Joined: 14 Aug 04
WASHINGTON - In a NASA study, scientists have concluded that when
Earth\'s climate warms, there is a reduction in the ocean\'s primary
food supply. This poses a potential threat to fisheries and
By comparing nearly a decade of global ocean satellite data with
several records of Earth\'s changing climate, scientists found that
whenever climate temperatures warmed, marine plant life in the form
of microscopic phytoplankton declined. Whenever climate temperatures
cooled, marine plant life became more vigorous or productive. The
findings will appear in the journal Nature on Dec. 7.
The results provide a preview of what could happen to ocean biology in
the future if Earth\'s climate warms as the result of increasing
levels of greenhouse gases in the atmosphere.
\"The evidence is pretty clear that the Earth\'s climate is changing
dramatically, and in this NASA research we see a specific consequence
of that change,\" said oceanographer and study co-author Gene Carl
Feldman of NASA\'s Goddard Space Flight Center, Greenbelt. Md. \"It is
only by understanding how climate and life on Earth are linked that
we can realistically hope to predict how the Earth will be able to
support life in the future.\"
Phytoplankton are microscopic plants living in the upper sunlit layer
of the ocean. They are responsible for approximately the same amount
of photosynthesis each year as all land plants combined. Changes in
phytoplankton growth and photosynthesis influence fishery yields,
marine bird populations and the amount of carbon dioxide the oceans
remove from the atmosphere.
\"Rising levels of carbon dioxide in the atmosphere play a big part in
global warming,\" said lead author Michael Behrenfeld of Oregon State
University, Corvallis. \"This study shows that as the climate warms,
phytoplankton growth rates go down and along with them the amount of
carbon dioxide these ocean plants consume. That allows carbon dioxide
to accumulate more rapidly in the atmosphere, which would produce
The findings are from a NASA-funded analysis of data from the
Sea-viewing Wide Field-of-view Sensor (SeaWiFS) instrument on the
OrbView-2 spacecraft, launched in 1997. SeaWiFS is jointly operated
by GeoEYE, Dulles, Va. and NASA.
The uninterrupted nine-year record shows in great detail the ups and
downs of marine biological activity or productivity from month to
month and year to year. Captured at the start of this data record was
a major, rapid rebound in ocean biological activity after a major El
Nino event. El Nino and La Nina are major warming or cooling events,
respectively, that occur approximately every 3-7 years in the eastern
Pacific Ocean and are known to change weather patterns around the
Scientists made their discovery by comparing the SeaWiFS record of the
rise and fall of global ocean plant life to different measures of
recent global climate change. The climate records included several
factors that directly effect ocean conditions, such as changes in sea
surface temperature and surface winds. The results support computer
model predictions of what could happen to the world\'s oceans as the
result of prolonged future climate warming.
\"When we compared changes in phytoplankton activity with simultaneous
changes in climate conditions, the agreement between the two records
was simply astonishing,\" Behrenfeld said.
Ocean plant growth increased from 1997 to 1999 as the climate cooled
during one of the strongest El Ni?o to La Ni?a transitions on record.
Since 1999, the climate has been in a period of warming that has seen
the health of ocean plants diminish.
The new study also explains why a change in climate produces this
effect on ocean plant life. When the climate warms, the temperature
of the upper ocean also increases, making it \"lighter\" than the
denser cold water beneath it. This results in a layering or
\"stratification\" of ocean waters that creates an effective barrier
between the surface layer and the nutrients below, cutting off
phytoplankton\'s food supply. The scientists confirmed this effect by
comparing records of ocean surface water density with the SeaWiFS
Joined: 29 Sep 04
We have to hope that this doesn\'t prove to be a seminal and prophetic report. Or hope that it\'s heeded.
Joined: 21 Oct 06
Why no body think about the more than 7 billion of people that brings every second a lot of Co2 and other gasses into the atmosphere, besides all the animals that do the same. Could that be a threat for our earth ?
Joined: 29 Sep 04
Quite a lot of members here do think that the number of human beings is a problem. And that problem #2 is the fact that the number is still rising rapidly. And that problem #3 is the lifestyles (ie behaviour) of some of the people.
Plants and non-human animals don\'t for the most part use fossil fuels (which in the circumstances is very fortunate). The animals that do use fossil fuel - animals raised intensively for food for humans - probably constitute problem #4, which is part of all the other problems.