Impact of CO2 enrichment on organic matter dynamics during nutrient induced coastal phytoplankton blooms
- A mesocosm experiment was conducted to investigate the impact of rising fCO(2) on the build-up and decline of organic matter during coastal phytoplankton blooms. Five mesocosms (similar to 38 mA(3) each) were deployed in the Baltic Sea during spring (2009) and enriched with CO2 to yield a gradient of 355-862 A mu atm. Mesocosms were nutrient fertilized initially to induce phytoplankton bloom development. Changes in particulate and dissolved organic matter concentrations, including dissolved high-molecular weight (> 1 kDa) combined carbohydrates, dissolved free and combined amino acids as well as transparent exopolymer particles (TEP), were monitored over 21 days together with bacterial abundance, and hydrolytic extracellular enzyme activities. Overall, organic matter followed well-known bloom dynamics in all CO2 treatments alike. At high fCO(2,) higher Delta POC:Delta PON during bloom rise, and higher TEP concentrations during bloom peak, suggested preferential accumulation of carbon-rich components. TEP concentration at bloom peakA mesocosm experiment was conducted to investigate the impact of rising fCO(2) on the build-up and decline of organic matter during coastal phytoplankton blooms. Five mesocosms (similar to 38 mA(3) each) were deployed in the Baltic Sea during spring (2009) and enriched with CO2 to yield a gradient of 355-862 A mu atm. Mesocosms were nutrient fertilized initially to induce phytoplankton bloom development. Changes in particulate and dissolved organic matter concentrations, including dissolved high-molecular weight (> 1 kDa) combined carbohydrates, dissolved free and combined amino acids as well as transparent exopolymer particles (TEP), were monitored over 21 days together with bacterial abundance, and hydrolytic extracellular enzyme activities. Overall, organic matter followed well-known bloom dynamics in all CO2 treatments alike. At high fCO(2,) higher Delta POC:Delta PON during bloom rise, and higher TEP concentrations during bloom peak, suggested preferential accumulation of carbon-rich components. TEP concentration at bloom peak was significantly related to subsequent sedimentation of particulate organic matter. Bacterial abundance increased during the bloom and was highest at high fCO(2). We conclude that increasing fCO(2) supports production and exudation of carbon-rich components, enhancing particle aggregation and settling, but also providing substrate and attachment sites for bacteria. More labile organic carbon and higher bacterial abundance can increase rates of oxygen consumption and may intensify the already high risk of oxygen depletion in coastal seas in the future.…
Verfasserangaben: | Anja Engel, Judith Piontek, Hans-Peter GrossartORCiDGND, Ulf Riebesell, Kai Georg SchulzORCiD, Martin Sperling |
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DOI: | https://doi.org/10.1093/plankt/fbt125 |
ISSN: | 0142-7873 |
ISSN: | 1464-3774 |
Titel des übergeordneten Werks (Englisch): | Journal of plankton research |
Verlag: | Oxford Univ. Press |
Verlagsort: | Oxford |
Publikationstyp: | Wissenschaftlicher Artikel |
Sprache: | Englisch |
Jahr der Erstveröffentlichung: | 2014 |
Erscheinungsjahr: | 2014 |
Datum der Freischaltung: | 27.03.2017 |
Freies Schlagwort / Tag: | TEP; mesocosm; ocean acidification; organic matter; phytoplankton |
Band: | 36 |
Ausgabe: | 3 |
Seitenanzahl: | 17 |
Erste Seite: | 641 |
Letzte Seite: | 657 |
Fördernde Institution: | Helmholtz Association [HZ-NG-102]; BMBF project SOPRAN [03F0611C]; BMBF project BIOACID [03F0608E]; Helmholtz Graduate School for Polar-and Marine Sciences (POLMAR) |
Organisationseinheiten: | Mathematisch-Naturwissenschaftliche Fakultät / Institut für Biochemie und Biologie |
Peer Review: | Referiert |