From the distant reaches of the universe, to black holes and Saturn’s rings, NASA explores some of the most far-out parts of space. But NASA also does research much closer to home. In fact, NASA Earth Science satellites are taking part in the management and recovery of an ecosystem right in our own backyard, the Chesapeake Bay.
By studying the landscape around the Chesapeake, NASA spacecraft such
as Landsat, Terra and Aqua are helping land managers figure out how to
battle the harmful pollutants that have added to the destruction of the
bay's once legendary productivity. While still a commercially important
ecosystem -- home to some 3,600 species -- four centuries of local
population growth have crippled the bay’s health, earning it a place on the U.S. Environmental Protection Agency’s “dirty waters” list and a 2007 overall grade of C-minus by the University of Maryland Center for Environmental Science.
Many of these harmful pollutants come from the Chesapeake Bay’s watershed, an area of about 64,000 square miles that covers parts of six states. Water from this massive region constantly drains into the bay, carrying with it sediments from erosion, excessive nutrients and other contaminants that hurt the bay’s water quality. This runoff also feeds large algae blooms that consume oxygen in the water; oxygen that crabs, fish and other bay species rely on.
Runoff carries more pollutants when it travels over paved surfaces and
cropland, versus marshland or forest. Land cover information from
satellite imagers like Landsat and the Moderate Resolution Imaging
Spectroradiometer (MODIS) help Bay managers identify the best places to
curb non-point source pollution.
“The impervious, tree cover and land cover type map products derived from Landsat data are used on a daily basis by the Chesapeake Bay Program,” says Scott Goetz, a NASA-funded scientist at Woods Hole Research Center, whose team used Landsat data to create a series of Chesapeake watershed maps.
The Chesapeake Bay Program is a unique regional partnership that leads
and directs the restoration of the bay. They often use Landsat data to
help build models that predict the location of nutrient loads and
identify areas where managers should take action towards conservation,
restoration and growth.
In addition, NASA sensors SeaWiFS and MODIS detect water color, and are
used to calculate sediment and chlorophyll concentrations. The National
Oceanic and Atmospheric Administration’s CoastWatch program provides this type of oceanographic data in near real-time to federal, state and local marine scientists, coastal resource managers and the general public.
Other organizations, such as the Virginia Department of Conservation
and Recreation and the Maryland Department of Natural Resources, also
use NASA-derived information to prioritize land conservation efforts.
The states have now set nutrient and sediment reduction targets for
each of the Chesapeake watershed sub-regions thanks to a
Landsat-enabled assessment of relative pollution contributions.
In all these ways, NASA satellites are helping Chesapeake Bay managers
reduce harmful pollutants. If the bay is ever to recover enough to be
taken off of the "dirty waters" list, NASA data will be essential for deciding how to best care for our troubled neighbor.
Article by Andrew Freeberg, NASA Goddard Space Flight Center.
|
 |
|
The Chesapeake Bay Landsat-7 Mosaic is a composite of eight Landsat-7
scenes acquired during the period of 1999-2002, where each pixel
represents about 15 square meters on the ground. The original dataset
was a false-color Landsat-7 (ETM+) image using bands 7,4,2 and the
panchromatic band (8). Color correction has been applied to resemble
natural looking colors. Image: NASA/Goddard Space Flight Center Scientific Visualization Studio |
|
