CS29 Phytoplankton & Primary Production
Date: Tuesday, June 11, 2002
Location: Poster Session - VCC
RengeforsK, Limnology, Dept. of Ecology, Lund University, Lund, Sweden, Karin.Rengefors@limnol.lu.se
Gustafsson, S, , Limnology, Dept. of Ecology, Lund Universi, Lund, Sweden, Susanne.Gustafsson@limnol.lu.se
Ståhl-Delbanco, A, , Limnology, Dept. of Ecology, Lund Universi, Lund, Sweden, Annika.Stahl@limnol.lu.se
Littoral and profundal sediments as inocula for phytoplankton blooms
Many phytoplankton species producer resting cysts, which form “seed banks” on lake sediments until they germinate and provide inocula for future populations. Here we addressed the question of whether the littoral or the profundal zone provides the inoculum of planktonic populations. We also investigated the factors that differentiate these habitats. We tested the effect of sediment origin (profundal vs. littoral), temperature, light, time, and bioturbation (artificial) on germination of several algal taxa. Highest germination was found in treatments with high temperature, light, and bioturbation. Absence of light reduced germination in all algae except Ceratium (Dinophyceae). Bioturbation enhanced the germination of all taxa, as did high temperature. There was also a difference between sediments. More diatoms and cyanobacteria germinated from the littoral sediment, while more Ceratium germinated from the profundal sediments. The results showed that Ceratium germinated in the first couple of days, followed by the cyanobacteria, and finally the diatoms. We conclude that with the exception of dinoflagellates, littoral sediments provide inocula for phytoplankton populations, due to higher temperature, more light, and more bioturbation.