Journal article
Effect of elevated CO2 on organic matter pools and fluxes in asummer Baltic Sea plankton community
Biogeosciences, Vol.12, pp.6181-6203
2015
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Source: InCites
Abstract
<p>Ocean acidification is expected to influence plankton community structure and biogeochemical element cycles. To date, the response of plankton communities to elevated CO2 has been studied primarily during nutrient-stimulated blooms. In this CO2 manipulation study, we used large-volume (~ 55 m3) pelagic in situ mesocosms to enclose a natural summer, post-spring-bloom plankton assemblage in the Baltic Sea to investigate the response of organic matter pools to ocean acidification. The carbonate system in the six mesocosms was manipulated to yield average <em>f</em>CO2 ranging between 365 and ~ 1230 μatm with no adjustment of naturally available nutrient concentrations. Plankton community development and key biogeochemical element pools were subsequently followed in this nitrogen-limited ecosystem over a period of 7 weeks. We observed higher sustained chlorophyll <em>a</em> and particulate matter concentrations (~ 25 % higher) and lower inorganic phosphate concentrations in the water column in the highest <em>f</em>CO2 treatment (1231 μatm) during the final 2 weeks of the study period (Phase III), when there was low net change in particulate and dissolved matter pools. Size-fractionated phytoplankton pigment analyses indicated that these differences were driven by picophytoplankton (< 2 μm) and were already established early in the experiment during an initial warm and more productive period with overall elevated chlorophyll <em>a</em> and particulate matter concentrations. However, the influence of picophytoplankton on bulk organic matter pools was masked by high biomass of larger plankton until Phase III, when the contribution of the small size fraction (< 2 μm) increased to up to 90 % of chlorophyll <em>a</em>. In this phase, a CO2-driven increase in water column particulate carbon did not lead to enhanced sinking material flux but was instead reflected in increased dissolved organic carbon concentrations. Hence ocean acidification may induce changes in organic matter partitioning in the upper water column during the low-nitrogen summer period in the Baltic Sea.</p>
Details
- Title
- Effect of elevated CO2 on organic matter pools and fluxes in asummer Baltic Sea plankton community
- Creators
- A J Paul - GEOMAR Helmholtz Centre for Ocean ResearchL T Bach - GEOMAR Helmholtz Centre for Ocean ResearchKai G Schulz - Southern Cross UniversityT Boxhammer - GEOMAR Helmholtz Centre for Ocean ResearchJ Czerny - GEOMAR Helmholtz Centre for Ocean ResearchE P Achterberg - GEOMAR Helmholtz Centre for Ocean ResearchD Hellemann - GEOMAR Helmholtz Centre for Ocean ResearchY Trense - University of LübeckM Nausch - Leibniz Institute for Baltic Sea ResearchM Sswat - GEOMAR Helmholtz Centre for Ocean ResearchU Riebesell - GEOMAR Helmholtz Centre for Ocean Research
- Publication Details
- Biogeosciences, Vol.12, pp.6181-6203
- Identifiers
- 3607; 991012821056602368
- Academic Unit
- School of Environment, Science and Engineering; Faculty of Science and Engineering; Science
- Resource Type
- Journal article