Browsing All Posts filed under »plants«

Restoration and invertebrates: Reappraising stream condition indicators

September 25, 2017

0

In degraded rivers and stream systems, the replanting of riparian vegetation is a common restoration activity, partly because increases in shading, nutrient interception and litter fall are expected to provide food and habitat benefits for aquatic communities. Changed habitat conditions should be reflected in indices of stream condition, such as those based on macroinvertebrate richness. […]

Ironing out harmful algal blooms

September 25, 2017

0

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

0

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

0

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

Comments Off on Coarse, shallow and wooden… but useful nonetheless

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. […]

Plankton migration is system-dependent

June 19, 2017

Comments Off on Plankton migration is system-dependent

Lake zooplankton commonly switch microhabitats on a regular day-night basis by migrating horizontally between stands of vegetation and open waters, or by migrating vertically between deep and surface waters. These movements have been explained in terms of the need to avoid predators (especially fish) and excessive ultraviolet radiation.  However, although zooplankton are known to seek […]

Planting vegetation to stop stream bank erosion: where’s the evidence?

June 19, 2017

Comments Off on Planting vegetation to stop stream bank erosion: where’s the evidence?

Increased rates of stream bank erosion and sediment movement in disturbed catchments have been attributed to changes in catchment hydrology caused by land clearing, channel modification, the trampling activities of livestock and the removal of riparian vegetation. Given that these effects are human-induced, it’s commonly assumed that they can also be reversed by human intervention, […]