Navigation Links
From the backyard to the ocean: New study shows streams act as key nitrogen filters
Date:3/12/2008

KNOXVILLE -- As spring arrives across the country, tourists returning to beaches will face the reality of "red tide" -- harmful blooms of algae that make water unfit for swimming and pose risks to humans and sea life.

What they may not realize is that the small streams running through their neighborhoods play a critical role in filtering out the nitrogen that feeds the algae blooms.

A new study published in this week's edition of the journal Nature by 31 scientists from across the country sheds new light on streams' role as a nitrogen filter, and uncovers data that show increases in nitrogen caused by human activities can make it harder for the streams to do their jobs.

"The filtering is a serial process and it's bigger than any one stream," said Patrick Mulholland, the study's lead author and a researcher with the University of Tennessee, Knoxville, and Oak Ridge National Laboratory. "What you see in your backyard, though, matters to the health of coastal oceans."

Excess nitrogen in streams is caused in large part by human activities, particularly overuse of nitrogen-based fertilizers, said Mulholland, and as nitrogen accumulates in increasingly larger bodies of water, it feeds the harmful algae growth that leads to red tide.

In addition, the excessive growths of algae consume large amounts of oxygen when they die and decompose, sometimes enough to make the water unable to support many forms of aquatic life. This problem has been especially pronounced in recent years in the Gulf of Mexico, impacting regional fisheries.

Mulholland and his colleagues, including UT Knoxville professor Lee Cooper, studied how a special, easily traceable form of nitrate made its way through 72 different streams across the U.S. and in Puerto Rico. They found that algae, fungi and bacteria in the streams consumed the nitrate, in essence causing the stream to store the nitrogen.

Nitrate -- used in the study because it is the most common form of nitrogen pollution -- also was permanently removed from the streams by certain bacteria that converted it into harmless nitrogen gas in a process called denitrification.

The researchers used the data they collected from the individual streams to create a model of how streams work to remove nitrogen. In doing so, they found that the streams are most effective as nitrogen filters when they were not overloaded with nitrogen from fertilizers and other human activity.

"There's a relationship between the concentration of nitrogen and how efficiently the streams can remove it," Mulholland said. "With too much nitrogen, they can be overloaded and unable to process the nitrogen as well."

He said the results showed that nitrogen was removed most effectively in cases where the nitrate entered the stream network near its origins and had the chance to make its way through a number of increasingly larger streams before moving into larger bodies of water, such as lakes, esturaries and the ocean.

"If we want to improve the situation, we need to do a better job reducing nitrogen inputs to our waters," he said.

The streams included in the study were located across a wide variety of regions and in areas where land is put to a number of different uses in order to get a broad perspective on how streams act as nitrogen filters.


'/>"/>

Contact: Jay Mayfield
jay.mayfield@tennessee.edu
865-974-9409
University of Tennessee at Knoxville
Source:Eurekalert

Related biology news :

1. Bad news for coastal ocean: less fish out, means more nitrogen in
2. Childhood obesity indicates greater risk of school absenteeism, Penn study reveals
3. A study by the MUHC and McGill University opens a new door to understanding cancer
4. Study begins to reveal clues to the cause and progression of sepsis
5. Clones on task serve greater good, evolutionary study shows
6. New study warns limited carbon market puts 20 percent of tropical forest at risk
7. New study examines how rearing environment can alter navigation
8. Study links cat disease to flame retardants in furniture and to pet food
9. New continent and species discovered in Atlantic study
10. Study shows link between alcohol consumption and hiv disease progression
11. Feeling hot, hot, hot: New study suggests ways to control fever-induced seizures
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:3/14/2016)... Florida , March 14, 2016 ... the growing mobile commerce market, announces the airing of a ... channels starting the week of March 21 st .  The ... CNBC, including its popular Squawk on the Street show. ... focused on the growing mobile commerce market, announces the airing ...
(Date:3/10/2016)... , March 10, 2016   Unisys Corporation (NYSE: ... Border Protection (CBP) is testing its biometric identity solution ... Diego to help identify certain non-U.S. citizens leaving ... The test, designed to help determine the efficiency and accuracy ... in February and will run until May 2016. --> ...
(Date:3/3/2016)... Calif. , March 3, 2016  FlexTech, a ... the categories of Innovation, Research & Development, Leadership in ... Leadership. This is the 9 th year of ... group of companies and individuals from past years ... based on a pre-described set of criteria, by a ...
Breaking Biology News(10 mins):
(Date:5/4/2016)... ... 2016 , ... The Children’s Tumor Foundation announced its annual month-long campaign to ... nerves throughout the body. It affects 1 in 3,000 people of all populations; there ... month of May, as well as online activities, Neurofibromatosis Awareness Month and “I Know ...
(Date:5/4/2016)... ... 2016 , ... PBI-Gordon Corporation is pleased to announce Doug Obermann has been ... career at PBI-Gordon in February 1988, after finishing his masters in agronomy from Iowa ... customer service to national product manager, to helping develop, name and launch many of ...
(Date:5/3/2016)... , May 3, 2016 ... (Genomics, Drug Discovery, Gene Expression) Lab-on-a-chip (IVD ... (Academics Institutes, Diagnostics Centers), Fabrication Technology (Microarrays, ... MarketsandMarkets, the market is expected to reach ... 7.63 Billion in 2015, growing at a ...
(Date:5/3/2016)... ... May 03, 2016 , ... In a list published by the ... state’s 76 fastest-growing private companies; a small percentage of the state's 615,000+ small businesses. ... the percent change in revenue from 2012 to 2015. , As this ...
Breaking Biology Technology: