ocean productivity and climate change

TREE vol. 5, no. 9, September 1990

currently being compared to one another and to the background mean, for they serve as one model of what the consequences of large- scale warming may be. In both cases there were substantial changes in the upper 100 m or so of the entire system. Both the thermocline and the nutricline deepened, and productivity was greatly diminished. Al- though some tropical species were transported to the north very near shore, this was not generally true over the entire system. Rather, warm, high-salinity water and its in- habitants intruded from the west- southwest. This normally occurs in most summers but during the two El NiAos it was greatly exaggerated. In addition to these two great positive temperature anomalies called El Nirios, there were other large, non- seasonal departures from mean conditions; these had other ecosystem signatures.

Sorting out the patterns of these climatic events and their ecosystem consequences is not an easy task. But repeatable patterns, as op- posed to randomness, do seem to exist, and therefore regulation is strongly implied and prediction a possibility.

Conclusion These two time series-one in the

Atlantic, the other in the Pacific - do provide bases for the definition of

‘change’. Departures from long-term mean conditions can be defined; further, the response of the biota to climatic anomalies can be de- scribed in terms of direction, magnitude and frequency. To the degree that large zooplankton can serve as a proxy for the state of the rest of the system, we have achieved some real insight into how climate affects oceanic ecosystems.

References I Haury, L.R., McGowan, I.A. and Wiebe, P.H. II9781 in Spatial Patterns in Plankton Communities (Steele, J.H., ed.), pp. 277-327, Plenum Press 2 Stommef, H. (1963) Science 139.572-576 3 Dickinson, R.E. and Cicerone. R.I. 119861 Nature319,109-II5 4 Ramanathan, V. (1988) Science 240, 293-299 5 Wiebe, P.H., Miller, C.B., McGowan, j.A. and Knox, R.A. II9871 Eos 68, 1178-l 190 6 Tont, S.A. II9891 Geophys. Monogr., Am. Geophys. Union 55, 161-163 7 Maddock, L., Harbour, D.S. and Boalch, G.T. ( 1989) /. Mar. Bio/. Assoc. UK 69, 229-244 8 Garrod, D.]. and Colebrook, I.M. (19781 Rapp. P-V. Reun.. Cons. Int. Expior. Mer 173, 128-144 9 Smith, P.E. (1972) Fish. Boll. 70, 849-874 IO MacCall, A.D. and Prager, M.H. (1988) Calif. Coop. Oceanic Fish. Invest. Rep. 29, 91-101 I I Radovich, I. ( 1981 I in Resource Management and Environmental Uncertainty: Lessons from Coastal Upwelling Fisheries IGlanz. M.H. and Thompson, I.D.. edsl, pp. 107-135, john

Ocean Satellite measurements and the development of new techniques have confirmed the importance of ocean biology in controlling the carbon dioxide (CO,) content of the atmosphere. The marine sedimentary record shows that climate change and the ocean carbon cycle are closely linked: during glacial periods, marine productivity was enhanced and atmospheric CO, levels were reduced. Global warming may have the opposite effect, with reduced uptake of CO, exacerbating the problems of climate change.

Marine photosynthesis is responsible fora worldwide annual conver- sion of 30-50 Gt (billion metric tons: 10’~ g) of carbon from dissolved, inorganic substrates to particulate,

Phillip Williamson and Patrick Holligan are at the NERC Plymouth Marine Laboratory, Prospect Place, Plymouth PLI 3DH, UK.

Wiley & Sons 12 Shepherd, I.G., Pope, I.G. and Cousens, R.D. (19841 Rapp. P-V. Reun.. Cons. Int. Expior. Mer 185, 255-267 I3 Cushing, D.H. (1982) Climate and Fisheries. Academic Press I4 Southward, A.!., Boalch, C.T. and Maddock, L. ( 1988) /. Mar. Biol. Assoc. UK 68,423-445 I5 Bellamy, l.c. (I8431 The Housekeeper’s Guide to the Fishmarket for Each Month of the Year: and an Account of the Fisheries of Devon and Cornwall, E. Nettleton, Plymouth

