Browsing All Posts filed under »water flow«

Springs – neglected ecosystems

March 26, 2022

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Springs can be defined as places on the Earth’s surface that are influenced by the exposure, and often the flow, of groundwater.  They support biodiverse ecosystems and have socioeconomic value as sources of water for drinking, agriculture, industry and recreation, , but they are often  highly vulnerable to human disturbance, such as groundwater depletion,  pollution, […]

How riparian trees  manage their water balance

March 26, 2022

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In riverine ecosystems, riparian vegetation supports aquatic and terrestrial biodiversity, stabilises river banks and modulates water flow between the stream and the floodplain.  However, stream channelisation has led to the widespread disconnection and loss of floodplain forests.  Successful riparian restoration schemes are those that create the conditions for plants to become established and survive fluctuating […]

Aquatic plants regulate downstream nutrients

March 26, 2022

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Just as the processes of respiration and nutrient uptake by living cells affect the chemistry of the human body, the activities of all life-forms in a body of water influence its metabolism and carbon dynamics.  In freshwater streams, aquatic plants and algae are important agents of metabolism because they act as the stream’s internal source […]

The net effect: caddis flies and streambed flow

March 26, 2022

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The beds of streams are dynamic interfaces where water, nutrients and living organisms move between surface and sub-surface environments, and streambed permeability has a significant influence on processes such as nitrogen cycling and organic matter decomposition.  Although the physics of streambed exchange are well understood, interactions between physical and biological processes have received relatively little […]

To be continued: the legacy of the River Continuum Concept

December 14, 2021

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A recent review examined the historical importance of the River Continuum Concept (RCC), which was introduced by Robin Vannote and co-workers in 1980.  This concept revolutionised stream ecology research by prompting a shift from a descriptive to a predictive approach and encouraging multidisciplinary collaboration between biologists, geomorphologists and geochemists.  The RCC became a key framework […]

Water flow through the beds of streams

December 14, 2021

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The permeability of saturated sediments at the bottom of streams, where surface water and groundwater can mix, has a strong influence on the exchange of mass and energy across the sediment-water interface.  Streambed permeability depends mainly on sediment properties such as pore networks and the size and sorting of particles, and can vary greatly, even […]

Aquatic ecosystem services: rethinking streamside planting

March 13, 2021

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Spatial patterns in the loss of natural land cover to agriculture have a significant effect on ecosystem services, including those provided by landscape features that interrupt runoff flows to rivers.  For example, the number, size and location of woodland patches all have an impact on ecosystem services such as sediment trapping, pollutant retention and the […]

Restoring overheated rivers

March 13, 2021

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One of the features of the so-called “urban stream syndrome” is thermal pollution caused by warm  environments in built-up areas, which can increase stream temperatures above the tolerance threshold for aquatic organisms.  The good news is that urban stream temperatures can be reduced by re-naturalisation measures designed to improve flood control, water quality and habitats.  […]

What determines leaf length in aquatic plants?

March 13, 2021

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Several genera of aquatic plants have very long strap-like leaves.  Leaf lifespan and growth are known to be influenced by plant life history and reproductive strategies, but there have been few attempts to understand the factors that regulate leaf size in aquatic plants.  Terrestrial plants have been better studied in this respect, but environmental factors […]

Water abstraction changes local food chains

March 13, 2021

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The alteration of river flows by damming or extracting water is a major threat to freshwater ecosystems that can lead to habitat changes and local species extinctions.  While the impacts of dams and large-scale diversions have been the subject of many studies, the cumulative effects of small water abstractions aren’t so well understood, even though […]