[Transcribed from NEWSCIENTIST - 24 March 2011, by Debora MacKenzie]
To whom still thinking that the world press is exacerbating the situation in Japan
Japan's damaged nuclear plant in Fukushima has been emitting radioactive iodine and caesium at levels approaching those seen in the aftermath of the Chernobyl accident in 1986. Austrian researchers have used a worldwide network of radiation detectors – designed to spot clandestine nuclear bomb tests – to show that iodine-131 is being released at daily levels 73 per cent of those seen after the 1986 disaster. The daily amount of caesium-137 released from Fukushima Daiichi is around 60 per cent of the amount released from Chernobyl.
The difference between this accident and Chernobyl, they say, is that at Chernobyl a huge fire released large amounts of many radioactive materials, including fuel particles, in smoke. At Fukushima Daiichi, only the volatile elements, such as iodine and caesium, are bubbling off the damaged fuel. But these substances could nevertheless pose a significant health risk outside the plant.
The organisation set up to verify the Comprehensive Nuclear-Test-Ban Treaty (CTBT) has a global network of air samplers that monitor and trace the origin of around a dozen radionuclides, the radioactive elements released by atomic bomb blasts – and nuclear accidents. These measurements can be combined with wind observations to track where the radionuclides come from, and how much was released.
The level of radionuclides leaking from Fukushima Daiichi has been unclear, but the CTBT air samplers can shed some light, says Gerhard Wotawa of Austria's Central Institute for Meteorology and Geodynamics in Vienna.
Wind
For the first two days after the accident, the wind blew east from Fukushima towards monitoring stations on the US west coast; on the third day it blew south-west over the Japanese monitoring station at Takasaki, then swung east again. Each day, readings for iodine-131 at Sacramento in California, or at Takasaki, both suggested the same amount of iodine was coming out of Fukushima, says Wotawa: 1.2 to 1.3 × 1017 becquerels per day.
The agreement between the two "makes us confident that this is accurate", he says. So do similar readings at CTBT stations in Alaska, Hawaii and Montreal, Canada – readings at the latter, at least, show that the emissions have continued.
In the 10 days it burned, Chernobyl put out 1.76 × 1018 becquerels of iodine-131, which amounts to only 50 per cent more per day than has been calculated for Fukushima Daiichi. It is not yet clear how long emissions from the Japanese plant will continue.
Similarly, says Wotawa, caesium-137 emissions are on the same order of magnitude as at Chernobyl. The Sacramento readings suggest it has emitted 5 × 1015 becquerels of caesium-137 per day; Chernobyl put out 8.5 × 1016 in total – around 70 per cent more per day.
"This is not surprising," says Wotawa. "When the fuel is damaged there is no reason for the volatile elements not to escape," and the measured caesium and iodine are in the right ratios for the fuel used by the Fukushima Daiichi reactors. Also, the Fukushima plant has around 1760 tonnes of fresh and used nuclear fuel on site, and an unknown amount has been damaged. The Chernobyl reactor had only 180 tonnes.
The amounts being released, he says, are "entirely consistent" with the relatively low amounts of caesium and iodine being measured in soil, plants and water in Japan, because so much has blown out to sea. The amounts crossing the Pacific to places like Sacramento are vanishingly small – they were detected there because the CTBT network is designed to sniff out the tiniest traces.
Dangerous isotopes
The Chernobyl accident emitted much more radioactivity and a wider diversity of radioactive elements than Fukushima Daiichi has so far, but it was iodine and caesium that caused most of the health risk – especially outside the immediate area of the Chernobyl plant, says Malcolm Crick, secretary of a United Nations body that has just reviewed the health effects of Chernobyl. Unlike other elements, he says, they were carried far and wide by the wind.
Moreover the human body absorbs iodine and caesium readily. "Essentially all the iodine or caesium inhaled or swallowed crosses into the blood," says Keith Baverstock, former head of radiation protection for the World Health Organization's European office, who has studied Chernobyl's health effects.
Iodine is rapidly absorbed by the thyroid, and leaves only as it decays radioactively, with a half-life of eight days. Caesium is absorbed by muscles, where its half-life of 30 years means that it remains until it is excreted by the body. It takes between 10 and 100 days to excrete half of what has been consumed.
While in the body the isotopes' radioactive emissions can do significant damage, mainly to DNA. Children who ingest iodine-131 can develop thyroid cancer 10 or more years later; adults seem relatively resistant. A study published in the US last week found that iodine-131 from Chernobyl is still causing new cases of thyroid cancer to appear at an undiminished rate in the most heavily affected regions of Ukraine, Belarus and Russia.
Caesium-137 lingers in the environment because of its long half-life. Researchers are divided over how much damage environmental exposure to low doses has done since Chernobyl. Some researchers think it could still cause thousands of new cases of cancer across Europe.
quinta-feira, 24 de março de 2011
sexta-feira, 18 de março de 2011
PROTECTION WALLS AGAINST TSUNAMIS IN JAPAN: DO THEY WORK?
