Navigation Links
Yale scientist helps pinpoint threats to life in world's rivers

The food chain - the number of organisms that feed on each other in the world's streams and rivers depends more upon the size of the stream and whether the waterways flood or run dry than the amount of available food resources, Yale University and Arizona State University (ASU) researchers report online in the Oct. 14 issue of the journal Science Express.

The findings suggest that large predators in river systems will be threatened by increased variability in water flow induced by climate change. The research also helps settle an old debate among ecologists about what determines the length of nature's food chains, which sustain all life on earth.

"The food web is a regulatory network of ecosystems, and for nearly 100 years ecologists have debated the causes of variation in the length of the food chains, said David Post, professor of ecology and evolutionary biology at Yale and co-author of the study.

Researchers from Yale, ASU, the University of Minnesota, and the U.S. Geological Survey studied 36 North American streams and rivers. The researchers found that food chains or the number of mouths that food passes through on the way to top predators got longer as the size of the body of water increased. The findings are similar to another study conducted by Post a decade ago that found the key factor in food chain length was lake size, not the amount of food resources in a system, as many ecologists had believed.

A longer food chain supports more organisms and larger predators such as big fish but may also increase the concentration of contaminants in larger predators. However, the new study found that the more streams and rivers dried up or flooded, the shorter the food chain. This in turns puts pressure on the ecosystem's ability to support organisms, particularly larger predators. In fact, when water is withdrawn from a stream or a river dries up it may be decades before the food chain recovers.

"Even very large rivers around the world are drying with increasing frequency and global climate models predict many rivers will experience more variable flows, both high and low," said John L. Sabo, professor of ecology, evolution and environmental science at ASU and co-author of the study. "Our results suggest these changes to hydrology will simplify river food webs and increase the likelihood of loosing many top predator fish species from aquatic ecosystems."

As climate variability increases, so will the number of disputes over water use, such as clash a decade ago between farmers and environmentalists over withdrawal of water from the Klamath River Basin, which flows from Oregon into northern California.

"Understanding what determines food chain length will help us make better policy decisions," Post said.


Contact: Bill Hathaway
Yale University

Related biology news :

1. UCSB scientists discover inner workings of potent cancer drug
2. Gladstone scientists uncover mechanism for the major genetic risk factor of Alzheimers disease
3. Scientists solve mystery of arsenic compound
4. Gladstone scientists link hepatitis C virus infection to fat enzyme in liver cells
5. Scientists watch cell-shape process for first time
6. Studying illnesses caused by worms: Scientists are learning how immune cells communicate
7. Scientists trick bacteria with small molecules
8. DFG awards 4 young scientists 2010 Bernd Rendel Prize
9. Scripps Research scientists develop novel test that identifies river blindness
10. AgriLife Research scientists complete two-year study on short-day onions
11. MBL scientists reveal findings of World Ocean Microbe Census
Post Your Comments:
(Date:11/12/2015)... Nov. 12, 2015  Arxspan has entered into ... and Harvard for use of its ArxLab cloud-based ... tools. The partnership will support the institute,s efforts ... chemical research information internally and with external collaborators. ... for managing the Institute,s electronic laboratory notebook, compound ...
(Date:11/10/2015)... NEW YORK , Nov. 10, 2015 /PRNewswire/ ... refers to behavioral biometrics that helps to identify ... prevent fraud. Signature is considered as the secure ... for the identification of a particular individual because ... offers more accurate results especially when dynamic signature ...
(Date:11/2/2015)... , Nov. 2, 2015  SRI International has been ... provide preclinical development services to the National Cancer Institute ... will provide scientific expertise, modern testing and support facilities, ... preclinical pharmacology and toxicology studies to evaluate potential cancer ... The PREVENT Cancer Drug Development Program is an ...
Breaking Biology News(10 mins):
(Date:12/1/2015)... 2015  CardioCell LLC, a Stemedica Cell Technologies ... cardiovascular indications, intends to proceed with finalizing a ... from a Heart Failure Advisory Board comprising cardiology ... Board members . In a recent meeting members ... and efficacy data from CardioCell,s on-going chronic heart ...
(Date:12/1/2015)... 1, 2015 Cepheid (Nasdaq: CPHD ) ... the Piper Jaffray Healthcare Conference in New ... is reaffirming its outlook for the fourth quarter of ... to discussing longer term business model expectations. ...  "We continue to be the fastest growing company of ...
(Date:11/30/2015)... ... November 30, 2015 , ... ... physicians, aesthetic practitioners and aesthetics professionals from Central America and abroad for the ... in Panama City, Panama Feb. 17-19, 2016. Testart will present and discuss new ...
(Date:11/30/2015)... /PRNewswire/ - BioAmber Inc. (NYSE: BIOA ), a leader in ... Business Act on Climate Pledge, alongside more than 140 companies ... Obama Administration to demonstrate an ongoing commitment to climate action ... COP21 Paris climate negotiations. ... Canada . --> BioAmber uses biotechnology to ...
Breaking Biology Technology: