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Background Information
About Phytoplankton,
Phytoplankton 
[These are a GREEN variety
as opposed to the BROWN or RED Phytoplankton]
Phytoplankton are algae, microscopic
single-celled plants that float in the surface waters of the oceans,
lakes, and rivers. In the ocean, they make up the base of the marine food
web, and are thus called the "pasture of the sea". Phytoplankton
make food by photosynthesis, and thus depend on sunlight and a source of
nutrients, such as nitrogen, carbon and phosphorous. Zooplankton, which
are microscopic (meaning:floating) animals, depend on phytoplankton for
nourishment, and other larger sea animals that eat off the zooplankton
and phytoplankton, are food for larger species in the marine food ecosystem.
Sunlight is scattered and
absorbed rapidly in surface waters and different wavelengths of light penetrate
to different depths. Sea water becomes progressively blue-green as it gets
deeper because the longer wavelengths of light are rapidly lost through
absorption. Plants need the sun's energy to combine carbon dioxide and
water to produce organic carbohydrates. Oxygen is the by-product of this
photosynthesis. The carbohydrates [food] produced by the phytoplankton
can nourish animals, which convert them into more complex compounds such
as fats and proteins. The reverse process of photosynthesis is "respiration",
through which energy is released for use in metabolic processes which keep
an organism alive.
Primary food production is
limited by
light, temperature, and the amounts of nutrients in the water. Temperature
determines the rate at which many chemical and biological reactions take
place, so seasonal variations occur as well as polar and tropical variations.
In several areas of the world, wind-driven upwellings occur between the
coast and the main boundary currents, due to interactions between the Trade
winds and the Coriolis
force. This intense mixing of water frees nutrients from the ocean
floor, and make them available for phytoplankton growth and production.
Ozone Depletion
Our protective ozone
layer in the atmosphere absorbs harmful Ultraviolet radiation from the
sun much like a protective blanket. Also, the ozone absorbs some energy
which is re-sent to warm the earth even more, like a cloud which prevents
these rays from returning back to the sun. Thus, it's thought of as one
of the "greenhouse" gases, along with carbon dioxide, methane, and water
vapor.
http://moby.ucdavis.edu/GAWS/122/1INDIA/Causes4.htm
[The above diagram was created
by the Davis Campus of the University
of California ]
Where there is less ozone, more Ultraviolet radiation gets through to
plants and animals on the Earth, and this may have a detrimental effect
on phytoplankton
growth.
Remote Sensing Research
Physical oceanographers
know that "happy" phytoplankton, which have rich harvests of food, give
off a color reflectance which can be detected with special instruments.
The chlorophyll pigments in the plants absorb light, and the plants themselves
scatter light. Thus, the color of rich phytoplankton blooms seen by an
observer appear blue-green, and pure water looks dark blue. Satellite instruments
measure the amount of reflected light of different wavelengths. Many different
species of plankton contribute to ocean color, but only a few species,
occuring in great numbers, are found at any one time or place. The
individual plants live at various depths, from the surface to nearly 100
meters, but most phytoplankton are found on the surface regions where
sunlight supports photosynthesis.
At the Rutgers University Institute
of Marine and Coastal Sciences, researchers are studying the marine
environment ecology and the effects of Ultraviolet radiation on the growth
of marine phytoplankton.They use several types of data collection. The
Leo-15, which stands for Longterm Ecosystem underwater Observatory,
is moored off the coast of Tuckerton, New Jersey, USA.
Upwelling Events
This is a NOAA
image of a New York Bight.When
constant southwest winds dominate the wind pattern along the Atlantic coast
for several consecutive days, warm water along our coast moves away from
the shore, and cold water from beneath moves in to replace it. This brings
fresh nutrients up to the sunny surface layers where the phytoplankton
use them for photosynthesis. Thus, even in cold waters of the coast of
Antarctica, some types of phytoplankton thrive. The Upwelling
events along the New Jersey shore often occur during the summertime,
so research in this area really begins to "hop" at the Rutgers University
Institute of Marine
and Coastal Sciences Remote Sensing labs.
Down welling is the opposite of an upwelling event,
so the combination of the organisms swimming towards the surface and the
water moving downwards results in a concentrated population which can be
seen on the ocean surface as long lines, streaks, or windows in the water.
Since the currents carry both nutrients and the organisms, a red tide may
continue for days or weeks. Red
tides are called this because the ocean water can look rust colored,
but the color varies from shades of red, pink, violet, orange, yellow,
blue, green or brown. Sometimes red tides can be hazardous for other ocean
animals. First, the phytoplankton may use up all the nutrients, out-competing
the other organisms. Then, as they die and decompose, the oxygen supply
used up by decomposing bacteria may cause the larger animals to suffocate
and die. A second way that red tides can harm an environment is by producing
poisonous by-products, called toxins. some of these toxins cause death
of fish, birds, and humans. The west coast of Florida is known for frequent
and extensive fish kills caused by red tides.
Global Climate Change
At last, there seems to
be significant evidence of
global, or worldwide, warmer temperatures, or global
warming. Evidence shows that there is more carbon dioxide in
the Earth atmosphere, and the "greenhouse effect" seems to be operating.
The concentration of carbon dioxide in the atmosphere has changed significantly
since the Industrial Revolution. Since then, humans on Earth have developed
a fossil-fuel-based global economy and lifestyle, and the amount of carbon
dioxide has increased as a result. As a result, less long-wavelength energy
from our Earth can escape to space. Many scientists believe this can lead
to a gradual
warming of the Earth, but others believe that different factors counteract
this warming effect. The Topex-Poseidon
researchers have created a graphic global conveyor belt for heat [shown
here
]
Carbon Cycle in Hydrology
Hydrology is the
study of bodies of water and the cycles of interactions which together
make up the Earth's Whole-climate ecology. The Carbon
Cycle involves the life cycle of carbon dioxide, which is an essential
agent in global warming.Carbon dioxide in the air is taken up by plants
(including Phytoplankton) and used in photosynthesis. As organic compounds
are used by these food-makers, some carbon dioxide is returned to the environment,
but most of the carbon is retained by their cells. The zooplankton and
other Phytoplankton-eaters get carbon when they eat plants, and higher-level
consumers get their carbon when they eat lower-level consumers as food.
Decomposers act on the dead organisms and extract carbon dioxide as a byproduct
to the air or ocean water. Because the oceans of our Earth are so deep
and vast in size, they act as a great "sink" which buffers the global climate
somewhat. In other words, the oceans absorb a great deal of carbon dioxide,
which in a larger abundance would tend to cause a significant increase
in global temperature. Phytoplankton are key in using up lots of carbon
dioxide from the atmosphere, so they are an important indicator of the
overall health of our planet.
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