Limnophase versus potamophase: how hydrological connectivity affects the zooplankton community in an oxbow lake (Vistula River, Poland) (original) (raw)
Related papers
Water, 2019
The zooplankton community structure and diversity were analysed against the gradient of floodplain lakes connectivity and water level under different flood-pulse dynamics in the Vistula River. The lakes differed in terms of hydrology, among others in the degree/type of their connection with the river (permanent, temporary and no connection). The study was conducted during the growing seasons in the years 2006-2013 and involved the lower Vistula River and three floodplain lakes: isolated, transitional and connected. Water samples were collected biweekly from April to September. Zooplankton was the most diverse and abundant in the transitional lake (the highest Shannon α-diversity index H' and Pielou's evenness index J'). The gentle washing of the lakes might have stimulated the development of zooplankton in accordance with the Intermediate Disturbance Hypothesis. The diversity and density of zooplankton were higher in the connected lake compared to the isolated one. We confirmed the hypothesis that zooplankton should be more abundant and diverse in floodplain lakes connected with the river (or transitional) than in isolated ones. Zooplankton analyses indicated that hydrological conditions (flood-pulse regime) contributed most substantially to zooplankton diversity and density in the floodplain lakes of the lower Vistula valley.
Floodplain lakes are important elements of landscapes with large rivers. In this study we compared planktonic communities of two oxbow lakes of the Vistula River. We investigated how the inflow of the river’s water affected their physicochemical and biological conditions including water temperature, water transparency, oxygen concentration, and macrophyte coverage of the bottom. These parameters in turn affected plankton community. The average phytoplankton abundance in the isolated lake was over two times lower than in the lake connected to the river. Cryptophyta dominated in the phytoplankton community in the isolated lake and diatoms – in the lake supplied with water from the river. The average abundance of zooplankton in the isolated lake was more than twice as high as that in the lake which was connected to the river. The first lake proved to be more attractive for zooplankton due to its stable living conditions (similar to the conditions observed in ponds), higher temperature in summer, and nutrient availability due to the high abundance of small phytoplankton. The results of our research indicate that species composition, plankton abundance, and Chl-a concentration depended on whether there was water exchange between the particular lake and the Vistula River. Hydrological conditions shaped the relationships between the components of the biota.
Limnological Papers v. 4,, 2009
" The research on zooplankton was being conducted during the vegetation season from April to October 2006, in three different types of oxbow lakes of the Lower Vistula – (isolated site 1, site 2 connected with the Vistula River by an inlet, and site 3 artificially isolated by a concrete embankment), as well as in the river - site 4 at the 736th km of its course. Zooplankton of the oxbow lakes was qualitatively and quantitatively much richer as compared to potamoplankton of the Vistula River - a higher number of species (sites 1, 2 and 3 - 44 species and site 4 – 25 species), the count (site 1-3 – on average 426 specimens/dm3 and site 4 – 94 specimens/dm3), as well as biomass (site 1-3 – on average 0.966 mg m.m./dm3 and site 4 – 0.066 mg m.m./dm3). More stable hydrological conditions prevailing in oxbow lakes are favourable to the development of zooplankton. When investigating the subsequent oxbow lakes, the following was found: the higher number of species (34 and 29) and higher average frequencies, as well as biomass at the sites isolated from the rapid exchange of water or sites completely isolated - site 2 (721 specimens/dm3, 1.220 mg m.m./dm3) and site 1 (443 specimens/dm3, 1.566 mg m.m./dm3). Based on the results presented in the publication, a conclusion can be drawn that the more the oxbow lake is isolated from the riverbed (more stable hydrological conditions) the richer the zooplankton gets. Although the delicate washing of the oxbow lake with waters of the Vistula River can enrich it with Rotifera (site 2). "
The structure and spatial heterogeneity of zooplankton in small lake river Wel (Poland)
The aim of the study was to determine changes in potamoplankton structure caused by lakes in the fluvial system of the small River Wel. The river flows through 10 lakes. The study was conducted in 2007 and 2008. The selection of sites enabled the assessment of the impact exerted by hydrological conditions of the river on zooplankton, as well as the determination of the effect of lakes situated within the river course on the analysed assemblage of organisms. In total 95 species were determined with an average abundance 1026 ind. 10 dm–3. Rotifers dominated qualitatively and quantitatively and among crustaceans – Copepods. Lakes seem to be the main source of zooplankton in the fluvial system of the Wel River. The lakes disturb the river continuum, but their impact on the structure of zooplankton is short-lived. Due to the presence of flow-through lakes along the river, species richness of zooplankton in the Wel River is similar to that in large rivers.
