Sulfide as a soil phytotoxin-a review.

In wetland soils and underwater sediments of marine, brackish and freshwater systems, the strong phytotoxin sulfide may accumulate as a result of microbial reduction of sulfate during anaerobiosis, its level depending on prevailing edaphic conditions. In this review, we compare an extensive body of literature on phytotoxic effects of this reduced sulfur compound in different ecosystem types, and review the effects of sulfide at multiple ecosystem levels: the ecophysiological functioning of individual plants, plant-microbe associations, and community effects including competition and facilitation interactions. Recent publications on multi-species interactions in the rhizosphere show even more complex mechanisms explaining sulfide resistance.

Multi-level effects of sulphur-iron interactions in freshwater wetlands in The Netherlands.

Although sulphur deposition rates in Europe have considerably decreased over the last decades, sulphate concentrations in freshwater wetlands are still high, as a result of drainage, nitrate pollution, and increased sulphur loads in rivers. High sulphur fluxes may cause sulphide toxicity and eutrophication, and strongly interfere with the biogeochemical cycling of iron and phosphorus. In the present study the ecotoxicological interactions between sulphur, phosphate, iron, and trace metals in freshwater wetlands are reviewed.

Predicting metal uptake by wetland plants under aerobic and anaerobic conditions.

Metal pollution can be a serious threat to ecosystems at a global scale. Although the bioavailability of potentially toxic metals is determined by many biotic and abiotic factors, including pH and redox potential, total metal concentrations in the soil are used widely to assess or predict toxicity. In the present study we tested the effect of desiccation of soils differing in acidification potential and total heavy metal contamination on the growth and metal uptake of three typical, common wetland species: Caltha palustris, Juncus effusus, and Rumex hydrolapathum.

Evidence for the involvement of betaproteobacterial Thiobacilli in the nitrate-dependent oxidation of iron sulfide minerals.

The Thiobacilli are an important group of autotrophic bacteria occurring in nature linking the biogeochemical cycles of sulfur and nitrogen. Betaproteobacterial Thiobacilli are very likely candidates for mediating the process of nitrate-dependent anoxic iron sulfide mineral oxidation in freshwater wetlands. A Thiobacillus denitrificans-like bacterium was present in an enrichment on thiosulfate and nitrate, derived from an iron-sulfide- and nitrate-rich freshwater environment.

Differential responses of the freshwater wetland species Juncus effusus L. and Caltha palustris L. to iron supply in sulfidic environments.

Sulfur pollution can lead to serious problems in freshwater wetlands, including phosphorus eutrophication and sulfide toxicity. We tested the effects of anaerobic iron-rich groundwater discharge in fens, simulated by iron injection, on two characteristic species (Juncus effusus and Caltha palustris) in a sulfidic environment. Biomass production of C.

Detoxifying toxicants: interactions between sulfide and iron toxicity in freshwater wetlands.

In many Dutch freshwater wetlands, concentrations of sulfate in the surface water and groundwater have increased. It is especially in peaty areas that this can lead to problems, including the reduction of sulfate to toxic sulfide. Our aquarium experiments showed that even low sulfide concentrations of 50 micromol/L are toxic to the freshwater macrophyte Nitella flexilis and the freshwater oligochaete Ophidonais serpentina.