http://www.ncbi.nlm.nih.gov/pubmed/26725204
Water Res. <http://www.ncbi.nlm.nih.gov/pubmed/26725204#> 2015 Dec 15.
pii: S0043-1354(15)30396-1. doi: 10.1016/j.watres.2015.11.070. [Epub
ahead of print]
Geo-engineering experiments in two urban ponds to control eutrophication.
Waajen G
<http://www.ncbi.nlm.nih.gov/pubmed/?term=Waajen%20G%5BAuthor%5D&cauthor=true&cauthor_uid=26725204>^1
, van Oosterhout F
<http://www.ncbi.nlm.nih.gov/pubmed/?term=van%20Oosterhout%20F%5BAuthor%5D&cauthor=true&cauthor_uid=26725204>^2
, Douglas G
<http://www.ncbi.nlm.nih.gov/pubmed/?term=Douglas%20G%5BAuthor%5D&cauthor=true&cauthor_uid=26725204>^3
, Lürling M
<http://www.ncbi.nlm.nih.gov/pubmed/?term=L%C3%BCrling%20M%5BAuthor%5D&cauthor=true&cauthor_uid=26725204>^4
.
Author information<http://www.ncbi.nlm.nih.gov/pubmed/26725204#>
Abstract
Many urban ponds experience detrimental algal blooms as the result of
eutrophication. During a two year field experiment, the efficacy of five
in situ treatments to mitigate eutrophication effects in urban ponds was
studied. The treatments targeted the sediment phosphorus release and
were intended to switch the ponds from a turbid phytoplankton-dominated
state to a clear-water state with a low phytoplankton biomass. Two
eutrophic urban ponds were each divided into six compartments
(300-400 m^2 ; 210-700 m^3 ). In each pond the following treatments were
tested: dredging in combination with biomanipulation (involving fish
biomass control and the introduction of macrophytes) with and without
the addition of the flocculant polyaluminiumchloride, interception and
reduction of sediment phosphorus release with lanthanum-modified
bentonite (Phoslock^® ) in combination with biomanipulation with and
without polyaluminiumchloride; biomanipulation alone; and a control.
Trial results support the hypothesis that the combination of
biomanipulation and measures targeting the sediment phosphorus release
can be effective in reducing the phytoplankton biomass and establishing
and maintaining a clear-water state, provided the external phosphorus
loading is limited. During the experimental period dredging combined
with biomanipulation showed mean chlorophyll-a concentrations of 5.3 and
6.2 μg L^-1 , compared to 268.9 and 52.4 μg L^-1 in the control
compartments. Lanthanum-modified bentonite can be an effective
alternative to dredging and in combination with biomanipulation it
showed mean chlorophyll-a concentrations of 5.9 and 7.6 μg L^-1 .
Biomanipulation alone did not establish a clear-water state or only
during a limited period. As the two experimental sites differed in their
reaction to the treatments, it is important to choose the most promising
treatment depending on site specific characteristics. In recovering the
water quality status of urban ponds, continuing attention is required to
the concurrent reduction of external phosphorus loading and to
maintaining an appropriate fish community.
Copyright © 2015 Elsevier Ltd. All rights reserved.
KEYWORDS:
Biomanipulation; Dredging; Lake restoration; Lanthanum-modified
bentonite; Phoslock(®); Polyaluminiumchloride
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