Elvia Thompson<br />Headquarters, Washington October 1, 2003<br />(Phone: 202/358-1696)<br /><br /><br />Rob Gutro<br />Goddard Space Flight Center, Greenbelt, Md.<br />(Phone: 301/286-4044)<br /><br /><br />Mark Shwartz<br />Stanford University News Service, Calif.<br />(Phone: 650/723-9296)<br /><br /><br />RELEASE: 03-309<br /><br /><br />HUGE ANTARCTIC ICEBERG MAKES A BIG SPLASH ON SEA LIFE <br /><br /><br /> NASA satellites observed the calving, or breaking off, <br />of one of the largest icebergs ever recorded, named "C-19.<br /><br /><br />C-19 separated from the western face of the Ross Ice Shelf <br />in Antarctica in May 2002, splashed into the Ross Sea, and <br />virtually eliminated a valuable food source for marine life. <br />The event was unusual, because it was the second-largest <br />iceberg to calve in the region in 26 months.<br /><br /><br />Over the last year, the path of C-19 inhibited the growth of <br />minute, free-floating aquatic plants called phytoplankton <br />during the iceberg's temporary stopover near Pennell Bank, <br />Antarctica. C-19 is located along the Antarctic coast and <br />has diminished little in size. Since phytoplankton is at the <br />base of the food chain, C-19 affects the food source of <br />higher-level marine plants and animals.<br /><br /><br />Kevin R. Arrigo and Gert L. van Dijken of Stanford <br />University, Stanford, Calif., used chlorophyll data from <br />NASA's Sea-viewing Wide Field-of-view Sensor (SeaWiFS). The <br />instrument, on the OrbView-2 satellite, also known as <br />SeaStar, was used to locate and quantify the effects of C-19 <br />on phytoplankton. The researchers were able to pinpoint <br />iceberg positions by using images from the Moderate <br />Resolution Imaging Spectroradiometer (MODIS), an instrument <br />aboard NASA's Terra and Aqua satellites. The findings from <br />this NASA-funded study appeared in a recent issue of the <br />American Geophysical Union's Geophysical Research Letters.<br /><br /><br />C-19 is about twice the size of Rhode Island. When it broke <br />off the Ross Ice Shelf, the iceberg was 32 km (almost 20 <br />miles) wide and 200 km (124 miles) long. It was not as large <br />as the B-15 iceberg that broke off of the same ice shelf in <br />2001 but among the largest icebergs ever recorded.<br /><br /><br />Since it was so large, C-19 blocked sea ice from moving out <br />of the southwestern Ross Sea region. The blockage resulted <br />in unusually high sea-ice cover during the spring and <br />summer. Consequently, light was blocked. Phytoplankton <br />blooms that occur on the ocean surface were dramatically <br />diminished, and primary production was reduced by over 90 <br />percent, relative to normal years.<br /><br /><br />Primary production is the formation of new plant matter by <br />microscopic plants through photosynthesis. Phytoplankton is <br />at the base of the food chain. If they are not able to <br />accomplish photosynthesis, all organisms above them in the <br />food chain will be affected. "Calving events over the last <br />two decades indicate reduced primary productivity may be a <br />typical consequence of large icebergs that drift through the <br />southwestern Ross Sea during spring and summer," Arrigo <br />said.<br /><br /><br />Arrigo and van Dijken also used imagery from the Defense <br />Meteorological Satellite Program (DMSP) satellite Special <br />Sensor Microwave Imager and Scanning Multichannel Microwave <br />Radiometer, managed by the U.S. Department of Defense. The <br />data was used to monitor the impact of C-19 on the movement <br />of sea ice. The data is archived at the National Snow and <br />Ice Data Center, University of Colorado, Boulder.<br /><br /><br />Arrigo said most of the face of the Ross Ice Shelf has <br />already calved. There is another large crack, but it is very <br />difficult to predict if and when another large iceberg will <br />result. <br /><br /><br />NASA's Earth Science Enterprise is dedicated to <br />understanding the Earth as an integrated system and applying <br />Earth System Science to improve prediction of climate, <br />weather, and natural hazards using the unique vantage point <br />of space.<br /><br /><br />For more information and images, on the Internet, visit:<br />http://www.gsfc.nasa.gov/topstory/2003/1010iceberg.html<br /><br /><br />For information about SeaWiFS on the Internet, visit:<br />http://seawifs.gsfc.nasa.gov/<br /><br /><br />For information about MODIS on the Internet, visit:<br />http://modis.gsfc.nasa.gov/<br /><br /><br />For information about DMSP, visit:<br />http://www.dmsp.ngdc.noaa.gov/

It has been discovered that some of cracks in the Pine Island Glacier's floating an ice shelf. The calculation shows that the impending iceberg could be as large as 340 square miles. It become very serious issue on marines life.