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Low pH preempts bloom development of a toxic haptophyte

Author:
Prosser, Krista N., Valenti, Theodore W., Jr., Hayden, Natanya J., Neisch, Michael T., Hewitt, Natalie C., Umphres, George D., Gable, George M., Grover, James P., Roelke, Daniel L., Brooks, Bryan W.
Source:
Harmful algae 2012 v.20 pp. 156-164
ISSN:
1568-9883
Subject:
Prymnesium, anthropogenic activities, biomass, climate change, lakes, pH, phytoplankton, population density, toxicity, zooplankton, United States
Abstract:
Harmful blooms of Prymnesium parvum in inland waters continue to expand, in part, due to anthropogenic influences and climate change. Several studies have identified the importance of elevated pH on increasing ambient toxicity associated with P. parvum in inland, coastal and marine systems. Influence of pH on P. parvum bloom dynamics, however, is less understood. Here, we evaluate whether pH influences P. parvum bloom development and ambient toxicity. We manipulated pH levels (7, 7.5, 8.5) of in situ experimental enclosures during 21d pre-bloom and bloom development experiments in Lake Granbury, TX, USA, an impoundment consistently impacted by P. parvum blooms. Neutral pH levels preempted P. parvum bloom development. Population densities never reached bloom proportions and no ambient toxicity to fish or cladocerans resulted. However, higher pH (8.5) allowed bloom formation to occur and resulted in ambient toxicity. During both experiments, reducing pH to 7 and 7.5 did not adversely affect phytoplankton or zooplankton biomass. Observations from this study provide initial evidence that pH appears to be a major factor governing P. parvum bloom formation and associated ambient toxicity in inland waters. This research further highlights the importance of developing an understanding of interactions among harmful blooms of P. parvum and pH responses in inland waters to anthropogenic activities and climatic changes.
Agid:
1126930