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:5/20/2016)... , May 20, 2016  VoiceIt is ... partnership with VoicePass. By working together, ... experience.  Because VoiceIt and VoicePass take slightly different ... engines increases both security and usability. ... excitement about this new partnership. "This ...
(Date:5/3/2016)... , May 3, 2016  Neurotechnology, a ... the MegaMatcher Automated Biometric Identification System (ABIS) ... large-scale multi-biometric projects. MegaMatcher ABIS can process multiple ... using any combination of fingerprint, face or iris ... MegaMatcher SDK and MegaMatcher Accelerator , ...
(Date:4/26/2016)... April 27, 2016 Research ... Multi-modal Biometrics Market 2016-2020"  report to their offering.  ... The analysts forecast the global multimodal ... 15.49% during the period 2016-2020.  Multimodal ... sectors such as the healthcare, BFSI, transportation, automotive, ...
Breaking Biology News(10 mins):
(Date:6/27/2016)... GUELPH, ON , June 27, 2016 /PRNewswire/ - BIOREM ... it has been advised by its major shareholders, Clean ... LP, United States based venture ... common shares of Biorem (on a fully diluted, as ... for the disposition of their entire equity holdings in ...
(Date:6/27/2016)... ... June 27, 2016 , ... ... Amgen, will join the faculty of the University of North Carolina Kenan-Flagler ... of strategy and entrepreneurship at UNC Kenan-Flagler, with a focus on the school’s ...
(Date:6/24/2016)... ... , ... While the majority of commercial spectrophotometers and fluorometers use the z-dimension ... are higher end machines that use the more unconventional z-dimension of 20mm. Z-dimension ... bottom of the cuvette holder. , FireflySci has developed several Agilent flow cell ...
(Date:6/23/2016)... /PRNewswire/ - FACIT has announced the creation of ... company, Propellon Therapeutics Inc. ("Propellon" or "the Company"), ... portfolio of first-in-class WDR5 inhibitors for the treatment ... represent an exciting class of therapies, possessing the ... cancer patients. Substantial advances have been achieved with ...
Breaking Biology Technology: