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| Titel |
Deposition of nitrogen and phosphorus on the Baltic Sea: seasonal patterns and nitrogen isotope composition |
| VerfasserIn |
C. Rolff, R. Elmgren, M. Voss |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 5, no. 6 ; Nr. 5, no. 6 (2008-12-10), S.1657-1667 |
| Datensatznummer |
250002931
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| Publikation (Nr.) |
 copernicus.org/bg-5-1657-2008.pdf |
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| Zusammenfassung |
| Atmospheric deposition of nitrogen and phosphorus on the central Baltic Sea
(Baltic Proper) was estimated monthly at two coastal stations and two
isolated islands in 2001 and 2002. Yearly nitrogen deposition ranged between
387 and 727 mg N m−2 yr−1 (average 617) and was composed
of ~10% organic N and approximately equal amounts of ammonium and
nitrate. Winter nitrate peaks at the isolated islands possibly indicated
ship emissions. Load weighted δ15N of deposited N was 3.7‰ and
0.35‰ at the coastal stations and the isolated islands respectively. Winter
δ15N was ~3‰ lighter than in summer, reflecting winter
dominance of nitrate. The light isotopic composition of deposited nitrogen
may cause overestimates of nitrogen fixation in basin-wide isotopic
budgeting, whereas relatively heavy deposition of ammonium during summer
instead may cause underestimates of fixation in budgets of the upper mixed
layer. δ15N in atmospherically deposited nitrate and ammonium
was estimated by regression to −7.9 and 13.5‰ respectively. Phosphorus
deposition showed no clear seasonal pattern and was considerably lower at
the isolated islands. Organic P constituted 20–40% of annual P
deposition. P deposition is unlikely to be a major source for cyanobacterial
blooms but may potentially prolong an ongoing bloom. |
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