Featured Research

from universities, journals, and other organizations

Aquatic 'dead zones' contributing to climate change

Date:
March 12, 2010
Source:
University of Maryland Center for Environmental Science
Summary:
The increased frequency and intensity of oxygen-deprived "dead zones" along the world's coasts can negatively impact environmental conditions in far more than local waters. Scientists explain that the increased amount of nitrous oxide produced in hypoxic waters can elevate concentrations in the atmosphere, further exacerbating the impacts of global warming and contributing to ozone "holes" that increase our exposure to harmful UV radiation.

Mississippi dead zone in 2006. The increased frequency and intensity of oxygen-deprived "dead zones" along the world's coasts can negatively impact environmental conditions in far more than just local waters.
Credit: NASA/Goddard Space Flight Center Scientific Visualization Studio

The increased frequency and intensity of oxygen-deprived "dead zones" along the world's coasts can negatively impact environmental conditions in far more than just local waters. In the March 12 edition of the journal Science, University of Maryland Center for Environmental Science oceanographer Dr. Lou Codispoti explains that the increased amount of nitrous oxide (N2O) produced in low-oxygen (hypoxic) waters can elevate concentrations in the atmosphere, further exacerbating the impacts of global warming and contributing to ozone "holes" that cause an increase in our exposure to harmful UV radiation.

"As the volume of hypoxic waters move towards the sea surface and expands along our coasts, their ability to produce the greenhouse gas nitrous oxide increases," explains Dr. Codispoti of the UMCES Horn Point Laboratory. "With low-oxygen waters currently producing about half of the ocean's net nitrous oxide, we could see an additional significant atmospheric increase if these 'dead zones' continue to expand."

Although present in minute concentrations in Earth's atmosphere, nitrous oxide is a highly potent greenhouse gas and is becoming a key factor in stratospheric ozone destruction. For the past 400,000 years, changes in atmospheric N2O appear to have roughly paralleled changes in carbon dioxide CO2 and have had modest impacts on climate, but this may change. Just as human activities may be causing an unprecedented rise in the terrestrial N2O sources, marine N2O production may also rise substantially as a result of nutrient pollution, warming waters and ocean acidification. Because the marine environment is a net producer of N2O, much of this production will be lost to the atmosphere, thus further intensifying its climatic impact.

Increased N2O production occurs as dissolved oxygen levels decline. Under well-oxygenated conditions, microbes produce N2O at low rates. But at oxygen concentrations decrease to hypoxic levels, these waters can increase their production of N2O.

N2O production rates are particularly high in shallow suboxic and hypoxic waters because respiration and biological turnover rates are higher near the sunlit waters where phytoplankton produce the fuel for respiration.

When suboxic waters (oxygen essentially absent) occur at depths of less than 300 feet, the combination of high respiration rates, and the peculiarities of a process called denitrification can cause N2O production rates to be 10,000 times higher than the average for the open ocean. The future of marine N2O production depends critically on what will happen to the roughly ten percent of the ocean volume that is hypoxic and suboxic.

"Nitrous oxide data from many coastal zones that contain low oxygen waters are sparse, including Chesapeake Bay," said Dr. Codispoti. "We should intensify our observations of the relationship between low oxygen concentrations and nitrous oxide in coastal waters."


Story Source:

The above story is based on materials provided by University of Maryland Center for Environmental Science. Note: Materials may be edited for content and length.


Journal References:

  1. Louis A. Codispoti. Interesting Times for Marine N2O. Science, March 12, 2010 DOI: 10.1126/science.1184945
  2. Sheng et al. A dinoflagellate exploits toxins to immobilize prey prior to ingestion. Proceedings of the National Academy of Sciences, 2010; 107 (5): 2082 DOI: 10.1073/pnas.0912254107

Cite This Page:

University of Maryland Center for Environmental Science. "Aquatic 'dead zones' contributing to climate change." ScienceDaily. ScienceDaily, 12 March 2010. <www.sciencedaily.com/releases/2010/03/100311141213.htm>.
University of Maryland Center for Environmental Science. (2010, March 12). Aquatic 'dead zones' contributing to climate change. ScienceDaily. Retrieved September 19, 2014 from www.sciencedaily.com/releases/2010/03/100311141213.htm
University of Maryland Center for Environmental Science. "Aquatic 'dead zones' contributing to climate change." ScienceDaily. www.sciencedaily.com/releases/2010/03/100311141213.htm (accessed September 19, 2014).

Share This



More Earth & Climate News

Friday, September 19, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Wildfires in CA Burn Forest Asunder

Raw: Wildfires in CA Burn Forest Asunder

AP (Sep. 18, 2014) An out-of-control Northern California wildfire has nearly 2,800 people from their homes as it continues to grow, authorities said Thursday. Authorities said a man has been arrested on suspicion of arson for starting the fire on Saturday. (Sept. 18) Video provided by AP
Powered by NewsLook.com
Raw: Elephant Undergoes Surgery in Tbilisi Zoo

Raw: Elephant Undergoes Surgery in Tbilisi Zoo

AP (Sep. 18, 2014) Grand the elephant has successfully undergone surgery to remove a portion of infected tusk at Tbilisi Zoo in Georgia. British veterinary surgeons used an electric drill to extract the infected piece. (Sept. 18) Video provided by AP
Powered by NewsLook.com
Raw: Scientists Examine Colossal Squid

Raw: Scientists Examine Colossal Squid

AP (Sep. 16, 2014) Squid experts in New Zealand thawed and examined an unusual catch on Tuesday: a colossal squid. It was captured in Antarctica's remote Ross Sea in December last year and has been frozen for eight months. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Man Floats for 31 Hours in Gulf Waters

Man Floats for 31 Hours in Gulf Waters

AP (Sep. 16, 2014) A Texas man is lucky to be alive after he and three others floated for more than a day in the Gulf of Mexico when their boat sank during a fishing trip. (Sept. 16) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins