44752
2016
2016
eng
6081
6093
13
13
article
Copernicus
Göttingen
1
--
--
--
Effects of ocean acidification on pelagic carbon fluxes in a mesocosm experiment
About a quarter of anthropogenic CO2 emissions are currently taken up by the oceans, decreasing seawater pH. We performed a mesocosm experiment in the Baltic Sea in order to investigate the consequences of increasing CO2 levels on pelagic carbon fluxes. A gradient of different CO2 scenarios, ranging from ambient (similar to 370 mu atm) to high (similar to 1200 mu atm), were set up in mesocosm bags (similar to 55m(3)). We determined standing stocks and temporal changes of total particulate carbon (TPC), dissolved organic carbon (DOC), dissolved inorganic carbon (DIC), and particulate organic carbon (POC) of specific plankton groups. We also measured carbon flux via CO2 exchange with the atmosphere and sedimentation (export), and biological rate measurements of primary production, bacterial production, and total respiration. The experiment lasted for 44 days and was divided into three different phases (I: t0-t16; II: t17-t30; III: t31-t43). Pools of TPC, DOC, and DIC were approximately 420, 7200, and 25 200 mmol Cm-2 at the start of the experiment, and the initial CO2 additions increased the DIC pool by similar to 7% in the highest CO2 treatment. Overall, there was a decrease in TPC and increase of DOC over the course of the experiment. The decrease in TPC was lower, and increase in DOC higher, in treatments with added CO2. During phase I the estimated gross primary production (GPP) was similar to 100 mmol C m(-2) day(-1), from which 75-95% was respired, similar to 1% ended up in the TPC (including export), and 5-25% was added to the DOC pool. During phase II, the respiration loss increased to similar to 100% of GPP at the ambient CO2 concentration, whereas respiration was lower (85-95% of GPP) in the highest CO2 treatment. Bacterial production was similar to 30% lower, on average, at the highest CO2 concentration than in the controls during phases II and III. This resulted in a higher accumulation of DOC and lower reduction in the TPC pool in the elevated CO2 treatments at the end of phase II extending throughout phase III. The "extra" organic carbon at high CO2 remained fixed in an increasing biomass of small-sized plankton and in the DOC pool, and did not transfer into large, sinking aggregates. Our results revealed a clear effect of increasing CO2 on the carbon budget and mineralization, in particular under nutrient limited conditions. Lower carbon loss processes (respiration and bacterial remineralization) at elevated CO2 levels resulted in higher TPC and DOC pools than ambient CO2 concentration. These results highlight the importance of addressing not only net changes in carbon standing stocks but also carbon fluxes and budgets to better disentangle the effects of ocean acidification.
Biogeosciences
10.5194/bg-13-6081-2016
1726-4170
1726-4189
wos2016:2019
WOS:000387456100002
Spilling, K (reprint author), Finnish Environm Inst, Marine Res Ctr, POB 140, Helsinki 00251, Finland.; Spilling, K (reprint author), Univ Helsinki, Tvarminne Zool Stn, JA Palmenin Tie 260, Hango 10900, Finland., kristian.spilling@environment.fi
BMBF [FKZ 03F06550, FKZ 03F0611]; Academy of Finland [259164, 263862]; Walter and Andree de Nottbeck Foundation; SAW project TemBi of the Leibniz Foundation; Darwin project; Royal Netherlands Institute for Sea Research (NIOZ); EU [228224]
importub
2020-03-22T12:48:01+00:00
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Kristian Spilling
Kai G. Schulz
Allanah J. Paul
Tim Boxhammer
Eric Pieter Achterberg
Thomas Hornick
Silke Lischka
Annegret Stuhr
Rafael Bermudez
Jan Czerny
Kate Crawfurd
Corina P. D. Brussaard
Hans-Peter Grossart
Ulf Riebesell
Institut für Biochemie und Biologie
Referiert
Import
41183
2016
2019
eng
13
544
postprint
1
2019-01-22
2019-01-22
--
