Re: Natural causes of "greenhouse gasses"
- From: "PerfectlyAble" <jrhw@xxxxxxxxx>
- Date: 30 Aug 2006 20:09:07 -0700
Taylor wrote:
A natural explanation for greenhouse gasses? Whooda thunk? A newly
understood natural feedback mechanism, more deserts means more plankton food
means more CO2 absorbtion...
______________________________________________
Ocean plankton absorb less CO2
Nutrient-stressed plant plankton had been mistaken as healthy
The amount of carbon absorbed by plant plankton in large segments of the
Pacific Ocean is much less than previously estimated, researchers say.
US scientists said the tiny ocean plants were absorbing up to two billion
tonnes less CO2 because their growth was being limited by a lack of iron.
Iron deposits provide nutrients for the microbes, which in turn grow by
absorbing atmospheric carbon dioxide.
The findings have been published in the science journal Nature.
About 50 billion tonnes of carbon dioxide was estimated to be absorbed by
the world's oceans, so the reduction could mean up to 4% less CO2 being
sequestered than previously thought, the team of US researchers said.
Phytoplankton (tiny plants) play a key role in the world's carbon cycle, as
they are involved in about half the Earth's photosynthesis; along with
zooplankton (tiny animals), they form the base of the whole ocean food web.
Fluorescence fingerprint
The paper's lead author Michael Behrenfeld, from Oregon State University,
said that when stressed by a lack of iron, the phytoplankton created
additional pigments that glowed green, unlike normal pigments.
Dust storms deposit iron particles in the oceans (Nasa Goddard Space Flight
Center)
But satellite imagery used to monitor the oceans' plankton blooms could not
distinguish the difference, he said: "That green colour was not an
indication of health, it was an indication of stress from the lack of iron."
Professor Behrenfeld and his colleagues examined 12 years of data gathered
from 36,000 miles (57,900 km) of ship tracks through the tropical Pacific
Ocean.
This allowed them to establish a "fluorescence fingerprint" of what parts of
the ocean were experiencing iron-stress, as well as areas suffering from a
lack of nitrogen - another key element for ocean productivity.
Professor Behrenfeld said: "Nitrogen and phosphorus are nutrients that come
up from the ocean bottom to feed the upper water column.
"Iron, on the other hand, can come from the deep, but it also enters the
ocean through dust deposited by the wind. Windstorms blowing sand and dust
off large deserts are a major source of iron for the world's ocean," he
added.
The researchers identified three large areas of the Pacific where
phytoplankton appeared to be suffering from a lack of iron - the southern
ocean around Antarctica, the sub-arctic north below Alaska, and a vast area
in the tropical Pacific centred on the equator.
Many questions
Professor Peter Burkill, from the University of Southampton's National
Oceanographic Centre, said the study was a welcome contribution to the
growing understanding of oceans' roles in the global carbon cycle.
"We use oceanographic research vessels but they are very limited in their
operational capabilities and are also very costly.
"So we are turning to other techniques, such as satellite imagery. These are
not perfect but they do have the advantage of allowing us to look at great
swaths of the oceans," he added.
"Studies such as this help to calibrate these models but there are many
other questions out there that still need to be answered, such as how the
oceans' physics work and what happens to the carbon that is drawn down."
Professor Behrenfeld has also been involved in previous experiments in which
iron was added to the ocean in an attempt to boost productivity.
The studies showed that it did boost phytoplankton growth, but it did not
deliver the results that models had predicted.
Professor Behrenfeld said introducing iron was complex: "When you first do
it, there is an explosion of growth.
"Then you add a bit more iron, and the phytoplankton respond a bit more," he
said. "But at the same time you are promoting plankton growth, the grazers
that feed on them come to life because they suddenly have a more abundant
food supply."
What grazers, Japan ate them all! Plankton growth is saturated,
the article states its due to a lack of Iron but that doesn't make a
whole lot of sense with the numbers of old wreaks, cars, etc
rotting around the worlds seabeds. Actually nothing is mowing
the plankton lawn, plankton can get older and so less able to
keepup with their organisms demand for Iron. Very much
like out dear gloriously flake of a President, missing the dots.
Republicians have saturated the highest levels of government
and nobody has been cutting them down to size. They've
got so bloated on Pork that what looks like a deficiency is
actually inability to metabolies more Pork. Bridges to nowhere
see the light of day.
..
http://news.bbc.co.uk/2/hi/science/nature/5298004.stm
.
- Follow-Ups:
- Re: Natural causes of "greenhouse gasses"
- From: testingtesting24
- Re: Natural causes of "greenhouse gasses"
- Prev by Date: Gas chambers at Auschwitz saved Jewish lives .... literally ..
- Next by Date: Re: Global Warming; Gulf Stream Decreased 30%
- Previous by thread: Gas chambers at Auschwitz saved Jewish lives .... literally ..
- Next by thread: Re: Natural causes of "greenhouse gasses"
- Index(es):
Relevant Pages
|
