Temperature effect on respiration and photosynthesis of the symbiont-bearing planktonic foraminifera $Globigerinoides\ ruber$ , $Orbulina\ universa$ , and $Globigerinella\ siphonifera$

• Published in: Limnology and Oceanography
• Main Authors: Lombard, F., Erez, J., Michel, E., Labeyrie, L.
• Other Authors: 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), The Hebrew University of Jerusalem (HUJ), 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), ANR-05-BLAN-0275,ForCLIM,Quantification de la variabilité hydrologique naturelle et anthropique de l'Atlantique nord à partir des foraminifères fossiles(2005)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2009
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces; environment; Planktonic foraminifera
• Online Access: https://hal.archives-ouvertes.fr/hal-02913778; https://hal.archives-ouvertes.fr/hal-02913778/document; https://hal.archives-ouvertes.fr/hal-02913778/file/lo.2009.54.1.0210.pdf; https://doi.org/10.4319/lo.2009.54.1.0210

International audience Respiration and photosynthesis of the planktonic foraminifera Globigerinoides ruber, Orbulina universa, andGlobigerinella siphonifera and their symbiotic algae were calculated from measured dissolved oxygen gradientsusing microelectrodes, using different temperatures in dark and light (250 mmol photon m$^{-2} s^{-12}$ conditions. Atone temperature (24°C) the respiration rate increased as a power function of the foraminiferan organic carbonmass with a 0.57 $\pm$ 0.18 exponent. The effect of temperature on respiration was quantified in two ways: bynormalizing the rates to the organic carbon mass and by normalizing the observed rates to a constant temperature(24°C). This latter normalization was also used for photosynthesis. The respiration rates increase as a function oftemperature for all species and can be described either with a $Q_{10}$ = 3.18 ($\pm$0.27) or with an Arrheniustemperature of $T_A$ = 10,293°K ($\pm$768°K). Similar calculations for net photosynthesis yielded a $Q_{10}$ 2.68($\pm$0.36) and a $T_A$ = 8766°K ($\pm$1203°K), and calculations for gross photosynthesis yielded a $Q_{10}$= 2.76 ($\pm$0.29) and a $T_A$ = 9026°K ($\pm$926°K). For the species studied, the photosynthesis : respiration ratio varied from moderate for $G.\ siphonifera$ (0.58) to very high (13) for $O.\ universa$. The high ratios indicate that photosynthesis is muchhigher than the carbon requirements for both foraminifera and symbiont growth. This excess carbon might be the source of organic exudates