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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.

XICHANG, Sichuan, July 27 (Xinhua)-- China successfully launched an orbiter into space at 5:44 a.m. Beijing Time Wednesday, as a part of its indigenous satellite navigation and positioning network known as Beidou, or Compass system, sources with the launch center said.The orbiter,launched from the Xichang Satellite Launch Center in southwestern Sichuan Province, was boosted by a Long March-3A carrier rocket into a geostationary orbit.China started to build up its own satellite navigation system to break its dependence on the U.S. Global Positioning System (GPS) in 2000.A Long March-3A carrier rocket lifts off at the Xichang Satellite Launch Center in southwest China's Sichuan Province, July 27, 2011. China successfully launched into space a ninth orbiter for its independent satellite navigation and positioning network known as Beidou, or Compass System here early WednesdayBetween October 2000 and May 2003, the country set up a regional satellite navigation system after launching three Beidou geostationary satellites.The system was known as Beidou-1 and is said to have played an important role in the rescue efforts following the devastating earthquake in May 2008 in Wenchuan as it provided the only channel connecting the quake-hit area and the outside.The Beidou-1 system can not meet growing demand, so a better functional Beidou-2 regional and global navigation system will be set up, Qi Faren, former chief designer for Shenzhou spaceships said in an interview with Xinhua early this year.From April 2007 to April this year, China launched another eight orbiters to form its Beidou-2 system, which will eventually consist of 35 satellites.The network will provide satellite navigation, time and short message services for Asia-Pacific regions by 2012 and global services by 2020.

XIAMEN, June 12 (Xinhua) -- Chinese mainland on Sunday announced a raft of measures on tourism, transportation, farmers and food safety to boost Taiwan's economic growth and cross-Strait relations.A pilot plan allowing mainlanders to visit Taiwan as individual tourists will start on June 28, which covers residents of Beijing, Shanghai and southeastern city of Xiamen at the first stage, said Wang Yi, head of the State Council's Taiwan Affairs Office.Wang told a conference at the weeklong Straits Forum being held in Xiamen of Fujian Province that the mainland and Taiwan also agreed to allow Fujian residents to visit the islands of Kinmen, Matsu and Penghu in the Taiwan Strait as individual tourists.Observers predict that the influx of mainland tourists will bring vitality to Taiwan's export-oriented economy which had greatly suffered from the global economic downturn.Currently, mainlanders are only allowed to visit Taiwan on package tours after the authorities lifted a partial ban in July 2008.At Sunday's conference, the two sides also announced to increase the number of cross-Strait passenger flights by more than 50 percent to 558 flights per week, and add terminals for the direct flights in four mainland cities, including one in northwestern city of Lanzhou, which brought the total number of cross-Strait flight terminals to 50 on both sides of the Strait.The moves aim to cope with the increasing number of mainlanders who wish to visit Taiwan.The number of mainland tourists traveling to the island reached 2.34 million as of the end of May, China's top tourism official said at the conference. There are also an increasing number of mainland business travelers and government delegations visiting Taiwan.Meanwhile, both sides agreed to "regulate airfares" for flights from Beijing and Shanghai to Taipei.Currently, the cheapest one-way ticket between Beijing and Taipei on Air China, the mainland's flagship carrier, costs around 1,300 yuan (about 200 U.S. dollars) while a full price one-way ticket costs more than 3,000 yuan, according to the airline's website.Some members of the public on both sides have complained about the high price.For the past decades, travelers had to transfer at other airports, particularly the one in Hong Kong, in order to reach Taiwan by air.In 2003, the two sides agreed to operate charter flights during Spring Festival, China's biggest public holiday.Regular direct flights across the Strait have been available since July 2008 to mainly serve mainland package tourists visiting Taiwan.The mainland also decided to facilitate entry and exit procedures for Taiwan residents and lower charges for endorsing their passports by 50 percent starting from July 1.Meanwhile, four "enterprising parks" will be set up in four cities of Fujian, central Henan and southwestern Guangxi provinces for Taiwan farmers launching agricultural startups on the mainland, said Wang Yi.Both sides also agreed to encourage mainland enterprises to purchase farm produce and other products listed in the early harvest program of the cross-Strait Economic Cooperation Framework Agreement (ECFA) directly in Taiwan.A general manager surnamed Lin of a farm produce company in Taiwan's southern city of Tainan said he hoped to seize the opportunity to benefit from the development of the island's farm and fishing sector as the mainland has become Taiwan's largest export market.Further, both sides agreed to strengthen cooperation and exchanges concerning nuclear power security and food safety.The third Straits Forum, which opened Saturday in Xiamen, facing Taiwan across the Strait, will close in the island's city of Taichung on Friday.

PARIS, Sept. 21 (Xinhua) -- European heavy-lift launcher Ariane 5 lifted off two communication satellites Wednesday from the Kourou launch centre in French Guiana, live broadcast of the launching process showed.The rocket, carrying the two communication satellites Arabsat 5C and SES-2, was launched at GMT 2138.This was the fifth heavy-lift mission of Ariane 5 in 2011. Arianespace had planned six Ariane 5 missions through 2011.The satellite Arabsat-5C was developed for the Arab Satellite Communications Organization (Arabsat) to provide satellite capacity in both C-band and Ka-band frequencies for a wide range of communications services.Jointly produced by Europe's EADS Astrium and Thales Alenia Space, it will be positioned at 20 degree East orbital location to cover the Middle East and Africa.Manufactured by Orbital Sciences Corporation of the United States, SES-2 will join the fleet of European satellite telecommunications operator SES, and is to be positioned at 87 degree West for coverage over North America and the Caribbean.Both Arabsat-5C and SES-2 have life-spans as long as 15 years.This Ariane 5 dual-passenger mission was postponed from Tuesday due to local strikes of French Guiana workers.Founded in 1980 as the world's first launch service and solutions company, Arianespace planned to achieve six Ariane 5 missions through 2011. Through 2010, heavy-lift workhorse Ariane 5 finished six missions, sending a dozen spacecraft into expected orbits.The next mission from Arianespace centre in Kourou was scheduled for Oct. 20 by medium-lift vehicle Soyuz. It will be Soyuz' first mission from French Guiana with a pair of satellites for Europe's Galileo satellite navigation system.

WASHINGTON, July 27 (Xinhua) -- The solar-powered, Jupiter- bound Juno spacecraft was secured into place on top of its rocket Wednesday in preparation for launch next month, the U.S. National Aeronautics and Space Administration (NASA) announced.The launch period for Juno opens Aug. 5 and extends through Aug. 26. For an Aug. 5 liftoff, the launch window opens at 11:34 a.m. EDT (1534 GMT) and remains open through 12:43 EDT (1643 GMT).Juno will arrive at Jupiter in July 2016 and orbit its poles 33 times to learn more about the gas giant's interior, atmosphere and aurora."We're about to start our journey to Jupiter to unlock the secrets of the early solar system," said Scott Bolton, the mission 's principal investigator from the Southwest Research Institute in San Antonio. "After eight years of development, the spacecraft is ready for its important mission."