Prof. Marian-Traian GOMOIUProf. Marian-Traian GOMOIUGeoEcoMar - Constantza, Romania, E-mail:GeoEcoMar - Constantza, Romania, E-mail: mtgmtg@@

ciercier..roro

UNDERSTANDING ECOSYSTEM COMPLEXITY – UNDERSTANDING ECOSYSTEM COMPLEXITY – BASIC PREREQUISITE FOR THE SUSTAINABLE BASIC PREREQUISITE FOR THE SUSTAINABLE DEVELOPMENT OF THE NW BLACK SEADEVELOPMENT OF THE NW BLACK SEA

Basic Principles and New Approaches on the NW Black Sea Ecosystems State Assessment :

applying the integrative, holistic approach to the knowledge and management of the NW Black Sea ecosystem;

benthic ecosystems as barometer of the ecological health state of the sea, which generates resources and services for socio-economic systems;

emerging role of marine geology in benthic ecology;

developing basic ecological concepts – complexity of ecosystems, resilience, vulnerability, disturbance, integrality of natural systems and socio-economic systems etc. in order to improve knowledge and management of the Black Sea;

understanding of the Black Sea biodiversity process and building human resources in the field.

Current adaptive management targets Current adaptive management targets for the Black Sea and Danube Basin for the Black Sea and Danube Basin

(Mee 2001)(Mee 2001)Long term objective (EcoQO): Long term objective (EcoQO): “to take “to take measures to reduce the loads of nutrients and measures to reduce the loads of nutrients and hazardous substances discharged to such hazardous substances discharged to such levels necessary to permit Black Sea levels necessary to permit Black Sea ecosystems to recover to conditions similar to ecosystems to recover to conditions similar to those observed in the 1960s”those observed in the 1960s”First operational target: First operational target: “urgent measures “urgent measures should be taken in the wider Black Sea Basin in should be taken in the wider Black Sea Basin in order to avoid that the loads of nutrients and order to avoid that the loads of nutrients and hazardous substances discharged into the hazardous substances discharged into the Seas exceed those that existed in the mid Seas exceed those that existed in the mid 1990s (these discharges are only incompletely 1990s (these discharges are only incompletely known)”known)”

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D ISTURBANCES AND BIODIVERSITY RESEARCH INWATERSHED - TRIBUTARY R IVERS - BLACK SEA

M ACRO -GEO -ECO SYSTEM

BSEP

APPLIED N

INTEG RATED PROGRAMECOLOGICAL STATE OF THE BLAC K SEA

ECOSYSTEM - RESOURC ES AND SERVICESTHEO RETICAL AND ECO LOGICAL PRI CIPLES

Conceptual framework for the integrated Program Impact,

Disturbance, Resilience and Rehabilitation on the

Black Sea Biodiversity and Health of Ecosystems

Conceptual framework

for the integrated Program Impact,

Disturbance, Resilience

and Rehabilitatio

n on the Black Sea

Biodiversity and Health

of Ecosystems

Sources/Sources/types of complexity : of complexity :

Spatial - visible in the forms of vegetation patterns and species distributions our ability to describe or quantify spatial pattern is poor

Temporal - arises from population dynamics, effects of fluctuating climate and weather, and from spatial complexity (include metapopulation dynamics, temporal population fluctuations, extinctions, invasions, succession, predator-prey cycles, etc.)

Structural - relationships within an ecosystem (include food web structure, community composition, networks of competition, and facilitation, etc.)

Ecosyste

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ple

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Process - many steps or components (soil formation, the decay of logs, and succession; during the decay of a log many organisms physically alter the log in a sequential manner over a prolonged period; succession involves facilitation, competition, immigration, changes in physical conditions (e.g., development of a litter layer), and even changes in the local climate. Piecing together the entire process is rarely easy in such cases.

Geometric - geometric aspects of ecological objects add considerable complexity to systems. An obvious example is a forest canopy or individual tree crown.

Sources/Sources/types of complexity : of complexity : Ecosyste

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Sources/Sources/types of complexity : of complexity :

Behavioral - often-overlooked aspect of overall ecosystem complexity; in contrast to the building blocks of physics, such as ideal gases and identical protons, living organisms exhibit behaviors based on the information contained in their DNA. Plants adapt their growth form to extant conditions. Animals become more adept at catching prey as they gain experience. In a few cases, models have tried to incorporate movement decisions or foraging behaviors into animal home range models, as well as in a few other contexts.

Ecosyste

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Ecosystem stress response Ecosystem stress response Can be described by using some simple notions such as:Can be described by using some simple notions such as:

• Stability - the degree of oscillation, the system exhibits, about its stable equilibrium point and

• Resiliency - minimum distance from the equilibrium point to the edge of the cloud, is measured by the minimum disturbance necessary to disrupt the system and cause it to move to a new equilibrium state.

• Integrity of a system refers to our sense of it as a whole. If a system is able to maintain its organization in the face of changing environmental conditions then it is said to have integrity. If a system is unable to maintain its organization than it has lost its integrity.

Change in Organization refers to changes in the function of a system and its internal connections (structure) so as to better carry out some organizational imperative. Environment refers to the biotic and abiotic components external to an ecosystem which impact upon it, including humans.)

Stress-response must be characterized by a richer set of Stress-response must be characterized by a richer set of concepts and the concept of integrity must be seen as concepts and the concept of integrity must be seen as multi-dimensional and encompassing a rich set of multi-dimensional and encompassing a rich set of ecosystem behaviours (Kay, 1991) .ecosystem behaviours (Kay, 1991) .

Ecosystem stress responseEcosystem stress response

Properties of ecosystems determining stress recovery

characteristics (Cairns and Dickson 1977)(Cairns and Dickson 1977) VULNERABILITY - lack of ability to resist irreversible damage (which requires a recovery time greater than a human life span); could be measured by the size of disturbance necessary to cause irreversible damage;

ELASTICITY - ability to recover after displacement of structure and/or function to a steady state closely approximating the original; could be measured by the rate of recovery after disturbance; INERTIA - ability of an ecosystem to resist displacement or disequilibrium in regards to either structure or function; could be measured by the size of the disturbance needed to displace the system;

Properties of ecosystems determining stress recovery

characteristics RESILIENCY (Holling, 1973) - number of

times a system can undergo the same disturbance and still snap back; Syn.: AMPLITUDE - area over which the system is stable (the same as Holling's resilience). Resilience - the minimum distance from the equilibrium point to the edge of the cloud; thus resilience is measured by the minimum disturbance necessary to disrupt the system and cause it to move to a new equilibrium state.

Stability - the degree of oscillation, the system exhibits, about its stable

equilibrium point. Although the Black Sea before the ’60s experienced extreme oscillations in some populations, the system almost always bounces back to its original state. It was resilient. Holling notes that resilient systems normally aren't stable and vice versa.

There are two kinds of stability involved (Hill, 1975) :

• "no-oscillation" stability - refers to the stability of the state variables in the absence of stress;

• "stability-resilience" - refers to the stability of the state variables while the system is under stress and after the stress is removed; this stability refers to the degree of oscillation (flutter) the system experiences while under stress and how quickly this is dampened out when the stress is removed.

       CONSTANCY - the lack of change in some parameter of the system;

       PERSISTENCE - the survival time of the system;

       INERTIA - the ability to resist external perturbations;

       ELASTICITY - the rate at which the system returns to its former state following a perturbation;

       AMPLITUDE - the area over which the system is stable (the same as Holling's resilience);

       CYCLICAL STABILITY - the property of a system to cycle about some central point or zone;

       TRAJECTORY STABILITY - the property of a system to move towards some final end point or zone despite differences in the starting points.

Orians (1975) has identified seven properties of ecosystems which are related

to their stability:

Genetic

Biochemical

Physiological Histopathological

Immunological

Reproductive

Communities Ecosystems

Population

Increase integration Ecological significance

Mec

han

isti

c u

nd

erst

and

ing

Min/Hours Days Weeks/Months Years Biological Generations Response Time

Biome

Landscape

Biomolecular

Hu

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pact

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res:

HUMAN ACTIVITIES

IMPACT and PRESSURES

ENVIRONMENTAL STRESS

Biomolecular Biochemical

Pathways

COMMUNITY ECOSYSTEM

Physiological Immunological

Pathological Biochemical and Metabolic

Pathways

Individual Effects (Metabolism, Growth

and Reproduction

POPULATION

BIOME LANDSCAPES

Success of Feeding and Reproduction

competition

Quality and Quantity of Food

Bioenergetic Behavioral

Direct Indirect

Mutation, recombination

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Ecosystem States:

Ecological changes:Ecological changes:        the changes may be short term with the environment returning to its previous condition, or

        the change may persist. What immediate effect will this have on the ecosystem's organization and hence its integrity? A series of questions must be asked:

1. Will the system be moved away from its optimum operating point?

  If the response is no, then organization and integrity are not immediately affected.