Effects of ocean acidification on pelagic carbon fluxes in a mesocosm experiment
About a quarter of anthropogenic CO2 emissions are currently taken up by the oceans, decreasing seawater pH. We performed a mesocosm experiment in the Baltic Sea in order to investigate the consequences of increasing CO2 levels on pelagic carbon fluxes. A gradient of different CO2 scenarios, ranging from ambient (similar to 370 mu atm) to high (similar to 1200 mu atm), were set up in mesocosm bags (similar to 55m(3)). We determined standing stocks and temporal changes of total particulate carbon (TPC), dissolved organic carbon (DOC), dissolved inorganic carbon (DIC), and particulate organic carbon (POC) of specific plankton groups. We also measured carbon flux via CO2 exchange with the atmosphere and sedimentation (export), and biological rate measurements of primary production, bacterial production, and total respiration. The experiment lasted for 44 days and was divided into three different phases (I: t0-t16; II: t17-t30; III: t31-t43). Pools of TPC, DOC, and DIC were approximately 420, 7200, and 25 200 mmol Cm-2 at the start of the experiment, and the initial CO2 additions increased the DIC pool by similar to 7% in the highest CO2 treatment. Overall, there was a decrease in TPC and increase of DOC over the course of the experiment. The decrease in TPC was lower, and increase in DOC higher, in treatments with added CO2. During phase I the estimated gross primary production (GPP) was similar to 100 mmol C m(-2) day(-1), from which 75-95% was respired, similar to 1% ended up in the TPC (including export), and 5-25% was added to the DOC pool. During phase II, the respiration loss increased to similar to 100% of GPP at the ambient CO2 concentration, whereas respiration was lower (85-95% of GPP) in the highest CO2 treatment. Bacterial production was similar to 30% lower, on average, at the highest CO2 concentration than in the controls during phases II and III. This resulted in a higher accumulation of DOC and lower reduction in the TPC pool in the elevated CO2 treatments at the end of phase II extending throughout phase III. The "extra" organic carbon at high CO2 remained fixed in an increasing biomass of small-sized plankton and in the DOC pool, and did not transfer into large, sinking aggregates. Our results revealed a clear effect of increasing CO2 on the carbon budget and mineralization, in particular under nutrient limited conditions. Lower carbon loss processes (respiration and bacterial remineralization) at elevated CO2 levels resulted in higher TPC and DOC pools than ambient CO2 concentration. These results highlight the importance of addressing not only net changes in carbon standing stocks but also carbon fluxes and budgets to better disentangle the effects of ocean acidification.
Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
10.25932/publishup-41183
urn:nbn:de:kobv:517-opus4-411835
1866-8372
online registration
Biogeosciences 13 (2016), pp. 6081–6093 DOI 10.3389/fpsyg.2015.00766
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true
CC-BY - Namensnennung 4.0 International
Kristian Spilling
Kai Georg Schulz
Allanah J. Paul
Tim Boxhammer
Eric Pieter Achterberg
Thomas Hornick
Silke Lischka
Annegret Stuhr
Rafael Bermúdez
Jan Czerny
Kate Crawfurd
Corina P. D. Brussaard
Hans-Peter Grossart
Ulf Riebesell
Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
544
eng
uncontrolled
tecdissolved organic nitrogen
eng
uncontrolled
sea plankton community
eng
uncontrolled
high CO2 ocean
eng
uncontrolled
Baltic Sea
eng
uncontrolled
elevated CO2
eng
uncontrolled
marine viruses
eng
uncontrolled
Atlantic-ocean
eng
uncontrolled
Natural-waters
eng
uncontrolled
Flow-cytometry
eng
uncontrolled
technical note
Geowissenschaften
Biowissenschaften; Biologie
open_access
Mathematisch-Naturwissenschaftliche Fakultät
Referiert
Open Access
Copernicus
Universität Potsdam
https://publishup.uni-potsdam.de/files/41183/pmnr544.pdf