I6 Hardy, A. (I9561 The Open Sea - Its Natural History - The World of Plankton, Collins I7 Oceanographic Laboratory, Edinburgh (1973) Bull. Mar. Ecoi. 7, I-174 I8 Clover, R.S. ( I9671 Symp. Zooi. Sot. London 19, 189-2 IO I9 Colebrook, I.M. (1982) /. Plankton Res. 4, 435-462 20 Dickson, R.R., Kelly, P.M., Colebrook, I.M.. Wooster, W.S. and Cushing. D.H. ( 1988) 1. Plankton Res. IO, 151-169 21 Colebrook. I.M. et ai. ( 1984) 1. Cons. Int. Explor. Mer 4 I, 304-306 22 Colebrook, I.M. and Taylor, A.H. (19841 Rapp. P-V. Reun., Cons. Int. Expior. Mer 183, 20-26 23 Colebrook, j.M. ( 1982) Oceanoi. Acta 5, 473-480 24 Radach, G. II9841 Rapp. P-V. Reun., Cons. lnt. Expior. Mer 185, 234-254 25 Brinton, E. (1976) fish. Bull. 74, 733-762 26 Chelton, D.B., Bemal, P.A. and McGowan, LA. (198211. Mar. Res. 40, 1095-I 125 27 Chelton, D.B. (I981 I Caiif Coop. Oceanic Fish. Invest. Rep. 22, 34-48 28 Bernal, P.A. ( 1979) Caiif Coop. Oceanic Fish. invest. Rep. 20, 89-101 29 Sette, O.E. and Isaacs, I.D. ( 1960) Caiif. Coop. Oceanic Fish. Invest. Rep. 7, l-2 I7 30 McGowan, I.A. ( 1985) in Ei Nifio North (Wooster, W.S. and Fluharty, D.L., edsl, pp. 166-184, University of Washington

Productivity and Climate Change

Phillip Williamson and Patrick M. Holligan organic material. As a result of such biogenic carbon fixation in the sunlit surface waters, there is an oceanic drawdown of CO, from the atmosphere of similar magnitude: an amount at least five times greater than the quantity of carbon released to the air by fossil fuel combustion and other human activities’,2.

All but a tiny fraction of the organic carbon in marine biomass is subsequently reconverted to CO, (the fate of all life on Earth), adding to the pool of around 35 000 Gt of inorganic carbon within the oceans. Balance is achieved by the release

of a proportion of that carbon pool to the atmosphere, through ocean circulation processes; the near- exactness of that equilibrium is shown by the stability of atmospheric CO, levels over the period IO 000-100 years before present. But many of the factors controlling biologically driven CO, uptake and physically driven CO, release are only loosely coupled, and will be affected in different ways by climate change. There is therefore a strong likelihood that perturbations in the ocean carbon cycle will have a profound influence on future

299


ATMOSPHERE

CO, uptake and release

Time for return to atmosphere:

days - months years - centuries

/22$23J Respiration J r521

PHYTOPLANKTON, ZOOPLANKTON

\ AND MICROORGANISMS

/

Upwelling and diff u&on

Fig. I. Biological processes have a major influence on the air-sea exchange of CO, and on the time scale for the transport of carbon within the ocean. DOC. dissolved organic carbon; POC, particulate organic

atmospheric CO, levels, limiting our ability to predict, and bring under control, anthropogenically induced global warming.

Two basic characteristics of oceanic ecosystems are of particular importance in assessing the influence of marine biota on climate and vice versa. Firstly, biomass in the sea is dominated by short-lived, microscopic organisms (autotrophic and heterotrophic) that inhabit the top 100 m of shelf seas and the open ocean; their abundance is spatially and temporally variable, matching the main spatial and temporal scales of physical features in the marine environment3B4. Thus, pel-

agic communities have an inher- ently high turnover rate, both in terms of metabolic activity and in the longevity of individual organisms; there is a correspondingly rapid breakdown of many of the products of photosynthesis, through the respiration of plants fphyto- plankton), animals (zooplankton and nekton 1 and decomposer organisms (protozoa and bacteria), and this returns CO, to surface waters.

Secondly, there are slow as well as fast pathways in the ocean carbon cycle. Around 1 O-l 5% of the production in the upper ocean is exported to deeper water56 as aggregates of plant and animal debris and excreta

falling to the sea floor (‘marine snow’17; as dissolved organic ma- teria18,9; and by the vertical mi- gration of crustacean omnivores, such as amphipods, feeding by night near the surface and defecat- ing by day below the thermoclineLO. Such processes rapidly remove carbon from the surface water, with material reaching the sea bed at 4000 m in the North Atlantic in 4-6 weeks”. However, because of the very slow rate of subsurface physical mixing and circulation, it may be hundreds or thousands of years before CO, resulting from the breakdown of organic material in mid and deep water is returned to the upper ocean for exchange with the atmosphere (Fig. I I. And for the small proportion (O.O5-0.5%) of photosynthetically fixed carbon that becomes incorpor- ated into sediments, the time scale for its remobilization, through geo- logical processes, is many millions of years.

Are the oceans the ‘missing sink’? There are a great many simplify-

ing assumptions made when esti- mating global flux values from geo- graphically incomplete data sets, derived from separate studies of different components of the ocean carbon cycle. There are also problems in measuring basic processes (e.g. primary production with its magnitude dependent on definition and method of determination41, and in determining the relative importance of components of the system that have only recently been recog- nized (e.g. dissolved organic car- bons and picoplanktonl. As a result, the precision of estimates for biologically mediated carbon uptake is at present insufficient to determine either the magnitude or the direction of the net air-sea carbon flux by comparison with (equally uncertain) first-principle estimates of physical exchange rates.

However, it is well established that increases in atmospheric CO, recorded to date only account for around half of the carbon released through fossil fuel combustion. Since a net accumulation of terrestrial biomass in the past 100 years has seemed unlikely (due to defores- tation and other land-use changes involving carbon release), it has been generally assumed that the oceans have served as the main

300


natural carbon sink, with a net uptake of around 3 Gt per annum. This view has recently been challenged by Tans eta/.12, who found a serious mismatch between inter-hemi- spheric atmospheric CO, budgets and measurements of CO, partial pressure (pC0,) in surface-ocean waters (the net air-sea flux of CO, is a function of windspeed and the difference in pC0, values between the two phases). For regions lacking pC0, data, including shelf seas, values were estimated from pCO,-temperature relationships.

On that basis, the net global ocean sink was estimated to be I Gt of carbon per year, with additional losses from the atmosphere of 2-3 Gt via a ‘missing sink’ in the northern hemisphere. Tans et a/.12 suggest that enhanced carbon uptake by temperate forests may be responsible, due to the stimulation of photosynthesis by increased atmospheric CO,.

It is unfortunately impracticable to measure terrestrial productivity (above and below ground) and associated gas exchanges with sufficient precision to test that hy- pothesis for natural ecosystems on land. However, there is considerable scope for improving the spatial and seasonal coverage of oceanic pC0, data, and such work is a shared (objective of two recently established international programmes: the Joint Global Ocean Flux Study (IGOFS) and the World Ocean Cir- culation Experiment (WOCE). UK research groups participating in IGOFS and WOCE are using underway sampling techniques to relate CO, parameters to other biological, chemical and physical features of the upper ocean. Preliminary results from the Northeast AtlanticI have shown that pC0, values are much more variable than was previously supposed, and are strongly influ- enced by phytoplankton abundance (Fig. 21. Temperature effects were also found, but the relation- ship was in the opposite direction to that assumed by Tans et al.

Thus, the oceans may yet prove to be the main ‘missing sink’ for CO, uptake from the atmosphere, when full account is taken of biologically driven seasonal effects, mesoscale influences, and the contribution of shelf seas to the ocean carbon cycle14.

Responsiveness to climate change Even if there were an exact bal-

ance at present between oceanic CO, uptake and release, that situ- ation is unlikely to be maintained under conditions of a global temperature rise of 2-5X as predicted for the next century. The reasons for expecting imbalances to arise are as follows. ?? Long-term studies of marine productivity and community structure have shown considerable varia- bility, with regional trends occurring in synchrony with relatively minor shifts in climatic properties; e.g. as shown by Continuous Plankton Re- corder data for the Northeast Atlan- ticI (see also McGowan, this issue). Worldwide effects have yet to be detected; however, the next gener- ation of ocean colour satellites will provide global comparisons of phytoplankton abundance, with ref- erence to the Coastal Zone Colour Scanner data of the 1980s. ?? As already noted, different components of the ocean carbon cycle operate on time scales covering four orders of magnitude (excluding sedimentary processes). Whilst biological processes in the upper ocean are closely coupled, on a day- to-day basis, with atmospheric variables (e.g. temperature and wind, affecting surface stratification and gas-exchange rates; also light and cloud cover), the penetration of temperature changes to the deep ocean (with effects on decompo- sition rates, chemical reactions and circulation patterns) may take 50- 100 years, or more if there is a slow- ing of deep-water formation at high latitudeslb. ?? In addition, the main regions of net CO, uptake and net CO, emis- sion are widely separated geo- graphically12, and thus are likely to be differentially affected by climate change.

