Prymnesium parvum: An emerging threat to inland waters

Abstract

Exxon Valdez. Cuyahoga River. Sandoz and the Rhine River. The names trigger memories of human activities that devastated aquatic ecosystems. The magnitude of such disasters prompted many countries to develop regulatory frameworks to manage risks of chemical contaminants to the environment and human health. For example, pesticides are thoroughly tested for adverse ecological effects. When unacceptable risks are identified, a variety of management efforts may be employed to minimize damage, including adjusting the amount or timing of pesticide application to riparian habitat to reduce the pesticide’s contact with adjacent aquatic systems. In contrast to chemical contaminants, however, standard management approaches are poorly developed for the aquatic toxins produced by algae during harmful algal blooms (HABs), such as the infamous ‘‘red tide.’’ Algal blooms result from a period of rapid growth of algae in response to a variety of environmental factors, and HABs produce toxins that negatively impact other organisms, including other aquatic life and even humans. The global increase in frequency and magnitude of HABs over the past few decades has resulted in damaging effects that range frommassive fish kills to public health threats such as ciguatera poisoning. Although the majority of HAB research has occurred in marine systems, on species such as Pfiesteria sp., Gambierdiscus toxicus, and Karenia brevis, HABs are increasing in inland waters. Unfortunately, the environmental conditions that cause HABs are complex and often species-specific, making it difficult— if not impossible—to develop a universal approach for managing HABs.