Browsing All Posts filed under »sediment«

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 […]

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 […]

Guidelines for conserving groundwater ecosystems

December 14, 2021

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Aquatic groundwater-dependent ecosystems include subsurface aquifers, springs, seepage wetlands and other groundwater-fed surface waters.  Their biodiversity is high: for example, in Europe around 13% of all freshwater animal species are found only in groundwater.  Many of these species are rare, with limited distributions, and some are “living fossils”.  Groundwater species deliver ecosystem services by recycling […]

How to capture the tiniest animals

December 14, 2021

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Although meiobenthic species are inconspicuous and the smallest animals living in aquatic sediments, they account for up to 80-90% of all animals in streams and lakes.  They play an important role in nutrient cycling, contribute up to half of all secondary production in freshwater food webs, and are good indicators of environmental pollution.  Meiofauna have […]

Assessing human impacts on river systems

September 28, 2021

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Because many river systems have been significantly modified as a result of human activities, indicators of changing river structure and function are very helpful in guiding our efforts to manage rivers on a sustainable basis.  A number of different indicators based on the hydrology, chemistry or biology of rivers have been developed, but in many […]

Costs of laissez-faire stewardship

June 7, 2021

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Stream pollution and the degradation of freshwater ecosystems have often been linked to waste discharges from coal mines.  Pollution often continues to occur for many years after a mine is closed because the mine gradually fills with groundwater and eventually releases contaminant flows at the surface.  In Australia there are over 50,000 abandoned mines (coal […]

Assessing river condition from the air

June 7, 2021

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Although attempts are commonly made to restore streams impacted by disturbance, follow-up monitoring to assess a project’s success is often minimal due to budget limitations.   However, new approaches involving the use of small unmanned aerial vehicles (drones) offer the possibilities for remote stream assessment, with potentially great gains in terms of cost-effectiveness and reduced field […]

Sound directions for the freshwater sciences

June 7, 2021

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A recent issue of the journal Freshwater Biology was devoted to the emerging field of ecoacoustics (the study of the ecological role of sounds), an exciting area with many applications in freshwater science.  So far, passive acoustic monitoring has been used mainly in terrestrial and marine environments, but recent studies reveal that inland waters support […]

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 […]

Crustaceans control the flow of groundwater

December 16, 2020

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Aquifers are an essential source of water for human needs and groundwater is the world’s most extracted raw material.   The capacity of aquifers to store and transport water critically depends on their hydraulic properties, which also have a strong influence on communities of underground lifeforms, including microbes, micro- and macro-invertebrates and fish.  Evidence is now […]