科研之友
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摘要
Cyanobacteria Harmful Algal Blooms (or CyanoHABs) represent one of the most conspicuous waterborne microbial hazards in aquatic environments mostly due to the production of harmful secondary metabolites, known as cyanotoxins. In this paper we assessed cyanobacteria blooms in a shallow, Mediterranean, highly eutrophic lake (Lake Pamvotis, NW Greece) in relation to critical environmental parameters using a multi-approach methodology. Microscopic (identification of cyanobacteria), immunological (ELISA), and molecular techniques (PCR) combined with physico-chemical parameters were used to monitor cyanobacteria blooms and the associated cyanotoxin production for 14 months on a monthly basis. Cyanobacteria were the main phytoplankton component, representing more than 75% of the total phytoplankton abundance throughout the study period; dominant species belonged to Microcystis, Anabaena and Aphanizomenon. Microcystins (MCs) were detected throughout the year in all sampling stations in concentrations ranging from 0.16 to 27 mu g L-1, indicating that toxic Anabaena and Microcystis strains are persistent and dominant. Saxitoxins (STXs) found in two samples (concentrations 1.3 and 2.1 mu g L-1) in the warm period, are reported here for the first time. The total MC concentration was positively correlated with temperature, nitrate nitrogen, ammonia nitrogen, and soluble reactive phosphorus, suggesting that high-temperatures and eutrophic conditions promote the growth of MC-producing genotypes. We also investigated a Micro cystis strain specific growth rate, which reached its maximum at 30 degrees C. Our data, combined with long-term data comparison of key limnological features, spanning a 25-year period, suggest that water temperature and nutrient loads may act synergistically to promote cyanobacterial dominance and persistence in Lake Pamvotis.
- 出版日期2014-10
