AME 80:209-222 (2017)  -  DOI:

Acute toxicity of the cosmopolitan bloom-forming dinoflagellate Akashiwo sanguinea to finfish, shellfish, and zooplankton

Ning Xu1,*,**, Meng Wang1,**, Yingzhong Tang2,3, Qun Zhang1, Shunshan Duan1, Christopher J. Gobler

1Department of Ecology/Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, Jinan University, Guangzhou 510632, PR China
2School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY 11794-5000, USA
3Key Laboratory of Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, Shandong, PR China
*Corresponding author:
**These authors contributed equally to this work

ABSTRACT: The unarmored dinoflagellate Akashiwo sanguinea is a well known cosmopolitan harmful alga; however, the toxic nature of this alga has yet to be examined using multiple clonal isolates. Here we examined the toxicity of 3 clonal cultures of A. sanguinea, including JX13 and JX14, isolated from Daya Bay, South China Sea, and AS2, isolated from Chesapeake Bay, USA, to multiple aquatic animals including species of finfish, shellfish, shrimp, and zooplankton. The whole-cell cultures of A. sanguinea exhibited acute lethal effects on the shrimp Litopenaeus vannamei, the bivalve Meretrix meretrix, and 2 species of fish (Mugil cephalus and Mugilidae sp.) with 72 h mortalities ranging from 20 to 100%. The sonicated and filtrated cultures were lethal to brine shrimp Artemia salina, while the filtrates of whole-cell cultures were not, suggesting that the toxins are intracellular. Boiling and freezing led to significant reductions in toxicity. A. sanguinea toxicity differed among the Chinese strains, and the hemolytic activity of 1 Chinese strain was 3‑fold greater than that of the US strain. Cultures in exponential phase displayed stronger toxicity, and the greatest toxicity of A. sanguinea was observed at 20°C and a salinity of 35, conditions optimal for growth of the alga. Toxicity was enhanced by increased nutrient supply, suggesting that this species could both directly (via increased growth) and indirectly (e.g. via enhanced toxin production) become more toxic in response to eutrophication. Collectively, our findings suggest that the ability to produce and release toxin(s) may promote A. sanguinea blooms by suppressing predators and competitors.

KEY WORDS: Akashiwo sanguinea · Toxicity · Hemolytic activity · Algal toxin · Aquatic animal · Harmful algal bloom

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Cite this article as: Xu N, Wang M, Tang Y, Zhang Q, Duan S, Gobler CJ (2017) Acute toxicity of the cosmopolitan bloom-forming dinoflagellate Akashiwo sanguinea to finfish, shellfish, and zooplankton. Aquat Microb Ecol 80:209-222.

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