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Bacteria Eat Up Oil in Antarctica |
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By Marcela Valente*
Argentine scientists are developing a biological process for combating oil spills in the extremely cold temperatures of the immense ice-covered continent.
BUENOS AIRES - For the past 25 years it has been known that certain bacteria are useful for cleaning up oil spills in warmer climates, where the microorganisms easily reproduce and decompose contaminants. This technique might now be used in Antarctica, thanks to the discoveries of two Argentine scientists.
Biologist Walter MacCormack, of the Argentine Antarctic Institute, and biochemist Lucas Ruberto, of the University of Buenos Aires, set out to find an efficient "biological remediation process" for extremely cold conditions, like those in Antarctica, where the average temperature is below freezing.
Such processes, using microorganisms to clean up soil contaminated by fossil fuels or heavy metals, have an established history.
But "the bacteria that break down fossil fuels tend to reproduce at temperatures between 20 and 30 degrees Celsius," MacCormack told Tierramérica.
"At four degrees, they do not grow, and the (decontamination) processes were not successful or were too slow to be considered efficient," he added.
And there was another problem.
The Madrid Protocol, which establishes environmental protection standards for Antarctica, prohibits the introduction of viruses, bacteria or any microorganism from other regions, and also bans taking samples from the frozen continent, except for previously authorized scientific purposes.
The Protocol is an annex of the Antarctic Treaty, which has been in force since 1961. There are 45 member states, with 12 holding consultative status: Argentina, Australia, Belgium, Britain, Chile, France, Japan, New Zealand, Norway, Russia, South Africa and United States.
These restrictions forced the Argentine scientists to use locally available bacteria in all of their tests. The solution came from the "sicrofilo facultativo", which can grow at very low temperatures but can adapt to a climate of more than 20 degrees Celsius.
The experiments were conducted at Argentina's bases on the Antarctic Peninsula, a thousand km south of South America, where the climate is less extreme than on greater Antarctica, and on summer days temperatures can reach 20 degrees.
The studies proved that biological remediation is possible in Antarctica, although there is not a single strategy: it depends on the extent of the contamination and on the history of the soils being treated.
For example, the scientists worked with the bacteria in soils saturated with petroleum products from nearby fuel storage tanks.
In that microenvironment of chronic contamination from repeated gasoline spills, the soil is "accustomed" to the micro-flora, which proliferate in the presence of phosphorous and nitrogen and which break up the polluting residues.
To speed up the process in experiments, more nutrients were added, which achieved the elimination of 80 percent of the petroleum derivatives in less than 60 days.
But in soils contaminated for the first time by an oil or gasoline spill the response of the autochthonous microbes was not as efficient. It was necessary to introduce more bacteria, isolated in the spill zone, in order to accelerate the degradation process.
Compared to other soil clean-up systems, like incineration or washing, biological remediation costs less.
The tests "confirm that even in extreme environments there is a remarkable adaptation of the bacteria to the contaminating compounds, and that the (bio-remediation) process could prove satisfactory during the short summer period," conclude MacCormack and Ruberto in their report.
The same technique can be used in the southern Argentine region of Patagonia, where the country's petroleum and natural gas wealth is concentrated. Approximately 75 percent of Argentina's fossil fuel output comes from the provinces of Neuquén and San Jorge, both in Patagonia.
Biological clean-up began to be utilized more than two decades ago as a complement to the physical removal of soils contaminated by oil spills.
If an oil tanker sinks and its load reaches land, microorganisms are set to work after the initial efforts to remove the oil that has spilled.
"At sea, physical removal of the contaminant is more efficient," explained MacCormack.
But for soils contaminated by fossil fuels, clean-up using bacteria is ideal, according to the researchers.
"The soil contains the spill, so it is localized and therefore easier to apply bio-remediation techniques," MacCormack said.
The most common accidents on land are pipeline ruptures or leaks in fuel tanks, as well as spills in transport.
On the frozen southern continent, where the Antarctic Treaty bans petroleum or mineral exploitation, the contamination risks arise from shipping and storing fuels.
The most serious accident occurred in Antarctica in 1989, when the Bahia Paraiso tanker sank off the coast of the peninsula, spilling some 600,000 liters of diesel fuel near the Palmer Base of the United States, biologist José María Acero told Tierramérica.
The consequences "were not catastrophic because it was light fuel and strong winds carried it out to sea," said Acero, head of environmental management for the Argentine Antarctic Institute.
But there are many "small accidents" in handling fuels for the many research bases, and these are resolved through contingency plans, he said.
"In 1994 at Argentina's Marambio Base, a valve on a fuel tank broke and we lost 80,000 liters of fuel," but now there are mechanisms in place to prevent such accidents.
But MacCormack and Ruberto's discovery is important because it could be used to deal with a major spill in Antarctica, a 14 million-square-km natural laboratory for scientific research.
* Marcela Valente is an IPS correspondent.
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