  If the response is yes, then the question becomes:

2. Does the system return to its original optimum operating point?

If the answer is yes, then there are three issues:

  How far is the system moved from its optimum operating point before returning?

  How long will it take to return to its optimum operating point?

  What is the stability of the system upon its return?

Certainly we know many ecological disturbances and change occurring in the Black Sea environment

Nevertheless, let’s hope the ecological pressure Nevertheless, let’s hope the ecological pressure will decrease simultaneously with the diminishing will decrease simultaneously with the diminishing fertilizers and other chemicals used in agriculture fertilizers and other chemicals used in agriculture or with the reduction of the fishing effort. But this or with the reduction of the fishing effort. But this is far from being all. There are also the is far from being all. There are also the manipulations of the hydrologic regime of Black manipulations of the hydrologic regime of Black Sea tributaries. There are also the large-scale Sea tributaries. There are also the large-scale variations. There are the global changes. There variations. There are the global changes. There are so many steps to establish, to know, without are so many steps to establish, to know, without which it is hard to predict the Black Sea evolution.which it is hard to predict the Black Sea evolution.

•B B – in – in stressful environment subject to periodic stressful environment subject to periodic perturbations that disrupperturbations that disruptt aand send sendnd back back thethe developmental processdevelopmental process; ; In situarion B, two hypothetical In situarion B, two hypothetical ser-bock loops ore shown following disrurbser-bock loops ore shown following disrurbaances nces indicated by indicated by tthe arrows; the biotic communihe arrows; the biotic communitty becomes y becomes adaptively perturbarion-dependent by moinroining a lower adaptively perturbarion-dependent by moinroining a lower level of organization that would be achieved in rhe level of organization that would be achieved in rhe absence of stress inpuabsence of stress inputt. . TTra

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ico

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n •A A - - in a benign in a benign environmenenvironmentt with low with low probabiliry of probabiliry of catastrophic catastrophic perturbationsperturbations;;

Sea level and Danube discharge evolution (1959 - 2003)

Sea level trend eq. = 0.1cm/year + 15.3

Q Danube (Km3/year) trend eq. = -0.3cm/year + 213.1

0

5

10

15

20

25

30

35

1959 1969 1979 1989 1999

Years

Sea

Lev

el -

Cen

tim

eter

s

0

50

100

150

200

250

300

350

Sea level Q Danube (Km3) Linear (Sea level) Linear (Q Danube (Km3))

Q D

an

ub

e (

Km

3/Y

ea

r)

Ecological changes:Ecological changes:

Ecological changes:Ecological changes:

Hydrotechnical works on the

Danube, tributaries and Danube Delta

Sea level changes

Stirring up atmospheric circulation

Sea level increase

1,5-2 mm/yr

Increase in the total energy of the

sea

Waves and stronger currents

Gradual flood of the land

Global weather changes

C O A S T A L E R O S I O N

Decrease of Danube sediment discharge 30-50%

Drcrease of beach sediment

supply

S

U

B

S

I

D

E

N

C

E

Harbour facility building and other

hydrotechnical ingeneering

works

Other anthropic activities

Urban and industrial

development

Beach clearing

Sand exploitation

Hydrological changes

Ecological changes

1,5 mm/yr

G l o b a l i n f l u e n c e s

A n t h r o p i c p r e s s u r e s

Pollution-Eutrophication

52-72 mil. t <1970 30-40 mil. t >1980

Biological resources reduction

Integrated management of coastal zone

Withdrawal of shore line: 10 - 70 m/yr (Sulina–Cap Midia) 0.2 - 0.5 m/yr (Constanta–Vama Veche)

Diagram of geoecological chain changes at the Romanian Black Sea

Coast

Danube Delta Coastal Line Recession in the Last Century

LakeA gigea

“P rof. Ioan Borcea”M arine B io logical

S tation

44°05’N

44°10’N

28°40’E

C o n s t a n t z a C i t yTo uristic

HarborTo m is

Danube - B lack S ea Canal

20 m

10

m

10 m

5 m

B l

a c

k

S e

a

1 9 9 0“P rof. Ioan Borcea”

M arine B io logicalS tation

44°05’N

44°10’N

28°40’E

20 m

To uristicHarborTo m is

C o n s t a n t z a Ci t y

B l

a c

k

S e

a

1 9 8 0

.......

..........................................

...

Medium and coarse sands

with

and

Ophelia bicornis

Donacilla cornea comm unity

Rocky bottoms covered by

Cystoseira brown algae and

associated fauna

LakeA gigea

10 m

5 m

C o n sta n tz a H a r b o r D ev e lo p m en t fro m 1 9 8 0 to 1 9 9 0 - lo ss o f h a b ita ts a n d c o m m u n ities

Evolution of nutrient loads in Danube Evolution of nutrient loads in Danube waterwater

P-PO4

0 10 20 30 40

1980

1983

1986

1989

1992

1995

1998

2001

Tons x 103Ecolo

gic

al ch

an

ges:

Ecolo

gic

al ch

an

ges:

Evolution of nutrient loads in Danube Evolution of nutrient loads in Danube waterwater

Ecolo

gic

al ch

an

ges:

Ecolo

gic

al ch

an

ges:

N-NO3

0 200 400 600 800

1988

1990

1992

1994

1996

1998

2000

2002

Tons x 103

A series of questions must be asked:

1. Will the system be moved away from its optimum operating point?

  If the response is no, then organization and integrity are not immediately affected.

  If the response is yes, then the question becomes:

2. Does the system return to its original optimum operating point?

If the answer is yes, then there are three issues:

  How far is the system moved from its optimum operating point before returning?

  How long will it take to return to its optimum operating point?

  What is the stability of the system upon its return?

After the Black Sea ecological crisis was confirmed worldwide, studied and managed equally by the scientific community, political

factors and civil society, and numerous publications appeared as a final proof, today

specialists think that the ecosystem ecological state witnesses a slight

recovery.

May we speak of a gradual recovery of the Black Sea? Do we witness an

improvement of the ecological situation of this sea? A betterment of the

planktonic and benthic ecosystems? A redressing of the fishing resources? Is the economic decline of the riparian

countries really saving the Black Sea?

Dynamics of average annual Phytoplankton abundance in the Romanian coastal waters in two consecutive periods -1983-1992 and 1993-2003 and

average lines for the periods

0

2

4

6

8

10

12

3[19

83/1

993]

4[19

84/1

994]

5[18

85/1

995]

6[19

86/1

996]

7[19

87/1

997]

8[19

88/1

998]

9[19

89/1

999]

0[19

90/2

000]

1[19

91/2

001]

2[19

92/2

002]

3[00

00/2

003]

Y e a r s of the two periods

Ab

un

dan

ce

- D

ensi

ty (

x 10

6 ce

lls.

L-1

83-'92

93-'03

Avg

Avg

Dynamic of average annual Phytoplancton abundance in the Romanian Coastal waters in two consecutive periods -1983-1992 and 1993-2003 and

the average lines for the periods

0

2

4

6

8

10

12

14

16

18

3[1

98

3/1

99

3]

4[1

98

4/1

99

4]

5[1

88

5/1

99

5]

6[1

98

6/1

99

6]

7[1

98

7/1

99

7]

8[1

98

8/1

99

8]

9[1

98

9/1

99

9]

0[1

99

0/2

00

0]

1[1

99

1/2

00

1]

2[1

99

2/2

00

2]

3[0

00

0/2

00

3]

Y e a r s of the two periods

Bio

ma

ss

(g

.m-3

)

