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 July 25, 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 July 25, 2014).

Share This




More Earth & Climate News

Friday, July 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Goma Cheese Brings Whiff of New Hope to DRC

Goma Cheese Brings Whiff of New Hope to DRC

Reuters - Business Video Online (July 24, 2014) The eastern region of the Democratic Republic of Congo, mainly known for conflict and instability, is an unlikely place for the production of fine cheese. But a farm in the village of Masisi, in North Kivu is slowly transforming perceptions of the area. Known simply as Goma cheese, the Congolese version of Dutch gouda has gained popularity through out the region. Ciara Sutton reports. Video provided by Reuters
Powered by NewsLook.com
Bill Gates: Health, Agriculture Key to Africa's Development

Bill Gates: Health, Agriculture Key to Africa's Development

AFP (July 24, 2014) Health and agriculture development are key if African countries are to overcome poverty and grow, US software billionaire Bill Gates said Thursday, as he received an honourary degree in Ethiopia. Duration: 00:36 Video provided by AFP
Powered by NewsLook.com
Higgins Breaks Record at Mt. Washington

Higgins Breaks Record at Mt. Washington

Driving Sports (July 24, 2014) Subaru Rally Team USA drivers David Higgins and Travis Pastrana face off against a global contingent of racers at the annual Mt. Washington Hillclimb in New Hampshire. Includes exclusive in-car footage from Higgins' record attempt. Video provided by Driving Sports
Powered by NewsLook.com
Storm Kills Three, Injures 20 at Virginia Campground

Storm Kills Three, Injures 20 at Virginia Campground

Reuters - US Online Video (July 24, 2014) A likely tornado tears through an eastern Virginia campground, killing three and injuring at least 20. Linda So 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:
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