Let's watch the video in the link below provided by CNN:
http://cnn.com/video/data/2.0/video/world/2011/03/18/dnt.model.town.gone.nhk.html
Copy and paste the entire address above into your web browser.
http://cnn.com/video/data/2.0/video/world/2011/03/18/dnt.model.town.gone.nhk.html
Copy and paste the entire address above into your web browser.
domingo, 27 de fevereiro de 2011
USGS Multimedia Gallery: African Dust, Coral Reefs and Human Health
[OBSERVAÇÃO preliminar importante (extraída do GLOSSÁRIO DE ECOLOGIA): "Estudos recentes realizados por Leon Rotstyn (do CSIRO − Commonwealth Scientific and Industrial Research Organisation, Instituição da Austrália) e por Ulrike Lohmann (da Universidade de Dalhousie, Canadá)mostraram que as interações entre dióxido de enxofre e formação de nuvens (poluentes emitidos nos EUA e Canadá) provocavam condensação e precipitação de chuvas na América do Norte, que assim deixavam de se deslocarem para o norte da África. O sofrimento nessa região tende a se agravar porque o solo desnudo (pelas secas contínuas) reflete mais radiação solar enquanto os aerossóis de poeira refletem os raios de volta, mantendo assim a atmosfera sempre quente; e sem vegetação a erosão eólica se acentua,
reduzindo assim as propriedades produtivas do solo"].
[Vejam o vídeo do USGS e depois, leiam todo o texto. Chamo a atenção para as afirmações de um dos cientistas entrevistados, GINGER GARRISON, que assinalei em negrito]
USGS Multimedia Gallery: African Dust, Coral Reefs and Human Health
Narrator - Coral reefs worldwide are in decline. Over the last three decades, coral reefs throughout the world have been damaged by human activities, powerful storms, abnormally high water temperatures, and diseases. Where coral has died, algae have quickly grown in its place. Scientists are particularly concerned because, once damaged, these key marine ecosystems are not recovering.
Ginger Garrison - Diseases were first reported on coral reefs in the Caribbean in the early 1970s. But today disease is considered probably the primary factor causing mortality in corals. Today, there are more diseases on coral reefs. There are more coral species that are affected by disease and disease is causing more mortality. Caribbean coral reefs were the first ones that were hit and hit hardest, the problem today is global and it is very serious.
Narrator: Currently, there are around 30 types of diseases or disease-like states recognized. Thus far, scientists have identified the causes of six coral diseases: sea-fan disease (or Gorgonian aspergillosis), black band disease, white plague, white pox, bacterial-induced bleaching, and pink-spot disease.
Why are the diseases on an increase? Why are they so widespread? Why are reefs worldwide in decline? What large-scale processes could be at work?
Hundreds of millions of tons of dust are carried each year from the Sahara and Sahel regions of Africa to the Caribbean, the eastern United States, and beyond. At times, these dust air masses cover the tropical Atlantic and the entire Caribbean Sea. Is this large-scale system having an effect on coral reefs throughout the Caribbean?
African desert locusts are known to be periodically carried along with the dust and arrive alive on several Caribbean islands. If a two-inch locust can survive the trip across the Atlantic, can smaller organisms such as the disease-causing microbes survive as well? Scientists at the U.S. Geological Survey are trying to determine whether downwind ecosystems are being harmed by nutrients, microbes, or chemical contaminants carried with African dust.
Suzette Mormon - By the time the African dust reaches the Caribbean, the particles are very small, about one micron in diameter. These fine particles are easily inhaled and less easily exhaled. The compositions of these particles are primarily clay with some other smaller amounts of gypsum and iron oxides. The iron oxides are important because they work as a sponge for other metals and they carry with them things, in particular arsenic.
Narrator - To test the hypothesis that African dust is a factor in the deteriorating state of Caribbean coral reefs, air samples were collected from the source region of Mali in Africa, off the western coast of Africa in Cape Verde, and at downwind sites in Trinidad and Tobago in the southeastern and the U.S. Virgin Islands in the northeastern Caribbean.
Suzette Mormon: The dust in the downwind sites had slightly lower concentrations of total metals but the bio-accessibility of these metals was higher. This may be related to the very fine particle size in these iron oxide coatings, which tends to absorb these metals on them and release them very easily. The very fine particles are very easy to inhale. We know that the less than 5-micron particles will travel further into the lungs. We know that these very fine particulate matters have been correlated health wise with increased rates of heart attack and stroke and exacerbations of asthma and other respiratory diseases.
Chris Kellogg: What we wanted to know is whether viable bacterial and fungal spores could be transported long distance across the ocean in African dust events, and the answer is yes. We found much higher numbers of microbes, say 10 to 100 times more cultured bacteria, when we tested air samples from Mali, West Africa, a source region, compared to downwind sites in the Caribbean. The downwind samples are complicated, because you have local aerosolized microbes and then you have microbes that have come in the dust and as of now there is no good way to tell the source of a microorganism. For example, Garriet Smith isolated Aspergillus sydowii, which is a fungus that causes disease in sea fans, from a dust event in the Virgin Islands, but the question remains is the source of that fungus local or long distance?
Narrator - Microarray technology recently developed at the Lawrence Berkeley Lab in California is using molecular techniques to identify microorganisms in dust samples.
Eoin Brodie: At Lawrence Berkeley National Lab, we have developed a microarray technology called the folic chip, which can be used to simultaneously detect up to 30,000 different types of bacteria in any environmental sample. Working with researchers at the USGS, we have been attempting to identify the microorganisms present in African dust samples, and we hope to correlate the presence of those organisms with coral disease and changes in human health in the Caribbean. We receive a filter sample containing dust. We extract the DNA and apply the DNA to this microarray device, the folic chip. Within 24 hours, we can identify the organisms present in a sample and then inform researchers at USGS which organisms are associated with dust and which organisms may be associated with coral disease.
