Key drivers structuring rotifer communities in ponds: insights into an agricultural landscape.

Understanding the influence of environmental and spatial factors on the structure of aquatic communities remains a major challenge in community ecology. This study aims to identify main drivers of rotifer abundance and diversity in ponds embedded in an intensive agricultural landscape in Northeast Germany. We studied 42 ponds of glacial origin (kettle holes) covering a wide range of environmental parameters.

Long-term behavior of groundwater chemistry in a periodically rewetted fen area covered with macrophytes.

We studied the long-term changes in groundwater composition in the context of peat restoration at a degraded water-table managed peatland site typical for many agriculturally used fen areas in the northern hemisphere. At the study site, peatland rewetting with groundwater control and pumped canal water was carried out in two periods: from 1997 to 2002 and from 2011 to 2013. The site was not managed between 2002 and 2011, which led to an unstable groundwater table that had declined in part.

Screening of prevailing processes that drive surface water quality of running waters in a cultivated wetland region of Germany - a multivariate approach.

The Spreewald wetland is a large, peaty, inland delta wetland in which the water level is managed by weirs in cascade belts across an extensive, partly channelized running water system. To model the quality of the water, 946 surface water samples from 43 sites were analyzed for 29 water quality parameters in two monitoring programs spanning a period of six years. In this study, we pursued a multivariate approach using nonlinear principal component analysis (Isomap) to identify the prevailing processes that control the water quality of the complex surface water system.

Microbial diversity and functional characterization of sediments from reservoirs of different trophic state.

Sediment samples from four reservoirs of different trophic state were compared with regard to chemical gradients in the pore water, composition of microbial communities and extracellular enzyme activities. The trophic state was clearly reflected by steep vertical concentration gradients of ammonium and alkalinity in the pore water. A high concentration of these parameters indicated a high microbial in situ activity in the more eutrophic reservoirs.