Carbon-13 labelling shows no effect of ocean acidification on carbon transfer in Mediterranean plankton communities. (15th February 2017)

• Record Type: Journal Article
• Authors: Maugendre, L.; Gattuso, J.-P.; de Kluijver, A.; Soetaert, K.; van Oevelen, D.; Middelburg, J.J.; Gazeau, F.
• Is Part Of: Estuarine, coastal and shelf science. Volume 186:Part A(2017)
• Page Start: 100
• Page End: 111
• Publication Date: 2017-02-15
• Subjects: Ocean acidification -- Plankton communities -- Carbon transfer -- 13C and biomarkers -- Mesocosm experiments -- Mediterranean Sea; Estuarine oceanography -- Periodicals; Coasts -- Periodicals; Estuarine biology -- Periodicals; Seashore biology -- Periodicals; Coasts; Estuarine biology; Estuarine oceanography; Seashore biology; Periodicals; 551.461805
• DOI: 10.1016/j.ecss.2015.12.018
• Languages: English
• ISSNs: 0272-7714

Abstract

Abstract: Despite an increasing number of experiments, no consensus has emerged on the effect of ocean acidification on plankton communities and carbon flow. During two experiments, performed in the Bay of Calvi (France, Corsica; summer 2012) and the Bay of Villefranche (France; winter 2013), nine off-shore mesocosms (∼50 m 3 ) were deployed among which three served as controls and six were enriched with CO2 to reach partial pressure of CO2 ( p CO2 ) levels from 450 to 1350 μatm and 350–1250 μatm in the Bay of Calvi and the Bay of Villefranche, respectively. In each mesocosm, inorganic 13 C was added in order to follow carbon transfer from inorganic via bulk particulate organic carbon and phytoplankton to bacteria by means of biomarkers as well as to zooplankton and settling particles. Despite very low plankton biomasses, labelled carbon was clearly transferred through plankton communities. Incorporation rates in the various plankton compartments suggested a slow-growing community based on regenerated production in the Bay of Calvi while in the Bay of Villefranche, fast-growing species were clearly dominating community production at the start with a shift toward slow-growing species during the experiment due to nutrient limitation. Both bulk and group-specific productions rates did not respond to increasing p CO2 levels. These experiments were the first conducted in the Mediterranean Sea under low nutrient concentrations and phytoplankton biomasses and suggest that ocean acidification may not significantly impact plankton carbon flows in low nutrient low chlorophyll (LNLC) areas. Highlights: Mesocosm experiments performed in two Mediterranean sites during two seasons. Inorganic 13 C was added to follow carbon transfer in plankton communities using biomarkers. Summer community production dominated by slow-growing species is representative of stratified nutrient limited conditions. Winter community evolved from a dominance of fast-growing species to slow-growing species, due to nutrient limitation. No detectable effect of ocean acidification on production and carbon transfer during both experiments.