Narrator - Although African dust has been carried out of the Sahara and into the Caribbean and the Americas for hundreds of thousands of years, there have been significant changes in the past 40 years: the quantity of dust has increased and the composition has changed. Scientists have identified carcinogens, neurotoxins, endocrine disruptors, and suppressors of immune systems.
Ginger Garrison - Greater amounts of dust have been carried out of the Sahara since the 1970s due to a number of factors: global climate, changes in regional meteorology, and local human activities. During that same time, the composition of the dust has changed. Toxic chemicals are produced by the combustion of biomass, fossil fuels, the burning of garbage, and things like plastics in the source region. These have been carried along with the dust particles from Africa into the Caribbean. At the same time in the source region, they are using pesticides for things such as malaria from mosquitoes, on their crops, and also against locust plagues, and those pesticides are also coming across.
Narrator -These chemicals can travel around the globe and have long-term effects on ecosystems because they persist in the environment, accumulate in organisms, and are toxic in low concentrations.
Ginger Garrison - The question is, can we really point our finger at any one source for this load of inorganic contaminants that we are finding in the atmosphere, both in Mali and also in the Caribbean, and we think not. We think that there is an underlying burden of contaminants. If you look at the pollution plume that will come out of the northeast United States, crosses the Atlantic into Europe, mixes with air pollution from Europe, that can conceivably be brought down south, especially with a cold front in winter, into Africa where it mixes with the African and Saharan air layer and then everything comes over into the Caribbean, comes around again.
Narrator - Scientists are beginning to test the toxicity of African dust and associated chemical contaminants on the life stages of many kinds of marine organisms, including corals, to see if they harm marine life and how they do so. Preliminary laboratory research has found some disturbing results. Two of the pesticides most commonly found in dust air samples from source and downwind sites were found to interfere with the settlement of coral larvae - an important stage in the life of a coral.
The movement of small particles of dust, metals, and toxic chemical pollutants through the air, across the oceans, and among continents is occurring. USGS research continues on this global issue.
reduzindo assim as propriedades produtivas do solo"].
[Vejam o vídeo do USGS e depois, leiam todo o texto. Chamo a atenção para as afirmações de um dos cientistas entrevistados, GINGER GARRISON, que assinalei em negrito]
USGS Multimedia Gallery: African Dust, Coral Reefs and Human Health
Narrator - Coral reefs worldwide are in decline. Over the last three decades, coral reefs throughout the world have been damaged by human activities, powerful storms, abnormally high water temperatures, and diseases. Where coral has died, algae have quickly grown in its place. Scientists are particularly concerned because, once damaged, these key marine ecosystems are not recovering.
Ginger Garrison - Diseases were first reported on coral reefs in the Caribbean in the early 1970s. But today disease is considered probably the primary factor causing mortality in corals. Today, there are more diseases on coral reefs. There are more coral species that are affected by disease and disease is causing more mortality. Caribbean coral reefs were the first ones that were hit and hit hardest, the problem today is global and it is very serious.
Narrator: Currently, there are around 30 types of diseases or disease-like states recognized. Thus far, scientists have identified the causes of six coral diseases: sea-fan disease (or Gorgonian aspergillosis), black band disease, white plague, white pox, bacterial-induced bleaching, and pink-spot disease.
Why are the diseases on an increase? Why are they so widespread? Why are reefs worldwide in decline? What large-scale processes could be at work?
Hundreds of millions of tons of dust are carried each year from the Sahara and Sahel regions of Africa to the Caribbean, the eastern United States, and beyond. At times, these dust air masses cover the tropical Atlantic and the entire Caribbean Sea. Is this large-scale system having an effect on coral reefs throughout the Caribbean?
African desert locusts are known to be periodically carried along with the dust and arrive alive on several Caribbean islands. If a two-inch locust can survive the trip across the Atlantic, can smaller organisms such as the disease-causing microbes survive as well? Scientists at the U.S. Geological Survey are trying to determine whether downwind ecosystems are being harmed by nutrients, microbes, or chemical contaminants carried with African dust.
Suzette Mormon - By the time the African dust reaches the Caribbean, the particles are very small, about one micron in diameter. These fine particles are easily inhaled and less easily exhaled. The compositions of these particles are primarily clay with some other smaller amounts of gypsum and iron oxides. The iron oxides are important because they work as a sponge for other metals and they carry with them things, in particular arsenic.
Narrator - To test the hypothesis that African dust is a factor in the deteriorating state of Caribbean coral reefs, air samples were collected from the source region of Mali in Africa, off the western coast of Africa in Cape Verde, and at downwind sites in Trinidad and Tobago in the southeastern and the U.S. Virgin Islands in the northeastern Caribbean.
Suzette Mormon: The dust in the downwind sites had slightly lower concentrations of total metals but the bio-accessibility of these metals was higher. This may be related to the very fine particle size in these iron oxide coatings, which tends to absorb these metals on them and release them very easily. The very fine particles are very easy to inhale. We know that the less than 5-micron particles will travel further into the lungs. We know that these very fine particulate matters have been correlated health wise with increased rates of heart attack and stroke and exacerbations of asthma and other respiratory diseases.
