Aquatic food webs in deep temperate lakes: Key species establish through their autecological versatility.

Microbial planktonic communities are the basis of food webs in aquatic ecosystems since they contribute substantially to primary production and nutrient recycling. Network analyses of DNA metabarcoding data sets emerged as a powerful tool to untangle the complex ecological relationships among the key players in food webs. In this study, we evaluated co-occurrence networks constructed from time-series metabarcoding data sets (12 months, biweekly sampling) of protistan plankton communities in surface layers (epilimnion) and bottom waters (hypolimnion) of two temperate deep lakes, Lake Mondsee (Austria) and Lake Zurich (Switzerland).

Widespread diminishing anthropogenic effects on calcium in freshwaters.

Calcium (Ca) is an essential element for almost all living organisms. Here, we examined global variation and controls of freshwater Ca concentrations, using 440 599 water samples from 43 184 inland water sites in 57 countries. We found that the global median Ca concentration was 4.

A global database of lake surface temperatures collected by in situ and satellite methods from 1985-2009.

Global environmental change has influenced lake surface temperatures, a key driver of ecosystem structure and function. Recent studies have suggested significant warming of water temperatures in individual lakes across many different regions around the world. However, the spatial and temporal coherence associated with the magnitude of these trends remains unclear.

Phytoplankton, pelagic community and nutrients in a deep oligotrophic alpine lake: ratios as sensitive indicators of the use of P-resources (DRP:DOP:PP and TN:TP:SRSi).

The different use of P-resources between two sites in the deep oligotrophic Traunsee was studied by seasonal and vertical patterns of phytoplankton and nutrients from 12/1997 to 10/1998. The P-resources were evaluated from the proportion between the P-fractions, the dissolved reactive P (DRP), dissolved non-reactive P (DOP) and particulate organic P (PP) and from the stoichiometry between nutrients, the total N (TN), the total P (TP) and soluble reactive Si (SRSi). Significant differences between an inshore site impacted by industrial tailings (Ebensee Bay, EB) and an open water reference site (Viechtau, VI) were evident from vertical profiles of both the P-accumulation (%PP of TP) evaluated by DRP:DOP:PP and the distribution of phytoplankton assessed by Si-exhaustion (TN:TP:SRSi), but not from the seasonal patterns of phytoplankton composition, S:V ratios of the algal community or surface layer nutrient dynamics.