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Titolo:
Direct effects of CO2 concentration on growth and isotopic composition of marine plankton
Autore:
Wolf-Gladrow, DA; Riebesell, U; Burkhardt, S; Bijma, J;
Indirizzi:
Alfred Wegener Inst Polar & Marine Res, D-27515 Bremerhaven, Germany Alfred Wegener Inst Polar & Marine Res Bremerhaven Germany D-27515 rmany
Titolo Testata:
TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY
fascicolo: 2, volume: 51, anno: 1999,
pagine: 461 - 476
SICI:
0280-6509(199904)51:2<461:DEOCCO>2.0.ZU;2-#
Fonte:
ISI
Lingua:
ENG
Soggetto:
PHOTOSYNTHETIC C-13 FRACTIONATION; GENERAL-CIRCULATION MODEL; SOUTHERN INDIAN-OCEAN; INORGANIC CARBON; ORGANIC-CARBON; ANTHROPOGENIC CO2; PHYTOPLANKTON GROWTH; SKELETONEMA-COSTATUM; SURFACE WATERS; FORAMINIFERA;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
94
Recensione:
Indirizzi per estratti:
Indirizzo: Wolf-Gladrow, DA Alfred Wegener Inst Polar & Marine Res, Postfach 12 01 61, D-27515 Bremerhaven, Germany Alfred Wegener Inst Polar & Marine Res Postfach 12 01 61 Bremerhaven Germany D-27515
Citazione:
D.A. Wolf-Gladrow et al., "Direct effects of CO2 concentration on growth and isotopic composition of marine plankton", TELLUS B, 51(2), 1999, pp. 461-476

Abstract

The assessment of direct effects of anthropogenic CO2 increase on the marine biota has received relatively little attention compared to the intense research on CO2-related responses of the terrestrial biosphere. Yet, due to the rapid air-sea gas exchange, the observed past and predicted future risein atmospheric CO2 causes a corresponding increase in seawater CO2 concentrations, [CO2], in upper ocean waters. Increasing [CO2] leads to considerable changes in the surface ocean carbonate system, resulting in decreases inpH and the carbonate concentration, [CO32-]. These changes can be shown tohave strong impacts on the marine biota. Here we will distinguish between CO2-related responses of the marine biota which (a) potentially affect the ocean's biological carbon pumps and (b) are relevant to the interpretation of diagnostic tools (proxies) used to assess climate change on geological times scales. With regard to the former, three direct effects of increasing [CO2] on marine plankton have been recognized: enhanced phytoplankton growth rate, changing elemental composition of primary produced organic matter, and reduced biogenic calcification. Although quantitative estimates of their impacts on the oceanic carbon cycle are not yet feasible, all three effects increase the ocean's capacity to take up and store atmospheric CO2 and hence, can serve as negative feedbacks to anthropogenic CO2 increase. With respect to proxies used in paleo-reconstructions, CO2-sensitivity is found in carbon isotope fractionation by phytoplankton and foraminifera. While CO2-dependent isotope fractionation by phytoplankton may be of potential use in reconstructing surface ocean pCO(2) at ancient times, CO2-related effectson the isotopic composition of foraminiferal shells confounds the use of the difference in isotopic signals between planktonic and benthic shells as a measure for the strength of marine primary production. The latter effect also offers an alternative explanation for the large negative swings in delta(13)C of foraminiferal calcite between glacial and interglacial periods. Changes in [CO32-] affect the delta(18)O in foraminiferal shells. Taking this into account brings sea surface temperature estimates for the glacial tropics closer to those obtained from other geochemical proxies.

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Documento generato il 14/07/20 alle ore 19:32:57