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Phytoplankton. unicellular & autotrophic species composition changes with season; some species may exhibit seasonal polymorphism important factors controlling community composition: nutrient availability herbivory competition. Phytoplankton Communities. "paradox of the plankton“
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Phytoplankton • unicellular & autotrophic • species composition changes with season; some species may exhibit seasonal polymorphism • important factors controlling community composition: • nutrient availability • herbivory • competition
Phytoplankton Communities • "paradox of the plankton“ • we expect competitive exclusion • we observe 1-2 dominates & several rare forms coexisting • Explanation • the environment is dynamic and heterogeneous • changing predation pressure
factors regulating growth • light & temperature • buoyancy regulation: increase surface area/volume, mucus, gas vacuole, fat accumulation • nutrient availability
Seasonal Patterns & Succession in Temperate Regions • biomass decreases in winter • biomass increases in spring; max. biomass in coincidence with spring mixing • decrease biomass in mid-summer due to high light intensity