Details

Autor(en) / Beteiligte

• Conan, Pascal
• Sondergaard, Morten
• Kragh, Theis
• Thingstad, Frede
• Pujo-Pay, Mireille
• le B. Williams, Peter J.
• Markager, Stiig
• Cauwet, Gustave
• Borch, Niels Henrik
• Evans, Dylan
• Riemann, Bo

Titel

Partitioning of Organic Production in Marine Plankton Communities: The Effects of Inorganic Nutrient Ratios and Community Composition on New Dissolved Organic Matter

Ist Teil von

• Limnology and oceanography, 2007-03, Vol.52 (2), p.753-765

Ort / Verlag

Waco, TX: American Society of Limnology and Oceanography

Erscheinungsjahr

2007

Quelle

Wiley Online Library All Journals

Beschreibungen/Notizen

• We investigated the partitioning of carbon, nitrogen, and phosphorus between particulate and dissolved production using 11-m₃ marine mesocosms (bags) in a Norwegian fjord with a salinity of 28.3, a chlorophyll concentration of 0.6 μg L¯1, an even biomass among five algal groups, and nitrogen limitation as the initial conditions. The experiment lasted 21 days in August. Addition of silicate (+Si) resulted in diatom dominance, while a more diverse community was present in treatments with no added Si (-Si). Addition of inorganic nutrients in a N : P gradient from 64 to 4 either conserved the initial N limitation or forced the plankton communities to P limitation. Per added limiting nutrient, the diatom-dominated bags produced more particulate (POC) and dissolved organic carbon (DOC) than the other bags. However, the relative partitioning of net production to POC and DOC did not differ as a function of the plankton communities. Between 22% and 33% of the net production accumulated as new DOC. The higher values were found in the N-limited bags. The production of new dissolved organic nitrogen (DON) was variable over time, and short periods of positive production were followed by removal (negative production). Between 6% and 22% of the assimilated N was[-]Abstract We investigated the partitioning of carbon, nitrogen, and phosphorus between particulate and dissolved production using 11-m₃C; marine mesocosms (bags) in a Norwegian fjord with a salinity of 28.3, a chlorophyll concentration of 0.6 g μL¯1, an even biomass among five algal groups, and nitrogen limitation as the initial conditions. The experiment lasted 21 days in August. Addition of silicate (+Si) resulted in diatom dominance, while a more diverse community was present in treatments with no added Si (-Si). Addition of inorganic nutrients in a N : P gradient from 64 to 4 either conserved the initial N limitation or forced the plankton communities to P limitation. Per added limiting nutrient, the diatom-dominated bags produced more particulate (POC) and dissolved organic carbon (DOC) than the other bags. However, the relative partitioning of net production to POC and DOC did not differ as a function of the plankton communities. Between 22% and 33% of the net production accumulated as new DOC. The higher values were found in the N-limited bags. The production of new dissolved organic nitrogen (DON) was variable over time, and short periods of positive production were followed by removal (negative production). Between 6% and 22% of the assimilated N was recovered asnew DON in the N-replete bags, while the DON production was very low during N limition. The community structure had no effects on nitrogen partitioning. Diatom domainance (+Si bags) resulted in P sequestration to particles and a constant low net production of dissolved organic phosphorus(DOP) across the nutrient grandient. The production of DOP was low in the P-limited(-Si) bags; however, with a surplus of inorganic P, most of the assilimited P(74% to 85%) was recovered as new DOP. The consequence was a huge sequestrtation to composition of new DOM in this experiment.