Factors controlling phosphorus release from sediments in coastal archipelago areas. Issue 1 (15th July 2016)

• Record Type: Journal Article
• Authors: Puttonen, Irma; Kohonen, Tuula; Mattila, Johanna
• Is Part Of: Marine pollution bulletin. Volume 108:Issue 1/2(2016:Jul.)
• Page Start: 77
• Page End: 86
• Publication Date: 2016-07-15
• Subjects: Baltic Sea -- Internal loading -- Sediment -- Phosphorus fractions -- Coastal zone -- Hypoxia; Marine pollution -- Periodicals; Marine Biology -- Periodicals; Water Pollution -- Periodicals; Mer -- Pollution -- Périodiques; Publications périodiques; Pollution des mers; Lutte antipollution; Electronic journals; 363.7394
• DOI: 10.1016/j.marpolbul.2016.04.059
• Languages: English
• ISSNs: 0025-326X

Abstract

Abstract: In coastal archipelago areas of the northern Baltic Sea, significantly higher phosphate concentrations (6.0 ± 4.5 μmol/l, mean ± SD) were measured in water samples close to the sediment surface compared with those from 1 m above the seafloor (1.6 ± 2.0 μmol/l). The results indicated notable phosphate release from sediments under the bottom water oxygen concentrations of up to 250 μmol/l, especially in areas that had experienced recent temporal fluctuation between oxic and hypoxic/anoxic conditions. No single factor alone was found to control the elevated PO4 -P concentrations in the near-bottom water. In addition to the oxygen in the water, the contents of potentially mobile phosphorus fractions, grain-size, the organic content at the sediment surface, and the water depth were all important factors controlling the internal loading of phosphorus. The complexity of this process needs to be accounted for in assessments of the internal loading of phosphorus and in potential mitigation plans. Highlights: High bottom water phosphate concentrations were measured in the Archipelago Sea. Phosphorus release from sediments hinders recovery from eutrophication. Bottom water monitoring underestimates the extent of hypoxia. Coastal sediments act as sources of phosphorus also when oxygen is present in the near-bottom water.