From: yee@trident.arc.nasa.gov (Peter E. Yee)
Subject: NASA studying Pacific Ocean plant productivity [Releases 92-135] (Forwarded)
Organization: NASA Ames Research Center, Moffett Field, CA
Date: Fri, 21 Aug 1992 18:44:22 GMT

Brian Dunbar
Headquarters, Washington, D.C.                                  August 20, 1992
(Phone:  202/358-0873)

Keith Koehler
Wallops Flight Facility, Wallops Island, Va.
(Phone:  804/824-1579)


RELEASE:  92-135

NASA STUDYING PACIFIC OCEAN PLANT PRODUCTIVITY

	NASA researchers will begin a 3-week airborne study on Aug. 20 to
increase understanding of microscopic plant productivity in the equatorial
region of the Pacific Ocean.

	Dr. Frank Hoge, principal investigator from Goddard Space Flight
Center's Wallops Flight Facility, Wallops Island, Va., said the principal
scientific objective is to understand why microscopic plant productivity is so
limited in the Pacific compared to the Atlantic Ocean.

	Microscopic plants, called phytoplankton, are an important part of the
marine food chain as nutrition for small animals and fish.  Phytoplankton also
plays an important role in the absorption of carbon dioxide from the
atmosphere.  Carbon dioxide is a "greenhouse gas" that traps heat near the
Earth's surface.  Increasing concentrations of carbon dioxide in the last 100
years, primarily through humans' use of fossil fuel, has led to concerns that
human activity may be increasing the Earth's temperature.

	Hoge points out that the Pacific Ocean equatorial region has amounts of
nutrient concentrations, sunlight and phytoplankton seed similar to those
found in the Atlantic Ocean.  However, phytoplankton in the Atlantic is more
abundant than in the Pacific, he said.

	The NASA-Wallops researchers will conduct their study during four
flights at 500 feet (152 meters) altitude, slightly less than the height of the
Washington Monument, using the Airborne Oceanographic Lidar (AOL) and
other instruments aboard Wallops' P-3B aircraft.  The flights are expected to
last about 12 hours each.


	The Wallops instruments on the aircraft allow researchers to survey
large stretches of the Pacific Ocean.  Hoge said the researchers will use
active and passive data-collection techniques to help them develop analytical
tools for future satellites that will map phytoplankton concentrations on a
world-wide scale.

	In addition to measuring the phytoplankton, the researchers also will
measure dissolved organic matter in the ocean.  Hoge said the organic matter
interferes with gathering accurate satellite phytoplankton measurements.

	The AOL transmits a green light pulse from a laser into the water where
the light is absorbed by the phytoplankton.  A receiver on the aircraft detects
the green light reflected from the water surface and red light which is
emitted by chlorophyll pigment in the phytoplankton.

	At the same time, another instrument on the aircraft is taking
measurements from sunlight reflected from the water and light emitted by
the chlorophyll.  Satellites, which lack the facilities to power a laser
system, measure changes in ocean color that indicate where concentrations of
phytoplankton are located.

	Wallops researchers will base their flights from Hilo, Hawaii.  They
will fly to 140 degrees west longitude and 5 degrees north of the equator.
Measurements will be taken in conjunction with the University of Washington
scientific research vessel "Thomas G. Thompson."

	Once the P-3 aircraft reaches 3 degrees south of the equator, the P-3
will turn toward the west taking measurements on both sides of the equator
as the plane advances towards Christmas Island.

	The NASA project is part of the Joint Global Ocean Flux Study
supported by the National Science Foundation, Washington, D.C.  The project
is managed by Wallops for NASA's Office of Space Science and Applications,
Washington, D.C.
Newsgroups: sci.environment,sci.engr.civil