mosses and are being colonized by lichens. Daily summer pre-cipitation, which is greater in the north and is sufficient forgrowth of mossbanks on Signy Island, South Orkney Islands(Fenton and Smith 1982), does not support vigorous growth ofmossbanks in Arthur Harbor at present. The ice and snow-patch recession must have been limited or it did not affect themoisture supply to the mossbank on the southernmost visitedsite, Green Island, where mosses are growing well.

The recession of a thin ice sheet on Carnage Point probablyoccurred relatively rapidly during the century (cf. Collins 1976;Smith 1982). Shortness of time available since the recession,rather than the construction of Palmer Station and use of trackedvehicles (Smith 1982), appears to be the reason for the sparsecolonization of most of the Carnage Point by plants. Nativeplants from Norsel Point were transplanted to Carnage Point totest this hypothesis.

Colonization and recovery after disturbance appear to bevery slow, especially in habitats less than optimal for plantgrowth. On Norsel Point, an old system of plots was pointedout to us by D. E. Murrish. Only a few mosses and lichensvegetate the vertical sides of the rnossbank where the peat wascut out (figure 2). This supports the hypothesis that the presentconditions in Arthur Harbor are not favorable for mossbanks. Inplaces where there is enough moisture and other conditions arefavorable, bryophytes which do not form rnossbanks may de-velop high cover in recovering communities (figure 3). Otherinvestigated human disturbances included the vicinity of Pal-mer Station, old Palmer Station on Norsel Point, British Base Non Norsel Point, Argentine base Primavera, Hughes Bay, andsites on Deception Island.

Dynamics of mature communities also appear to be veryslow. Dead plants have high cover and occur in up to 20 squaremeter-patches on both fine material and rocks. Most plantswere probably killed during austral summers with excep-tionally bad weather and icy conditions; some plants could havebeen killed during unusual droughts. Due to slow decomposi-

tion in the cold environment, the dead plants persist and pre-vent recolonization and community recovery for long periods.Common disturbances by animals may have adverse or sub-sidizing effects.

Studies of plant strategies and seedling survival in variouscommunities have been initiated. Competition and environ-ment manipulation transplant experiments with native plantswere started on Carnage Point. Transport of propagules by birdswill be investigated.

This research was supported by National Science Foundationgrant DPP 82-01047. I would like to thank Captain P. Lenie, thecrew of the iIv Hero, and the Palmer Station personnel for theirgreat support.

References

Collins, N. J . 1976. The development of moss-peat banks in relation tochanging climate and ice cover on Signy Island in the maritimeAntarctic. British Antarctic Survey Bulletin, 43, 85-102.

Fenton, J . H. C., and R. I. L. Smith. 1982. Distribution, compositionand general characteristics of the moss banks of the maritime Ant-arctic. British Antarctic Survey Bulletin, 51, 215-236.

Hattersley-Smith, C. 1983. Personal communication.Lipps, J. H. 1978. Man's impact along the Antarctic Peninsula. In B. C.

Parker (Ed.), Environmental impact in Antarctica. Blacksburg, Va.: Vir-ginia Polytechnic Institute and State University.

Smith, R. I. L. 1982. Plant succession and re-exposed moss banks on adeglaciated headland in Arthur Harbor, Anvers Island. British Ant-arctic Survey Bulletin, 51, 193-199.

Smith, R. I. L. 1983. Personal communication.Smith, R. I. L., and R. W. M. Corner. 1973. Vegetation of the Arthur

Harbour—Argentine Island region of the Antarctic Peninsula. BritishAntarctic Survey Bulletin, 33 & 34, 89-122.

Turquet, J. 1906. La vie vegOtale au pole sud. In J . -B. Charcot (Ed.), Le"Français" au pole sud. Journal de l'Expédition Antarctique Française,1903-1905. Paris: Ernest Flammarion.

Walton, D. W. H. 1983. Personal communication.

