Description
Responses of Toxic Algae to Environmental Variables in the Pearl River Estuary and Hong Kong WatersXin Li, Meng Yan, Sam K.F. Yiu, Veronica T.T. Lam, Jiarui GU, Yim-Ling Mak, Tak-Cheung Wai, Priscilla T.Y. Leung, Paul K.S. Lam
The emerging threat of toxic algae to marine ecosystems has attracted worldwide attention. They are capable of producing toxins that can cause fish kills or even cause severe intoxication in humans. In previous study, toxic algae that can produce lipophilic algal toxins were found in Pearl River Estuary (PRE) and Hong Kong (HK) waters, but their toxin producing mechanisms remain unrevealed. Besides, the information on the toxin levels in environmental samples of this area, is largely unknown. The present study aims to investigate the distribution of typical lipophilic algal toxins (LATs) in seawater samples collected from PRE and HK waters and to verify the relationship between LATs in seawater and environmental factors, e.g. temperature and salinity. Five types of lipophilic algal toxins (OA, DTX1, YTX, PTX2, GYMA) were detected in seawater samples from PRE, and the distribution patterns varied among toxins. The toxins were mainly detected in areas with salinity between 20-30‰ and temperature 24-26°C. According to correlation analysis, the various levels of LATs detected in seawater samples and their different distribution patterns should be largely associated with the environmental factors. The effects of temperature and salinity on the growth, toxicity, and toxin production of toxic algae were also investigated under laboratory conditions to compare with field study. Growth curves, Fv/Fm, phaeo-pigments, brine shrimps bioassay, LATs in algal extracts were studied to evaluate the responses of HK species Coolia malayensis to temperature and salinity. A series of correlation analysis were conducted. Coolia malayensis showed positive correlation with temperature in terms of the photosynthesis efficiency, toxicity, and levels of putative LATs. More upcoming results of the laboratory experiments on salinity will be discussed too.
| Period | 25 Feb 2019 → 1 Mar 2019 |
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| Event type | Conference |