Impact of CO2 enrichment on organic matter dynamics during nutrient induced coastal phytoplankton blooms

DOI

A mesocosm experiment was conducted to investigate the impact of rising fCO2 on the build-up and decline of organic matter during coastal phytoplankton blooms. Five mesocosms (~38 m³ each) were deployed in the Baltic Sea during spring (2009) and enriched with CO2 to yield a gradient of 355-862 µatm. 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 fCO2, higher dPOC:dPON 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 fCO2. We conclude that increasing fCO2 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.

Supplement to: Engel, Anja; Piontek, Judith; Grossart, Hans-Peter; Riebesell, Ulf; Schulz, Kai Georg; Sperling, Martin (2014): Impact of CO2 enrichment on organic matter dynamics during nutrient induced coastal phytoplankton blooms. Journal of Plankton Research, 36(3), 641-657

Identifier
DOI https://doi.org/10.1594/PANGAEA.861365
Related Identifier IsSupplementTo https://doi.org/10.1093/plankt/fbt125
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.861365
Provenance
Creator Engel, Anja ORCID logo; Piontek, Judith ORCID logo; Grossart, Hans-Peter ORCID logo; Riebesell, Ulf (ORCID: 0000-0002-9442-452X); Schulz, Kai Georg ORCID logo; Sperling, Martin
Publisher PANGAEA
Contributor GEOMAR - Helmholtz Centre for Ocean Research Kiel
Publication Year 2014
Rights Creative Commons Attribution 3.0 Unported; https://creativecommons.org/licenses/by/3.0/
OpenAccess true
Representation
Resource Type Supplementary Publication Series of Datasets; Collection
Format application/zip
Size 2 datasets
Discipline Earth System Research
Spatial Coverage (10.030 LON, 54.530 LAT)
Temporal Coverage Begin 2009-05-20T00:00:00Z
Temporal Coverage End 2009-07-05T23:59:00Z