Skua and petrel sightings in interiorantarctic ranges—Thiel and southern

Pensacola Mountains

ARTHUR B. FORD

U.S. Geological SurveyMenlo Park, California 94025

Geologic field parties occasionally have unusual oppor-tunities to observe rare birdlife in interior parts of Antarctica farfrom coastal nesting sites, where most ornithologic studies arecarried out. Such sightings are of great importance to knowl-edge of the behavior and territorial range of antarctic seabirds

(Halle 1973). According to Halle (1973), the reporting of birdobservations may generally be overlooked, because of scientists'overspecialization in narrow research fields. This failure to re-port observations probably accounts for the scarcity of reports ofsightings near the South Pole after those from Robert F. Scott's1911-1912 polar journey. On that expedition, south-polar skuas(Catharacta maccormicki) were observed within 260 kilometers ofthe South Pole (Eklund 1964)—it was not until December1967-January 1968 [when birds were sighted near there (Halle1973)] and in summer 1977-1978 [(Axelrod 1979), when solitaryskuas visited Amundsen-Scott South Pole Station] that the nextreportings of sightings were published. In a 1962 experiment totest the flight and navigational abilities of this species, six adultskuas were flown by airplane to the South Pole and released; inless than 10 days, at least one had made its way back to its CapeCrozier nest 1,330 kilometers away (Eklund 1964). From thisstudy it is reasonable to conclude that birds are capable ofnavigating far inland and that the lack of reported sightings

218 ANTARCTIC JOURNAL

qP

90°W-

does not mean that there are no birds away from the coastalregions.

This report describes several bird sightings during U.S. Geo-logical Survey geologic fieldwork in the 1960's and 1970's insome of the ranges of the Transantarctic Mountains closest tothe South Pole.

Thiel Mountains. Field parties were stationed in the ThielMountains (figure) during January 1961 and from earlyNovember 1961 to early January 1962. We were placed by R4Daircraft from Byrd Station. A highly visible base camp with aJamesway hut was established on a broad expanse of snow andice about 15 kilometers from the nearest mountains. In the twosummers, we were visited on a single occasion by a solitaryskua that arrived at about 0830 hours, 11 January 1961. Becausewe were inside the hut, we did not see the skua's arrival. Whendiscovered, the bird was standing on the camp refuse pile about50 meters from the hut. In our rush to photograph our firstvisitor, we frightened it off, and it flew southward, disappearingover the horizon of the polar plateau.

We were surprised on the following day to find a small chick-enlike leg bone at the top of the refuse pile. Since our dinnermenus had consisted only of Bolton trail rations—meat-barstews, soups, and pemmican—the bone had to have beenbrought by the skua and left behind in its hasty departure. Thevisit was a few days after Major A. Havola's 1960-1961 Byrd-Poletractor traverse (figure), passing near the Thiel Mountains. Wetherefore considered it likely that the skua had picked up thebone from a traverse-party midden, but it might also havepicked it up from Byrd Station or elsewhere. In our hasty identi-fication, we neglected to consider that the bone might even havebeen that of another antarctic bird. In any case, it is of interestthat the bird was carrying such provision for its long interiorflight.

Map showing areas of bird sightings, 1961-1966.

The fact that the bird was alone and that it appeared so soonafter the tractor traverse suggests that the skua was followingvehicle tracks, until our camp became visible. When it left, theskua appeared to be generally following Havola's traverse routetoward the South Pole. The skua could not have been guided byaircraft contrails, as was suggested by Axelrod (1979) in herreport of skua flights in other interior regions, because therewere no aircraft operating in the vicinity and because our campwas 500 kilometers from the flight route between McMurdo andSouth Pole Stations, too great a distance for the contrails to bevisible. With their keen eyesight (Eklund 1964), skuas shouldeasily be able to follow a chain of nunataks southward to thisarea from the Ellsworth Mountains, about 500 kilometers away,where there have been more numerous visits by south-polarskuas (Splettstoesser 1981). However, in this case, the coinci-dence in timing with the tractor traverse suggests that this skuawas guided by the vehicle tracks.

