Effects of nutrient enrichment on Prymnesium parvum population dynamics and toxicity: results from field experiments, Lake Possum Kingdom, USA

Aquatic Microbial Ecology

Leslie Schwierzke¹  James P. Grover¹  Bryan W. Brooks¹  Daniel L. Roelke¹  Richard Kiesling¹  Fabiola Ureña-Boeck¹  Jason Baker¹  Reagan M. Errera¹  James L. Pinckney¹ 

关键词: Harmful algal bloom;    HAB;    Management;    Mitigation;    Immigration;    Barley straw extract;   

DOI  :  10.3354/ame046125

学科分类：生物科学（综合）

来源: Inter-Research

【 摘 要 】

ABSTRACT: Large fish kills associated with toxic populations of the haptophyte Prymnesium parvum occur worldwide. In the past 5 yr, incidences of P. parvum blooms in inland water bodies of Texas (USA) have increased dramatically, where cell densities in excess of 1 × 10⁷ cells l^–1 are typically observed. We conducted field experiments (Lake Possum Kingdom) during the fall and early spring of 28 d duration using 24 enclosures of 1.57 m³ each. The experiments investigated the effect of nutrient enrichment, immigration of P. parvum and addition of barley straw extract on phytoplankton biomass and assemblage structure, P. parvum population density, zooplankton biomass and assemblage structure, bacteria, and toxicity. Nutrient enrichment stimulated P. parvum population growth beyond bloom proportions (>1 × 10⁷ cells l^–1). However, P. parvum did not dominate the assemblage under these conditions, as it does during natural blooms. Instead, euglenophytes and chlorophytes dominated. Toxicity, estimated using fish (Pimephales promelas) and cladoceran (Daphnia magna) bioassays and which is linked to P. parvum’s allelopathic and mixotrophic effectiveness, was greatly reduced (eliminated in many cases) under conditions of nutrient enrichment. The suppression of toxicity by nutrient addition suggested that targeted and time-limited nutrient manipulations might be used to mitigate the effects of P. parvum blooms. Immigration of P. parvum into natural assemblages and addition of barley straw extract had no significant effect on plankton dynamics.

【 授权许可】

Unknown