COVID-19 and surface water quality: Improved lake water quality during the lockdown.

Turbidity dynamics during spring storm events in an urban headwater river system: the Upper Tame, West Midlands, UK.

The processes and biomass that characterize any ecosystem are fundamentally constrained by the total amount of energy that is either fixed within or delivered across its boundaries. Ultimately, ecosystems may be understood and classified by their rates of total and net productivity and by the seasonal patterns of photosynthesis and respiration. Such understanding is well developed for terrestrial and lentic ecosystems but our understanding of ecosystem phenology has lagged well behind for rivers. The proliferation of reliable and inexpensive sensors for monitoring dissolved oxygen and carbon dioxide is underpinning a revolution in our understanding of the ecosystem energetics of rivers. Here, we synthesize our current understanding of the drivers and constraints on river metabolism, and set out a research agenda aimed at characterizing, classifying and modeling the current and future metabolic regimes of flowing waters.

https://aslopubs.onlinelibrary.wiley.com/doi/epdf/10.1002/lno.10726

The metabolic regimes of flowing waters

Linkages between land management activities and water quality in an intensively farmed catchment in southern New Zealand

Modeling sediment impact on the transport of fecal bacteria.

Suspended sediment causes a range of environmental damage, including benthic smothering, irritation of fish gills, and transport of sorbed contaminants Much of the impact, while sediment remains suspended, is related to its light attenuation, which reduces visual range in water and light availability for photosynthesis Thus measurement of the optical attributes of suspended matter in many instances is more relevant than measurement of its mass concentration Nephelometric turbidity, an index of light scattering by suspended particles, has been widely used as a simple, cheap, instrumental surrogate for suspended sediment, that also relates more directly than mass concentration to optical effects of suspended matter However, turbidity is only a relative measure of scattering (versus arbitrary standards) that has no intrinsic environmental relevance until calibrated to a ‘proper’ scientific quantity Visual clarity (measured as Secchi or black disc visibility) is a preferred optical quantity with immediate environmental relevance to aesthetics, contact recreation, and fish habitat Contrary to common perception, visual clarity measurement is not particularly subjective and is more precise than turbidity measurement Black disc visibility is inter-convertible with beam attenuation, a fundamental optical quantity that can be monitored continuously by beam transmissometry Visual clarity or beam attenuation should supplant nephelometric turbidity in many water quality applications, including environmental standards

R. J. Davies-Colley

Papers

Turbidity suspeni)ed sediment, and water clarity: a review