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Hogerheijde MR Bergin EA Brinch C Cleeves LI Fogel JK Blake GA Dominik C Lis DC Melnick G Neufeld D Panić O Pearson JC Kristensen L Yildiz UA van Dishoeck EF 《Science (New York, N.Y.)》2011,334(6054):338-340
Icy bodies may have delivered the oceans to the early Earth, yet little is known about water in the ice-dominated regions of extrasolar planet-forming disks. The Heterodyne Instrument for the Far-Infrared on board the Herschel Space Observatory has detected emission lines from both spin isomers of cold water vapor from the disk around the young star TW Hydrae. This water vapor likely originates from ice-coated solids near the disk surface, hinting at a water ice reservoir equivalent to several thousand Earth oceans in mass. The water's ortho-to-para ratio falls well below that of solar system comets, suggesting that comets contain heterogeneous ice mixtures collected across the entire solar nebula during the early stages of planetary birth. 相似文献
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Sanda Skejić Ivona Marasović Olja Vidjak Grozdan Kušpilić Živana Ninčević Gladan Stefanija Šestanović Natalija Bojanić 《Aquaculture Research》2011,42(9):1393-1405
In this study, we investigated the physical, chemical and biological parameters of the water column at two stations under different trophic conditions during a 1‐year period (from September 2005 to September 2006) in an aquaculture area. The investigation was performed monthly at a station inside the fish farm in Maslinova Bay (middle Adriatic Sea, Croatia) and at a control station located in the Hvar Channel in the vicinity of the farm. The results showed that the concentrations of dissolved nutrients were slightly enhanced at the farm station in comparison with the control station, although those differences were not statistically significant, nor were the differences in oxygen saturation recorded during the investigation period. As opposed to the chemical parameters, considerably higher deviations were recorded for biological parameters as demonstrated by a significant increase in phytoplankton biomass and primary production (measured in situ) at the farm station, particularly during the summer season. Phytoplankton community structure analysis showed that the phytoplankton composition at the farm was mostly determined by seasonal changes rather than by the influence of fish farming. In Maslinova Bay, no causal links were identified between increased biomass and the appearance of toxic species. 相似文献
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