The dynamics and role of limnetic zooplankton in Loosdrecht lakes (The Netherlands)
Hydrobiologia, 1992
The paper summarizes the results of a ten-year (1981-1991) zooplankton research on the Lake Loosdrecht, a highly eutrophic lake. The main cause of the lake's eutrophication and deteriorating water quality was supply up to mid 1984 of water from the River Vecht. This supply was replaced by dephosphorized water from the Amsterdam-Rhine Canal in 1984. The effects of this and other restoration measures on the lake's ecosystem were studied. Despite a reduction in the external P-load from ca. 1.0 g P me2 y-l to ca. 0.35 g rnp2 y-l now, the filamentous prokaryotes, including cyanobacteria and Prochlorothrix, continue to dominate the phytoplankton. Among the crustacean plankton Bosmina spp, Chydorus sp. and three species of cyclopoid copepods and their nauplii are quite common. Though there was no major change in the composition of abundant species, Daphnia cucullata, which is the only daphnid in these lakes, became virtually extinct since 1989. Among about 20 genera and 40 species of rotifers the important ones are: Anuraeopsis j?ssa, Keratella cochlearis, Filinia longiseta and PoZyarthra. The rotifers usually peak in midsummer following the crustacean peak in spring. The mean annual densities of crustaceans decreased during 1988-1991. Whereas seston (< 150 pm) mean mass in the lake increased since 1983 by 20-60%, zooplankton (> 150 pm) mass decreased by 15-35x. The grazing by crustacean community, which was attributable mainly to Bosmina, had mean rates between 10 and 25% d-'. Between 42 and 47% of the food ingested was assimilated. In spring and early summer when both rotifers and crustaceans have their maximal densities the clearance rates of the rotifers were much higher. Based on C/P ratios, the zooplankton (> 150 pm) mass contained 2.5 times more phosphorus than seston (< 150 pm) mass so that the zooplankton comprised 12.5 y0 of the total-P in total particulate matter in the open water, compared with only 4.5% of the total particulate C. The mean excretion rates of P by zooplankton varied narrowly between 1.5 and 1.8 pg P l-' d-', which equalled between 14 and 28% d-' of the P needed for phytoplankton production. The lack of response to restoration measures cannot be ascribed to one single factor. Apparently, the external P-loading is still not low enough and internal P-loading, though low, may be still high enough to sustain high seston levels. Intensive predation by bream is perhaps more important than food quality (high concentrations of filamentous cyanobacteria) in depressing the development of large-bodied zooplankton grazers, e.g. Daphnia. This may also contribute to resistance of the lake's ecosystem to respond to rehabilitation measures.
Impact of water level fluctuation in the shaping of zooplankton assemblage in a shallow lake
Croatian Journal of Fisheries
Shallow lakes are strongly affected by global climate changes reflected in significant parameters of ecosystem deterioration, i.e. biodiversity decrease, and water turbidity. Zooplankton research in Škrčev kut oxbow lake (Krapina River watershed, NW Croatia, Europe) was conducted during the summer of 2012 and 2013 with the aim to determine the effect of inter-annual, short-timescale changes of hydrological regime on environmental conditions, macrophytes, zooplankton and fish assemblage within an oxbow lake in the temperate region. Within one-year period the water level increased by 2 meters. This caused a significant reduction of floating-leaved macrophytes (i.e. Nuphar lutea), while turbidity, ortho-phosphate and chlorophyll a concentrations increased. These altered ecological conditions were reflected in the shift from floating-leaved macrophytes at the lower water level to phytoplankton-dominated lake at the higher water level. Zooplankton underwent significant alteration in asse...