Study was carried out to analyze the distribution and migration patterns,soil-to-plant transfer and potential health risks of chromium in soil-vegetable system in areas near a ferro-alloy manufactory in Hunan province...Study was carried out to analyze the distribution and migration patterns,soil-to-plant transfer and potential health risks of chromium in soil-vegetable system in areas near a ferro-alloy manufactory in Hunan province.The results show that soils near sewer outlet,sewer channel and in control area are averaged 2 239.5,995.33 and 104.9 mg/kg,respectively.The total Cr has a relative accumulation in soil depth of 200-400 mm near the sewer outlet,mainly enriches in the surface layer（0-200 mm） near the sewer channel and decreases gradually in unpolluted soils.The differential concentration level of enrichment between layers is little.The results also indicate that the three vegetables of celery,lettuce and Chinese cabbage are able to convert the potentially toxic Cr（Ⅵ） species into the non-toxic Cr（Ⅲ） species,and the chromium contents in the edible parts of the vegetables are averaged 11.95 mg/kg.The transfer factors of the three vegetables follow the order：Chinese cabbage lettuce celery.The estimated total daily intake of chromium substantially exceeds the dietary allowable value,which may pose health risks to local population.展开更多
Accurately quantifying waterfowl migration patterns is pertinent to monitor ecosystem health and control bird-borne infectious diseases. In this review, we summarize the current understanding of the environmental mech...Accurately quantifying waterfowl migration patterns is pertinent to monitor ecosystem health and control bird-borne infectious diseases. In this review, we summarize the current understanding of the environmental mechanisms that drive waterfowl migration and then investigate the effect of intra- and inter-annual change in food supply and temperature(e.g., climate change) on their migration patterns. Recent advances in remote sensing and animal tracking techniques make it possible to monitor these environmental factors over a wide range of scales and record bird movements in detail. The synergy of these techniques will facilitate substantial progress in our understanding of the environmental drivers of bird migration. We identify prospects for future studies to test existing hypotheses and develop models integrating up-todate knowledge, high-resolution remote sensing data and high-accuracy bird tracking data. This will allow us to predict when waterfowl will be where, in response to shortand long-term global environmental change.展开更多
Recent studies suggest that the energetic demands of long-distance migration might lower the pool of resources available for costly immune defenses. Moreover, migration could amplify the costs of parasitism if animals...Recent studies suggest that the energetic demands of long-distance migration might lower the pool of resources available for costly immune defenses. Moreover, migration could amplify the costs of parasitism if animals suffering from para- site-induced damage or depleted energy reserves are less able to migrate long distances. We investigated relationships between long-distance migration, infection, and immunity in wild fall-migrating monarch butterflies Danaus plexippus. Monarchs migrate annually from eastern North America to central Mexico, accumulating lipids essential for migration and winter survival as they travel southward. Monarchs are commonly infected by the debilitating protozoan parasite Ophryocystis elektroscirrha （OE）. We collected data on lipid reserves, parasite loads, and two immune measures （hemocyte concentration and phenoloxidase activity） from wild monarchs migrating through north GA （USA） to ask whether （1） parasite infection negatively affects lipid reserves, and （2） greater investment in lipid reserves is associated with lower immune measures. Results showed that monarchs sampled later in the fall migration had lower but not significantly different immune measures and significantly higher lipid reserves than those sampled earlier. Lipid measures correlated negatively but only nearly significantly with one measure of immune defense （phenoloxidase activity） in both healthy and infected monarchs, but did not depend on monarch infection status or parasite load. These results provide weak support for a trade-off between energy reserves and immune defense in migrants, and suggest that previously-demonstrated costs of OE infection for monarch migration are not caused by depleted lipid reserves .展开更多
基金Project (2009ZX07212-001-01) supported by the Key Project of National Natural Science Foundation for Water Pollution Control and RemediationProject (50925417) supported by the National Funds for Distinguished Young Scientists+1 种基金Project (50830301) supported by the National Natural Science Foundation of ChinaProject (51074191) supported by the National Natural Science Foundation of China
文摘Study was carried out to analyze the distribution and migration patterns,soil-to-plant transfer and potential health risks of chromium in soil-vegetable system in areas near a ferro-alloy manufactory in Hunan province.The results show that soils near sewer outlet,sewer channel and in control area are averaged 2 239.5,995.33 and 104.9 mg/kg,respectively.The total Cr has a relative accumulation in soil depth of 200-400 mm near the sewer outlet,mainly enriches in the surface layer（0-200 mm） near the sewer channel and decreases gradually in unpolluted soils.The differential concentration level of enrichment between layers is little.The results also indicate that the three vegetables of celery,lettuce and Chinese cabbage are able to convert the potentially toxic Cr（Ⅵ） species into the non-toxic Cr（Ⅲ） species,and the chromium contents in the edible parts of the vegetables are averaged 11.95 mg/kg.The transfer factors of the three vegetables follow the order：Chinese cabbage lettuce celery.The estimated total daily intake of chromium substantially exceeds the dietary allowable value,which may pose health risks to local population.