Patuxent Range. No avian visits were observed during field-work in the period 10 November 1962 to 5 February 1963 in thePatuxent Range, where we were placed, and in midseason re-supplied, by R41) aircraft. A visit by a single south-polar skuawas, however, observed the following summer when a snow-mobile traverse party, working mainly in the Neptune Range tothe north, crossed the Academy Glacier to revisit the PatuxentRange. As the snowmobile traverse party approached the1962-1963 summer's Jamesway-hut base camp near the southmargin of the glacier, at 1910 hours, 18 December 1963, the skuasuddenly appeared and cavorted around the moving sledges.When the vehicles stopped, the bird landed a few tens of metersfrom the party but refused to eat morsels of chocolate andcanned pemmican that were tossed out to it (Schmidt personalcommunication). The skua remained behind when the party leftand was not seen again. Aircraft were not operating in thevicinity before or during its visit.

Pecora Escarpment. During the 1962-1963 Patuxent Rangefieldwork, we made a snowmobile traverse southward for a firstvisit to the then-unnamed Pecora Escarpment (figure), whichwe had seen on the horizon of distant aerial photography. Alengthy blizzard made travel hazardous and stopped the tra-verse at latitude 85°30'S on the Patuxent Ice Stream. At 0015hours on 10 January, the screeching calls of bird surprised usand brought us out of our tent to see the visitor. The sighting ofthis bird, later identified (Watson 1975, plate 6) as a snow petrel(Pagodroma nivea), was reported by Schmidt and Ford (1963, p.23), who described it as follows: ". . . the only non-human lifeof any type seen during the entire 3 months in the field was onesnow petrel sighted on 6 January (sic), well south of the Patux-ent Mountains, at about latitude 85.5° 5 on the long trip to thesouthern nunataks. The bird appeared at midnight on a beau-tiful sunny clear day after 3'/2 days of storm and white-outconditions, and its wild diving and swooping antics within feetof our clicking cameras indicated a delight as great as our own inseeing another form of life. The petrel departed on a straightnortherly course toward the Patuxent Mountains after cavortingfor more than 5 minutes." (The date was erroneously reportedas 6, rather than 10, January.) Again, only vehicle tracks wereavailable as possible guides for the visit. Although sightings ofsnow petrels seem to be much less common than of skuas ininland areas, petrels have been reported from the EllsworthMountains (Splettstoesser 1981), Marie Byrd Land (Rugh 1974),and Victoria Land (Ricker 1964). Our sighting of this species,however, is much farther south than any other sighting knownto the writer.

1983 REVIEW 219

Central and northern ranges of the Pensacola Mountainswere studied during early November to February summer sea-sons of 1963-1964 and 1965-1966 and for shorter periods inseveral later years. No avian visits were observed in the Nep-tune Range in 1963-1964. However, in 1965-1966, numerousbut uncounted visits by skuas to the large midden of a 40-person helicopter base facility in the north-central NeptuneRange were doubtless attracted by the abundant helicopter,LC-130 Hercules, and R4D aircraft activity that summerthroughout the Pensacola Mountains. During work in January1974 and November-December 1976 and 1978 in areas of theDufek Massif and the Forrestal Range, lying north of the Nep-tune Range, birds were sighted on but a single occasion: in mid-December 1978, two snow petrels were seen from afar flyingover Davis Valley (82°30' S 51° W) at the northeast end of DufekMassif (Reynolds fieldnotes). Near the south margin of theFilchner Ice Shelf and only about 500 kilometers from the Wed-deli Sea, this broad ice-free valley containing a small pond, algalmats, and abundant meltwater would appear to be attractive toseabirds. The sighting of the two birds in but 4 days of work inthe valley suggests that it is.

References

Axelrod, B. 1979. Observations of south polar skuas at Dome C. Ant-arctic Journal of the U.S., 14(5), 173.

