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LOS ANGELES, June 17 (Xinhua) -- The size of low-oxygen zones created by respiring bacteria is extremely sensitive to changes in depth caused by oscillations in climate, thus posing a distant threat to marine life, a new study suggests."The growth of low-oxygen regions is cause for concern because of the detrimental effects on marine populations -- entire ecosystems can die off when marine life cannot escape the low- oxygen water," said lead researcher Curtis Deutsch, assistant professor of atmospheric and oceanic sciences at University of California, Los Angeles."There are widespread areas of the ocean where marine life has had to flee or develop very peculiar adaptations to survive in low- oxygen conditions," Deutsch said in the study to be published in an upcoming print edition of the journal Science.A team led byDeutsch used a specialized computer simulation to demonstrate for the first time that fluctuations in climate can drastically affect the habitability of marine ecosystems.The study also showed that in addition to consuming oxygen, marine bacteria are causing the depletion of nitrogen, an essential nutrient necessary for the survival of most types of algae."We found there is a mechanism that connects climate and its effect on oxygen to the removal of nitrogen from the ocean," Deutsch said. "Our climate acts to change the total amount of nutrients in the ocean over the timescale of decades."Low-oxygen zones are created by bacteria living in the deeper layers of the ocean that consume oxygen by feeding on dead algae that settle from the surface. Just as mountain climbers might feel adverse effects at high altitudes from a lack of air, marine animals that require oxygen to breathe find it difficult or impossible to live in these oxygen-depleted environments, Deutsch said.Sea surface temperatures vary over the course of decades through a climate pattern called the Pacific Decadal Oscillation, during which small changes in depth occur for existing low-oxygen regions, Deutsch said. Low-oxygen regions that rise to warmer, shallower waters expand as bacteria become more active; regions that sink to colder, deeper waters shrink as the bacteria become more sluggish, as if placed in a refrigerator."We have shown for the first time that these low-oxygen regions are intrinsically very sensitive to small changes in climate," Deutsch said in remarks published Friday by the American Association for the Advancement of Science on its website. "That is what makes the growth and shrinkage of these low-oxygen regions so dramatic."Molecular oxygen from the atmosphere dissolves in sea water at the surface and is transported to deeper levels by ocean circulation currents, where it is consumed by bacteria, Deutsch said."The oxygen consumed by bacteria within the deeper layers of the ocean is replaced by water circulating through the ocean," he said. "The water is constantly stirring itself up, allowing the deeper parts to occasionally take a breath from the atmosphere."A lack of oxygen is not the only thing fish and other marine life must contend with, according to Deutsch. When oxygen is very low, the bacteria will begin to consume nitrogen, one of the most important nutrients that sustain marine life."Almost all algae, the very base of the food chain, use nitrogen to stay alive," Deutsch said. "As these low-oxygen regions expand and contract, the amount of nutrients available to keep the algae alive at the surface of the ocean goes up and down. "Understanding the causes of oxygen and nitrogen depletion in the ocean is important for determining the effect on fisheries and fish populations, he said.

WASHINGTON, Sept. 27 (Xinhua) -- At least 13 people had been killed amid 72 sickened in 18 states in listeria outbreak traced to Colorado cantaloupes, making it the most deadly U.S. outbreak of food-borne infection since 1998, the Centers for Disease Control and Prevention (CDC) said Tuesday in a statement posted on its website.Of the 13 deaths, four were in New Mexico, two were in Colorado, two were in Texas, and there was one each in Kansas, Maryland, Missouri, Nebraska and Oklahoma.Victims range in age from 35 to 96 years, with an average age of 78. All of the illnesses started on or after July 31.The figures were the latest confirmed as of Monday morning, according to the CDC. But they may well rise in the still-widening outbreak as state and local officials are investigating three additional deaths that may be connected.In 1998, 21 people died from listeria linked to tainted hot dogs, according to a CDC online database.The Food and Drug Administration on Sept. 14 warned consumers not to eat cantaloupes from Colorado's Rocky Ford region shipped by Jensen Farms. The cantaloupes with the brand name Rocky Ford were distributed from July 29 to Sept. 10 in at least 17 states.Listeria is a common bacterium that typically causes mild illness in healthy people, but can cause severe illness in older people and those with compromised immune systems. It also can cause miscarriages and stillbirths in pregnant women and severe infections in new babies.Listeria infections lead to about 1,600 serious illnesses each year and about 260 people die, according to the CDC.The CDC estimates that about 48 million people in the U.S. each year get sick from tainted food, with about 128,000 hospitalized and 3,000 deaths.

