科研之友
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摘要
Larvae of Chironomidae are distributed world-wide and are very abundant in eutrophic water bodies affected by cyanobacterial blooms. However, there is little information on the effect of cyanobacteria and their metabolites on these aquatic organisms. Our studies revealed that benthic species of Chironomus inhabiting a hypertrophic lake where blooms of microcystin (MC) and/or anatoxin-a (ANTX)-producing filamentous Planktothrix agardhii, Dolichospermum spp. and Cuspidothrix issatschenkoi occur, fed on these cyanobacteria and accumulated cyanotoxins. Up to 3.2 mu g MCs g(-1) F.W. and up to 185 mu g ANTX g(-1) F. W. were detected. Of the four MC variants detected in the cyanobacterial biomass [Asp3, Dhb7] MC-RR and MC-LR prevailed, whereas in the larvae it was [Asp(3), Dhb(7)] MC-RR and MC-LA. The effect of pure MC-LR and ANTX as well as crude extracts of MC-producing P. agardhii and ANTX-producing D. lemmermannii on lake and riverine larvae of Chironomus spp. was also compared. The assays revealed that pure cyanotoxins (concentrations: 0.83-3.32 mg L-1) were generally less toxic to riverine larvae than cyanobacterial extracts containing approximately 10-times less toxins. The survival of both the lake and riverine Chironomus larvae did not decrease when exposed to environmentally relevant concentrations of cyanotoxins (< 0.20 mg L-1). The larvae were also highly resistant to higher amounts (up to 0.35 mg ANTX L-1 and 0.42 mg MCs L-1) of extracellular toxins. In the natural environment, Chironomus larvae exposed to toxins contained in cyanobacterial prey, dissolved in water and/or bound to bottom sediments may be very important vectors of cyanotoxins to higher levels in aquatic food chains. To the best of our knowledge, this is the first report on the accumulation of ANTX and effects of cyanotoxins on Chironomus larvae.
- 出版日期2014