Eklund, C. R. 1964. The antarctic skua. Scientific American, 210(2),94-100,

Halle, L. J . 1973. Eagle of the South Pole. Audubon, 75(2), 84-89.Reynolds, R. L. 1978. Field notes (personal communication).Ricker, J. 1964. Bird records of Victoria Land, 1962-63. The Emu, 64(1),

20-27.Rugh, D. J . 1974. Bird sightings in Marie Byrd Land. Antarctic Journal of

the U.S., 9(4), 103-104.Schmidt, D. L. 1983. Personal communication.Schmidt, D. L., and A. B. Ford. 1963. U.S. Geological Survey in the

Patuxent Mountains. Bulletin of the U.S. Antarctic Projects Officer, 4(8),20-24.

Splettstoesser, J . E 1981 Bird sightings in the Ellsworth Mountains andother inland areas. Antarctic Journal of the U.S., 16(5), 177-179.

Watson, C. E. 1975. Birds of the antarctic and sub-antarctic. (AntarcticResearch Series, American Geophysical Union). Washington, D.C.:American Geophysical Union.

Strategies for growth and survival ofantarctic oasis lake biota

BRUCE C. PARKER,ALFRED T. MIKELL, and

GEORGE M. SIMMONS, JR.

Biology DepartmentVirginia Polytechnic Institute and

State UniversityBlacksburg, Virginia 24061

The primary aim of our 3-year study was to characterize theextent to and mechanisms by which organisms native to theunusual southern Victoria Land lakes are adapted for survivaland growth under certain environmental extremes. The secondyear report addressed adaptations of algae, heterotrophic bacte-ria, and an aquatic moss to low light, low temperature, hyper-salinity, and high concentrations of dissolved oxygen. We alsodiscussed adaptations of the lakes' modern algalbacterialstromatolites to nonturbulence and the absence of metazoa(Parker et al. 1982a). Additional new information on these lakesinclude Cathey and others (1982); Kaspar and others (1982);Love and others (1982, 1983); Parker and others (1982b, c);Seaburg, Kaspar, and Parker (in press); Seaburg and Parker (inpress); Simmons and others (1983); and Wharton, Parker, andSimmons (in press). During this third year, we have furtheredour understanding of the adaptations to low light, low tem-perature, high dissolved oxygen; also, we have obtained new

evidence for phosphorus limitation and stromatolite structure,distribution, and lipid content.

Low light. Seaburg and others (in press) have produced thefirst estimate of the photosynthetic quantum efficiency for aphytoplankton community in high latitude polar ecosystems,namely for Lakes Bonney, Fryxell, Hoare, and Vanda. Theirestimates indicate that the phytoplankton of these four lakeseither (1) convert light to organic matter more efficiently or (2)trap light more efficiently than freshwater or marine phy-toplankton elsewhere.

During the 1982-1983 field season microbial mat from theanoxic depths of Lake Fryxell fixed significant levels of car-bon-14 bicarbonate (H 14CO 3 ) and carbon-14-acetate at in situlow-light levels. This suggests the presence of the anaerobicphotosynthetic bacteria (e.g., Rhodospirillaceae, Chromatiaceaeand/or Chlorobiaceae).

Low temperature. Seaburg and Parker (in press) examinedfreshwater Virginia algae isolated from both cold (less than 6°C)and warm (greater than 20°C) habitats using methods identicalwith those applied earlier to antarctic lake algal isolates (Sea-burg, Parker, and Simmons 1981). Comparison of data showsclearly that the antarctic lakes have a significantly higher pro-portion of algal taxa adapted to good growth at the coldertemperatures and correspondingly are more frequently inhib-ited by the warmer temperatures.

Experiments during the 1982-1983 field season also showedthat dark respiration measured as carbon-14 dioxide ("CO,)evolution from unilabeled glucose in lake water was highest atabout 12°C, less but still appreciable at 4°C, and severely inhib-ited at 20°C.

Oxygen effects. Mikell, Parker, and Simmons (1983) haveshown that high dissolved oxygen levels simulating those of thesub-ice waters of southern Victoria Land lakes severely inhibitthe growth and metabolism of planktonic bacteria from the

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