Subscribe free to our newsletters via your
. Earth Science News .

Subscribe free to our newsletters via your

Amazon Outflow Is Found To Power Ocean Capture Of Carbon Dioxide

True-color image of the Amazon River outflow, which extends thousands of kilometers into the Atlantic Ocean. Credit: Norman Kuring/NASA
by Staff Writers
New York NY (SPX) Jul 29, 2008
Nutrients washed out of the Amazon River are powering huge amounts of previously unexpected plant life far out to sea, thus trapping atmospheric carbon dioxide, according to a new study.

Until now, the areas around the Amazon and other great rivers had been thought to be emitting CO2, so the study may affect climate scientists' calculations of how the greenhouse gas acts. The study appears in this week's Proceedings of the National Academy of Sciences.

"This new understanding allows us to better think about how carbon dioxide is cycled between the atmosphere and the oceans, and how this might change in the future," said lead author Ajit Subramaniam, a biological oceanographer at Columbia University's Lamont-Doherty Earth Observatory. Lamont is part of The Earth Institute.

The Amazon River is the world's largest, accounting for nearly a fifth of earth's river input to the oceans. Using satellite imagery and samples taken at sea over three years, Subramaniam and colleagues outlined a rich plume of microscopic phytoplankton nourished by its outflow, covering 1.3 million square kilometers (500,000 square miles), an area about twice the size of Texas.

Tropical waters are generally considered poor because they lack nitrogen, a nutrient essential for plants, so the scientists were surprised to find so much life. The secret: a predominance of diazotrophs, photosynthetic microorganisms that fix nitrogen directly from the air.

They were able to bloom far from shore because the Amazon also washes other needed nutrients eroded from land: phosphorus, iron and silicon. Plants use large amounts of carbon dioxide for photosynthesis, so the region, previously estimated to emit a yearly 30 million tons of CO2, is probably soaking that amount back up, said Subramaniam.

Furthermore, once the diazotrophs bloom, they tend to sink quickly to the bottom, more or less permanently removing the CO2 from the air. Because excess human-generated CO2 is warming the atmosphere, artificial trapping of CO2, or "sequestration," has become a subject of rising interest. Here, the scientists showed, it is happening naturally on an unexpected scale.

Each year the world's oceans are thought to absorb about 2 billion tons of CO2 from the atmosphere, but the amount permanently sequestered by sinkage is unclear. The new discovery may tilt the estimated balance between air and oceans by only about 2%, said Subramaniam.

However, he said, "it alters our view about the processes that we think are going on. There may be other surprises out there." Studies of other large rivers including the Congo, Orinoco and Mekong suggest that similar processes may be taking place there.

Subramaniam said that climate change, booming human populations and intensified land uses could alter the workings of the great river basins.

For instance, ongoing conversion of Amazonian rainforest into farmland may increase outwash of nutrients; in some regions, future warming could greatly increase rainfall, and thus river flows. On the other hand, proposed large dam projects on rivers like the Orinoco could cut flow by as much as half. "The whole process could change," said Subramaniam. "But we can't predict how it will change, or what the outcome will be."

Email This Article
Comment On This Article

Share This Article With Planet Earth DiggDigg RedditReddit
YahooMyWebYahooMyWeb GoogleGoogle FacebookFacebook

Related Links
The Earth Institute at Columbia University
Water News - Science, Technology and Politics

Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News

Amazon powers Atlantic Ocean's carbon sink: study
Chicago (AFP) July 21, 2008
Nutrients carried by the Amazon River help create a carbon sink deep in the Atlantic Ocean, a study released Monday has found.

  • Japanese say careful preparations saved them from quake
  • Asia forges agreement towards joint disaster taskforce
  • Chinese Earthquake Provides Lessons For Future
  • Asia's disaster response in spotlight at security talks

  • Climate Change In The USA To Cost Billions
  • Greenhouse Gases May Be Released As Destruction Of Wetlands Worsens
  • Limes May Help Cut CO2 Levels Back To Pre-Industrial Levels
  • Ontario joins US carbon trading clan

  • GOCE Prepares For Shipment To Russia
  • NASA Works To Improve Short-Term Weather Forecasts
  • ESA To Consult The Science Community On Earth Explorer Selection
  • NASA's Deep Impact Films Earth As An Alien World

  • Shell says it eases some Nigerian pipeline production after attack
  • China's largest oil and gas producer cuts jobs: state media
  • Workers struggle to clean up oil spill on Mississippi
  • Scientists work on garbage for gas

  • New Evidence Of Battle Between Humans And Ancient Virus
  • Dengue cases in Philippines rise by 43 percent: government
  • Using Biostatistics To Detect Disease Outbreaks
  • A Viral Cloaking Device

  • Stars Of The Deep
  • Various Species' Genes Evolve To Minimize Protein Production Errors
  • Prevailing Theory Of Aging Challenged In Worm Study
  • New Population Of Highly Threatened Greater Bamboo Lemur Found

  • Air Quality Forecasts For China
  • Air Pollution Is Causing Widespread And Serious Impacts To Ecosystems
  • Study: Early Los Alamos toxin leaks higher
  • California passes strict shipping pollution laws

  • China allows quake-hit families to have more children
  • Outdoor Enthusiasts Scaring Off Native Carnivores In Parks
  • Archaeologists Trace Early Irrigation Farming In Ancient Yemen
  • Research Publications Online: Too Much Of A Good Thing

  • The content herein, unless otherwise known to be public domain, are Copyright 1995-2007 - SpaceDaily.AFP and UPI Wire Stories are copyright Agence France-Presse and United Press International. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by SpaceDaily on any Web page published or hosted by SpaceDaily. Privacy Statement