Dissolved phosphorus in the Baltic Sea — Occurrence and relevance

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• 作者：Monika Nausch^a ; ^{monika.nausch@io-warnemuende.de} ; Gü ; nther Nausch^b ; ^{guenther.nausch@io-warnemuende.de}
• 关键词：Baltic Sea ; Dissolved organic phosphorus ; Bioavailable phosphorus ; Dissolved inorganic phosphorus ; Spatial distribution
• 刊名：Journal of Marine Systems
• 出版年：2011
• 出版时间：July 2011
• 年：2011
• 卷：87
• 期：1
• 页码：37-46
• 全文大小：879 K

文摘

The spatial variability of dissolved organic phosphorus (DOP) concentrations throughout the whole Baltic Sea was investigated during two cruises in summer 2008 and in late winter/early spring 2009. In addition, bioavailable phosphorus was detected in the central Baltic and in the Gulfs of Bothnia and Finland during the summer cruise.

Highest summer DOP concentrations of 0.32 ± 0.05 μM have been estimated in the Baltic Proper, followed by the Gulf of Finland to be having a mean concentration of 0.25 ± 0.01 μM. DOP decreased down to 0.12 μM in the Bothnian Bay. Similar low concentrations were found in the Skagerrak. The same spatial DOP pattern but at a lower concentration level like in summer 2008 was estimated in the central and northern regions during the cruise in late winter/early spring 2009. The bioavailable and refractory DOP fractions (B-DOP and R-DOP, respectively) were determined in time course experiments excluding C- and N-limitation. In all basins, the R-DOP constituted a higher proportion of DOP compared to B-DOP. A gradient has been observed from the northernmost station of the Bothnian Bay to the southern Gotland Basin. In the Bothnian Bay, B-DOP exhibited the lowest amounts of only 0.01 μM comprising 8 % of DOP, highest concentrations occurred in the Gotland Basin constituting a proportion of 25–29 % . In the Gulf of Finland, B-DOP comprised a proportion up to 46 % of DOP at lower concentrations compared to the Gotland Basin. Thus the Bothnian Bay was depleted in total bioavailable phosphorus (DIP + B-DOP) opposite to the southern Baltic Proper where the sum of B-DOP + DIP was 40 times higher.