Chris Kellogg: What we wanted to know is whether viable bacterial and fungal spores could be transported long distance across the ocean in African dust events, and the answer is yes. We found much higher numbers of microbes, say 10 to 100 times more cultured bacteria, when we tested air samples from Mali, West Africa, a source region, compared to downwind sites in the Caribbean. The downwind samples are complicated, because you have local aerosolized microbes and then you have microbes that have come in the dust and as of now there is no good way to tell the source of a microorganism. For example, Garriet Smith isolated Aspergillus sydowii, which is a fungus that causes disease in sea fans, from a dust event in the Virgin Islands, but the question remains is the source of that fungus local or long distance?
Narrator - Microarray technology recently developed at the Lawrence Berkeley Lab in California is using molecular techniques to identify microorganisms in dust samples.
Eoin Brodie: At Lawrence Berkeley National Lab, we have developed a microarray technology called the folic chip, which can be used to simultaneously detect up to 30,000 different types of bacteria in any environmental sample. Working with researchers at the USGS, we have been attempting to identify the microorganisms present in African dust samples, and we hope to correlate the presence of those organisms with coral disease and changes in human health in the Caribbean. We receive a filter sample containing dust. We extract the DNA and apply the DNA to this microarray device, the folic chip. Within 24 hours, we can identify the organisms present in a sample and then inform researchers at USGS which organisms are associated with dust and which organisms may be associated with coral disease.
Narrator - Although African dust has been carried out of the Sahara and into the Caribbean and the Americas for hundreds of thousands of years, there have been significant changes in the past 40 years: the quantity of dust has increased and the composition has changed. Scientists have identified carcinogens, neurotoxins, endocrine disruptors, and suppressors of immune systems.
Ginger Garrison - Greater amounts of dust have been carried out of the Sahara since the 1970s due to a number of factors: global climate, changes in regional meteorology, and local human activities. During that same time, the composition of the dust has changed. Toxic chemicals are produced by the combustion of biomass, fossil fuels, the burning of garbage, and things like plastics in the source region. These have been carried along with the dust particles from Africa into the Caribbean. At the same time in the source region, they are using pesticides for things such as malaria from mosquitoes, on their crops, and also against locust plagues, and those pesticides are also coming across.
Narrator -These chemicals can travel around the globe and have long-term effects on ecosystems because they persist in the environment, accumulate in organisms, and are toxic in low concentrations.
Ginger Garrison - The question is, can we really point our finger at any one source for this load of inorganic contaminants that we are finding in the atmosphere, both in Mali and also in the Caribbean, and we think not. We think that there is an underlying burden of contaminants. If you look at the pollution plume that will come out of the northeast United States, crosses the Atlantic into Europe, mixes with air pollution from Europe, that can conceivably be brought down south, especially with a cold front in winter, into Africa where it mixes with the African and Saharan air layer and then everything comes over into the Caribbean, comes around again.
Narrator - Scientists are beginning to test the toxicity of African dust and associated chemical contaminants on the life stages of many kinds of marine organisms, including corals, to see if they harm marine life and how they do so. Preliminary laboratory research has found some disturbing results. Two of the pesticides most commonly found in dust air samples from source and downwind sites were found to interfere with the settlement of coral larvae - an important stage in the life of a coral.
The movement of small particles of dust, metals, and toxic chemical pollutants through the air, across the oceans, and among continents is occurring. USGS research continues on this global issue.
sexta-feira, 18 de fevereiro de 2011
USGS Multimedia Gallery: The Effects of Urbanization on Stream Ecosystems (extended) Part III: Study Results
[Hello dear friends: this is a quite interesting video from the UNITED STATES GEOLOGICAL SURVEY, about urban development that influences stream ecosystems, an approach that interests particularly to us, because most of our urban waterflows are also affected in a similar way. I have chosen just one of the 3 videos they have of the project]
Jerry McMahon: Over the last 10 years the US Geological Survey’s National Water Quality Assessment Program has examined the effects of urban development on stream ecosystems. In this study, the two primary objectives were first of all to look at the physical, chemical and biological responses of streams to urban development. And also, to look at how those responses varied across the country. OK, our first finding was that all three biological communities we examined, algae, invertebrates and fish responded to urban development. Urban development significantly affected one or more biological communities in eight of the nine metropolitan study areas with Denver being the exception.
In Portland, which is shown in this slide, all three communities responded negatively to urban development. Because invertebrate communities showed the strongest and most consistent response to urban development across the country, we will focus on the response of macroinvertebrate. The second finding is that declines in aquatic insect communities are noted at the early stages of urban development. Unlike the hypothesized response, even small levels of urban development had an immediate negative effect on aquatic insects. There’s no period of resistance to the effects of urban development. This is illustrated by the immediate decline in the aquatic insect community composition as the level of urban development in the Boston study watersheds increases. This response is continuous over the entire range of urban development. The aquatic insect communities studied in the Boston watersheds never reach a state of exhaustion.
