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:6/3/2016)... 2016 Das DOTM ... Nepal hat ein 44 Millionen ... Kennzeichen, einschließlich Personalisierung, Registrierung und IT-Infrastruktur, an ... und Implementierung von Identitätsmanagementlösungen. Zahlreiche renommierte internationale ... teilgenommen, aber Decatur wurde als konformste und ...
(Date:5/24/2016)... 24, 2016 Ampronix facilitates superior patient care by providing unparalleled technology to ... display is the latest premium product recently added to the range of products distributed ... ... ... Imaging- LCD Medical Display- Ampronix News ...
(Date:5/3/2016)... Lithuania , May 3, 2016  Neurotechnology, ... released the MegaMatcher Automated Biometric Identification System ... of large-scale multi-biometric projects. MegaMatcher ABIS can process ... accuracy using any combination of fingerprint, face or ... MegaMatcher SDK and MegaMatcher Accelerator ...
Breaking Biology News(10 mins):
(Date:6/27/2016)... Chapel Hill, N.C. (PRWEB) , ... June 27, ... ... of U.S. commercial operations for Amgen, will join the faculty of the ... will serve as adjunct professor of strategy and entrepreneurship at UNC Kenan-Flagler, with ...
(Date:6/24/2016)... , June 24, 2016 Epic Sciences ... detects cancers susceptible to PARP inhibitors by targeting ... cells (CTCs). The new test has already been ... in multiple cancer types. Over 230 ... damage response pathways, including PARP, ATM, ATR, DNA-PK ...
(Date:6/23/2016)... ... June 23, 2016 , ... UAS LifeSciences, one ... of their brand, UP4™ Probiotics, into Target stores nationwide. The company, which has ... add Target to its list of well-respected retailers. This list includes such fine ...
(Date:6/23/2016)... HOUSTON , June 23, 2016 ... agreement with the Cy-Fair Sports Association to serve ... of the agreement, Houston Methodist Willowbrook will provide ... education and connectivity with association coaches, volunteers, athletes ... partner with the Cy-Fair Sports Association and to ...
Breaking Biology Technology: