[One-Minute World News] from [BBC NEWS]
[Science & Environment]
Page last updated at 23:35 GMT, Monday, 18 January 2010
By Mark Kinver
Science and environment reporter, BBC News
Exxon Valdez oil trapped by beach gravel, says study
{Oil from the Exxon Valdez spill was found just inches below the surface}
Large quantities of oil spilled during the 1989 Exxon Valdez disaster can still be found beneath gravel beaches in Alaska, a study has discovered.
Writing in Nature Geoscience, a team of scientists found that oil just a few inches down was dissipating up to 1,000 times slower than oil on the surface.
They suggested that a lack of oxygen and nutrients in the gravel was slowing the dispersal of the remaining oil.
The results could have implications for cleaning up future spills, they added.
Considered to be one of the worst environmental disasters of its kind, the Exxon Valdez tanker spilled 38,000 tonnes of crude oil into Alaska's Prince William Sound after the vessel hit a reef.
As a result, more than 2,000km (1,250 miles) of coastline was affected, killing thousands of seabirds and having a serious impact on the region's fishing industry.
In the five years after the disaster, the oil was shown to be dispersing at a rate of about 70% each year.
Most clean-up operations in the area ended in 1992 because the remaining oil was expected to disperse within a few years.
Lingering legacy
A later study discovered that the oil was disappearing at a rate of just 4% each year, and that an estimated 20,000 gallons remained in the beaches.
{The spill was one of the worst environmental disasters of its kind}
Researchers led by Professor Michel Boufadel from Temple University in Philadelphia, US, carried out a three-year study on a number of beaches to find out the cause behind the lingering deposits.
Prof Boufadel, director of the university's Center for Natural Resources Development and Protection, said the gravel beaches they examined were made up of two layers: a top level that was highly permeable, and a lower level that had very low permeability.
While the two layers were made from the same material, he said the lower level had become compacted as a result of tidal movements, limiting the volume of seawater that was able to penetrate the gravel.
In their paper, the team observed that the upper layer temporarily stored the oil, while it slowly and continuously filled the lower layer.
"You have a high amount of oxygen in the seawater, so you would think that the oxygen would diffuse in the beach and get down 2-4 inches (5-10cm) into the lower layer and get to the oil," said Prof Boufadel.
"But the outward movement of [fresh groundwater] in the lower level is blocking the oxygen from spreading down into that lower level."
{Scientists carried out the study to find out why the oil was "locked" in beaches}
He explained that oxygen and nutrients were needed to sustain micro-organisms that "ate" the oil.
However, without the necessary supply of the key ingredients reaching the lower level, the biodegradation of the oil was occurring at a much slower rate.
"We suggest that similar dynamics could operate on tidal gravel beaches around the world, which are particularly common in mid- and high-latitude regions," the team wrote in their paper.
"Thus, our findings are of direct application for the susceptibility of beaches worldwide to long-term oil contamination and provide guidelines for remediating oil-polluted beaches."
They added that climate change was reducing ice cover, "exposing the Arctic to oil exploitation and shipping" and increasing the risk of oil spills in the future.
Professor Boufadel and his team are now exploring ways to deliver the necessary levels of oxygen and nutrients to affected areas to accelerate the dissipation of the remaining oil.
[Science & Environment]
Page last updated at 22:53 GMT, Monday, 18 January 2010
By Doreen Walton
Science reporter, BBC News
Malignant malaria found in apes
{The malaria parasite was found in a sample from the cross river gorillla}
The parasite which causes malignant malaria in humans has been identified in gorillas for the first time.
Researchers analysed faeces from wild gorillas in Cameroon and blood samples from a captive animal from Gabon.
The study says increasing contact between humans and primates due to logging and deforestation raises the risk of transmission of new pathogens.
The research findings are published in Proceedings of the National Academy of Sciences journal.
New genetic sampling techniques allowed scientists from France, Cameroon, Gabon and the US to examine evidence of malaria parasites in the faecal matter of wild gorillas and chimpanzees in Cameroon.
"Sampling malaria parasites from apes in the wild has until now been very difficult", said Dr Francisco Ayala from the University of California, Irvine.
The team also took blood samples from wild born, pet animals in Gabon.
DNA evidence of Plasmodium falciparum, the parasite that causes malignant malaria in humans, was found in faecal samples from two gorilla subspecies, the highly endangered cross-river gorilla and the western lowland gorilla.
{{Even if it were eradicated in humans we would still have the problem that it's present in apes}
Dr Francisco Ayala, University of California, Irvine}
The parasite was identified in a blood sample from a captive gorilla.
Malaria parasites were first identified in chimpanzees and gorillas in Africa by scientists working in the 1920s.
But this new technology has allowed scientists to confirm the presence of P. falciparum.
Disease reservoir
P. falciparum is the most deadly type of malaria infection.
It is most common in Africa, south of the Sahara, where the World Health Organization says it accounts for a large part of the extremely high mortality in the region.
The study says that human destruction of the natural forest habitat means more contact with primates and greater chances of pathogen transmission between the two, including from humans to the endangered great apes.
Dr Ayala said the findings underline the danger of contact between the two. "Even if it were eradicated in humans we would still have the problem that it's present in apes and therefore they would be a reservoir for the disease.
"It's not clear what we can do with respect to this problem other than trying to decrease contact."
Endemic?
Dr Ian Hastings, senior lecturer at the Liverpool School of Medicine said it would help to know more about the spread of the parasite in gorillas.
"Mosquitoes often bite different species. Often they have a preference but if they can't find what they want to bite they'll just go and bite something else," he said.
"The question is whether this is just sporadic infection that's come from humans after the mosquito bit an infected person and passed it on to gorillas or whether it's endemic and is passed from gorilla to gorilla."
Dr Ayala acknowledges that Plasmodium parasites are much less malignant for apes than humans because primates have been exposed to them for so long.
"They have had P. reichenowi and perhaps other species for thousands or millions of generations, so one expects less malignancy to have taken place over time."
[Science & Environment]
Page last updated at 23:35 GMT, Monday, 18 January 2010
By Mark Kinver
Science and environment reporter, BBC News
Exxon Valdez oil trapped by beach gravel, says study
{Oil from the Exxon Valdez spill was found just inches below the surface}
Large quantities of oil spilled during the 1989 Exxon Valdez disaster can still be found beneath gravel beaches in Alaska, a study has discovered.
Writing in Nature Geoscience, a team of scientists found that oil just a few inches down was dissipating up to 1,000 times slower than oil on the surface.
They suggested that a lack of oxygen and nutrients in the gravel was slowing the dispersal of the remaining oil.
The results could have implications for cleaning up future spills, they added.
Considered to be one of the worst environmental disasters of its kind, the Exxon Valdez tanker spilled 38,000 tonnes of crude oil into Alaska's Prince William Sound after the vessel hit a reef.
As a result, more than 2,000km (1,250 miles) of coastline was affected, killing thousands of seabirds and having a serious impact on the region's fishing industry.
In the five years after the disaster, the oil was shown to be dispersing at a rate of about 70% each year.
Most clean-up operations in the area ended in 1992 because the remaining oil was expected to disperse within a few years.
Lingering legacy
A later study discovered that the oil was disappearing at a rate of just 4% each year, and that an estimated 20,000 gallons remained in the beaches.
{The spill was one of the worst environmental disasters of its kind}
Researchers led by Professor Michel Boufadel from Temple University in Philadelphia, US, carried out a three-year study on a number of beaches to find out the cause behind the lingering deposits.
Prof Boufadel, director of the university's Center for Natural Resources Development and Protection, said the gravel beaches they examined were made up of two layers: a top level that was highly permeable, and a lower level that had very low permeability.
While the two layers were made from the same material, he said the lower level had become compacted as a result of tidal movements, limiting the volume of seawater that was able to penetrate the gravel.
In their paper, the team observed that the upper layer temporarily stored the oil, while it slowly and continuously filled the lower layer.
