Episodic loadings of phosphorus influence growth and composition of benthic algae communities in artificial stream mesocosms

WATER RESEARCH

卷:185

Article

Pearce, Nolan J. T.^1,2  Thomas, Kathryn E.³  Lavoie, Isabelle⁴  Chambers, Patricia A.³  Yates, Adam G.^1,2 

[1] Univ Western Ontario, 1156 Richmond St, London, ON, Canada

[2] Canadian Rivers Inst, 1156 Richmond St, London, ON, Canada

[3] Environm & Climate Change Canada, Canada Ctr Inland Waters, 867 Lakeshore Rd, Burlington, ON, Canada

[4] Inst Natl Rech Sci, Ctr Eau Terre Environm, 490 Rue Couronne, Quebec City, PQ, Canada

关键词: Algae;    Diatoms;    Eutrophication;    Phosphorus;    Loading pattern;   

DOI  :  10.1016/j.watres.2020.116139

来源: Elsevier

【 摘 要 】

Phosphorus (P) is an essential macronutrient for algal communities, but in excess can exacerbate stream eutrophication. However, P loadings to streams vary temporally from continuous to episodic as a result of inputs from point and non-point sources, respectively. P loading pattern can thus alter the temporal availability of P and may influence effects of P enrichment on algal communities. We assessed how P loading pattern influences algal biomass and composition by conducting a 29-day P enrichment experiment in nine artificial streams exposed to either: (1) continuous P enrichment; (2) episodic P enrichment, or; (3) no P enrichment. P enrichment increased algal biomass accrual, but peak biomass did not differ between continuously and episodically enriched treatments. Maximum absolute growth rates were also comparable between P enriched treatments. However, episodic P additions sustained elevated rates of biomass accrual, whereas absolute growth rates in the continuously enriched communities declined towards the end of the experiment. P enrichment resulted in comparable increases in relative abundance of chlorophytes and decreased proportions of bacillariophytes and charophytes in algal communities for continuously and episodically enriched treatments. However, composition of bacillariophyte (diatom) assemblages differed significantly among all P enrichment treatments in accordance with species autecological attributes for P. Our results demonstrate that episodic and continuous P enrichment may augment algal biomass similarly. Yet, P loading pattern regulated the composition of algal communities. Thus, remedial management strategies for the control of nuisance algae production may require focus on the predominant source of P to streams. Finally, species specific responses of diatom assemblages to P enrichment and associated loading patterns suggests this taxonomic group may have potential as diagnostic indicators for identifying the presence of key nutrient sources associated with eutrophication of stream ecosystems. (C) 2020 Elsevier Ltd. All rights reserved.

【 授权许可】

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