Abstract

Background: In lakes that have become eutrophic due to sewage discharges or nutrient runoff from land,problems such as algal blooms and oxygen deficiency often persist even when nutrient supplies have beenreduced. One reason is that phosphorus stored in the sediments can exchange with the water. There areindications that the high abundance of phytoplankton, turbid water and lack of submerged vegetation seen inmany eutrophic lakes may represent a semi-stable state. For that reason, a shift back to more natural clear-waterconditions could be difficult to achieve.In some cases, though, temporary mitigation of eutrophication-related problems has been accomplished throughbiomanipulation: stocks of zooplanktivorous fish have been reduced by intensive fishing, leading to increasedpopulations of phytoplankton-feeding zooplankton. Moreover, reduction of benthivorous fish may result in lowerphosphorus fluxes from the sediments. An alternative to reducing the dominance of planktivores and benthivoresby fishing is to stock lakes with piscivorous fish. These two approaches have often been used in combination.The implementation of the EU Water Framework Directive has recently led to more stringent demands formeasures against eutrophication, and a systematic review could clarify whether biomanipulation is efficient as ameasure of that kind.Methods: The review will examine primary field studies of how large-scale biomanipulation has affected waterquality and community structure in eutrophic lakes or reservoirs in temperate regions. Such studies can be basedon comparison between conditions before and after manipulation, on comparison between treated and nontreatedwater bodies, or both. Relevant outcomes include Secchi depth, concentrations of oxygen, nutrients,suspended solids and chlorophyll, abundance and composition of phytoplankton, zooplankton and fish, andcoverage of submerged macrophytes.

Published in

Environmental Evidence
2013, Volume: 2, number: 9
Publisher: BioMed Central

SLU Authors

• Gårdmark, Anna

  • Department of Aquatic Resources (SLU Aqua), Swedish University of Agricultural Sciences
    

Associated SLU-program

SLUsystematic


Sustainable Development Goals

SDG6 Ensure availability and sustainable management of water and sanitation for all
SDG14 Conserve and sustainably use the oceans, seas and marine resources for sustainable development


UKÄ Subject classification

Ecology


Publication identifier

DOI: https://doi.org/10.1186/2047-2382-2-9

Permanent link to this page (URI)

https://res.slu.se/id/publ/53480