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| Titel |
Metabolic balance of the plankton community in Arctic coastal water in relation to increased pCO2 levels |
| VerfasserIn |
Tsuneo Tanaka, Samir Alliouane, Jean-Pierre Gattuso |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250048449
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| Zusammenfassung |
| The effect of ocean acidification on the balance between gross community production (GCP)
and community respiration (CR) (i.e. net community production, NCP) of Arctic plankton
communities was investigated as part of the 2010 EPOCA experiment at Ny-Ålesund,
Spitsbergen. Coastal surface water was enclosed in 9 mesocosms and subject to 8 pCO2
levels (2 replicated controls and 7 enhanced pCO2 treatments), and the response of the
plankton community was monitored for one month. Waters from the mesocosms
were incubated in BOD bottles in quadruplicate and incubated for 24 h for NCP
and for 48 h for CR at in situ temperature. Dissolved oxygen (DO) concentration
was determined with automated Winkler titration method using a potentiometric
end-point detection. Changing rate of DO (NCP, CR) was determined by linear
regression of DO against time. GCP was calculated as the difference between NCP and
CR.
The enclosed waters were characterized by low concentrations of nutrients and chlorophyll
until inorganic nutrients (N, P, Si) were added on Day 13. After the nutrient addition,
chlorophyll increased in all the mesocosms. NCP, CR, and GCP were in a range of -4.4 to 5.0,
-5.6 to 0, and -0.5 to 6.9 μmolO2 l-1 d-1, respectively, before the nutrient addition. NCP
slightly increased after the nutrient addition (range: -2.9 to 7.9 μmolO2 l-1 d-1), while CR
changed little (range: -4.5 to -0.7 μmolO2 l-1 d-1). Hence, GCP tended to increase (range:
0 to 11.2 μmolO2 l-1 d-1) after the nutrient addition. However, these parameters did not
show a consistent response to the increase of pCO2 based on the data comparison at a given
day of the measurement. When changing rates of DO were integrated for two periods (before
and after the nutrient addition), NCP and GCP were unaffected by enhanced pCO2 before
the nutrient addition, while both significantly decreased with increase of pCO2
after the nutrient addition. No significant change of CR was detected. These data
suggest that ocean acidification may reduce NCP and GCP in Arctic coastal waters. |
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