The historical perspective A recent analysis of global sea-

surface temperatures has indicated an increase of 0.2-0.X since 190017. However, regional changes have not always been in phase, and many areas of the northern hemisphere experienced a marked cooling in the period 1950-1980. Whilst these climatic changes may have caused a net global change in export production (the downward flux of biogenic

h 3.0- P E _

g - z 2.0-

8 - b -

2 1 .o- -I I I

00 06 12 18 24

Time (h)

Fig. 2. During the spring bloom in the North Atlantic, the variations in partial pressure of CO, (pCO,I in surface waters are closely correlated with spatial varia- bility in photosynthetic activity. Underway measurements along a 300 km transect around 47“N 2O”W, May 1989. Adapted from Ref. I?.

carbon from the upper ocean), it is unlikely that this has been of sufficient magnitude to be detected in marine sediments.

But the more substantial temperature changes of the Quaternary ice-age cycle (of similar magnitude to those predicted for the next 100 years by global-warming scenarios) have left strong evidence in the sedimentary record for major perturbations in oceanic productivity; this is shown by carbon isotope data18,19, by the species composition of planktonic foramin- ifera assemblageszo, and by direct measurement of the organic carbon content of marine sediments2’. These studies have indicated that export production in equatorial regions was around twice as high during glacial periods as it is now, with

160 ’ 80 w 0 Thousand years ago

Fig. 3. Changes in the global distribution of carbon during Earth’s ice-age cycle: a comparison of atmospheric CO, levels 1 ice-core data from Antarctica) and the productivity-related carbon isotope signal (difference in ‘%I’% ratios bktween planktonic and benthic for- aminifera. from the eastern tropical Pacific). Data from Refs 18. I9 and 22.

301


Organic volatiles

;

t................... : Dissolved CO,

: :

i , :.._j. . . . . . . . Detritus

7, 7, THERMOCLINE ,_--3_____---___------_- +-:----

.:

E .g *._:__..*-

_...-*- : . ..- .- rz ,./ ..--

>” z 1,

Export production: + t the ‘biological pump’ i

Fig. 4. The main pathwaysofdissolved and particulate material controlling carbon fluxes into, out of and within the upper ocean.

the global value being up to 50% greater.

Such changes would have brought about a reduction in atmospheric CO, (as observed in ice-core data**; Fig. 31, an effect enhanced by circulation changes that increased the alkalinity of polar surface waters23. Examination of phase relationships strongly suggests that the main CO, increases preceded the increases in temperature19, although they were not of sufficient magnitude to be the only forcing factor. Changes in atmospheric methane levels, in plan- etary albedo and in the poleward transport of heat by the ‘ocean con- veyor belt’24 are believed to have provided additional positive feedback, accelerating the climate change that was initially induced by orbital changes with a 100 000 year periodicity.

There were also considerable changes in terrestrial vegetation during glacial periods, but it is unlikely that these would have favoured a net uptake of carbon from the atmosphere. Thus, recon- struction of vegetation types indi- cates that desert and grassland expanded at the expense of forests, with increases in land area (due to sea-level changes) offset by the greater extent of permanent ice cover25.

302

Effects of global warming There are no geologically recent

palaeoclimatological precedents for the ‘enhanced interglacial’ conditions predicted for the next century by General Circulation Models (GCMs). The behaviour of the ocean carbon cycle under those conditions has therefore to be determined by understanding the basic processes controlling the flux of CO, across the sea surface, the export of carbon from the upper ocean, and its fate in mid and deep waters. Whilst preliminary models of these processes are being developed within the JGOFS programme, much more in- formation is required before the biological (and physical) properties of the oceans can be realistically included in coupled ocean- atmosphere GCMs.

Nevertheless, it can be expected that global warming will result in a warmer, more stable surface layer, with that effect greatest in temperate oceans that are currently subject to winter mixing and summer stratification. Such regions are at present characterized by a surface primary production that is two or three times higher than that of the permanently stratified, nutrient-poor subtropical and equatorial waters*$ whilst high- latitude ocean regions show a net annual uptake of CO,, lower lati-

tudes are either in near-equilibrium or show a net efflux’*.

It is conjectured that there will be three main effects of warming, and hence enhanced stratification, on open-ocean plankton in temperate and subpolar regions: lower primary production, as a result of reduced upward mixing of nutrients (although partly compensated by a longer production season I; lower downward fluxes of organic matter due to changes in size composition of the biota, with increased ef- ficiency in grazing and recycling (to retain nutrients in surface waters); and a shift from siliceous (diatom) to calcareous (coccolithophore) phytoplankton communities27, affecting the capacity of the upper ocean to hold CO,. All these effects would tend to decrease the oceanic uptake of carbon in an area such as the North Atlantic.

Whether or not such a scenario of positive feedback would have a sig- nificant effect on climate change would depend on the magnitude of the response, and on the degree to which it might be offset by increases in productivity elsewhere, e.g. in polar seas (which are at present covered by ice1 and in upwelling regions on western continental mar- gins28. Other feedback mechanisms associated with changing patterns of ocean productivity may also be important, including: the effect of phytoplankton sulphur emissions on cloud formation2’ and rainfall acidity, affecting the radiation balance and weathering processes; effects of surface-ocean warming on the release of ‘greenhouse’ gases other than CO, (e.g. nitrous oxide, methane and halocarbons); and effects of phytoplankton on light (and heat) absorption at the sea surface.

None of these effects is a direct response to temperature or to increased CO,, and the complex inter- actions of the pelagic community that determine carbon fluxes in and out of the upper ocean (Fig. 41 can- not be simulated under experimen- tal conditions in the laboratory. One of the highest priorities in environmental research for the next decade must therefore be to carry out the fieldwork needed to estab- lish quantitative models for these relationships - and hence the response of the ocean biota to


changes in their physical environment due to global warming - through process studies, surveys and the application of remote- sensing techniques to the global range of marine ecosystems.

Such work will show whether changes in the strength of the ocean CO, sink due to biological activity can be expected to have a major influence on the future rate of global warming and the likelihood of achieving long-term climatic stability. On the basis of previous changes in Earth’s climate, the magnitude of response by the ocean carbon cycle may be at least as great as any changes that we can make by curbing CO, emissions from fossil fuels.

Acknowledgements We thank our colleagues within the NERC

Biogeochemical Ocean Flux Study and the IGOFS programme who have contributed to the practical and theoretical development of these concepts.

References I Bolin. 6. I19861 in The Changing Carbon Cycle: A Global Analysis ITrabalka, J.R. and

Reichle, D., edsl, pp. 403-424, Springer- Verlag 2 Moore, B. and Bolin, B. ( 19861 Oceanus 29, 9-15 3 Steele. I.H. (19891 Oceanus 32, 4-9 4 Holligan, P.M. I19891 Adv. Bat. Res. 16, 193-252 5 Longhurst. A.R. and Harrison, W.G. (19891 Prog. Oceanogr. 22, 47-l 23 6 Eppley, R.W. ( 19891 in Productivity of the Ocean: Present and Past (Berger. W.R., Smetacek, V.S. and Wefer, G., edsl, pp. 85-97, john Wiley & Sons 7 Shanks, A.L. and Trent. I.D. t 19801 Deep- Sea Res. 27, 137-l 43 8 Sugimura. Y. and Suzuki, Y. II9881 Mar. Chem. 24, 105-131

9 Toggweiler, I.R. (1989) in Productivity of the Ocean: Present and Past (Berger, W.R., Smetacek. VS. and Wefer, G., edsl, pp. 65-83, lohn Wiley & Sons IO Angel, M.V. (19891 Prog. Oceanogr. 22, l-46

I I Lampitt, R.S. ( 19851 Deep-Sea Res. 32, 885-897 I2 Tans, P.P., Fung, I.Y. and Takahashi. T. t 19901 Science 247, 1431-1438 I3 Turner, D.R. et a/. ( 19891 in Third International Conference on Analysis and Evaluation of Atmospheric CO, Data Present and Past (Extended Abstracts), pp. 135-139, World Meteorological Organization

