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EFFECTS OF NUTRIENT ENRICHMENT ON NATURAL POPULATIONS OF THE BROWN TIDE PHYTOPLANKTON AUREOCOCCUS ANOPHAGEFFERENS (CHRYSOPHYCEAE) 1
Author(s) -
Keller Aimee A.,
Rice Robin L.
Publication year - 1989
Publication title -
journal of phycology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.85
H-Index - 127
eISSN - 1529-8817
pISSN - 0022-3646
DOI - 10.1111/j.0022-3646.1989.00636.x
Subject(s) - mesocosm , biology , bay , nutrient , phytoplankton , diatom , algal bloom , algae , bloom , abundance (ecology) , zoology , botany , ecology , oceanography , geology
The brown tide picoalga Aureococcus anophagefferens Hargraves et Sieburth was present in approximately equal numbers in 12 large scale (13,000 L) mesocosms at the start of a nutrient addition experiment in June 1985. Increases in abundance in untreated systems mimicked the pattern of bloom development in Narragansett Bay, Rhode Island, the seawater source for the experiment. Aureococcus increased to maximal values of 2.6 × 10 9 cells. L −1 and persisted at high numbers (10 8 cells·L −1 ) for 7–8 weeks. In nutrient addition tanks, the picoalgae bloomed briefly (1–3 weeks) but rapidly declined to the usual level (∼10 7 cells·L −1 ) for eukaryotic algae in Narragansett Bay. The decline in picoalgae abundance was followed by an increase in total diatoms in all nutrient treated tanks. Mean picoalgae abundance in the mesocosms and the bay was significantly (P < 0.05) and inversely correlated (r = –0.93) with mean concentration of dissolved inorganic nitrogen. The persistence of the brown tide species in control mesocosms and Narragansett Bay appears related to its ability to grow at very low concentrations of dissolved inorganic nitrogen, levels previously shown to limit diatom growth.