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author Tremblay, Pascale
Fine, M
Maguer, Jean-François
Grover, Renaud
Ferrier-Pagès, Christine
author_facet Tremblay, Pascale
Fine, M
Maguer, Jean-François
Grover, Renaud
Ferrier-Pagès, Christine
collection Datos científicos de ciencias marinas y ambientales
contents This study has examined the effect of low seawater pH values (induced by an increased CO2 partial pressure) on the rates of photosynthesis, as well as on the carbon budget and carbon translocation in the scleractinian coral species Stylophora pistillata, using a new model based on 13C labelling of the photosynthetic products. Symbiont photosynthesis contributes to a large part of the carbon acquisition in tropical coral species, and it is thus important to know how environmental changes affect this carbon acquisition and allocation. For this purpose, nubbins of S. pistillata were maintained for six months at two pHTs (8.1 and 7.2, by bubbling seawater with CO2). The lowest pH value was used to tackle how seawater pH impacts the carbon budget of a scleractinian coral. Rates of photosynthesis and respiration of the symbiotic association and of isolated symbionts were assessed at each pH. The fate of 13C photosynthates was then followed in the symbionts and the coral host for 48 h. Nubbins maintained at pHT 7.2 presented a lower areal symbiont concentration, and lower areal rates of gross photosynthesis and carbon incorporation compared to nubbins maintained at pHT 8.1. The total carbon acquisition was thus lower under low pH. However, the total percentage of carbon translocated to the host as well as the amount of carbon translocated per symbiont cell were significantly higher under pHT 7.2 than under pHT 8.1 (70% at pHT 7.2 vs. 60% at pHT 8.1), such that the total amount of photosynthetic carbon received by the coral host was equivalent under both pHs (5.5 to 6.1 µg C/cm**2/h). Although the carbon budget of the host was unchanged, symbionts acquired less carbon for their own needs (0.6 compared to 1.8 µg C/cm**2/h), explaining the overall decrease in symbiont concentration at low pH. In the long term, such decrease in symbiont concentration might severely affect the carbon budget of the symbiotic association.
format Dataset Open Access
id pangaea_https___doi_org_10_1594_PANGAEA_831725
institution PANGAEA
language en
publishDate 2013
publisher PANGAEA
record_format pangaea
spellingShingle Photosynthate translocation increases in response to low seawater pH in a coral-dinoflagellate symbiosis
Tremblay, Pascale
Fine, M
Maguer, Jean-François
Grover, Renaud
Ferrier-Pagès, Christine
Alkalinity, total; Animalia; Aragonite saturation state; Benthic animals; Benthos; Bicarbonate ion; Calcite saturation state; Calculated using CO2SYS; Calculated using seacarb after Nisumaa et al. (2010); Carbon, incorporated; Carbon, inorganic, dissolved; Carbon, lost; Carbon, translocated; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Cell density; Chlorophyll a; Chlorophyll c2; Cnidaria; Coast and continental shelf; Containers and aquaria (20-1000 L or < 1 m**2); Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Gross photosynthesis rate, carbon dioxide; Laboratory experiment; OA-ICC; Ocean acidification; Ocean Acidification International Coordination Centre; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); Percentage; pH, total scale; Potentiometric; Primary production/Photosynthesis; Proteins; Red Sea; Respiration; Respiration rate, carbon dioxide; Salinity; Sample ID; Single species; Species; Stylophora pistillata; Temperate; Temperature, water
This study has examined the effect of low seawater pH values (induced by an increased CO2 partial pressure) on the rates of photosynthesis, as well as on the carbon budget and carbon translocation in the scleractinian coral species Stylophora pistillata, using a new model based on 13C labelling of the photosynthetic products. Symbiont photosynthesis contributes to a large part of the carbon acquisition in tropical coral species, and it is thus important to know how environmental changes affect this carbon acquisition and allocation. For this purpose, nubbins of S. pistillata were maintained for six months at two pHTs (8.1 and 7.2, by bubbling seawater with CO2). The lowest pH value was used to tackle how seawater pH impacts the carbon budget of a scleractinian coral. Rates of photosynthesis and respiration of the symbiotic association and of isolated symbionts were assessed at each pH. The fate of 13C photosynthates was then followed in the symbionts and the coral host for 48 h. Nubbins maintained at pHT 7.2 presented a lower areal symbiont concentration, and lower areal rates of gross photosynthesis and carbon incorporation compared to nubbins maintained at pHT 8.1. The total carbon acquisition was thus lower under low pH. However, the total percentage of carbon translocated to the host as well as the amount of carbon translocated per symbiont cell were significantly higher under pHT 7.2 than under pHT 8.1 (70% at pHT 7.2 vs. 60% at pHT 8.1), such that the total amount of photosynthetic carbon received by the coral host was equivalent under both pHs (5.5 to 6.1 µg C/cm**2/h). Although the carbon budget of the host was unchanged, symbionts acquired less carbon for their own needs (0.6 compared to 1.8 µg C/cm**2/h), explaining the overall decrease in symbiont concentration at low pH. In the long term, such decrease in symbiont concentration might severely affect the carbon budget of the symbiotic association.
title Photosynthate translocation increases in response to low seawater pH in a coral-dinoflagellate symbiosis
topic Alkalinity, total; Animalia; Aragonite saturation state; Benthic animals; Benthos; Bicarbonate ion; Calcite saturation state; Calculated using CO2SYS; Calculated using seacarb after Nisumaa et al. (2010); Carbon, incorporated; Carbon, inorganic, dissolved; Carbon, lost; Carbon, translocated; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Cell density; Chlorophyll a; Chlorophyll c2; Cnidaria; Coast and continental shelf; Containers and aquaria (20-1000 L or < 1 m**2); Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Gross photosynthesis rate, carbon dioxide; Laboratory experiment; OA-ICC; Ocean acidification; Ocean Acidification International Coordination Centre; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); Percentage; pH, total scale; Potentiometric; Primary production/Photosynthesis; Proteins; Red Sea; Respiration; Respiration rate, carbon dioxide; Salinity; Sample ID; Single species; Species; Stylophora pistillata; Temperate; Temperature, water
url https://doi.org/10.1594/PANGAEA.831725