Our third finding is that urban development is often accompanied by a loss of pollution sensitive species and a shift toward communities that are dominated by pollution tolerance species. EPT Richness represents the sum of sensitive insect species in the order of Ephemeroptera - mayflies, Plecoptera – stoneflies and Trichoptera – caddisfly. This figure indicates the difference in the number of sensitive EPT invertebrate species found in watersheds at the high end of the urban gradient and at the low end. A substantial decline in EPT species richness occurred in all but the Denver, Dallas and Milwaukee study areas. Measures of EPT Richness are commonly used to assess biological condition of stream in state biomonitoring program.
A biological community that includes sensitive species is often an indication of healthy stream ecosystem and therefore changes in the presence of sensitive species provides useful information about the biological condition of the stream. Our fourth finding is that important regional differences existed in the types of land cover that were being converted to urban uses. Across the nine regions of the country that were studied, urban development occurred primarily through the conversion of either agricultural or forested lands. Forest is the dominant pre-urban development land cover in Portland, Salt Lake City, Birmingham, Atlanta, Raleigh and Boston; whereas, in the other three study areas land being converted to urban uses is associated with some form of agricultural activity. The characteristics and activities associated with these two land cover types may mask or escalate the influence of urban development on stream ecosystems.
For example, although agricultural practices have evolved dramatically in the last hundred years, nutrient enrichment, soil erosion, monocultural practices and the loss of natural habitat are still major concerns. Watersheds where the predominant pre-urban development land cover is agricultural land already have some degree of water quality impairment prior to the urbanization that can obscure the effects of urban development. This may help explain the very small loss of sensitive taxa in areas where urban development occurs on land that previously was in agricultural uses. Sensitive species had already been lost before urban development occurred. So how can this information be used?
The information we’ve developed on the response of stream ecosystems to urban development will help urban planners and other stakeholders clarify the most appropriate strategies in managing, protecting and restoring urban streams. Two findings are of particular importance. First, the fact that macroinvertebrate community conditions starts degrading almost immediately once urban development begins suggests that a great deal of caution should be exercised in thinking that there is a safe zone of urban development at least for a stream’s macro invertebrate communities. Second, we now know that streams in different regions of the country respond differently to urban development. This is due to regional differences in the overall template of factors that affects stream ecosystems such as climate and the types of land that are being developed for urban uses. These regional factors also affect the response of hydrology, habitat, water chemistry and stream biota. Management approaches have to be shaped by an understanding of how this regional template helps determine what is possible to achieve in terms of water quality, criteria and standing.
For additional information about our project, please visit the project website where you can obtain both reports as well as the data used in the project. I’m Jerry McMahon and on behalf of all my colleagues, I’d like to thank you for your interest in understanding the effects of urban development on stream ecosystems.
USGS Multimedia Gallery: The Effects of Urbanization on Stream Ecosystems (extended) Part III: Study Results
Jerry McMahon: Over the last 10 years the US Geological Survey’s National Water Quality Assessment Program has examined the effects of urban development on stream ecosystems. In this study, the two primary objectives were first of all to look at the physical, chemical and biological responses of streams to urban development. And also, to look at how those responses varied across the country. OK, our first finding was that all three biological communities we examined, algae, invertebrates and fish responded to urban development. Urban development significantly affected one or more biological communities in eight of the nine metropolitan study areas with Denver being the exception.
In Portland, which is shown in this slide, all three communities responded negatively to urban development. Because invertebrate communities showed the strongest and most consistent response to urban development across the country, we will focus on the response of macroinvertebrate. The second finding is that declines in aquatic insect communities are noted at the early stages of urban development. Unlike the hypothesized response, even small levels of urban development had an immediate negative effect on aquatic insects. There’s no period of resistance to the effects of urban development. This is illustrated by the immediate decline in the aquatic insect community composition as the level of urban development in the Boston study watersheds increases. This response is continuous over the entire range of urban development. The aquatic insect communities studied in the Boston watersheds never reach a state of exhaustion.
Our third finding is that urban development is often accompanied by a loss of pollution sensitive species and a shift toward communities that are dominated by pollution tolerance species. EPT Richness represents the sum of sensitive insect species in the order of Ephemeroptera - mayflies, Plecoptera – stoneflies and Trichoptera – caddisfly. This figure indicates the difference in the number of sensitive EPT invertebrate species found in watersheds at the high end of the urban gradient and at the low end. A substantial decline in EPT species richness occurred in all but the Denver, Dallas and Milwaukee study areas. Measures of EPT Richness are commonly used to assess biological condition of stream in state biomonitoring program.
A biological community that includes sensitive species is often an indication of healthy stream ecosystem and therefore changes in the presence of sensitive species provides useful information about the biological condition of the stream. Our fourth finding is that important regional differences existed in the types of land cover that were being converted to urban uses. Across the nine regions of the country that were studied, urban development occurred primarily through the conversion of either agricultural or forested lands. Forest is the dominant pre-urban development land cover in Portland, Salt Lake City, Birmingham, Atlanta, Raleigh and Boston; whereas, in the other three study areas land being converted to urban uses is associated with some form of agricultural activity. The characteristics and activities associated with these two land cover types may mask or escalate the influence of urban development on stream ecosystems.
For example, although agricultural practices have evolved dramatically in the last hundred years, nutrient enrichment, soil erosion, monocultural practices and the loss of natural habitat are still major concerns. Watersheds where the predominant pre-urban development land cover is agricultural land already have some degree of water quality impairment prior to the urbanization that can obscure the effects of urban development. This may help explain the very small loss of sensitive taxa in areas where urban development occurs on land that previously was in agricultural uses. Sensitive species had already been lost before urban development occurred. So how can this information be used?
