SEAWIFS
SENSOR MARKS FIVE YEARS
DOCUMENTING EARTH'S DYNAMIC BIOSPHERE (For
images and animations, click here) In
the last five years, scientists have been able to monitor our changing planet
in ways never before possible. The Sea-viewing Wide Field-of-View Sensor (SeaWiFS),
aboard the OrbView-2 satellite, has given researchers an unprecedented view of
the biological engine that drives life on Earth -- the countless forms of plants
that cover the land and fill the oceans. "There
is no question the Earth is changing. SeaWiFS has enabled us, for the first time,
to monitor the biological consequences of that change -- to see how the things
we do, as well as natural variability, affect the Earth's ability to support life,"
said Gene Carl Feldman, SeaWiFS project manager at NASA's Goddard Space Flight
Center, Greenbelt, Md. Click
here for full press release. INTRODUCTION
Right now,
almost half the oxygen you breathe is made by tiny single celled sea plants called
phytoplankton. With the launch of the Sea-viewing Wide Field-of-view Sensor (SeaWiFS)
five years ago on board the Orbview 2 satellite scientists had a new tool for
studying how these plants interact with the world. Their discoveries are revolutionizing
our understanding of our planet. PULSE
OF THE PLANET
If
the Earth had a heartbeat, its pulse has just been taken. Using fives years of
continual data from an orbiting instrument called SeaWiFS, NASA scientists have
amassed a first look at how carbon moves through the biosphere. Carbon is one
of the most essential elements for life, and experts say that this research is
a major step in the effort to monitor overall planetary health, from climate change
to the rhythms of life in oceans and on land. This web page highlights the most
remarkable and graceful participants in this dance of life.
NORTH ATLANTIC BLOOM Phytoplankton
thrives on two things: nutrients and sunlight. Every spring phytoplankton spreads
across the North Atlantic, like flowers spreading across open meadows. These explosive
growths of phytoplankton are called “blooms” and the North Atlantic
has one of the largest regular blooms in the world. How big is it? In this visualization
the area covered in green is larger than the Amazon rainforest in South America.
It’s so large that zooplankton, the next link on the food chain can’t
eat it all.
EXPLOSION IN THE GALAPAGOS This
sequence shows an instance when phytoplankton exploded around the Galapagos Islands,
signaling the beginning of a La Nina. Deep, cold, nutrient rich waters replaced
the warm El Nino waters that had choked off the phytoplankton’s food. This
color-enhanced image documents plankton concentrations during May 9-24, 1998,
and shows life returning in remarkable abundance. High phytoplankton concentrations
are shown in red.
REBOUND FROM EL NINO The
bloom associated with the 1997 to 1998 El Nino to La Nina transition event splashed
across the Pacific Ocean like pigment thrown across empty canvas. Jetting from
west to east for about 6,214 km, the explosive, yet short-lived growth spurt coincided
with significant rising of cold nutrient rich waters brought about by La Nina.
During the powerful 1997 El Nino event, SeaWiFS recorded little or no significant
growth of phytoplankton in the equatorial Pacific. HARMFUL
ALGAE BLOOM Every
good plankton needs an evil twin. For phytoplankton it’s red tide. March
28, 2001, scientists at NASA released satellite pictures of a cloud of algae that
was blamed for killing hundreds of tons salmon in the Atlantic. The culprit: a
slimy, green algae called chattonella that smothered the fish, killing 700 tons
off arm-raised salmon. The harmful algae bloom (HAB) was first detected on March
19, 2001. In the animation, the first image is a "true-color" shot of
the area; the second image is color enhanced, where the red indicates high concentrationsof
the poisonous chattonella algae along with phytoplankton. SAHARA
DUST REACHES THE U.S. If
you didn’t think weather from Africa could affect the United States, think
again. Dust from the annual Sahara sand storms the size of Spain reaches all the
way to Florida. Scientists speculate that these dust storms may be linked to red
tides in the Gulf. Eating shellfish poisoned by red tides can lead to paralysis
and memory problems.
AMAZON
RIVER OUTLET GIVES LIFE After
a 4000-mile journey through South America, the outflow from the Amazon River gives
life to phytoplankton. The sea plants thrive on the nutrients provided by the
Amazon. Along the Eastern side of South America, a bright red tail waves against
the largely blue-green background of surrounding Atlantic Ocean. That’s the
signature of intense photosynthesis. Billions of phytoplankton making their home
in those currents, feeding off carbon saturated foodstuffs and turning sunlight
into energy for life. BLACK
WATER EVENT When
a slimy black gelatinous mass swept through Florida Bay in early 2002 threatening
coral and marine life, SeaWiFS captured the scene from above. Images taken February
4, 2002, at the height of the black water event shows different colors of water
in Florida Bay. Scientists have linked the black water to a large algae bloom
fed by land run off. The development, growth and decline of the event can be seen
in the images taken January 9, February 4 and March 28, 2002. WHITING
EVENT It’s
mysterious, suspicious and white. Could it be another plankton bloom? Probably
not. NASA's SeaWiFS captured a mysterious flush of color spreading across Lake
Michigan, probably caused by elevated levels of calcium carbonate (chalk) sediment.
