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Seasonal changes in Baltic Sea seston stoichiometry: the influence of diazotrophic cyanobacteria

2010; Inter-Research; Volume: 407; Linguagem: Inglês

10.3354/meps08551

1616-1599

Jakob Walve, Ulf Larsson,

Marine Biology and Ecology Research

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 407:13-25 (2010) - DOI: https://doi.org/10.3354/meps08551 Seasonal changes in Baltic Sea seston stoichiometry: the influence of diazotrophic cyanobacteria Jakob Walve*, Ulf Larsson Department of Systems Ecology, Stockholm University, 106 91 Stockholm, Sweden *Email: jakob.walve@ecology.su.se ABSTRACT: We studied nutrient deficiency of Baltic Sea phytoplankton, as indicated by C:N:P ratios in filamentous N2-fixing (diazotrophic) cyanobacteria and size-fractions of seston. Samples were collected during an annual cycle in the NW Baltic proper (1998, Landsort Deep) and in 2 summers in the central Baltic proper (1997 and 1998, Gotland Basin). Generally, seston C:N:P ratios in the top 20 m were close to Redfield values. There was a transient increase in the C:N ratio at the end of the phytoplankton spring bloom (to ~9 mol:mol), concomitant with the depletion of dissolved inorganic N (DIN), but not dissolved inorganic phosphorus (DIP), indicating that phytoplankton became N-limited at the end of the spring bloom. In early summer (May–June), seston C:N:P ratios indicated weak N limitation of the community of small phytoplankton. From June through summer, seston size-fractions <10 µm accumulated mainly C and N, resulting in a September peak in seston C:P and N:P ratios (201 and 23 mol:mol, respectively) in the surface water. This change occurred in parallel with an increase in C:P and N:P ratios of diazotrophic filamentous cyanobacteria to levels indicative of severe P limitation of cyanobacterial growth. This suggests that the cyanobacterial P demand and new N from their N2 fixation caused a weak P deficiency also in non-diazotrophs. However, the small increase in seston N:P, as well as a seston C:N above the Redfield ratio, indicate that N and P are nearly colimiting for non-diazotrophs at the culmination of the cyanobacterial bloom in late summer. KEY WORDS: Seston · Element ratios · Nutrient limitation · Stoichiometry · Baltic Sea · Cyanobacteria · Size fraction Full text in pdf format PreviousNextCite this article as: Walve J, Larsson U (2010) Seasonal changes in Baltic Sea seston stoichiometry: the influence of diazotrophic cyanobacteria. Mar Ecol Prog Ser 407:13-25. https://doi.org/10.3354/meps08551 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 407. Online publication date: May 20, 2010 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2010 Inter-Research.