T he annual cycle of greening and degreening of plants is probably the most obvious sign of life on Earth. It is caused by the biosynthesis of ∼10 tons of chlorophylls (Chls) in spring and their degradation in fall. The biochemistry of Chl breakdown to linear tetrapyrroles has been worked out in land plants (1), but little was known about the process in marine organisms, which contribute a comp...

were prepared from two enteric bacterial species, Escherichia coli and Enterococcus faecalis. Counts of CFU of NSB and RSB and total numbers of RSB and FLB were monitored over time, both in the presence and in the absence of natural microbiota. In the presence of natural microbiota, no differences were observed between CFU counts of NSB and RSB, but RSB total numbers were 1 to 4 orders of magni...

Introduction Mercury has been well known as an environmental pollutant for several decades. As early as the 1950’s it was established that emissions of mercury to the environment could have serious effects on human health. These early studies demonstrated that fish and other wildlife from various ecosystems commonly attain mercury levels of toxicological concern when directly affected by mercur...

Ecological monitoring and assessment is fundamental for effective management of ecosystems. As an introduction to this Special Issue, this editorial provides an overview of “Ecological Monitoring, Assessment, and Management in Freshwater Systems”. This issue contains a review article on monitoring surface waters, and research papers on data management, biological assessment of aquatic ecosystem...

Climate change modulates the effects of solar UV radiation on biogeochemical cycles in terrestrial and aquatic ecosystems, particularly for carbon cycling, resulting in UV-mediated positive or negative feedbacks on climate. Possible positive feedbacks discussed in this assessment include: (i) enhanced UVinduced mineralisation of above ground litter due to aridification; (ii) enhanced UV-induced...

Geologic processes strongly influence water and sediment quality in aquatic ecosystems but rarely are geologic principles incorporated into routine biomonitoring studies. We test if elevated concentrations of metals in water and sediment are restricted to streams downstream of mines or areas that may discharge mine wastes. We surveyed 198 catchments classified as "historically mined" or "unmine...