Regulation of growth and toxicity of a mixotrophic microbe: implications for understanding range expansion in Prymnesium parvum

Autor: Richard M. Zamor, Anne C. Easton, James D. Easton, Brenda Allison, Jessica E. Beyer, K. David Hambright
Rok vydání: 2014
Předmět:
Zdroj: Freshwater Science. 33:745-754
ISSN: 2161-9565
2161-9549
Popis: The rapid range expansion of the toxigenic marine haptophytic alga Prymnesium parvum in inland aquatic systems across the southern USA and beyond has prompted great interest in the ecology and evolution- ary biology of this invasive bloom-forming species. Researchers have speculated that increased toxicity and heterotrophy in suboptimal environments allow blooms to develop in these new inland habitats that seem to represent extremes relative to P. parvum's perceived optimal niche. We used a laboratory-based study to eluci- date the roles of salinity and nutrient availabilities in P. parvum growth and toxicity under environmental con- ditions representative of hypereutrophic reservoirs of the southwestern USA in which P. parvum blooms are now common. We found evidence that nutrient conditions favoring toxigenesis in P. parvum are suboptimal for growth and bloom formation, whereas conditions conducive to high growth rates are less favorable for toxigen- esis. In contrast, both growth and toxicity scaled positively with salinity. Taken in the context of the documented biogeography of P. parvum and that toxigenesis in P. parvum probably evolved in support of heterotrophic nutrient acquisition, our results suggest that P. parvum's apparent range expansion into and across the USA is driven by increasing availabilities of salty and nutrient-rich systems, rather than by its toxigenic abilities.
Databáze: OpenAIRE
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