Browsing All Posts filed under »geology«

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, […]

Lake management gets harder as the climate changes

March 26, 2022

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Excessive inflows of nutrients, especially phosphorus in fertilisers, pesticides and sewage, reduce water quality in lakes and reservoirs and can encourage toxic algal blooms, often with serious implications for public health, food security and biodiversity.  Increases in nutrient inputs are partly due to increased rainfall associated with  climate change.  And the availability and residence times […]

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 […]

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 […]

Pressures on groundwater

March 16, 2021

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Groundwater irrigation plays a central role in sustaining world agriculture.  In northwest Bangladesh, which is that country’s main cropping area,  groundwater supports 96% of agricultural production in the dry season.  In recent decades there has been a large increase in cropping, and thus the demand for groundwater.  However, water balance modelling shows that several other […]

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 […]

Ecosystem impacts of invasive carp

December 16, 2020

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The common carp (Cyprinus carpio) is one of the world’s most widespread invasive fish species and has a reputation for causing ecological damage.  It’s thought that the excretion of nutrients by dense populations of carp stimulates algal growth, which increases turbidity, and that the feeding and spawning activities of carp further increase turbidity by bringing […]

Dissolved organics in lakes: soils are good indicators

June 25, 2020

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Dissolved organic matter (DOM) is the largest source of organic carbon in aquatic ecosystems.  As well as being a key building block for freshwater food chains, DOM affects the clarity of water and the transport of metals and pollutants.    In lakes, DOM originates from in-lake production and from decaying plant material washed in from the […]

Exposed sediments boost greenhouse emissions

March 31, 2020

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In lowland rivers in continental and Mediterranean climatic zones, temporary islands and bars emerge from the riverbed at times of low flow and are submerged during floods. The period of submersion controls primary production and the decomposition of organic matter, and thus the metabolism of the whole river.  Changing river heights affect oxygen levels in […]

Soils as a guide to wetland condition

March 31, 2020

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Because wetlands provide valuable ecosystem services but are vulnerable to human impacts, increasing efforts have been made to develop indicators of wetland condition.  Wetland ecosystems are normally described by reference to three core dimensions, namely hydrology, biological communities and soils, but the most poorly developed condition indices are those based on soils, which don’t feature […]