The information we’ve developed on the response of stream ecosystems to urban development will help urban planners and other stakeholders clarify the most appropriate strategies in managing, protecting and restoring urban streams. Two findings are of particular importance. First, the fact that macroinvertebrate community conditions starts degrading almost immediately once urban development begins suggests that a great deal of caution should be exercised in thinking that there is a safe zone of urban development at least for a stream’s macro invertebrate communities. Second, we now know that streams in different regions of the country respond differently to urban development. This is due to regional differences in the overall template of factors that affects stream ecosystems such as climate and the types of land that are being developed for urban uses. These regional factors also affect the response of hydrology, habitat, water chemistry and stream biota. Management approaches have to be shaped by an understanding of how this regional template helps determine what is possible to achieve in terms of water quality, criteria and standing.
For additional information about our project, please visit the project website where you can obtain both reports as well as the data used in the project. I’m Jerry McMahon and on behalf of all my colleagues, I’d like to thank you for your interest in understanding the effects of urban development on stream ecosystems.
USGS Multimedia Gallery: The Effects of Urbanization on Stream Ecosystems (extended) Part III: Study Results
sábado, 5 de fevereiro de 2011
AFRICAN SNAILS THE LATEST WEAPON IN POLLUTION CONTROL
[SCIENTIFIC AMERICAN video]
[Watch the video: http://www.scientificamerican.com/video.cfm?id=776291606001][and follow the text below, extracted by Breno Grisi]
The Achatina snail [Achatina fulica] is usually found in the sub-Saharan Africa. This one is it working in Russia. Its task it is to sample the atmosphere at the water treatment plant at St. Petersburg, monitoring air pollution produced by the sewage works incinerator. The living sensor reacts to gases in the air, according to environmentalist researcher [Russian researcher].
When gas concentration changes drastically the molecules get disturbed. It can change relatively and it can behave as a connective one. At the same time the frequency of [...] rates increases, as a matter of fact, this reaction is a test for air pollution.
Scientist are able to monitoring changes in the snail heart beat and behaviour by watching it in real time on a computer screen. This kind of snail can live for up to 10 years, it [...] to 20cm in length. It was chosen for the task because they have lungs and breathe in a similar way to humans. The snails are not being exposed to dangerous levels of gas, says leader researcher [...] Snails are not breathing smoke but a gas with a thousand times lower concentration of the smoke. Why? Because people are concerned about the quality of air outside the plant restricted zone.
Animals have been involved in the environmental monitoring in St. Petersburg before with crayfish tasting water quality in the [Never???] river. Now this not so little snail is joining the effort to clean up the atmosphere. [...]
[Watch the video: http://www.scientificamerican.com/video.cfm?id=776291606001][and follow the text below, extracted by Breno Grisi]
The Achatina snail [Achatina fulica] is usually found in the sub-Saharan Africa. This one is it working in Russia. Its task it is to sample the atmosphere at the water treatment plant at St. Petersburg, monitoring air pollution produced by the sewage works incinerator. The living sensor reacts to gases in the air, according to environmentalist researcher [Russian researcher].
When gas concentration changes drastically the molecules get disturbed. It can change relatively and it can behave as a connective one. At the same time the frequency of [...] rates increases, as a matter of fact, this reaction is a test for air pollution.
Scientist are able to monitoring changes in the snail heart beat and behaviour by watching it in real time on a computer screen. This kind of snail can live for up to 10 years, it [...] to 20cm in length. It was chosen for the task because they have lungs and breathe in a similar way to humans. The snails are not being exposed to dangerous levels of gas, says leader researcher [...] Snails are not breathing smoke but a gas with a thousand times lower concentration of the smoke. Why? Because people are concerned about the quality of air outside the plant restricted zone.
Animals have been involved in the environmental monitoring in St. Petersburg before with crayfish tasting water quality in the [Never???] river. Now this not so little snail is joining the effort to clean up the atmosphere. [...]
domingo, 30 de janeiro de 2011
NEW HYBRID CAR FROM VW - GOOD NEWS, IN ECOLOGICAL TERMS
[Reproduced from NEWSCIENTIST, 27 January 2011]
N.B. In bold face some advantageous advances, in ecological terms
In a world of soaring fuel prices it's certainly a smart move.
While Volkswagen's new XL1 "Super Efficient Vehicle" might look like a "futuristic" concept car designed sometime in the late 1980s, its figures are undoubtedly impressive.
Unveiled at the Qatar motor show on Tuesday night, the XL1 claims an incredible fuel consumption of just 0.9 litres per 100 kilometres (equivalent to 239 miles per gallon). VW also says it emits just 24 grams of carbon dioxide per kilometre.
The remarkable figures are all down to a combination of a 0.8-litre diesel engine and an electric motor couple with clever weight-saving design and superior aerodynamics.
While these do not produce a huge amount of power, the car's carbon-fiber body means it weighs just 795 kilograms, allowing it to accelerate from 0 to 100 km/h in 11.9 seconds. Not bad going for a hybrid.
