Featured Research

from universities, journals, and other organizations

Fishery collapse near Venezuela linked to climate change

Date:
October 18, 2012
Source:
University of South Carolina
Summary:
Even small increases in temperature from global warming are causing climatology shifts harmful to ocean life, a new study shows. Modest changes in temperature have significantly altered trade wind intensity in the southern Caribbean, undercutting the supply of key phytoplankton food sources and causing the collapse of some fisheries there.

Storm clouds off the Venezuelan coast.
Credit: Robert Thunell, University of South Carolina

Even small increases in temperature from global warming are causing climatology shifts harmful to ocean life, a new study in the Proceedings of the National Academies of Science shows. Modest changes in temperature have significantly altered trade wind intensity in the southern Caribbean, undercutting the supply of key phytoplankton food sources and causing the collapse of some fisheries there.

"Global warming isn't occurring uniformly over the Earth's surface -- it's been much greater at the high latitudes in the Northern Hemisphere than it has been for the low latitudes," said co-author Robert Thunell, a University of South Carolina researcher. "Because of that, some people have said, 'Well, we're probably not going to see much biotic change at low latitudes,' but we show nicely in this paper that even when the climatological changes are relatively modest, they can have a big impact on the marine ecosystem."

The paper is the product of nearly 15 years of observations in a highly collaborative NSF-funded effort between researchers at USC, Stony Brook University, the University of South Florida and several Venezuelan institutions. Since late 1995, monthly observations of a range of variables, from nutrient and chlorophyll concentrations to meteorological readings, have been collected at a single location off the coast of Venezuela to establish a long-range record.

The sea surface temperature was found to have increased somewhat, about 1 degree Celsius, over the decade-and-a-half. But the effect on the sea life was much more pronounced: beginning in 2006, the population of microscopic diatoms, dinoflagellates and coccolithophorids plummeted, along with the local harvest of sardines.

The team thinks the drastic change in ecology results from climatology shifts that go beyond a small temperature increase.

"The intertropical convergence zone is where the northeast and southeast trade winds converge," said Thunell, of the Department of Earth and Ocean Sciences in USC's College of Arts and Sciences. "It's basically the thermal equator, and it doesn't sit right on the geographic equator because it's a little bit warmer in the north. That's because there's more land mass in the northern hemisphere.

"And because of that extra land mass, the northern hemisphere is actually heating more than the southern hemisphere through global warming. We've proposed that this thermal equator, over the last 15 years, has moved a little bit farther northward. So the strength of the trade winds now over our region of study has decreased."

That diminished wind is cutting the food supply for some fish, the team concludes. The upwelling of ocean water, which is a source of nutrients for phytoplankton, depends on the mixing that winds provide. Less wind thus means less mixing, fewer nutrients for phytoplankton, and fewer phytoplankton to sustain the fish population.

"That's a big deal. The plankton near the surface of the ocean are the base of the food chain," Thunell said. "This climatological change is driving a change in the food web structure, which we're now seeing affect the fisheries."


Story Source:

The above story is based on materials provided by University of South Carolina. The original article was written by Steven Powell. Note: Materials may be edited for content and length.


Journal Reference:

  1. G. T. Taylor, F. E. Muller-Karger, R. C. Thunell, M. I. Scranton, Y. Astor, R. Varela, L. T. Ghinaglia, L. Lorenzoni, K. A. Fanning, S. Hameed, O. Doherty. Ecosystem responses in the southern Caribbean Sea to global climate change. Proceedings of the National Academy of Sciences, 2012; DOI: 10.1073/pnas.1207514109

Cite This Page:

University of South Carolina. "Fishery collapse near Venezuela linked to climate change." ScienceDaily. ScienceDaily, 18 October 2012. <www.sciencedaily.com/releases/2012/10/121018094853.htm>.
University of South Carolina. (2012, October 18). Fishery collapse near Venezuela linked to climate change. ScienceDaily. Retrieved October 21, 2014 from www.sciencedaily.com/releases/2012/10/121018094853.htm
University of South Carolina. "Fishery collapse near Venezuela linked to climate change." ScienceDaily. www.sciencedaily.com/releases/2012/10/121018094853.htm (accessed October 21, 2014).

Share This



More Earth & Climate News

Tuesday, October 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Traditional Farming Methods Gaining Ground in Mali

Traditional Farming Methods Gaining Ground in Mali

AFP (Oct. 20, 2014) He is leading a one man agricultural revolution in Mali - Oumar Diatabe uses traditional farming methods to get the most out of his land and is teaching others across the country how to do the same. Duration: 01:44 Video provided by AFP
Powered by NewsLook.com
How Detroit's Money Woes Led To U.N.-Condemned Water Cutoffs

How Detroit's Money Woes Led To U.N.-Condemned Water Cutoffs

Newsy (Oct. 20, 2014) The United Nations says water is a human right, but should it be free? Detroit has cut off water to residents who can't pay, and the U.N. isn't happy. Video provided by Newsy
Powered by NewsLook.com
Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-Fuel Impala

Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-Fuel Impala

3BL Media (Oct. 20, 2014) Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-fuel Impala Video provided by 3BL
Powered by NewsLook.com
White Rhino's Death In Kenya Means Just 6 Are Left

White Rhino's Death In Kenya Means Just 6 Are Left

Newsy (Oct. 20, 2014) Suni, a rare northern white rhino at Ol Pejeta Conservancy, died Friday. This, as many media have pointed out, leaves people fearing extinction. Video provided by Newsy
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