Primary production during nutrient-induced blooms at elevated CO2 concentrations

By J. Egge, T. Thingstad, A. Larsen, A. Engel, J. Wohlers, R. Bellerby, U. Riebesell. 2009

108 citations recorded by the source corpus.

Abstract. A CO2 enrichment experiment (PeECE III) was carried out in 9 mesocosms in which the seawater carbonate system was manipulated to achieve three different levels of pCO2. At the onset of the experimental period, nutrients were added to all mesocosms in order to initiate phytoplankton blooms. Primary production rates were measured by in-vitro incubations based on 14C-incorporation and oxygen production/consumption. Size fractionated particulate primary production was also determined by 14C incubation and is discussed in relation to phytoplankton composition. Primary production rates increased in response to nutrient addition and a net autotrophic phase with 14C-fixation rates up to 4 times higher than initial was observed midway through the 24 days experiment before net community production (NCP) returned to near-zero and 14C-fixation rates dropped below initial values. No clear heterotrophic phase was observed during the experiment. Based on the 14C-measurements we found higher cumulative primary production at higher pCO2 towards the end of the experiment. CO2 related differences were also found in size fractionated primary production. The most noticeable responses to CO2 treatments with respect to primary production rates occurred in the second half of the experiment when phytoplankton growth had become nutrient limited, and the phytoplankton community changed from diatom to flagellate dominance. This opens for two alternative hypotheses that the effects are either associated with mineral nutrient limited growth, and/or with a change in phytoplankton species composition. The lack of a clear net heterotrophic phase in the last part of the experiment supports the idea that a substantial part of production in the upper layer was not degraded locally, but either accumulated or exported vertically.

Subfields: Global and Planetary Change, Oceanography

View Paper: https://www.semanticscholar.org/paper/7a3a8e08f07b36aeb7aa297410b992a62cf0e870

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Citations in the corpus

Mechanisms of Microbial Carbon Sequestration in the Ocean - Future Research Directions (2014, background): “For example, the contradictory responses of phytoplankton TEP production to OA (Engel et al., 2004a; Schulz et al., 2008; Egge et al., 2009) indicates that additional factors, such as total alkalinity (Mari, 2008; Passow, 2012) or nutrient stoichiometry (Corzo et al., 2000; Staats et al., 2000;…”
Dissolved organic matter (DOM) release by phytoplankton in the contemporary and future ocean (2014, unknown): “However, analysis of the TEP concentrations from the same experiment by Egge et al. (2009) showed no difference in TEP production between the different pCO2 treatments.”
Mesocosm Experiments as a Tool for Ecological Climate-Change Research (2013, unknown): “…plants Eco S M L T CO2_fert Seas. plants Eco S M L Edwards et al. (2006) T Nutrients Seas. plants Eco S M L M CO2_pH Microinverts Eco L M M Egge et al. (2009) M Diversity Seas. plants Comm M S M Ehlers et al. (2008) M Warming Seas. plants Comm M S M T Warming Inverts Comm S S M Eisenhauer…”
Mesocosm CO 2 perturbation studies: from organism to community level (2008, background): “– cumulative14C primary production (Egge et al., 2007)”
Coupling of heterotrophic bacteria to phytoplankton bloom development at different pCO 2 levels: a mesocosm study (2008, methodology): “An overview of all studies performed and their major results are given by Riebesell et al. (2008). 2 Materials and methods”
Effects of increased atmospheric CO 2 on small and intermediate sized osmotrophs during a nutrient induced phytoplankton bloom (2007, background): “…al. Title Page Abstract Introduction Conclusions References Tables Figures ◭ ◮ ◭ ◮ Back Close Full Screen / Esc Printer-friendly Version Interactive Discussion EGU The only group with higher biomass (this study) and production (Egge et al., 2007 2 ) at 1×CO2 than at 2× and 3×CO2 was Synechococcus.”
Microzooplankton grazing and phytoplankton growth in marine mesocosms with increased CO 2 levels (2008, background): “We compared the pigment data to microscopic counts (data not shown), as well as to plankton analyses from the mesocosms (Egge et al., 2007; Schulz et al., 2007), and found it to be consistent.”