500 years of trophic-state history of a hypertrophic Dutch dike-breach lake

Autor: André F. Lotter, Holger Cremer, Oliver Heiri, Maarten van Hardenbroek, Emiliya P. Kirilova
Rok vydání: 2009
Předmět:
Zdroj: Journal of Paleolimnology. 43:829-842
ISSN: 1573-0417
0921-2728
Popis: We present a palaeolimnological study encompassing five centuries of trophic-state change of the dike-breach lake De Waay located on the Rhine- Meuse delta (the Netherlands). Diatom-inferred total phosphorus (TP) concentrations indicate hypertrophic epilimnetic conditions ((300 l gl -1 TP) since the formation of the lake in the fifteenth century until the end of the eighteenth century. Cladocera data support the reconstructed trophic state and indicate turbid conditions in lake De Waay during this period. High inferred TP concentrations as well as the amount of Ti in the sediment reflect numerous flooding events. From the nineteenth century onwards reconstructed TP concentrations decreased to 40-150 l gl -1 due to improvements in sewage and dike systems that considerably diminished direct river flooding and seepage-derived nutrients. As a consequence, the increased stability of littoral habitats led to an increased diversity of the Cladocera assemblages. The most significant decrease in TP concentrations to *40 l gl -1 occurred between about 1900 and 1930. This mesotrophic phase was a consequence of the isolation of the lake from catchment drainage and the introduction of a highly elaborate flood control during this period. However, since the mid twentieth century a eutrophication trend is preserved in the record, likely related to increased agricultural activity in the vicinity of the lake. Our results emphasize that land- use and trophic-state history must be taken into account when evaluating the ecological status of lakes for water management and protection actions, espe- cially for lakes in landscapes that are strongly modified by human action.
Databáze: OpenAIRE
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