The XL1's "unique" stylings mean that it only seats two passengers but its aerodynamic profile has been sculpted so that it can boast an impressive 0.186 drag coefficient. VW says it plans to start production of the XL1 by 2013, but the German car manufacturer is not the only big gun looking to exploit the resurgence in interest in electric cars.
Electric vehicles dominated proceedings at the recent Detroit car show, scooping most of the top awards, and Audi's R8 E-Tron all-electric supercar wowed the crowds at CES this year.
sábado, 15 de janeiro de 2011
HELLO CONSCIOUS BRAZILIANS! IT’S TIME TO WAKE UP!!!
Congresspersons in Brazil have been lobbied by “ruralists” (farmers strongly interested in agribusiness), to perform amendments to our “Código Florestal Brasileiro” (Brazil’s Forest Code) aiming to reduce the extension of natural areas protected by our present environmental legislation, with respect to rivers and stream margins, top of hills and mountains, and their slopes. The amendment to the code would also change the current requirement that Amazonian landowners must retain 80% of their land as legal forest reserves. The amendment would also provide amnesty to any farmers or ranchers who have practised illegal deforestation by incorporating over 40 million hectares of illegally deforested land.
Especially with respect to riparian vegetation we presently know that any terrestrial ecosystem fragment is affected by external factors, like high temperature and sun radiation, blasts of wind and lower air and soil humidity. This is what we call edge effects. Experiments in tropics revealed that such effects extend for about 100m inside the forest fragment. Therefore, it is not difficult to conclude how big the negative effects would be to fragments with much less than 100m wide! The politicians who support the amendments to Brazil’s Forest Code (YES! the same politicians who approved the increase of their own salary in 61.8%!!!) stipulate that riparian vegetation of small rivers and streams should be reduced from the current 15m (in 10m wide rivers) to 5m. Yet, vegetation of hills and mountains tops and of their slopes may be exploited. Farmers might use these fragile habitats for cultivation. Such modification of law that protects such fragile environments are being planned by the lobbists even after the 2008 environmental disaster which occurred in Rio de Janeiro, the ones that happened in the Northeastern states of Pernambuco and Alagoas in June/2010, and the present tragedy that has destroyed everything downhill, again in Rio de Janeiro. This time the tragedy in Rio inflicted almost 600 casualties to local population (it can be more in the next days!). Natural disaster? Fierce storm of Nature? May be. But with quite strong anthropic collaboration.
Let us observe how important it is to estimate the external effects on a forest fragment, be it a square or rectangular fragment. A square fragment 2km at each one of its side makes up a 4km2 area (four square kilometers); and a rectangular fragment measuring 1km at one side by 4km at the other side totals also four square kilometers. However, the perimeters of these forms of fragment are different: the four sides of the square area sums up 8km; and the four sides of the rectangular area sums up 10km. So the rectangular fragment would be more affected by the edge effect. This latter area is similar to riparian edges of rivers and streams. Suffice it to say how bad will be the consequences to riparian areas if their plants cover is reduced! The rivers sedimentation (= bed agradation) will certainly be increased and floods will certainly happen quite frequently, and catastrophically as it happened in Pernambuco and Alagoas recently.
Local authorities, in my point of view, are the most important actors of such tragedies. Main reasons: 1) They are responsible for allowing people to build their houses in slopes of hills, down in the valleys, close to rivers margins… and practically at any place poor people intend to dwell. 2) They are also responsible for not providing environmental education to people who are used to throw their wastes in the rivers from which they obtain their drinking water! 3) Deforestation (logging, slash-and-burn cultivation…) are practised under slackness and complacency of authorities.
I still have to emphasize some important ecological factors affected by reduction of vegetation cover proposed in the amendment. Some few examples: 1) In the state of São Paulo, 45 of the 66 fish species of fresh waters and threatened to extinction live in streams (according to biologist Lilian Casati of "Universidade Estadual de São Paulo". 2)Reptiles and amphibians living in wetlands will also be impacted by the reduction of riparian vegetation; and according to biologist Luis Felipe of the "UNICAMP-Universidade de Campinas" places with the least protection (proposed by the amendment to Brazil's Forest Code) are the ones with highest biodiversity!!! 3) Mountains (their tops and slopes)are important shelters for reptiles (in the amendment natural habitats above 1800m altitude will no more be permanently protected areas).
The leader congressman responsible for the amendments to Brazil’s Forest Code, Mr Aldo Rebello, says that many Brazilian researchers were consulted to elaborate the amendments. But oddly his experts’ advice differs strongly of experts’ investigations who has published on environmental degradation which resulted from reduction of riparian vegetation in our ecosystems (see METZGER et al., Science, vol. 329, 10/July/2010; and in Portuguese see site http://eco.ib.usp.br/lepac/codigo_florestal.html, and in this site download the essay: Sparovek_etal_2010.pdf).
Mr Rebello, the federal deputy who claims that “it is necessary to conquer those new environments to expand our agriculture” is strongly opposed by the general chief of environmental research (Celso Manzatto) at EMBRAPA – The Brazilian Agricultural Research Corporation, who says: “We showed in the last 20 years that we are able to gain in productivity without the need to incorporate new lands. This does not mean that we are going to have zero deforestation! What we need but we do not have done it yet, is a policy to organize our territory pointing out which areas must be occupied for production of animal husbandry in the future”.
