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Blooming of Microcystis aeruginosa in the reservoir of the reclaimed land and discharge of microcystins to Isahaya Bay (Japan)
Purpose In the reservoir created in the reclaimed land in Isahaya Bay, Japan, Microcystis aeruginosa , which produces microcystins (MCs), bloomed every year, and the water with high levels of MCs in the reservoir has been often drained to Isahaya Bay to adjust the water level. The principal aims of...
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Published in: | Environmental science and pollution research international 2012-09, Vol.19 (8), p.3257-3267 |
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Main Authors: | , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | Purpose
In the reservoir created in the reclaimed land in Isahaya Bay, Japan,
Microcystis aeruginosa
, which produces microcystins (MCs), bloomed every year, and the water with high levels of MCs in the reservoir has been often drained to Isahaya Bay to adjust the water level. The principal aims of this study are to clarify the water conditions suitable for blooming of
M. aeruginosa
in the reservoir, to follow the amount of distribution of MCs inside and outside the reservoir, and to discuss how blooming of
M. aeruginosa
is controlled in the reservoir and how MCs produced by
Microcystis
spread or accumulate in the aquatic environment.
Method
We monitored the water quality (temperature, salinity, dissolved inorganic nitrogen (DIN), and dissolved inorganic phosphorus) in the reservoir with seasonal blooming of microalgae including phytoplankton and
M. aeruginosa
using the concentrations of chlorophyll
α
and MCs, respectively, and collected the surface sediment in the reservoir and the bay to determine the MC content using the ELISA method.
Result
M. aeruginosa
bloomed in extremely low DIN conditions of the water in warm seasons (spring and late summer to autumn). The year-mean standing stock of MCs was approximately 34.5 kg in the water and 8.4 kg in the surface sediment in the reservoir. Approximately 64.5 kg of MCs was discharged with the effluent to the bay in a year.
Conclusion
Since a large amount of MCs always suspends in the water in the reservoir and it has been discharged to the bay, suspension-feeding animals are exposed most seriously to the high levels of MCs occurring in these areas. We need to pay attention to the danger of widespread dispersal of MCs and biological concentration of MCs by fish and clam inside and outside the reservoir. |
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ISSN: | 0944-1344 1614-7499 |
DOI: | 10.1007/s11356-012-0835-y |