83-'92

93-'03

Avg

Avg

Annual mean phytoplankton quantities - numerical density

(103 cells.L-1) and biomass (mg.m-3) - between 2000 and

2002 and multi-annual means for in the 9th and 10th decades

in Constantza near-shore waters

0 2000 4000 6000 8000 10000

1983-1990

1991-2000

2000

2001

2002

T i

m e

p

e r

i o

d s

Phytoplankton abundance

Biomass

Density

Benthic biota in NW Black Sea - 2003

0

5

10

15

20

25

30

35

40

45

50

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 28 31 33 35 39 40 54

Number of occurences

Nu

mb

er o

f ta

xa

0

10

20

30

40

50

60

70

80

90

100

Cu

mu

lati

ve c

urv

e o

f %

tax

a

Taxa % Cumulative

Benthic biota in NW Black Sea - 2003

0

5

10

15

20

25

30

35

40

45

501 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 28 31 33 35 39 40 54

Number of occurences

Nu

mb

er o

f ta

xa

0

10

20

30

40

50

60

70

80

90

100

Cu

mu

lati

ve c

urv

e o

f %

tax

a

Taxa % Cumulative

Dynamics of fishing catches in the Romanian Black Sea Waters during the period of 1970 - 2002

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

1970

1972

1974

1976

1978

1980

1982

1984

1986

1988

1990

1992

1994

1996

1998

2000

2002

Y e a r

Ton

s

Demersal f ishing Pelagic f ishing Total f ishing

Dynamics of turbot chaches (Psetta maeotica )at the Romanian Black Sea Coasts between 1950 - 2003

1

10

100

100019

50

1954

1958

1962

1966

1970

1974

1978

1982

1986

1990

1994

1998

2002

Y e a r s

Turb

ot

chat

ches

- (

Ton

s+1)

Fish catches dynamics at the Romanian Black Sea Coast

1

10

100

1000

10000

1970 1975 1980 1985 1990 1995 2000 2001 2002Y e a r s

Fis

h c

atc

he

s -

(To

ne

s+

1)

Merlangus merlangus euxinus Mullus barbatus ponticus

Acipenseridae Gobiidae var.

Squalus acanthias Solea vulgaris

Platichtys flescus luscus

Dynamics of fishing catches in the Romanian Black Sea Waters during the period of 1970 - 2002

0 2000 4000 6000 8000 10000 12000 14000 16000 18000

1970

1972

1974

1976

1978

1980

1982

1984

1986

1988

1990

1992

1994

1996

1998

2000

2002Y

e a

r s

T o n s

Demersal f ishing

Pelagic f ishing

Multiannual catches [Tons - (Ln N+1) ] of marine fishes at the Romanian Black Sea Coast (redrawn after Radu et al., 2004)

02

4

6

8

10Sprattus sprattus

Engraulis encrasicolus

Trachurus ponticus

Pomatomus saltatrix

Mugil cephalus

Alosa caspia nordmani

Atheina boyeri

Clupeonella cultriventris

Sturgeons

Psetta maeotica

Mullus barbatus ponticus

Merlangus merlangus euxinus

Gobiida var.

