Browsing All Posts filed under »water quality«

How the food web affects river restoration

October 8, 2018

0

River restoration commonly  concentrates on improving habitat quality for threatened fish populations.  However, because stream fish are strongly influenced by food availability, competition and predation, a case can be made for also incorporating food web modelling into the restoration process.  A group of environmental scientists developed an ecosystem model and applied it to a river-floodplain […]

A clearer picture of suspended sediment

October 8, 2018

0

Because many pollutants adsorb onto the surfaces of fine sediment particles, sediment transport plays a central role in distributing contaminants throughout river systems.  However, current models of sediment and pollutant transfer are complex and complicated by the fact that key processes such as adsorption, erosion and deposition aren’t easily  observed.  Belgian scientists have responded to […]

Urban trees protect local water bodies

September 25, 2017

Comments Off on Urban trees protect local water bodies

As a result of nutrient transfer from the land, urban waterways often have high concentrations of nitrogen and phosphorus, which can lead to algal blooms, low water clarity, oxygen depletion and species loss. Nutrient enrichment problems also extend to urban groundwater, where water quality can be compromised.  Although nutrients moving from land to groundwater water […]

A disturbing mix

June 19, 2017

Comments Off on A disturbing mix

The common carp (Cyprinus carpio) has been introduced to many locations around the world and is highly invasive.  Its habit of foraging by digging in the bottom substrate significantly alters freshwater systems by uprooting plants, resuspending sediment, and increasing turbidity and the release of nutrients.  However, the extent to which aquatic nutrient flows are affected […]

How river transport affects dissolved organic matter

December 13, 2016

Comments Off on How river transport affects dissolved organic matter

In most rivers, the downstream transport of dissolved organic matter (DOM) makes large amounts of energy available to aquatic ecosystems. The River Continuum Concept (RCC) of Vannote et al. (1980) provided a useful framework for studying the influence of organic material from headwater streams on the structure and function of downstream ecosystems. The RCC hypothesized […]

Polluting antidepressants are more potent in high-pH systems

December 13, 2016

1

The increased use of antidepressants in society means that the pollution of freshwater systems by SSRIs (serotonin selective reuptake inhibitors) is becoming more prevalent. SSRIs persist in the environment, bioaccumulate in animals, influence a wide range of physiological and behavioural processes and are toxic at high concentrations. Although it’s been established that SSRI toxicity is […]

Top predator boosts species richness – but not in alien ecosystems

December 13, 2016

Comments Off on Top predator boosts species richness – but not in alien ecosystems

The spiny water flea Bythotrephes longimanus is a large cladoceran, a specialised carnivore and a top predator. Invasions of North American lakes by Bythotrephes have been linked to dramatic changes in food web structure and reductions in species diversity, which seems to contradict the expectation that top predators increase the evenness and diversity of aquatic […]