Browsing All Posts filed under »flow«

Surface walkers need impure water

March 30, 2019

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  By affecting the way that the surface layer of water is renewed, patterns of subsurface flow have a big influence on many environmental processes, such as evaporation, cooling, aeration and the absorption of atmospheric CO2.  In natural waters, the presence of small amounts of surfactants creates a surface film, about 50 µm thick, that […]

How fire affects stream communities

March 30, 2019

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  By removing riparian vegetation, wildfires can have significant effects on river ecology, especially in headwater systems where fringing plant life helps to regulate stream temperature and provides a source of carbon in the form of leaf litter and woody debris.  To help understand the impacts of fire on streams, and the length of time […]

Keeping track of groundwater

March 30, 2019

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  Groundwater provides almost half of the world’s supply of water for drinking and irrigation.  Intensive groundwater use has led to the depletion and pollution of aquifers, to the extent that about a fifth of all aquifers are now over-exploited.  In an attempt to manage water resources effectively, new systems of water accounting have been […]

Restoring urban streams: a new twist

March 30, 2019

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  Urban stream environments typically display symptoms of degradation – such as increased temperatures, nutrient and chemical pollution, simplified habitat structure and reduced biodiversity – that are collectively referred to as the Urban Stream Syndrome.  Freshwater scientists generally accept that urban stream degradation is driven mainly by hydrological changes associated with stormwater runoff over impervious […]

Getting river history right

March 30, 2019

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  Information on past climate patterns can prove invaluable when assessing the responses of freshwater ecosystems to environmental change, but what are the implications for ecological understanding if beliefs about climate history are incorrect?  This question has been explored by scientists who used the Murray River, Australia’s largest river system, as a case study.  Hydrologically, […]

How rivers befriend seabirds

January 14, 2019

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Where rivers flow into the ocean, the density fronts between fresh and salt water masses help to concentrate zooplankton and larval fish, making them more available to predators.  For example, freshwater discharge from the Columbia River creates a large brackish plume that can stretch for hundreds of kilometres along the North American coast, and nutrient […]

Turbulent times for freshwater plants

January 14, 2019

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Water movement is one of the most important factors affecting the distribution of aquatic plants, and has a beneficial or detrimental impact  depending on the magnitude of flow.  Japanese researchers compared the effects of steady flow and turbulence on three plant species with different types of morphology: western waterweed (Elodea nuttallii) with whorled leaves, curly-leaved […]