Phytoplankton strategies and time scales in a eutrophic reservoir

Abstract

Phytoplankton species groups were studied in a eutrophic reservoir at different time scales (daily, weekly, monthly and yearly) . Four strategic groups along the r-K continuum were defined and their seasonal time courses were followed . Their temporal distribution of relative biomass reflected resource partitioning because each strategic group dominated the phytoplankton community at different times in the year. However, the relationships between strategic groups changed with the time scale involved . At the daily scale an inverse relationship between rand K-groups occurred whereas at supradaily scales such relationships did not hold . Species groups reflected strategic groups . No relationship between population growth and losses was found, suggesting that both were not counterbalanced . In the long term (supraannual) the phytoplankton community changed very much in this reservoir, its ecological memory being small as compared with that of lakes .

Adaptations in phytoplankton life strategies to imposed change in a shallow urban tropical eutrophic reservoir, Garças Reservoir, over 8 years

“…Study of different strategies focusing on r and K models have been discussed and applied for several years already (McArthur & Wilson, 1967;Grime, 1977;Pianka, 1977;Margalef, 1978;Araúzo & Cobelas, 1994;Santos & Calijuri, 1998). Reynolds (1980Reynolds ( , 1984Reynolds ( , 1988Reynolds ( , 1997 applied to the phytoplankton Grime's (1979) three strategies (C, S, and R) model first designed for terrestrial vegetation.…”

Population dynamics: seasonal variation of phytoplankton functional groups in brazilian reservoirs (Billings and Guarapiranga, São Paulo)

“…The application of the concept of phytoplankton functional groups in temperate regions has been used by several authors (Arauzo and Cobelas, 1994;Reynolds, 1997;Huszar et al, 2003;Padisäk et al, 2003). Reynolds et al (2002) proposed a list of functional groups, based on their tolerances and sensitivities and on their occurrence in different environmental conditions.…”

The phytoplankton of some gravel-pit lakes in Spain

“…During summer, however, temperature may adversely affect the cornmunities in the warmer lakes (Table 3); it is known that some phytoplankton algae are prone to infections by fungal parasites, above their optimal growth temperature, which usually results in their rapid disappearance (Masters, 1971;Arauzo et al, 1987a,b;Van Donk, 1989). The survival of a phytoplankton species depends on its capacity to respond to environmental change (Sommer, 1981;Arauzo & Alvarez Cobelas, 1994b). However, it is only occasionally possible to determine the dominant environmental factors in such a process.…”

“…Numerous studies have been performed on the response of phytoplankton communities in lakes and reservoirs across annual cycles (monthly or weekly: Reynolds, 1984;Le Cohu et a]., 1991;Eloranta, 1993;Arauzo & Alvarez Cobelas, 1994a;Barone & Flores, 1994), as well as on shorter or longer scales of observation (hourly, daily, or multiannual: Lund, 1978;Harris & Trimbee, 1986;Reynolds & Bellinger, 1992;Alvarez Cobelas & Arauzo, 1994;Arauzo & Alvarez Cobelas, 1994b;Vrba et a]., 1995). However, it is not common to address such objectives by comparing lentic systems, closely apposed and with a similar origin.…”