Epilithic communities in a lake littoral zone: the role of water-column transport and habitat development for dispersal and colonization of meiofauna

Abstract

During the past 30 y, periphyton has been recognized as a key component in the benthos of lake littoral zones. However, the role of meiofauna-sized organisms living in the periphyton and mechanisms regulating and influencing those communities largely have been neglected, and the process of community development and colonization pathways of periphytic meiofauna are unknown in lakes. We studied these processes on littoral hard substrates in an oligotrophic lake. We manipulated the access of meiofauna to artificial hard substrates for a period of 57 d in a field experiment. In one treatment, the direct colonization pathway via active crawling was prohibited by elevating substrates into the water column. Development of the meiofaunal community was compared between elevated and nonelevated (control) treatments. In addition, relationships among the meiofaunal communities on the substrates in the field experiment and those in sediment traps and on natural hard substrates were examined. Periphyton biomass (chlorophyll a, total organic matter) and inorganic matter increased significantly in both experimental treatments throughout the experiment. Meiofauna colonized the substrates quickly and reached maximum densities of 107 ind./cm 2. The initial colonization phase (2-8 d) was characterized by a great variation in meiofaunal community structure; rotifers and crustaceans were the most abundant groups. Communities became less variable during the experiment and resembled natural communities on hard substrates at the end of the experiment. In general, development of meiofaunal abundance and periphyton biomass was rapid and proceeded similarly in both treatments. Our results show that colonization of littoral hard substrates can be driven by water-column transport of meiofauna and point to the importance of this pathway for dispersal and colonization of hard substrates by meiofauna.

Integrating Economic and Ecological Benchmarking for a Sustainable Development of Hydropower

“…The tiles introduced into the newly-prepared and filled control mesocosm represented newly-inundated reservoir littoral. The experimental timeframe for measuring growth of inundated littoral followed previous estimates from colonization experiments, which have shown that a plateau in algal community development was reached after three weeks [26]. Consequently, the experimental period of 5 weeks ensured that we observed the loss of a natural benthic algal community.…”

“…To approximate realistic WLF as the treatment, we applied fluctuations that were previously found to be the most common in terms of frequency and amplitude in alpine reservoirs in the Swiss Alps [5]: a 12 h period of emptying and filling, respectively; with an amplitude of 40 cm corresponding to half the filling level of 80 cm. White square ceramic tiles (10 cm by 10 cm) were used as a standardized substrate because of the unified, easy-to-sample area, homogenous albedo and uniform angle towards the water surface [26]. Five tiles were placed in rows each 10 cm from the water surface (45 tiles × 2 mesocosms).…”

Ecology of Marine Meiofauna

“…Mas essas características gerais, que corroboram a teoria de biogeografia de ilhas, também dependem do grau de maturidade e complexidade das associações dos vizinhos doadores de espécies; se são dominados por oportunistas generalistas ou especialistas (AZOVSKY, 1988). Neste contexto, isolamento em pequenas lagoas ou massas de águas costeiras pode ser de relevância estrutural para as comunidades de meiofauna (PETERS et al, 2007). Em longo prazo, isso pode conduzir à deriva genética das populações (PETERS et al, 2007).…”

“…Neste contexto, isolamento em pequenas lagoas ou massas de águas costeiras pode ser de relevância estrutural para as comunidades de meiofauna (PETERS et al, 2007). Em longo prazo, isso pode conduzir à deriva genética das populações (PETERS et al, 2007).…”

A mesocosm experiment investigating the effects of substratum quality and wave exposure on the survival of fish eggs

“…Another common strategy is to spawn soon after a rise in water level (Gafny et al 1992;Ali and Kadir 1996;Ozen and Noble 2002) because no biofilm has yet developed on freshly inundated substrata. Because periphytic biofilm can develop within 14 days or less (Gafny et al 1992;Peters et al 2007), the window of opportunity in which fishes that spawn in shallow water can benefit from biofilm-free substrata is narrow.…”