Navigation Links
Scientists show that streams are critical to preservation of oceanic coastal zones
Date:3/12/2008

The plight of the worlds oceans is dire, according to recent studies, through insults from human-derived activities depopulating and damaging reefs, altering coastlines, and creating pollutants, such as nitrogen runoff from terrestrial watersheds.

A study by 31 aquatic biologists involving 72 stream sites in the United States and Puerto Rico has found that one critical buffer to excess nitrogen run off from agricultural and urban areas turns out to be small streams and rivers. The findings are published March 12 in the journal Nature.

We found that nitrate was filtered from stream water by tiny organisms such as algae, fungi and bacteria, says Patrick Mulholland, lead author of the study and a member of Oak Ridge National Laboratorys Environmental Sciences Division, with a joint appointment at the University of Tennessee. Further, our model showed that the entire stream network is important in removing pollution from stream water.

The study used a rare nitrogen isotope to examine the effects of nitrogen loading in streams. The researchers analyzed its removal relative to the amount of nitrogen present in the stream overall. The results showed that much of the nitrogen was removed by bacteria, in a process called denitrification that releases harmless nitrogen gas to the atmosphere. However, the study also demonstrated that as nitrate loads increase, the efficiency of removal was reduced.

Our study shows that nitrogen loading compromises the ability of streams to retain or transform nitrate, a major pollutant that has been associated with lake and stream eutrophication, groundwater pollution, and coastal dead zones, says Nancy Grimm, an ecologist at Arizona State University who has been involved with the project since the 1980s.

Presently its believed that small streams and rivers remove three-quarters of the excess nitrogen contamination before it reaches the oceans by acting as sinks. However, the researchers findings published in Nature suggest that as land use changes, and shifts to increasing nitrogen loads occur, that this buffering capacity could be overwhelmed. Nitrogen pollution could generate algal blooms, oxygen depletion (dead zones) and death to coral, fish and shellfish in coastal zones.

Grimm believes that the long-term, collaborative nature of the project supporting this study, which has incorporated two separate experiments each conducted in a range of ecosystems, was key to advancing understanding of stream nitrogen dynamics far beyond what could be accomplished with a single-investigator grant focused on one region.

As a professor in ASUs School of Life Sciences, Grimm is no stranger to long-term collaborative efforts. For the last 10 years she has led the Central Arizona-Phoenix Long-term Ecological Research (CAP-LTER) project centered on the analysis of urban-semi-arid ecosystem relationships. The co-director of CAP-LTER is anthropologist Charles Redman, director of ASUs School of Sustainability.

With her collaborators, Grimm has established a conceptual basis for including human choice and action in theory of urban ecosystem dynamics. Grimm and her counterparts empirical work on biogeochemistry, species distribution and abundance, and designed aquatic ecosystems in cities have revealed that many ecological features are best explained by combinations of social and biophysical drivers. Grimm was also the first to describe nitrogen cycling in desert streams, work that led directly to the long-term collaboration and the experiments described in the Nature article.

The findings published in Nature underscore the critical interplay that exists between human action and ecosystems dynamics and capacity, and emphasizes the management imperative of controlling nitrogen loading to streams and protecting or restoring stream ecosystems to maintain or enhance their nitrogen removal functions.


'/>"/>

Contact: Margaret Coulombe
margaret.coulombe@asu.edu
480-727-8934
Arizona State University
Source:Eurekalert

Related biology news :

1. Scientists to discover why flamingos are in the pink of health -- in the poo!
2. Scientists believe photograph depicts wolverine in California
3. Scientists successfully treat new mouse model of inflammatory bowel disease
4. Genes hold the key to how happy we are, scientists say
5. Scientists uncover a novel mechanism that regulates carbon dioxide fixation in plants
6. Bright lights: Mystery of glowing antibody solved by Scripps research scientists
7. Scientists discover how cigarette smoke causes cancer: Study points to new treatments, safer tobacco
8. Exeter scientists pour cold water on EU bird policy
9. Yale scientists create artificial cells that boost the immune response to cancer
10. Scientists unravel the genetic coding of the pea
11. Scientists discover giant fossil frog from hell
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:4/5/2017)... 2017 KEY FINDINGS The global ... a CAGR of 25.76% during the forecast period of ... factor for the growth of the stem cell market. ... MARKET INSIGHTS The global stem cell market is ... geography. The stem cell market of the product is ...
(Date:4/3/2017)... 2017  Data captured by IsoCode, IsoPlexis ... a statistically significant association between the potency ... and objective response of cancer patients post-treatment. ... whether cancer patients will respond to CAR-T ... as to improve both pre-infusion potency testing and ...
(Date:3/30/2017)... 2017 The research team of The Hong ... fingerprint identification by adopting ground breaking 3D fingerprint minutiae recovery and ... speed and accuracy for use in identification, crime investigation, immigration control, ... ... A research team led ...
Breaking Biology News(10 mins):
(Date:10/9/2017)... DIEGO , Oct. 9, 2017  BioTech ... biological mechanism by which its ProCell stem cell ... critical limb ischemia.  The Company, demonstrated that treatment ... amount of limbs saved as compared to standard ... the molecule HGF resulted in reduction of therapeutic ...
(Date:10/9/2017)... ... October 09, 2017 , ... The Giving ... marijuana products targeting the needs of consumers who are incorporating medical marijuana into ... in Phoenix, Arizona. , As operators of two successful Valley dispensaries, The Giving ...
(Date:10/7/2017)... ... October 06, 2017 , ... Phase ... metagenome deconvolution product, featuring the first commercially available Hi-C kit. Researchers can ... Hi-C metagenome deconvolution using their own facilities, supplementing the company’s full-service ProxiMeta ...
(Date:10/6/2017)... (PRWEB) , ... October 06, 2017 , ... ... host a lunch discussion and webinar on INSIGhT, the first-ever adaptive clinical trial ... Investigator, Dana-Farber Cancer Institute. The event is free and open to the public, ...
Breaking Biology Technology: