Patterns of variability characterizing marine phytoplankton, with examples from Narragansett Bay

Some features of the patterns of variability which characterize phytoplankton species occurrences. community organization. biomass levels, blooms, and associated physicochemical growth regulators are considered. Phytoplankton variability occurs in various patterns: as cycles, trends, fluctuations, unusual events, irregular pulses; at various scales: hourly or less. daily, seasonally. annually, decadal, etc.; even chaotically. and at various frequencies. Variability in winter-spring bloom inception, duration and magnitude is discussed, and 11 types of species-specific patterns of variability are described, with some examples from Narragansett Bay highlighted. It is suggested that the variable response capabilities of planktonic communities act as restructuring mechanisms which allow the community and its foodweb linkages to modify their dynamics to accommodate the changed(-ing) environmental conditions. The distinction between point and threshold events embedded within patterns of plankton variability is discussed. The inadequacy of traditional monitoring approaches and the need to replace such sampling strategies with a combination of observational and process-oriented, in situ rate measurements to quantify the causes and effects of plankton variability are pointed out. (C) 1998 International Council for the Exploration of the Sea.