Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Everglades phosphorus limits on the right track, but more is needed

25.10.2007
State and federal standards for phosphorus releases into the Everglades seem sufficient to protect the huge wetland’s resident plants and animals from damage, but pollutant levels still reach double or triple safe levels near some of the Everglades’ outer edges.

A six-year study led by Duke University scientists tracked how various phosphorus levels affected natural communities in two research sites inside the Everglades.

In an Oct. 24, 2007 report in the online edition of the research journal Environmental Science and Technology, the study’s authors conclude that current standards protect the wetland. But they warn high phosphorus levels persist in the outer edges of the Everglades despite the construction of nearly 40,000 acres of storm water treatment areas to reduce the harmful effects of nutrient runoff from development and agriculture.

"They’ve made significant strides in reducing the amount of phosphorus input," said Curtis Richardson, a professor of resource ecology at Duke’s Nicholas School of the Environment and Earth Sciences and the study’s first author. "But a lot of work remains to be done to meet the criteria that they set."

Phosphorus is the key ingredient in fertilizers applied by the agribusinesses and housing subdivisions that have spread in an arc around the Everglades. It is carried in rainwater runoff into the wetlands, where scientists suspect it can harm organisms even in very small doses.

In response to this threat, regulators have begun massive efforts to reduce phosphorus levels by impounding and treating flood waters and encouraging best management practices on upstream farmlands.

Florida and U.S. Environmental Protection Agency guidelines limit phosphorus levels to 10 micrograms (millionths of a gram) per liter of water over a five-year period. Peaks as high as 15 micrograms over a year’s time are allowed at individual measuring sites.

In a study supported by the EPA and the Everglades Area Agricultural Environmental Protection District of South Florida, Richardson’s team conducted dosing experiments on the organisms living in two pristine test sites in the Everglades’ northern region to demonstrate how various phosphorus concentrations would affect them. They then developed a risk-based phosphorus threshold for the Everglades.

Within those sites, known as mesocosms, the scientists were able to demonstrate a selected pollution level’s impact on such key Everglades species as the bladderwort Utricularia purpurea, a waterplant that can stop photosynthesizing and die when phosphorus levels get too high, Richardson said.

The researchers found that levels in excess of 15 micrograms per liter –- the high end of the chosen government limits -- cause an imbalance in the algae, plant and small animal communities that make up the marshland environment.

To make sure their microcosm findings were not biased by the scale of the testing conditions, the researchers also assessed how real world levels of phosphorus changed along a 10-kilometer length of the Everglades and measured effects on small animal communities living there.

Results of the mesocosm and real-world analysis suggests that a rigid standard of 10 micrograms per liter may be over-protective for all parts of the Everglades the authors wrote. Instead, they suggest a "threshold protective" zone of 12 to 15 micrograms per liter would be adequate as well as more realistic for such a changeable system, especially at the edge of the northern Everglades.

"Most interior areas of the Everglades are currently at or below this threshold zone," they wrote and will be maintained if they can reduce inputs to the suggested protective threshold zone.

"The difficulty is setting rigorous standards for a system that is subject to massive hurricanes, droughts and fires, which greatly alter nutrient concentrations," said Richardson, who also directs the Duke Wetland Center.

Tim Lucas | EurekAlert!
Further information:
http://www.duke.edu

More articles from Ecology, The Environment and Conservation:

nachricht Upcycling 'fast fashion' to reduce waste and pollution
03.04.2017 | American Chemical Society

nachricht Litter is present throughout the world’s oceans: 1,220 species affected
27.03.2017 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Fighting drug resistant tuberculosis – InfectoGnostics meets MYCO-NET² partners in Peru

28.04.2017 | Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

 
Latest News

Wireless power can drive tiny electronic devices in the GI tract

28.04.2017 | Medical Engineering

Ice cave in Transylvania yields window into region's past

28.04.2017 | Earth Sciences

Nose2Brain – Better Therapy for Multiple Sclerosis

28.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>