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4 results on '"COCCOLITHOPHORE CALCIFICATION"'

1. The ecological response of natural phytoplankton population and related metabolic rates to future ocean acidification.

Author

Liu, Haijiao, Zhao, Yuying, Wu, Chao, Xu, Wenzhe, Zhang, Xiaodong, Zhang, Guicheng, Thangaraj, Satheeswaran, and Sun, Jun

Subjects
*PHYTOPLANKTON, *GLOBAL warming, *ACIDIFICATION, *MARINE ecology
Abstract

Ocean acidification (OA) and global warming-induced water column stratification can significantly alter phytoplankton-related biological activity in the marine ecosystem. Yet how these changes may play out in the tropical Indian Ocean remains unclear. This study investigated the ecological and metabolic responses of the different phytoplankton functional groups to elevated CO2 partial pressure and nitrate deficiency in two different environments of the eastern Indian Ocean (EIO). It is revealed that phytoplankton growth and metabolic rates are more sensitive to inorganic nutrients rather than CO2. The combined interactive effects of OA and N-limitation on phytoplankton populations are functional group-specific. In particular, the abundance and calcification rate of calcifying coccolithophores are expected to be enhanced in the future EIO. The underlying mechanisms for this enhancement may be ascribed to coccolithophore's lower carbon concentrating mechanisms (CCMs) efficiency and OA-induced [HCO3−] increase. In comparison, the abundance of non-calcifying microphytoplankton (e.g., diatoms and dinoflagellates) and primary productivity would be inhibited under those conditions. Different from previous laboratory experiments, interspecific competition for resources would be an important consideration in the natural phytoplankton populations. These combined factors would roughly determine calcifying coccolithophores as "winners" and non-calcifying microphytoplankton as "losers" in the future ocean scenario. Due to the large species-specific differences in phytoplankton sensitivity to OA, comprehensive investigations on oceanic phytoplankton communities are essential to precisely predict phytoplankton ecophysiological response to ocean acidification. [ABSTRACT FROM AUTHOR]

Published
2022
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2. Enhanced ocean-atmosphere carbon partitioning via the carbonate counter pump during the last deglacial

Author

Duchamp-Alphonse, Stéphanie, Siani, Giuseppe, Michel, Elisabeth, Beaufort, Luc, Gally, Yves, Jaccard, Samuel, Géosciences Paris Sud (GEOPS), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Paléocéanographie (PALEOCEAN), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Collège de France (CdF (institution))-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA), Institute of Geological Sciences [Bern], University of Bern, Oeschger Centre for Climate Change Research (OCCR), French INSU/LEFE - CHICO project, Swedish Research Council [VR-349-2012-6278], Swiss National Science Foundation [PP00P2-144811, PP00P2_172915], Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Collège de France (CdF)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Institut National de la Recherche Agronomique (INRA)

Subjects
EXPORT PRODUCTION, Science, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, CO2 CONCENTRATION, DEEP SOUTHERN-OCEAN, VENTILATION, NATURAL IRON FERTILIZATION, ORGANIC-MATTER, [SDU]Sciences of the Universe [physics], PHYTOPLANKTON, COCCOLITHOPHORE CALCIFICATION, lcsh:Q, PRESERVATION, ICE-AGE, lcsh:Science, 550 Earth sciences & geology
Abstract

International audience; Several synergistic mechanisms were likely involved in the last deglacial atmospheric pCO$_2$ rise. Leading hypotheses invoke a release of deep-ocean carbon through enhanced convection in the Southern Ocean (SO) and concomitant decreased efficiency of the global soft-tissue pump (STP). However, the temporal evolution of both the STP and the carbonate counter pump (CCP) remains unclear, thus preventing the evaluation of their contributions to the pCO$_2$ rise. Here we present sedimentary coccolith records combined with export production reconstructions from the Subantarctic Pacific to document the leverage the SO biological carbon pump (BCP) has imposed on deglacial pCO$_2$. Our data suggest a weakening of BCP during the phases of carbon outgassing, due in part to an increased CCP along with higher surface ocean fertility and elevated [CO$_{2aq}$]. We propose that reduced BCP efficiency combined with enhanced SO ventilation played a major role in propelling the Earth out of the last ice age.

Published
2018
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3. Enhanced ocean-atmosphere carbon partitioning via the carbonate counter pump during the last deglacial

Author

Siani, Giuseppe, Michel, Elisabeth, Beaufort, Luc, Gally, Yves, Jaccard, Samuel L., and Duchamp-Alphonse, Stephanie

Subjects
NATURAL IRON FERTILIZATION, DEEP SOUTHERN-OCEAN, ICE-AGE, COCCOLITHOPHORE CALCIFICATION, CO2 CONCENTRATION, EXPORT PRODUCTION, ORGANIC-MATTER, PHYTOPLANKTON, PRESERVATION, VENTILATION
Abstract

Several synergistic mechanisms were likely involved in the last deglacial atmospheric pCO(2) rise. Leading hypotheses invoke a release of deep-ocean carbon through enhanced convection in the Southern Ocean (SO) and concomitant decreased efficiency of the global softtissue pump (STP). However, the temporal evolution of both the STP and the carbonate counter pump (CCP) remains unclear, thus preventing the evaluation of their contributions to the pCO(2) rise. Here we present sedimentary coccolith records combined with export production reconstructions from the Subantarctic Pacific to document the leverage the SO biological carbon pump (BCP) has imposed on deglacial pCO(2). Our data suggest a weakening of BCP during the phases of carbon outgassing, due in part to an increased CCP along with higher surface ocean fertility and elevated [CO(2)aq]. We propose that reduced BCP efficiency combined with enhanced SO ventilation played a major role in propelling the Earth out of the last ice age.

Published
2018

4. Coccolitophore calcification is independent of carbonate chemistry in the tropical ocean

Author

Marañón, E. (Emilio), Balch, W.M. (William M.), Cermeño, P. (Pedro), Sobrino, C. (Cristina), Fernández, A. (Ana), Huete-Ortega, M. (María), López-Sandoval, D.C. (Daffine C.), Delgado, M. (Maximino), Estrada, M. (Marta), Álvarez, M. (Marta), Fernández-Guallart, E. (Elisa), Pelejero, C. (Carles), and González, N. (Natalia)

Subjects
calcification, intercalibration, Inorganic carbon, Primary production, Malaspina, carbonate chemistry, tropical oceanic areas, Carbonates, chemistry, coccolithophores, coccolithophore calcification
Abstract

Article, Short-term experiments indicate that seawater acidification can cause a decrease in the rate of calcification by coccolithopores, but the relationship between carbonate chemistry and coccolithophore calcification rate in natural assemblages is still unclear. During the Malaspina 2010 circumnavigation, we measured primary production, calcificatiion, coccolithophore abundance, particulate inorganic carbon (PIC) concentration, and the parameters of the carbonate system, along basin-scale transects in the tropical Atlantic, Indian and Pacific oceans. Euphotic layer-integrated calcification and mean cell-specific calcification to primary production (CP/PP) ratio was relatively invariant among ocean basins, with an overall mean value of 0.05+-0.04. Extrapoling this value to the entire ocean would result in a global pelagic calcification rate of 2.4 PtC /year. The mean PIC concentration in surface waters was 1.8 +-1.6 mgC/m3 and its turnover time averaged 20 d. We combined our data of calcification, primary production, and carbonate chemistry from Malaspina 2010 with those obtained during two previous cruises in the northern Arabian Sea. Both the CP/PP ratio and cell-specific calcification were largely constant across a wide range of calcite saturation rate (1.5-6.5), [HCO3-]/[H+] (0.08-0.24; mol:umol), and pH (7.6-8.1), which indicates that calcification by natural coccolithophore assemblages was independent of carbonate chemistry. Our results suggest that coccolithophore calcification, at least in tropical regions, may not be decreasing in the currently acidifying ocean.

Published
2016

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