"You have a high amount of oxygen in the seawater, so you would think that the oxygen would diffuse in the beach and get down 2-4 inches (5-10cm) into the lower layer and get to the oil," said Prof Boufadel.
"But the outward movement of [fresh groundwater] in the lower level is blocking the oxygen from spreading down into that lower level."
{Scientists carried out the study to find out why the oil was "locked" in beaches}
He explained that oxygen and nutrients were needed to sustain micro-organisms that "ate" the oil.
However, without the necessary supply of the key ingredients reaching the lower level, the biodegradation of the oil was occurring at a much slower rate.
"We suggest that similar dynamics could operate on tidal gravel beaches around the world, which are particularly common in mid- and high-latitude regions," the team wrote in their paper.
"Thus, our findings are of direct application for the susceptibility of beaches worldwide to long-term oil contamination and provide guidelines for remediating oil-polluted beaches."
They added that climate change was reducing ice cover, "exposing the Arctic to oil exploitation and shipping" and increasing the risk of oil spills in the future.
Professor Boufadel and his team are now exploring ways to deliver the necessary levels of oxygen and nutrients to affected areas to accelerate the dissipation of the remaining oil.
[Science & Environment]
Page last updated at 22:53 GMT, Monday, 18 January 2010
By Doreen Walton
Science reporter, BBC News
Malignant malaria found in apes
{The malaria parasite was found in a sample from the cross river gorillla}
The parasite which causes malignant malaria in humans has been identified in gorillas for the first time.
Researchers analysed faeces from wild gorillas in Cameroon and blood samples from a captive animal from Gabon.
The study says increasing contact between humans and primates due to logging and deforestation raises the risk of transmission of new pathogens.
The research findings are published in Proceedings of the National Academy of Sciences journal.
New genetic sampling techniques allowed scientists from France, Cameroon, Gabon and the US to examine evidence of malaria parasites in the faecal matter of wild gorillas and chimpanzees in Cameroon.
"Sampling malaria parasites from apes in the wild has until now been very difficult", said Dr Francisco Ayala from the University of California, Irvine.
The team also took blood samples from wild born, pet animals in Gabon.
DNA evidence of Plasmodium falciparum, the parasite that causes malignant malaria in humans, was found in faecal samples from two gorilla subspecies, the highly endangered cross-river gorilla and the western lowland gorilla.
{{Even if it were eradicated in humans we would still have the problem that it's present in apes}
Dr Francisco Ayala, University of California, Irvine}
The parasite was identified in a blood sample from a captive gorilla.
Malaria parasites were first identified in chimpanzees and gorillas in Africa by scientists working in the 1920s.
But this new technology has allowed scientists to confirm the presence of P. falciparum.
Disease reservoir
P. falciparum is the most deadly type of malaria infection.
It is most common in Africa, south of the Sahara, where the World Health Organization says it accounts for a large part of the extremely high mortality in the region.
The study says that human destruction of the natural forest habitat means more contact with primates and greater chances of pathogen transmission between the two, including from humans to the endangered great apes.
Dr Ayala said the findings underline the danger of contact between the two. "Even if it were eradicated in humans we would still have the problem that it's present in apes and therefore they would be a reservoir for the disease.
"It's not clear what we can do with respect to this problem other than trying to decrease contact."
Endemic?
Dr Ian Hastings, senior lecturer at the Liverpool School of Medicine said it would help to know more about the spread of the parasite in gorillas.
"Mosquitoes often bite different species. Often they have a preference but if they can't find what they want to bite they'll just go and bite something else," he said.
"The question is whether this is just sporadic infection that's come from humans after the mosquito bit an infected person and passed it on to gorillas or whether it's endemic and is passed from gorilla to gorilla."
Dr Ayala acknowledges that Plasmodium parasites are much less malignant for apes than humans because primates have been exposed to them for so long.
"They have had P. reichenowi and perhaps other species for thousands or millions of generations, so one expects less malignancy to have taken place over time."
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