Browsing All Posts filed under »community«

Seasonal shifts in microbial communities

June 26, 2022

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Biofilms (slime layers) containing bacteria, algae and other small organisms are found on submerged surfaces and form the base of most freshwater food webs, but relatively little is known about how freshwater biofilms respond to environmental variables such as water flow, temperature, nutrient availability and land-use changes.  Researchers at the University of Auckland, New Zealand […]

Issues with environmental DNA

June 26, 2022

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In recent years, the development of techniques for recovering DNA from a wide range of environments, including water, ice, soil and sediments, has revolutionised studies of biodiversity and large-scale ecological processes.  However, we know very little about what happens to DNA after it’s released into the environment, which means that there’s a possibility that sampling […]

Invasive fish species take over in Singapore

December 14, 2021

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Cichlids make up a large family of freshwater fish with centres of native distribution in Africa and South America.  Cichlid species vary widely in terms of feeding habits, reproductive strategies and environmental tolerances, and their capacity for adaptive radiation in areas such as the African Great Lakes is legendary. Unfortunately, with human assistance many of them […]

How big should samples of aquatic vegetation be?

December 14, 2021

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When sampling aquatic vegetation what plot size should you use?  Ideally, the aim should be to choose the smallest area in which the species in the plant community in question are adequately represented – in graphical terms, this is when the curve of the number of species plotted against sample area flattens out. For terrestrial […]

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 […]

Land use patterns can aggravate toxic plankton blooms

September 28, 2021

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An understanding of how environmental factors affect the composition of biological communities is a crucial prerequisite for managing challenges due to climate change, land use practices and invasive species.  However, establishing the significance of interacting local and regional factors that vary widely across space and time is a challenge in itself.   Canadian biologists set out […]

Key wetland species deliver most ecosystem services

September 28, 2021

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There’s a lot of evidence that in ecosystems such as grasslands and forests, biodiversity is positively related to productivity and to the efficiency of nutrient recycling and decomposition.   On this basis it can be argued that the loss of biodiversity is likely to damage the delivery of ecosystem services.  However, in the case of wetlands, […]

Earthquakes and groundwater

September 28, 2021

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Studies have shown that earthquake activity can change the chemistry of nearby groundwater reserves – for example, strong increases in chlorides and sulphates in groundwater were recorded in the period before and after the Kobe earthquake of 1995.  Such changes can alter the communities of organisms living in the aquifer and lead to the extinction […]