Aleph Null
02-11-2005, 09:34 AM
http://www.wired.com/news/technology/0,1282,66571,00.html?tw=wn_tophead_3
Pollution May Feed Plankton
By Amit Asaravala
02:00 AM Feb. 11, 2005 PT
A surprising chain of events and chemical reactions link a rise in air pollution over land to a decrease in a common greenhouse gas over sea, announced researchers at the Georgia Institute of Technology on Thursday.
The chain includes the participation of dust storms in the Gobi Desert, the buildup of harmful sulfur dioxide over coastal industrial zones, and a burst in the population of tiny plants in the sea known as phytoplankton, said the researchers. The end result is a decrease in atmospheric carbon dioxide, they said. Carbon dioxide contributes to global warming by preventing heat from escaping the atmosphere, the way the walls of a greenhouse prevent heat from escaping an enclosed space.
The researchers acknowledged the seemingly ironic twist in their findings, but noted that the study should not be taken as evidence to ease regulations on polluters. Rather, it's a sign that more research is needed to understand the effect that humans have on the environment, they said.
"The link shows how fragile this environment is," said the study's lead author Nicholas Meskhidze, a postdoctoral fellow at Georgia Tech's School of Earth and Atmospheric Sciences. "All this is tied up and it's a very delicate balance. Every time you change something, it has consequences."
Reducing the amount of sulfur dioxide emitted by factories is still an important goal because the acid rain it causes is still harmful to humans and the environment, he added.
Meskhidze and his co-author, professor William Chameides, used data from ground, air and satellite observations made over Asia in 2001 for their study. The data revealed a process that begins with the formation of small dust storms over the Gobi Desert in northern China and southern Mongolia. The storms pick up large quantities of the mineral iron and carry it to industrialized regions along the coast, like Shanghai. There, the iron mixes with the sulfur dioxide that factories have pumped into the air.
The mixing process lowers the acidity of the dust to a level where the iron can easily be dissolved in water. The transformed iron is carried out to sea in a storm before settling in the water, where it becomes the ultimate nutrient for phytoplankton. To complete the chain, the phytoplankton bloom and begin to use up carbon dioxide during the process of photosynthesis.
Larger dust storms don't seem to have the same effect because their acidity is reduced by the great amounts of calcium carbonate that they carry. In essence, they can't pick up enough sulfur dioxide to convert the iron into a dissolvable form.
A paper outlining this process and the study's conclusions will appear in the Feb. 16 issue of the Journal of Geophysical Research -- Atmospheres.
Though Meskhidze said he stands by his results, he cautioned that further research is needed to understand just how much carbon dioxide is being pulled from the air through this process. It will also be important to see if the process is being repeated in other locations around the world where dust storms and air pollution mix, he said.
"This is the first step in the right direction," he said. "It says that we need to start thinking about these sorts of connections in the ecosystem. There could be way more mechanisms involved and more links to be found."
Pollution May Feed Plankton
By Amit Asaravala
02:00 AM Feb. 11, 2005 PT
A surprising chain of events and chemical reactions link a rise in air pollution over land to a decrease in a common greenhouse gas over sea, announced researchers at the Georgia Institute of Technology on Thursday.
The chain includes the participation of dust storms in the Gobi Desert, the buildup of harmful sulfur dioxide over coastal industrial zones, and a burst in the population of tiny plants in the sea known as phytoplankton, said the researchers. The end result is a decrease in atmospheric carbon dioxide, they said. Carbon dioxide contributes to global warming by preventing heat from escaping the atmosphere, the way the walls of a greenhouse prevent heat from escaping an enclosed space.
The researchers acknowledged the seemingly ironic twist in their findings, but noted that the study should not be taken as evidence to ease regulations on polluters. Rather, it's a sign that more research is needed to understand the effect that humans have on the environment, they said.
"The link shows how fragile this environment is," said the study's lead author Nicholas Meskhidze, a postdoctoral fellow at Georgia Tech's School of Earth and Atmospheric Sciences. "All this is tied up and it's a very delicate balance. Every time you change something, it has consequences."
Reducing the amount of sulfur dioxide emitted by factories is still an important goal because the acid rain it causes is still harmful to humans and the environment, he added.
Meskhidze and his co-author, professor William Chameides, used data from ground, air and satellite observations made over Asia in 2001 for their study. The data revealed a process that begins with the formation of small dust storms over the Gobi Desert in northern China and southern Mongolia. The storms pick up large quantities of the mineral iron and carry it to industrialized regions along the coast, like Shanghai. There, the iron mixes with the sulfur dioxide that factories have pumped into the air.
The mixing process lowers the acidity of the dust to a level where the iron can easily be dissolved in water. The transformed iron is carried out to sea in a storm before settling in the water, where it becomes the ultimate nutrient for phytoplankton. To complete the chain, the phytoplankton bloom and begin to use up carbon dioxide during the process of photosynthesis.
Larger dust storms don't seem to have the same effect because their acidity is reduced by the great amounts of calcium carbonate that they carry. In essence, they can't pick up enough sulfur dioxide to convert the iron into a dissolvable form.
A paper outlining this process and the study's conclusions will appear in the Feb. 16 issue of the Journal of Geophysical Research -- Atmospheres.
Though Meskhidze said he stands by his results, he cautioned that further research is needed to understand just how much carbon dioxide is being pulled from the air through this process. It will also be important to see if the process is being repeated in other locations around the world where dust storms and air pollution mix, he said.
"This is the first step in the right direction," he said. "It says that we need to start thinking about these sorts of connections in the ecosystem. There could be way more mechanisms involved and more links to be found."