Featured Research

from universities, journals, and other organizations

Subtle Biotic Changes Have Big Environmental Impact

Date:
July 11, 1997
Source:
University Of Wisconsin-Madison
Summary:
A new finding, reported by researchers from UW-Madison in this week's (July 11) edition of the journal Science, is the first to show that only slight rearrangement of an intact ecosystem's food web can directly influence the atmosphere.

MADISON - By changing the composition of fish populations in a lake, scientists have found a switch by which the flow of carbon between lakes and the atmosphere can be turned on, off, or reversed.

Related Articles


The finding, reported by researchers from the University of Wisconsin-Madison in this week's (July 11) edition of the journal Science, is the first to show that only slight rearrangement of an intact ecosystem's food web can directly influence the atmosphere.

The discovery is important because it demonstrates that single, seemingly subtle changes in ecosystems can have far-reaching consequences, and are capable of disrupting the fundamental biogeochemical processes of the Earth.

"Linkages in ecosystems are both stronger and stranger than we imagined," said Stephen R. Carpenter, a UW-Madison limnologist who, with fellow limnologists Daniel E. Schindler and James F. Kitchell, authored the report. "Biological processes have powerful feedbacks to processes that are normally thought to be purely physical or chemical in nature."

While lakes occupy a very small area of the planet's surface, the discovery that simple biotic change is capable of altering the exchange of carbon between the atmosphere and the Earth's surface raises questions of global significance, said Carpenter.

"To what extent could fertilization of the oceans and alteration of oceanic food webs affect global carbon cycles? In fact, runoff from land is now enriching coastal oceans to unprecedented levels, and industrial fishing is causing massive changes in marine food webs. So the global experiment is underway," said Carpenter.

Carbon, an essential nutrient in lakes, typically flows from the land in the formof dead leaves and other organic matter that accumulates and decays underwater. Usually, these processes lead to a surplus of carbon dioxide in lakes. Excess carbon in a lake is released as a gas, carbon dioxide, to the atmosphere.

When there is a deficit of carbon dioxide, however, lakes draw the gas directly from the atmosphere.

Working on an isolated, undeveloped suite of lakes in Michigan's Upper Peninsula, the Wisconsin scientists were able to manipulate the flow of carbon between an entire, intact ecosystem and the atmosphere by placing either minnows or bass at the apex of the lake food web.

Bass, by preying on the minnows that consume algae-grazing zooplankton, effectively increased the flow of carbon to the atmosphere by freeing zooplankton from their predators. The booming zooplankton populations grazed the algae to the point where they were no longer a force to use the lake's excess carbon. The lakes, in effect, became pumps, expelling unused carbon to the atmosphere.

In lakes dominated by minnows, whose menus include algae-eating zooplankton, burgeoning algae populations and their photosynthetic requirements resulted in a carbon deficit, and the lakes become carbon sinks, drawing carbon directly from the atmosphere.

"This effect of fishes on gas exchange results from the changes in aquatic food webs that are regulated by the species of fish present in a particular lake," said Schindler.

The changes in lakes, Schindler emphasized, will not have implications for global climate. However, the new understanding of the processes that alter the exchange of carbon dioxide between lakes and the atmosphere can be generalized to other ecosystems such as oceans.

"Although the consequences ... are much less known for marine systems than for lakes, we should expect that the ecological responses to exploitation are similar in many ways," Schindler said.

The work done by the Wisconsin scientists was funded by the National Science Foundation and conducted under the auspices of the UW-Madison Center for Limnology.

###- Terry Devitt (608) 262-8282, [email protected]

(Editor's note: Limnologist Daniel E. Schindler is in transition from the University of Wisconsin-Madison to the University of Washington in Seattle. He can best be reached through the University of Washington's Office of News and Information at(206) 543-2580.)


Story Source:

The above story is based on materials provided by University Of Wisconsin-Madison. Note: Materials may be edited for content and length.


Cite This Page:

University Of Wisconsin-Madison. "Subtle Biotic Changes Have Big Environmental Impact." ScienceDaily. ScienceDaily, 11 July 1997. <www.sciencedaily.com/releases/1997/07/970711093659.htm>.
University Of Wisconsin-Madison. (1997, July 11). Subtle Biotic Changes Have Big Environmental Impact. ScienceDaily. Retrieved November 26, 2014 from www.sciencedaily.com/releases/1997/07/970711093659.htm
University Of Wisconsin-Madison. "Subtle Biotic Changes Have Big Environmental Impact." ScienceDaily. www.sciencedaily.com/releases/1997/07/970711093659.htm (accessed November 26, 2014).

Share This


More From ScienceDaily



More Earth & Climate News

Wednesday, November 26, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Bolivian Recycling Initiative Turns Plastic Waste Into School Furniture

Bolivian Recycling Initiative Turns Plastic Waste Into School Furniture

Reuters - Innovations Video Online (Nov. 26, 2014) Innovative recycling project in La Paz separates city waste and converts plastic garbage into school furniture made from 'plastiwood'. Tara Cleary reports. Video provided by Reuters
Powered by NewsLook.com
Antarctic Sea Ice Mystery Thickens... Literally

Antarctic Sea Ice Mystery Thickens... Literally

Newsy (Nov. 25, 2014) Antarctic sea ice isn't only expanding, it's thicker than previously thought, and scientists aren't sure exactly why. Video provided by Newsy
Powered by NewsLook.com
3D Map of Antarctic Sea Ice to Shed Light on Climate Change

3D Map of Antarctic Sea Ice to Shed Light on Climate Change

Reuters - Innovations Video Online (Nov. 24, 2014) A multinational group of scientists have released the first ever detailed, high-resolution 3-D maps of Antarctic sea ice. Using an underwater robot equipped with sonar, the researchers mapped the underside of a massive area of sea ice to gauge the impact of climate change. Ben Gruber reports. Video provided by Reuters
Powered by NewsLook.com
Car Park Solution for Flexible Green Energy

Car Park Solution for Flexible Green Energy

Reuters - Innovations Video Online (Nov. 24, 2014) A British solar power start-up says that by covering millions of existing car park spaces around the UK with flexible solar panels, the country's power problems could be solved. Suzannah Butcher reports. Video provided by Reuters
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:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

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