Characterisation and quantification of phosphorus release from profundal bottom sediments in two dimictic lakes during summer stratification

• Main Authors: Günter SCHLUNGBAUM†, Uwe SELIG
• Format: Article
• Language: English
• Published: PAGEPress Publications 2003-08-01
• Series: Journal of Limnology
• Subjects: phosphorus release, phosphorus fractionation, sediment, redox condition, dimictic lakes
• Online Access: http://www.jlimnol.it/index.php/jlimnol/article/view/302
• ISSN: 1129-5767; 1723-8633

Phosphorus release from the sediment in two dimictic lakes was compared during the summer stratification. Soluble reactive phosphate (SRP) and also NH4 + were released from the anoxic sediment into the water column in Lake Dudinghausen and Lake Tiefer. The sediment released NH4 + and SRP only when oxygen and nitrate/nitrite were absent. Besides the SRP concentration in the hypolimnion, P-binding in the upper sediment changed during summer stratification in both lakes. In Lake Dudinghausen a decrease in the redox-sensitive bound P was observed in the upper sediment. Only in this lake does the classic anoxic P-release by reduction of the FeOOH-phosphate complex play a dominant role. In both lakes, however, the contents of organically bound P increased in the upper 0.5 cm layer during the summer stratification. P-release was calculated using four different methods. The calculated P-release during summer stratification varied between 15 and 207 mg P m-2 y-1 in Lake Dudinghausen and between 22 and 55 mg P m-2 y-1 in Lake Tiefer.