Squalus acanthias

1980-1990

1991-2002

Stopping the flow of littoral currents of Danubian sediments

Stopping the flow of littoral currents of Danubian sediments

Deviating offshorethe southward littoral drift of

sediments

Deviating offshorethe southward littoral drift of

sediments

Deficit of the sedimentary balance of touristic beaches

Deficit of the sedimentary balance of touristic beaches

Beach erosionBeach erosion

Withdrawal of the shore line with 15 - 70 m between

1979 - 1997

Withdrawal of the shore line with 15 - 70 m between

1979 - 1997

Emergency hydrotechnical works, without scientific basis

Emergency hydrotechnical works, without scientific basis

Artificial sand deposits

Artificial sand deposits

Movement of erosion field

towards neighbouring zones

Movement of erosion field

towards neighbouring zones

Ecological changesof habitats

and biodiversity

Ecological changesof habitats

and biodiversity

Disappearance of Ophelia – Mesodesma

biocoenoses

Disappearance of Ophelia – Mesodesma

biocoenoses

Reduction in the populations of

calciferic species forming sediments

Reduction in the populations of

calciferic species forming sediments

Disappearance of algal populations attenuating

erosion energy

Disappearance of algal populations attenuating

erosion energy

Removing the shell deposits

from the beach

Removing the shell deposits

from the beach

Sand exploitation

Sand exploitation

CONEX

ACTIVITIES

CONEX

ACTIVITIES

Bu

ildin

g h

arb

ou

r b

reak

wat

ers

Mid

ia,

Con

sta

nţa

Su

d -

Ag

igea a

nd

Man

galia

Imp

act

of

bu

ild

ing

har

bo

urs

on

th

e m

arin

e ec

osy

stem

s -

R

om

ania

n B

lack

Sea

Co

ast

Inputs of building jetties at the Sulina branch mouth of the Danube

River

Building the jetties system at the Sulina branch mouth and maintaining navigability depths at the channel bar

Decompensation of beach depositions of terrigenous

sediments southward along the Romanian littoral

Erosion Sulina - Sf. Gheorghe

Sector

Discharging the dredged material away from the

circulation system along the littoral

Appearance of an anticyclonic current south of the channel

Stopping littoral drift of

sediments from South Chilia

Branch

Taking alluvia load of the

Sulina branch out of littoral

circuit

Maintaining navigability

depths at the Sulina bar

through dredging

Disturbing the currents

system in the area

- 800 – 900 thousand m3/yr - 600 – 850 thousand m3/yr

Inputs of building jetties at the Sulina branch mouth of the Danube River

Main ecological chain changes triggered by the development of maritime transport

MM AA RR II TT II MM EE TT RR AA NN SS PP OO RR TT DD EE VV EE LL OO PP MM EE NN TT

Increasing demand for ships Ships building

Building Harbours & Port

facilities

Increasing maritime traffic

and exchanges between harbours

Enlarging interconnected

harbours network

Increasing man interference into marine

environment

Coastal zone industrialization and urbanization

Changes of the coastline

Loss/changes of the habitats and

landscapes

Changing patterns of water

circulation & sediments

distribution

Changes in the regime of physical

& chemical conditions

Loss of biodiversity

Pollution/ Contamination

Risks of ecological

accidents

Changes in bioproductivity

Increasing potential of organism species

spreading in new areas

Merchandise transportation:

ore oil & oil products

chemicals bulk goods

containerised merchandise

Ballast water

(larvae)

Changing structure of native

populations

Marine Fishing & Aquaculture

Offshore drilling & mining

Military operations

Waste disposal/dumping

Introduction of new species

Ship hull (adults & larvae)

CONCLUSIONSCONCLUSIONSSlight recovery of the NW Black Sea ecosystems:Slight recovery of the NW Black Sea ecosystems:

Biodiversity, with a little higher number of species is slightly better than in the last decades, 272 taxa (250 spcies and 22 supra-specific taxa – Nematoda and Nemertini worms, Harpacticoida crustacians, Bryozoa, Chironomida etc.).

Abundance of benthic populations is regular towards better, the general average values for the NW Black Sea, 0 – 125 m being 159,000 indvs.m-2 for numerical density and 470 g.m-2 for biomass.

There is a large variation of the abundance of benthic populations from one station to another, but the average values of the three continental shelves (Ukraine, Romania, Bulgaria) are similar: 9246 - 12660 indvs.m-2 and 462.14 - 465.2 g.m-2 for macrobenthos and 149795 - 164376 indvs.m-2 and 5.6 - 20.9 g.m-2 for meiobenthos.

CONCLUSIONSCONCLUSIONSThe occurrence of some recurrent species, considered

almost extinct 2-3 decades ago, represents a positive event, promising for the future recovery of the ecosystem.

Benthos populations have a random distribution, in patches, being characterized by occurrence of some meta-populations.

The existence of two-year old mussels in this area is also promising and contrasts with the situation in the late 1980s where all new recruits were killed by the annual appearance of the dead zone.

The recovery of the benthic system is rather weak. There The recovery of the benthic system is rather weak. There are still uncertainties and it is too early to draw a high are still uncertainties and it is too early to draw a high

confidence conclusion on the recovery, the evaluation of confidence conclusion on the recovery, the evaluation of the Black Sea ecosystem state represents a complex, the Black Sea ecosystem state represents a complex,

laborious, time consuming and rather imprecise process laborious, time consuming and rather imprecise process for the moment.for the moment.