14 Walsh, 1.1. (I9891 in Productivity of the Ocean: Present and Past (Berger. W.R., Smetacek, V.S. and Wefer. G., edsl, pp. 175-191, fohn Wiley&Sons

I5 Dickson, R.R., Kelly, P.M., Colebrook, j.M., Wooster, W.S. and Cushing, D.H. 11988) /. Plankton Res. IO, I5 I-I 69 I6 Stouffer, R.I., Manabe, S. and Bryan, K. II9891 Nature 342,660-662 I7 Folland. C.K. and Parker, D.E. 11990) in Climate-Ocean interaction (Schlesinger, M., ed.), pp. 21-52, Kluwer Academic Publishers I8 Berger, W.H., Smetacek. VS. and Wefer, G. II9891 in Productivity of the Ocean: Present and Past (Berger, W.R., Smetacek, VS. and Wefer, G., edsl, pp. l-34, lohn Wiley G Sons 19 Shackleton, NJ. and Pisias, N.G. (19851 Geophys. Monogr. 32,303-3 I7 20 Mix, A.C. ( 19891 Nature 337, 541-544 21 Muller. P.I. and Suess, E. (19791 Deep- Sea Res. 26A, 1347-l 362 22 Barnola, I.M., Raynaud, D.. Korotkevich. Y.S. and Lorius, C. II9871 Nature 329, 408-4 I4 23 Broecker, W.S. and Peng, T-H. (19891 Global Biogeochem. Cycles 3,2 15-239 24 Broecker, W.S. and Denton, C.H. (1989) Geochim. Cosmochim. Acta 53,2465-2501 25 Prentice, K.C. and Fung, I.Y. (1990) Nature 346,48-51 26 Berger, W.H. II9891 in Productivity of the Ocean: Present and Past I Berger, W.R., Smetacek, V.S. and Wefer, C., edsl, pp. 429-455, John Wiley&Sons 27 Dymond, j. and Lyle, M. (19851 Limnol. Oceanogr. 30.699-7 I 2 28 Bakun, A. (I9901 Science 247, 198-201 29 Charlson, R.I., Lovelock, I.E., Andreae, M.O. and Warren, S.G. (19871 Nature 326, 655-66 I

Using Ecosystem Models to Assess Potential Consequences of Global

Climatic Change H.H.Shugart

Predicting ecosystem response to climate change is a dynamic version of the classic problem of understanding vegetation- climate interrelations. Computer models can synthesize current knowledge and are important tools for understanding possible ecosystem dynamics under changed con- difions. Models based on individual plant biology and natural history have been tested with respect to their ability to simu- late vegetation response to changed climate, and are being applied to assess the potential effects of future climate change.

At the turn of the century, it was noted that there is a high degree of convergence of plant form in similar climates. In some ways, these simi- larities appear to transcend taxonomic relations. For example, in Mediterranean climates in southern Africa, Chile or Australia, the plants and vegetation resemble those in similar climates in France or Italy, even though the taxonomic affin- ities of many of the components of

H.H. Shugart is at the Dept of Environmental Sciences, The University of Virginia, Charlottesville, VA 22903, USA.

the vegetation are different. Ex- plaining these patterns inspired the earlier plant geographers - Drude, Graebner, Warming, and Schimper - to postulate relationships between climate and plant structure whose causalities are still being explored today at both the plant’ and veg- etation2-4 level.

The classic question of why the vegetation in widely separated places with similar climates is alike has been recast as a topical scientific problem, namely the evaluation of global climate change. The rising level of CO, (and other’greenhouse’ gases) in the atmosphere, and its consequences, have been called an ‘uncontrolled experiment’ on the earth’s geophysical and biotic sys-

tems5. The level of uncertainty about the response of the earth’s atmosphere to this change is very high6. Nevertheless, the prediction of the response of the earth’s vegetation to global climate change is a remarkably rich scientific challenge that hearkens back to the classic plant geographers.

The evaluation of the effects of change in the earth’s climate with respect to terrestrial ecosystems can be broken down into three scientific problem areas. Recognizing that the concentrations of CO, and other gases in the atmosphere are climatic variables, sensu stricta, one can ask whether, under conditions of a climate change, one would expect:

(< 1990 ‘lsetiter S;~en~e Publtshers lid IUKI 0169 5347.90602 00 303

ocean productivity and climate change

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