Browsing All Posts filed under »nutrients«

Riparian roots help streams breathe

December 21, 2017

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In aquatic systems, especially those with abundant plants, dissolved oxygen concentrations often show strong daily fluctuations because there’s a net input of oxygen from photosynthesis during the day but a net loss of oxygen due to   respiration at night.  When researchers working on a small tropical stream in São Paulo State, Brazil recorded this pattern […]

Deforestation means defishation

December 21, 2017

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The impacts of tropical deforestation on terrestrial biodiversity are well known but only a few studies have considered the impacts of deforestation on freshwater systems.  Such effects are likely to be significant, given the importance of riparian vegetation as a source of nutrients and the high abundances of fish in tropical floodplain forests.  In a […]

More clarity on climate change

December 21, 2017

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Although climate change is warming many lakes around the world, there are big variations in their rate of temperature increase.  This variability is thought to be partly due to the fact that lakes differ widely in terms of water clarity, which is affected by factors such as land management, rainfall and changes in dissolved organic […]

Ironing out harmful algal blooms

September 25, 2017

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An understanding of how iron affects the supply of nutrients in aquatic systems may open the door to better success in managing harmful algal blooms. In highly productive lakes, the release of phosphorus stored in the bottom sediment can encourage bloom development, but nutrient release is retarded in the presence of iron, which precipitates phosphorus […]

Urban trees protect local water bodies

September 25, 2017

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As a result of nutrient transfer from the land, urban waterways often have high concentrations of nitrogen and phosphorus, which can lead to algal blooms, low water clarity, oxygen depletion and species loss. Nutrient enrichment problems also extend to urban groundwater, where water quality can be compromised.  Although nutrients moving from land to groundwater water […]

How cell size affects algal chemicals

September 25, 2017

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The chemical composition of microalgae – organisms such as green algae, diatoms and dinoflagellates – influences their food web interactions and the way they compete for nutrients, as well as their suitability for human exploitation in the form of biofuels, nutraceuticals and aquaculture feeds.   Because microalgae cover a wide range of cell sizes (less than […]

Coarse, shallow and wooden… but useful nonetheless

June 19, 2017

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Coarse woody debris (CWD) derived from shoreline trees provides an important, spatially complex habitat and a food source for lake-dwelling organisms. Here are some interesting facts about lake CWD, taken from a recent review paper: In the absence of the physical action of flowing water, CWD breaks down more slowly in lakes than in streams. […]