Effects of reduced salt concentrations on plant communities in the River Werra (Germany)

Abstract

a b s t r a c tThe reduction and equalization of the salt concentrations in the River Werra have resulted in a gradual recovery of the aquatic flora. Spatial high-resolution macrophyte mappings document the spread of the aquatic vascular plants in the middle and lower River Werra. Simultaneously, the plankton blooms have declined. Changes in the composition of the algal communities including diatoms also indicated lower salinity. In addition to the salinity, high nutrient concentrations, waste water discharges and structural degradation are important stressors in the River Werra as shown by e.g. low species richness of vascular plants and the common occurrence of pollution tolerant diatoms. From the existing data it is clear that an encompassing improvement of the ecological conditions in the River Werra can only be achieved by further restoration measures considering all stressors.

Spatial and temporal relationships among watershed mining, water quality, and freshwater mussel status in an eastern USA river

“…Evans et al (2014) demonstrated temporal decay of geologic influence on individual mine discharges, a finding that influenced our approach here. Bäthe and Coring (2011) and Coring and Bäthe (2011) reported declining mining-origin salinity over a 17-year period in Germany's River Table 4 Dissolved trace metals and other trace elements in the Powell River, 2000-2011, as concentrations and relative to CCC (estimated at 100 mg/L hardness); with statistically significant results of linear model testing for spatial (vs. river km) and temporal (vs. time) effects on the elements. (1-3.59) 1.4 (0.8-3.0) ns ns a pos = positive; neg = negative; ns = not significant (p b 0.05).…”

Biological effects of anthropogenic salt-load on the aquatic Fauna: A synthesis of 17 years of biological survey on the rivers Werra and Weser

“…For example at the Gerstungen monitoring site Nitrogen concentrations varied between 1.35 and 20.7 mg/l, the total phosphorus concentrations were 0.12-0.85 mg/l in the time period from 2005 to 2007 (Dietrich and Schumann 2006;Thüringer Landesanstalt für Umwelt und Geologie 2007;Bäthe 2009). The River Werra exhibits a phytal biomass production that is many times greater than in other rivers of similar size (DVWK 1998;Bäthe 2009;Coring and Bäthe this volume). The autotrophic biomass production has increasingly affected water quality in the rivers Werra and Weser with so-called secondary pollution.…”

Regulations are needed to protect freshwater ecosystems from salinization

“…The lack of monitoring and management standards is problematic because even if the sources of salinization were to be eliminated immediately, salts will remain in freshwater environments for years or decades [9,17,18]. Moreover, enacting regulations to protect these systems might present significant challenges, because many activities causing freshwater salinization are associated with significant sources of economic and social wellbeing [19].…”