Meteorological forcing of plankton dynamics in a large and deep continental European lake |
| |
Authors: | D Straile |
| |
Institution: | 1.Limnologisches Institut, Universit?t Konstanz, D-78457 Konstanz, Germany e-mail: dietmar.straile@uni-konstanz.de Fax: +49-7531-883533,DE |
| |
Abstract: | The timing of various plankton successional events in Lake Constance was tightly coupled to a large-scale meteorological phenomenon,
the North Atlantic Oscillation (NAO). A causal chain of meteorological, hydrological, and ecological processes connected the
NAO as well as winter and early spring meteorological conditions to planktonic events in summer leading to a remarkable memory
of climatic effects lasting over almost half a year. The response of Daphnia to meteorological forcing was most probably a direct effect of altered water temperatures on daphnid growth and was not mediated
by changes in phytoplankton concentrations. High spring water temperatures during ”high-NAO years” enabled high population
growth rates, resulting in a high daphnid biomass as early as May. Hence, a critical Daphnia biomass to suppress phytoplankton was reached earlier in high-NAO years yielding an early and longer-lasting clear-water
phase. Finally, an earlier summer decline of Daphnia produced in a negative relationship between Daphnia biomass in July and the NAO. Meteorological forcing of the seasonal plankton dynamics in Lake Constance included simple temporal
shifts of processes and successional events, but also complex changes in the relative importance of different mechanisms.
Since Daphnia plays an important role in plankton succession, a thorough understanding of the regulation of its population dynamics provides
the key for predictions of the response of freshwater planktonic food webs to global climate change.
Received: 15 February 1999 / Accepted: 23 August 1999 |
| |
Keywords: | NAO Daphnia Populations dynamics Seasonal succession Ecological memory |
本文献已被 SpringerLink 等数据库收录! |
|