Featured Research

from universities, journals, and other organizations

Black Water Turns The Tide On Florida Coral

Date:
April 22, 2003
Source:
NASA/Goddard Space Flight Center--EOS Project Science Office
Summary:
In early 2002, a patch of "black water" spanning over 60 miles in diameter formed off southwestern Florida and contributed to severe coral reef stress and death in the Florida Keys, according to results published from research funded by NASA, the U.S. Environmental Protection Agency and the National Oceanic and Atmospheric Administration (NOAA). The "black water" contained a high abundance of toxic and non-toxic microscopic plants.

In early 2002, a patch of "black water" spanning over 60 miles in diameter formed off southwestern Florida and contributed to severe coral reef stress and death in the Florida Keys, according to results published from research funded by NASA, the U.S. Environmental Protection Agency and the National Oceanic and Atmospheric Administration (NOAA). The "black water" contained a high abundance of toxic and non-toxic microscopic plants.

Chuanmin Hu and other colleagues at the Institute for Marine Remote Sensing of the University of South Florida (USF), St. Petersburg, Fla., and colleagues from the Florida Fish and Wildlife Conservation Commission (FFWCC) and the University of Georgia, co-authored an article on this phenomenon that appeared as the cover story of a recent issue of the American Geophysical Union's Geophysical Research Letters.

"The water appeared black in satellite imagery because the concentration of the microscopic plants and other dissolved matters were high," Hu said. Because plants and dissolved matter absorb sunlight, they reduce the amount of light normally reflected from the ocean.

When a red-tide bloom occurs the water takes on various hues of red or brown. While not all microscopic plants contribute to red tides, the darker hue created by both the plankton and the harmful algal blooms made the water appear black when seen from the satellite.

When Hu and his colleagues examined the data collected by divers from the dark water area in the Florida Keys, they discovered a 70 percent decrease in stony coral cover, a 40 percent reduction of coral species, and a near-elimination of sponge colonies at two reef sites after the dark water passed. By examining satellite images and field survey data, the authors concluded that the coral reef ecosystem was stressed by microscopic organisms and toxins contained in the dark water.

The "black water" event caused alarm among local fishermen, divers, and the public, as the color of the water was unusual and fish seemed to avoid this large area of dark water. Satellite instruments such as the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) aboard Orbimage's SeaStar satellite and the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA's Terra and Aqua satellites provide information on ocean color that allows scientists to monitor the health of the water and the shallow benthic (ocean bottom) environment. The SeaWiFS and MODIS measurements of the dark water led to a number of investigations to help clarify the issues and to provide answers to the public's concerns.

During January 2002, SeaWiFS detected the dark-colored water in the Florida Bight, just southwest of the Everglades. In fall 2001, the SeaWiFS images showed an extensive red tide off Florida's central west coast, near Charlotte Harbor.

Red tides occur every year off Florida and are known to cause fish kills, coral stress and mortality, and skin and respiratory problems in humans. They are caused by high concentration of microscopic plants called dinoflagellates. Other microorganisms called cyanobacteria can also cause harmful algal blooms. The waters containing this red tide migrated to the south along the coast.

Winter storms caused large amounts of fresh water to drain from the Everglades into Florida Bight (the curve in the shoreline from the Keys north to Everglades National Park on the mainland), carrying high levels of nutrients such as silicate, phosphorus, and nitrogen to the sea. These caused a bloom of the microscopic marine plants known as diatoms in the same patch. The bloom turned the water dark and the "black water" patch re-circulated for several months in a slow clockwise motion off southwest Florida in the Florida Bight. Slowly, the dark water drifted farther south and toward the Florida Keys. By May 2002, the "black water" had moved through passages in the Florida Keys, dispersing into the Atlantic and the Gulf Stream.

Co-authors on this research article included Serge Andrefouet and Frank E. Muller-Karger of USF; Keith E. Hackett, Michael K. Callahan, and Jennifer L. Wheaton of FFWCC, St. Petersburg, Fla.; and James W. Porter of the University of Georgia, Athens, Ga.

NASA funded part of this research as part of its Earth Science mission to understand and protect our home planet. NASA's Earth Science Enterprise is dedicated to understanding the Earth as an integrated system and applying Earth System Science to improve prediction of climate, weather, and natural hazards using the unique vantage point of space.


Story Source:

The above story is based on materials provided by NASA/Goddard Space Flight Center--EOS Project Science Office. Note: Materials may be edited for content and length.


Cite This Page:

NASA/Goddard Space Flight Center--EOS Project Science Office. "Black Water Turns The Tide On Florida Coral." ScienceDaily. ScienceDaily, 22 April 2003. <www.sciencedaily.com/releases/2003/04/030422074114.htm>.
NASA/Goddard Space Flight Center--EOS Project Science Office. (2003, April 22). Black Water Turns The Tide On Florida Coral. ScienceDaily. Retrieved September 16, 2014 from www.sciencedaily.com/releases/2003/04/030422074114.htm
NASA/Goddard Space Flight Center--EOS Project Science Office. "Black Water Turns The Tide On Florida Coral." ScienceDaily. www.sciencedaily.com/releases/2003/04/030422074114.htm (accessed September 16, 2014).

Share This



More Earth & Climate News

Tuesday, September 16, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

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
Researchers Explore Shipwrecks Off Calif. Coast

Researchers Explore Shipwrecks Off Calif. Coast

AP (Sep. 16, 2014) Federal researchers are exploring more than a dozen underwater sites where they believe ships sank in the treacherous waters west of San Francisco in the decades following the Gold Rush. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Isolated N. Korea Asks For International Help With Volcano

Isolated N. Korea Asks For International Help With Volcano

Newsy (Sep. 16, 2014) Mount Paektu volcano in North Korea is showing signs of life and there's not much known about it. 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:
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