Potent allelopathy and non-PSTs, non-spirolides toxicity of the dinoflagellate Alexandrium leei to phytoplankton, finfish and zooplankton observed from laboratory bioassays
Document Type
Article
Publication Date
8-1-2021
Abstract
The dinoflagellate genus Alexandrium has been well known for causing paralytic shellfish poisoning (PSP) worldwide. Several non-PSP toxin-producing species, however, have shown to exhibit fish-killing toxicity. Here, we report the allelopathic activity of Alexandrium leei from Malaysia to other algal species, and its toxicity to finfish and zooplankton, via laboratory bioassays. Thirteen microalgal species that co-cultured with Al. leei revealed large variability in the allelopathic effects of Al. leei on the test algae, with the growth inhibition rates ranging from 0 to 100%. The negative allelopathic effects of Al. leei on microalgae included loss of flagella and thus the motility, damages of chain structure, deformation in cell morphology, and eventually cell lysis. The finfish experienced 100% mortality within 24 h exposed to the live culture (2000-6710 cells center dot mL-1), while the rotifer and brine shrimp exhibited 96-100% and 90-100% mortalities within 48 h when exposed to 500-6000 cells center dot mL-1 of Al. leei. The mortality of the test animals depended on the Al. leei cell density exposed, leading to a linear relationship between mortality and cell density for the finfish, and a logarithmic relationship for the two zooplankters. When exposed to the treatments using Al. leei whole live culture, cell-free culture medium, extract of algal cells in the f/2-Si medium, extract of methanol, and the re-suspended freeze-and-thaw algal cells, the test organisms (Ak. sanguinea and rotifers) all died at the cell density of 8100 cells center dot mL-1 within 24 h. Toxin analyses by HILIC-ESI-TOF/MS and LC-ESI-MS/MS demonstrated that Al. leei did not produce PSP-toxins and 13-desmethyl
Keywords
Harmful algal blooms (HABs), Ichthyotoxicity, Allelochemicals, Marine medaka, Brine shrimp, Rotifer
Divisions
ocean
Funders
National Natural Science Foundation of China (NSFC)[41776125],National Natural Science Foundation of China (NSFC)[41976134],Science & Technology Basic Resources Investigation Program of China[2018FY100200]
Publication Title
Science of The Total Environment
Volume
780
Publisher
Elsevier
Publisher Location
RADARWEG 29, 1043 NX AMSTERDAM, NETHERLANDS