基金supported by the National Natural Science Foundation of China(41471347 and 41401484)Tsinghua University(2012Z02287)
文摘Accurately quantifying waterfowl migration patterns is pertinent to monitor ecosystem health and control bird-borne infectious diseases. In this review, we summarize the current understanding of the environmental mechanisms that drive waterfowl migration and then investigate the effect of intra- and inter-annual change in food supply and temperature(e.g., climate change) on their migration patterns. Recent advances in remote sensing and animal tracking techniques make it possible to monitor these environmental factors over a wide range of scales and record bird movements in detail. The synergy of these techniques will facilitate substantial progress in our understanding of the environmental drivers of bird migration. We identify prospects for future studies to test existing hypotheses and develop models integrating up-todate knowledge, high-resolution remote sensing data and high-accuracy bird tracking data. This will allow us to predict when waterfowl will be where, in response to shortand long-term global environmental change.
基金We thank M. Maudsley and M. Weath- ers for conducting PO assays and assisting with monarch cap- ture, hemocyte counts, and parasite load quantification A. Davis for analysis of morphometric wing data L. Brower, T. Maddox and the UGA Analytical Chemistry Lab for guidance and resources for lipid extractions, and the Altizer lab and two anonymous reviewers for comments on previous drafts of the manuscript. Funding for this project was provided by the Na- tional Science Foundation （grant DEB-0643831 to S.A. and a Graduate Research Fellowship to D.S.） and the UGA Inte- grated Life Science Program to D.S.
文摘Recent studies suggest that the energetic demands of long-distance migration might lower the pool of resources available for costly immune defenses. Moreover, migration could amplify the costs of parasitism if animals suffering from para- site-induced damage or depleted energy reserves are less able to migrate long distances. We investigated relationships between long-distance migration, infection, and immunity in wild fall-migrating monarch butterflies Danaus plexippus. Monarchs migrate annually from eastern North America to central Mexico, accumulating lipids essential for migration and winter survival as they travel southward. Monarchs are commonly infected by the debilitating protozoan parasite Ophryocystis elektroscirrha （OE）. We collected data on lipid reserves, parasite loads, and two immune measures （hemocyte concentration and phenoloxidase activity） from wild monarchs migrating through north GA （USA） to ask whether （1） parasite infection negatively affects lipid reserves, and （2） greater investment in lipid reserves is associated with lower immune measures. Results showed that monarchs sampled later in the fall migration had lower but not significantly different immune measures and significantly higher lipid reserves than those sampled earlier. Lipid measures correlated negatively but only nearly significantly with one measure of immune defense （phenoloxidase activity） in both healthy and infected monarchs, but did not depend on monarch infection status or parasite load. These results provide weak support for a trade-off between energy reserves and immune defense in migrants, and suggest that previously-demonstrated costs of OE infection for monarch migration are not caused by depleted lipid reserves .