For most of the year the calcium carbonate remains dissolved in the cold water,
but as the lake warms, the calcium carbonate precipitates out of the water, forming
clouds of very small solid particles that from above appear as bright swirls.
Lake Erie is known for its white sediment, but this ghostly appearance in Lake
Michigan is unusual. A whiting event is caused when high concentrations of calcium
carbonate lead to the formation of chalky white clouds of the material underwater,
which "rain" calcium carbonate on the lake bottom. POSTER
CHILD, FALKLAND ISLANDS This
plankton bloom is probably the most photogenic. This picture showing a region
near the Falkland Islands is one of the most colorful portraits of the ocean.
There is a variety of deep blues, aqua and greens. The project manager of the
SeaWiFS research program liked this bloom so much that it became a poster on his
office door. BERING
SEA One
of the first images returned by SeaWiFS was of a bright blue light emanating from
the Bering Sea. It was a persistent and widespread bloom of the coccolithophorid.
This type of bloom is usually short-lived, but the bloom in the Bering Sea, seen
the summer of 1997, persisted into October. It reappeared the following spring
and summer. This phenomenon indicated that significant changes were occurring
in the Bering Sea -- changes that were related to larger alterations in the Pacific
Ocean and the global climate. LIONS
IN THE NORTH ATLANTIC Phytoplankton
can be quite creative. Check out what looks like a bright blue tiger found off
the coast of Newfoundland. Scientists speculate it’s a coccolithophore bloom.
LAUNCH OF SeaWiFS SeaWiFS
blasted into space August 1, 1997 on board the Orbview 2 satellite. Dropped from
an airplane at 40,000 feet, a Pegasus rocket lifted the satellite to its initial,
parking orbit of 278 kilometers. Through a series of rocket firings, the satellite's
orbit was slowly raised to its operational altitude of 705 kilometers above the
earth. SeaWiFS is considered a low cost mission, many orders of magnitude less
expensive than other Earth observing instruments. In scientific terms, however,
this little instrument has proved to be one of the space agency’s star performers,
it's highly focused mission parameters netting huge scientific returns for researchers
studying a wide variety of questions. CARBON’S
MOVEMENT THROUGH THE BIOSPHERE Life
in its most common forms demand a ready supply of a particular element if it’s
to thrive: carbon. Carbon is the root of all life on Earth, and as its complex
dance carries it through the biosphere, the Earth’s state of health responds.
By monitoring the color of reflected light via satellite, in this case. SeaWiFS,
scientists can determine how successfully plant life is photosynthesizing. A measurement
of photosynthesis is essentially a measurement of successful growth, and growth
means successful use of ambient carbon. Phytoplankton currently accounts for about
half of the Earth’s carbon sink, a process whereby the ocean plants absorb
carbon dioxide from the air for growth. The absorption of carbon dioxide by phytoplankton
plays a mitigating role in unrestrained global warming.
THINK SMALL: PHYTOPLANKTON AND THE CARBON CYCLE’S FOUNDATION
The
ocean is filled with life. One of the most important varieties found there is
the most humble: phytoplankton. They’re tiny, single celled plant organisms
that form the base of the oceanic food chain. For years, researchers have only
been able to study phytoplankton in discrete areas and synthesize a variety of
suppositions about how it interacts with the natural world. A global look at these
miniscule plants has not been possible, until now. DEEP
WATER FEAST: UPWELLINGS BRING NUTRIENTS TO THE SURFACE Large
phytoplankton blooms tend to coincide with natural phenomena that drive nutrient
rich water to the surface. The process is called upwelling. Here’s what’s
happening: winds coming off principal land masses push surface layers of water
away from the shore. Into the resulting wind-driven void deeper water underneath
the surface layers rushes in toward the coast,
bringing with it nutrients for
life to bloom. It’s different on the equator. There, water currents on either
side of the hemispheric dividing line are generally moving in opposite directions--again
due to planetary rotation and the Coriolis effect. As those currents rush past
each other they stensibly "peel back" the surface of the ocean, creating
a void for deeper water to rush in and take its place. Back
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