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921.
PALAEOSHORELINES AS INDICATOR OF LATE CENOZOIC CLIMO-TECTONIC CHANGES IN LADAKH TRANS HIMALAYA:AN ILLUSTRATION FROM TSO KAR LAKE1 BhattacharyyaA .Vegetationandclimateduringthelast 30 0 0 0 yearsinLadakh [J] .Palaeogeogr,Palaeoclimatol,Palaeoecol,1989,73:2 5~ 38.
2 CerlingTE .LateCenozoicvegetationchange,atmosphericCO2 andtectonics[A] .Ruddiman ,W .F .,ed .Tectonicupliftandclimatechange[M] .NewYork:PlenumPress,1998.313~ 2 2 7.
… 相似文献
922.
923.
腐泥的复合层是富有机碳的深色沉积物 ,为地中海上新世—更新世沉积记录中特有的沉积特征。这些层位特别引人关注是因为 :⑴现代地中海的生物生产力通常很低 ;⑵大洋中大部分有机物的最终结局是被氧化了和侵蚀了 ,而并非在海洋地层中聚集下来。因此腐泥记录了与目前这个大的半封闭海环境明显不同的古环境条件下有机物的生产和保存。解释深海腐泥各种成因的假设包括海洋原始生产力的提高。有机物供给的增加、海底缺氧和有机物保存能力增强。通常 ,这种解释认为腐泥与地球轨道运行周期最小值一致 ,后者是季节性变化增强的周期 ,并且腐泥的出现… 相似文献
924.
正Dykes are primarily extensional fractures that form perpendicular to the minimum principal compressive stress,which have been extensively studied in the world during the past decades for various reasons including the 相似文献
925.
Williams JN Hollander AD O'Geen AT Thrupp LA Hanifin R Steenwerth K McGourty G Jackson LE 《Carbon balance and management》2011,6(1):11
Background
Quantification of ecosystem services, such as carbon (C) storage, can demonstrate the benefits of managing for both production and habitat conservation in agricultural landscapes. In this study, we evaluated C stocks and woody plant diversity across vineyard blocks and adjoining woodland ecosystems (wildlands) for an organic vineyard in northern California. Carbon was measured in soil from 44 one m deep pits, and in aboveground woody biomass from 93 vegetation plots. These data were combined with physical landscape variables to model C stocks using a geographic information system and multivariate linear regression.Results
Field data showed wildlands to be heterogeneous in both C stocks and woody tree diversity, reflecting the mosaic of several different vegetation types, and storing on average 36.8 Mg C/ha in aboveground woody biomass and 89.3 Mg C/ha in soil. Not surprisingly, vineyard blocks showed less variation in above- and belowground C, with an average of 3.0 and 84.1 Mg C/ha, respectively.Conclusions
This research demonstrates that vineyards managed with practices that conserve some fraction of adjoining wildlands yield benefits for increasing overall C stocks and species and habitat diversity in integrated agricultural landscapes. For such complex landscapes, high resolution spatial modeling is challenging and requires accurate characterization of the landscape by vegetation type, physical structure, sufficient sampling, and allometric equations that relate tree species to each landscape. Geographic information systems and remote sensing techniques are useful for integrating the above variables into an analysis platform to estimate C stocks in these working landscapes, thereby helping land managers qualify for greenhouse gas mitigation credits. Carbon policy in California, however, shows a lack of focus on C stocks compared to emissions, and on agriculture compared to other sectors. Correcting these policy shortcomings could create incentives for ecosystem service provision, including C storage, as well as encourage better farm stewardship and habitat conservation.926.
Irizuki T Takimoto A Sako M Nomura R Kakuno K Wanishi A Kawano S 《Marine pollution bulletin》2011,62(10):2030-2041
This study focuses on the relationships of water and sediment quality with meiobenthos (Ostracoda) over the past 100 years, using a sediment core obtained from Suo-Nada in the Seto Inland Sea, Japan. We compared high-resolution ostracode results with geochemical and sedimentological data obtained from the study core as well as with rich environmental monitoring data that are available. R-mode cluster analysis revealed two bioassociations (BC, KA). Until the1960s, assemblages continued to show high diversity. They changed in approximately 1970, when excessive nutrients and organic matter began to be supplied, and most species decreased in number. All species of bioassociation BC were dominant again by the mid-1990s; however, those of bioassociation KA containing infaunal species did not increase and have been absent or rare since the 1970s because organic pollution of sediments has continued to date. This study provided robust baseline for ostracode-based long-term environmental monitoring in East Asia. 相似文献
927.
Stewart KR Keller JM Templeton R Kucklick JR Johnson C 《Marine pollution bulletin》2011,62(7):1396-1409
To assess threats to endangered species, it is critical to establish baselines for contaminant concentrations that may have detrimental consequences to individuals or populations. We measured contaminants in blubber and fat from dead leatherback turtles and established baselines in blood and eggs in nesting turtles. In fat, blubber, blood and eggs, the predominant PCBs were 153 + 132, 187 + 182, 138 + 163, 118, and 180 + 193. Total PCBs, 4,4′-DDE, total PBDEs and total chlordanes were significantly and positively correlated between blood and eggs, suggesting maternal transfer. Significant positive relationships also existed between fat and blubber in stranded leatherbacks. Less lipophilic PCBs appeared to more readily transfer from females to their eggs. PBDE profiles in the four tissues were similar to other wildlife populations but different from some turtle studies. Concentrations were lower than those shown to have acute toxic effects in other aquatic reptiles, but may have sub-lethal effects on hatchling body condition and health. 相似文献
928.
Human pharmaceuticals, like the lipid lowering agent gemfibrozil and the non-steroidal anti-inflammatory drug diclofenac are causing environmental concern. In this study, the marine mussel (Mytilus spp.) was exposed by injection to environmentally relevant and elevated (1 μg/L and 1000 μg/L) concentrations of both compounds and biomarker expression was observed. Gemfibrozil exposure induced biomarkers of stress (glutathione S-transferase and metallothionein) at both concentrations 24 h and 96 h after exposure, respectively. Biomarkers of damage (lipid peroxidation (LPO) and DNA damage) were significantly affected, as well as the biomarker for reproduction, alkali-labile phosphate assay, indicating the potential oxidative stress and endocrine disrupting effect of gemfibrozil. Diclofenac significantly induced LPO after 96 h indicating tissue damage. Additionally standard toxicity tests using the marine species Vibrio fischeri, Skeletonema costatum and Tisbe battagliai showed differences in sensitivity to both drugs in the mg/L range. Results indicate a suite of tests should be used to give accurate information for regulation. 相似文献
929.
930.
Galatius A Dietz R Rigét FF Sonne C Kinze CC Lockyer C Bossi R 《Marine pollution bulletin》2011,62(7):1476-1483
Eighty-five stranded or bycaught harbor porpoises collected from the Danish North Sea between 1980 and 2005 were analyzed for perfluorochemicals in the liver. PFOS was the predominant compound, making up on average 88.9% of the ∑PFC, followed by PFOSA (7.8%). PFUnA (1.9%) and PFDA (1.2%) were detected in most samples. PFHxS, PFNA and PFOA were only found in a minority of the samples. We found substantial differences in PFC concentrations among life history stages, the highest concentrations were found in neonates, suckling juveniles and lactating females. Such differences should be considered when PFC levels in wildlife are evaluated. The high concentrations found in young porpoises are of concern as PFCs have known toxic effects on the development of the central nervous system and reproductive organs. Despite efforts to reduce PFC emissions, a decreasing temporal trend of concentrations was not detected for any compound. PFCA concentrations were found to be increasing. 相似文献