Top Predators Have Sway Over Climate

Feb. 17, 2013 — University of British Columbia researchers have found that when the animals at the top of the food chain are removed, freshwater ecosystems emit a lot more carbon dioxide into the atmosphere.

"Predators are disappearing from our ecosystems at alarming rates because of hunting and fishing pressure and because of human induced changes to their habitats," says Trisha Atwood, a PhD candidate in the Department of Forest and Conservation Sciences in the Faculty of Forestry at UBC.

For their study, published February 19 in the journal Nature Geoscience, Atwood and her colleagues wanted to measure the role predators play in regulating carbon emissions to better understand the consequences of losing these animals.

Predators are bigger animals at the top of the food chain and their diets are composed of all the smaller animals and plants in the ecosystem, either directly or indirectly. As a result, the number of predators in an ecosystem regulates the numbers of all the plants and animals lower in the food chain. It's these smaller animals and plants that play a big role in sequestering or emitting carbon.

When Atwood and her colleagues removed all the predators from three controlled freshwater ecosystems, 93 per cent more carbon dioxide was released into the atmosphere.

Continued:  http://www.sciencedaily.com/releases/2013/02/130219091014.htm

Unexpected Crustacean Diversity Discovered in Northern Freshwater Ecosystems

ScienceDaily (Mar. 2, 2012) — Freshwater ecosystems in northern regions are home to significantly more species of water fleas than traditionally thought, adding to evidence that regions with vanishing waters contain unique animal life.


The new information on water fleas -- which are actually tiny crustaceans -- comes from a multi-year, international study that was published Feb. 24 in the journal Zootaxa.

The researchers scoured the globe seeking the creatures and found them inhabiting northern lakes and ponds in locations from Alaska to Russia to Scandinavia.

After analyzing the anatomy and genetic makeup of many different specimens, the team conclusively determined that at least 10 species of the crustaceans existed -- five times as many as thought for much of the last century.

More than half the diversity was found in northern latitudes, where rapid freshwater habitat loss is occurring due to melting permafrost, increased evaporation and other changes tied to climate change.

Read on:  http://www.sciencedaily.com/releases/2012/03/120302193936.htm