The need of amendment to Brazil’s Forest Code is also opposed by Gerd Sparovek (in the essay mentioned above), who says that we must expand our agriculture to areas where we have been practising extensive cattle farming with very low productivity (1.1 animal per hectare) [the average productivity in Southeastern Brazil is 4.5 animals per hectare]. Gerd Sparovek estimates that circa 61 million hectares are in such conditions, among the 211 million hectares exploited in cattle farming.
Unfortunately, not only politicians but many key actors in our society do not realize that “a long time has elapsed from the stage we had to conquer by slash-and-burn forests to the present stage of commitment to preservation and restoration”.
Especially with respect to riparian vegetation we presently know that any terrestrial ecosystem fragment is affected by external factors, like high temperature and sun radiation, blasts of wind and lower air and soil humidity. This is what we call edge effects. Experiments in tropics revealed that such effects extend for about 100m inside the forest fragment. Therefore, it is not difficult to conclude how big the negative effects would be to fragments with much less than 100m wide! The politicians who support the amendments to Brazil’s Forest Code (YES! the same politicians who approved the increase of their own salary in 61.8%!!!) stipulate that riparian vegetation of small rivers and streams should be reduced from the current 15m (in 10m wide rivers) to 5m. Yet, vegetation of hills and mountains tops and of their slopes may be exploited. Farmers might use these fragile habitats for cultivation. Such modification of law that protects such fragile environments are being planned by the lobbists even after the 2008 environmental disaster which occurred in Rio de Janeiro, the ones that happened in the Northeastern states of Pernambuco and Alagoas in June/2010, and the present tragedy that has destroyed everything downhill, again in Rio de Janeiro. This time the tragedy in Rio inflicted almost 600 casualties to local population (it can be more in the next days!). Natural disaster? Fierce storm of Nature? May be. But with quite strong anthropic collaboration.
Let us observe how important it is to estimate the external effects on a forest fragment, be it a square or rectangular fragment. A square fragment 2km at each one of its side makes up a 4km2 area (four square kilometers); and a rectangular fragment measuring 1km at one side by 4km at the other side totals also four square kilometers. However, the perimeters of these forms of fragment are different: the four sides of the square area sums up 8km; and the four sides of the rectangular area sums up 10km. So the rectangular fragment would be more affected by the edge effect. This latter area is similar to riparian edges of rivers and streams. Suffice it to say how bad will be the consequences to riparian areas if their plants cover is reduced! The rivers sedimentation (= bed agradation) will certainly be increased and floods will certainly happen quite frequently, and catastrophically as it happened in Pernambuco and Alagoas recently.
Local authorities, in my point of view, are the most important actors of such tragedies. Main reasons: 1) They are responsible for allowing people to build their houses in slopes of hills, down in the valleys, close to rivers margins… and practically at any place poor people intend to dwell. 2) They are also responsible for not providing environmental education to people who are used to throw their wastes in the rivers from which they obtain their drinking water! 3) Deforestation (logging, slash-and-burn cultivation…) are practised under slackness and complacency of authorities.
I still have to emphasize some important ecological factors affected by reduction of vegetation cover proposed in the amendment. Some few examples: 1) In the state of São Paulo, 45 of the 66 fish species of fresh waters and threatened to extinction live in streams (according to biologist Lilian Casati of "Universidade Estadual de São Paulo". 2)Reptiles and amphibians living in wetlands will also be impacted by the reduction of riparian vegetation; and according to biologist Luis Felipe of the "UNICAMP-Universidade de Campinas" places with the least protection (proposed by the amendment to Brazil's Forest Code) are the ones with highest biodiversity!!! 3) Mountains (their tops and slopes)are important shelters for reptiles (in the amendment natural habitats above 1800m altitude will no more be permanently protected areas).
The leader congressman responsible for the amendments to Brazil’s Forest Code, Mr Aldo Rebello, says that many Brazilian researchers were consulted to elaborate the amendments. But oddly his experts’ advice differs strongly of experts’ investigations who has published on environmental degradation which resulted from reduction of riparian vegetation in our ecosystems (see METZGER et al., Science, vol. 329, 10/July/2010; and in Portuguese see site http://eco.ib.usp.br/lepac/codigo_florestal.html, and in this site download the essay: Sparovek_etal_2010.pdf).
Mr Rebello, the federal deputy who claims that “it is necessary to conquer those new environments to expand our agriculture” is strongly opposed by the general chief of environmental research (Celso Manzatto) at EMBRAPA – The Brazilian Agricultural Research Corporation, who says: “We showed in the last 20 years that we are able to gain in productivity without the need to incorporate new lands. This does not mean that we are going to have zero deforestation! What we need but we do not have done it yet, is a policy to organize our territory pointing out which areas must be occupied for production of animal husbandry in the future”.
The need of amendment to Brazil’s Forest Code is also opposed by Gerd Sparovek (in the essay mentioned above), who says that we must expand our agriculture to areas where we have been practising extensive cattle farming with very low productivity (1.1 animal per hectare) [the average productivity in Southeastern Brazil is 4.5 animals per hectare]. Gerd Sparovek estimates that circa 61 million hectares are in such conditions, among the 211 million hectares exploited in cattle farming.
Unfortunately, not only politicians but many key actors in our society do not realize that “a long time has elapsed from the stage we had to conquer by slash-and-burn forests to the present stage of commitment to preservation and restoration”.
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