Grazer-induced defense in Phaeocystis globosa (Prymnesiophyceae): Influence of different nutrient conditions

• We examined the combined effects of grazer infochemicals and nutrient status on colony development ofPhaeocystis globosa cultures grown under nitrogen and phosphorus (NP)–sufficient, P-deficient, and N-deficientconditions exposed to high and low Acartia spp. density filtrates. Changes in colony development relative tocontrols receiving no grazer signals were estimated. P. globosa colony development responded to grazerinfochemicals regardless of nutrient status, although the expression of the response varied between nutrients.Significant colony suppression (in terms of percent of cells allocated to colonies) occurred in both NP-sufficientand P-deficient experiments, with the response being dependent on the density of grazers for NP-sufficient cells.The percent of cells in colonial form in N-deficient P. globosa decreased in response to low grazer density filtratesbut increased in response to high grazer density filtrates. These opposite results for the N-deficient experiment arerelated to a high mortality of Acartia in the high grazer density filtrate treatment, which may affect theinfochemicals released from such grazers

Ämnesord

NATURVETENSKAP  -- Biologi -- Ekologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Ecology (hsv//eng)

Nyckelord

Akvatisk ekologi

Aquatic Ecology

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