ROME, Sept. 27 (Xinhua) -- The 30th general assembly of the International Council for Science (ICSU) kicked off here on Tuesday to address key global challenges, featuring over 275 scientists and experts from all over the world.The goal of the four-day event, hosted for the first time in Rome by the National Research Center (CNR) as Italy's scientific member at ICSU, is to discuss how science can contribute to boosting sustainable development, fighting climate change, increasing well-being and health in the changing urban environment and tackling the side-effects of progress.At the official opening ceremony, CNR president Francesco Profumo stressed that scientific research was the key to solving all current crises."It's during times of crises that inventions, great strategies and discoveries are made," he said quoting Albert Einstein."Global cooperation is crucial in addressing society's needs. In the wake of the negative economic outlook we are witnessing research and technological transfer can turn into efficient instruments to guide countries towards a solid development giving us the tools to tackle with lucidity the great obstacles we face," observed Profumo.Appealing to both private and public institutions, Profumo thus urged to boost strategic partnerships between universities, governments and research centres."We must create a network of knowledge-sharing together with enterprises in order to multiply and better implement growth and well-being opportunities. But in order to do so concrete political decisions must be undertaken and financial resources are needed," he added.

COPENHAGEN, June 7 (Xinhua) -- The outbreak of infections caused by E. coli bacteria may be over in Denmark as no new cases have been reported here since Friday.According to Denmark's National Serum Institute (NSI), there are 18 confirmed cases of severe intestinal infection caused by exposure to the bacteria as of Monday. No new infections have been reported since Friday, it added.The confirmed cases are said to consist of 10 men and 8 women aged between 23 and 81 years of age. Seven show symptoms of kidney failure which is associated with advanced stages of the infection.All but one are believed to have contracted the infection while traveling in northern Germany, where the outbreak started, the NSI said.So far, the E. coli infection has claimed 21 lives in Germany, which reports over 2,100 confirmed and suspected cases. It has also spread to 12 countries according to the World Health Organization (WHO)."This particular strain of E.coli has been identified in some people sporadically in the past, but it has not been known to have been associated with outbreaks in the past," a WHO spokesperson said Friday, adding it was a "very, very rare strain."Health authorities in Germany now suspect bean sprouts as the source of contamination in this outbreak, although this is yet to be confirmed.Dr Kaare Moelbak, an epidemiologist at NSI told Danish media Sunday that bean sprouts were a "very likely" source of contamination.Cucumbers were initially suspected and Denmark's food authority continues to warn against eating raw tomato, cucumber or lettuce from Germany until the source is established.Children are normally most vulnerable to E. coli infection but most of those infected in this outbreak are above the age of 20 years, Moelbak told Xinhua last week.He said children are likely less affected by this outbreak as they usually eat fewer salads than adults.In Germany, it is mostly women who have been affected by the infection. Moelbak explained the skew in infections saying women tend to choose to eat more vegetables than men, in comments made to Danish media Thursday.

BEIJING, Sept. 4 (Xinhua) -- Officials and delegations from China and African countries have gathered at a seminar being held in Beijing to discuss rural development and economic growth.The seven-day seminar kicked off on Sunday, attracting representatives from China and 11 African countries to exchange views and experiences related to the seminar's theme of "agriculture and rural development."Justin Lin Yifu, chief economist and senior vice president of the World Bank, said at the seminar's opening ceremony that African countries should take cues from China's experience in creating a series of policies to bolster agricultural and rural development, as these policies have also facilitated the country's economic growth.Hu Jinglin, assistant to China's Minister of Finance, said improved agricultural cooperation between China and Africa will help enhance global grain security.China has worked on 142 cooperative agricultural projects with 14 African countries to date. In addition, it has sent 104 agricultural experts to 33 African countries to train more than 4,200 local agricultural technicians.