| Popis: |
Current ecological thinking offers two alternative explanations of measured structure in phytoplankton assemblages. First, interest has been rekindled in the ability of competition theory (Slobodkin 1961; MacArthur 1969; May 1975) to explain patterns of species replacement in phytoplankton (Dugdale 1967; Tilman 1977; Tilman et al. 1981). Competition theory posits that differential rates of use of essential nutrients, relative to rates of their supply, confer advantages in growth rate to different algal species. Changes in algal community structure that result from competition alter the food sources to consumer populations. Changes in the composition of higher trophic levels may ultimately occur. From this perspective, the food web appears structured from the bottom-up (McQueen et al. 1986) in relation to spatial and temporal variability in light intensity, water temperature, and resource availability. |
