the role of Scientific Rep-resentative to international organisations, coordinates and funds the Germancontribution towards large-scale international research programmes, and sup-ports international scientific relations. Another important role of the DFG is to provide policy advice to parliaments andpublic authorities on scientific issues. A large number of expert commissions andcommittees provide the scientific background for the passing of new legislation,primarily in the areas of environmental protection and health care. The legal status of the DFG is that of a private association. Its member organisa-tions include research universities, the Academies of Sciences and Humanities,research organisations of general scientific importance, the Max Planck Societyand the Fraunhofer Society, as well as a number of scientific associations. Inorder to meet its responsibilities, the DFG receives funding from the Germanfederal government and the federal states, as well as an annual contributionfrom the Donors’ Association for the Promotion of Sciences and Humanities inGermany.


Washington DC,I Street NW,Suite 540, is

the address of the DFG’s liaison officein the United States. Not only areDFG grant recipients in the USA su-pervised from here, but information isalso provided to American scientistsabout research in Germany, in orderto promote the further growth oftransatlantic research ties.

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