Are sea otters being exposed to subsurface intertidal oil residues from the Exxon Valdez oil spill?     

Boehm PD  Page DS  Neff JM  Brown JS 《Marine pollution bulletin》2011,62(3):581-589

Twenty years after the Exxon Valdez oil spill, scattered patches of subsurface oil residues (SSOR) can still be found in intertidal sediments at a small number of shoreline locations in Prince William Sound, Alaska. Some scientists hypothesize that sea otters continue to be exposed to SSOR by direct contact when otters dig pits in search of clams. This hypothesis is examined through site-specific examinations where SSOR and otter-dug pits co-occur. Surveys documented the exact sediment characteristics and locations on the shore at the only three subdivisions where both SSOR and otter pits were found after 2000. Shoreline characteristics and tidal heights where SSOR have persisted are not suitable habitat for sea otters to dig pits during foraging. There is clear separation between areas containing SSOR and otter foraging pits. The evidence allows us to reject the hypothesis that sea otters encounter and are being exposed by direct contact to SSOR.  相似文献   

Marine mammals and debris in coastal waters of British Columbia, Canada     

Williams R  Ashe E  O'Hara PD 《Marine pollution bulletin》2011,62(6):1303-1316

Entanglement in and ingestion of synthetic marine debris is increasingly recognized worldwide as an important stressor for marine wildlife, including marine mammals. Studying its impact on wildlife populations is complicated by the inherently cryptic nature of the problem. The coastal waters of British Columbia (BC), Canada provide important habitat for marine mammal species, many of which have unfavorable conservation status in the US and Canada. As a priority-setting exercise, we used data from systematic line-transect surveys and spatial modeling methods to map at-sea distribution of debris and 11 marine mammal species in BC waters, and to identify areas of overlap. We estimated abundance of 36,000 (CIs: 23,000-56,600) pieces of marine debris in the region. Areas of overlap were often far removed from urban centers, suggesting that the extent of marine mammal-debris interactions would be underestimated from opportunistic sightings and stranding records, and that high-overlap areas should be prioritized by stranding response networks.  相似文献   

Polybrominated diphenyl ethers and their hydroxylated/methoxylated analogs: environmental sources, metabolic relationships, and relative toxicities   总被引：2，自引：0，他引：2  

Wiseman SB  Wan Y  Chang H  Zhang X  Hecker M  Jones PD  Giesy JP 《Marine pollution bulletin》2011,63(5-12):179-188

Brominated compounds are ubiquitous in the aquatic environment. The polybrominated diphenyl ether (PBDE) flame retardants are anthropogenic compounds of concern. Studies suggest that PBDEs can be biotransformed to hydroxylated brominated diphenyl ethers (OH-BDE). However, the rate of OH-BDE formation observed has been extremely small. OH-BDEs have also been identified as natural compounds produced by some marine invertebrates. Another class of compounds, the methoxylated BDEs (MeO-BDEs), has also been identified as natural compounds in the marine environment. Both the OH-BDEs and MeO-BDEs bioaccumulate in higher marine organisms. Recent studies have demonstrated that MeO-BDEs can be biotransformed to OH-BDEs and this generates greater amounts of OH-BDEs than could be generated from PBDEs. Consequently, MeO-BDEs likely represent the primary source of metabolically derived OH-BDEs. Given that for some endpoints OH-BDEs often exhibit greater toxicity compared to PBDEs, it is prudent to consider OH-BDEs as chemicals of concern, despite their seemingly "natural" origins.  相似文献   

黄铁矿标型特征在找矿中的应用:以赵家堡子金矿为例     

刘洪涛  李忠满  李大中 《矿物学报》2011,(Z1):58-60

1概述黄铁矿是金矿床中常见的主要金属硫化物,同时也是金的主要载体矿物,因此研究黄铁矿标型特征对指导金矿的找矿非常重要。黄铁矿化学式为FeS2,常含有As、Co、Ni、Se、Te、Sb、Cu、Au、Ag等的细分散混入物。Co、Ni类质同象代替Fe,形成FeS2—CoS2和FeS2—NiS2系列,随Co、Ni代替Fe的含量增加,晶胞增  相似文献   

大洋钻探计划     

Rabi.  PD 沈锡昌 《地质科学译丛》1990,7(2):85-86

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花岗岩类构造环境的判别   总被引：1，自引：0，他引：1  

Mani.  PD 张佩华 《地质科学译丛》1990,7(3):22-28

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花岗岩类的构造环境判别     

Mani.  PD 许峰林 《国外花岗岩类地质与矿产》1990,(3):22-27

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顾及地形坡度的SRTM和ASTER加权融合     

郑婷婷  陈传法  刘洪涛 《测绘通报》2020,(4):121-124

为了克服现有SRTM和ASTER各自缺陷,提升公共DEM精度,本文提出了一种顾及地形坡度的SRTM和ASTER加权融合方法。首先对两种DEM进行地理配准;然后计算不同坡度等级下SRTM和ASTER的高程误差,并得到DEM融合权重;最后采用加权平均法对SRTM和ASTER进行融合。高精度控制点的检验表明：融合后DEM精度有明显提高,相比于原始SRTM和ASTER高程误差,标准差分别降低了5.65 m和1.20 m。  相似文献   

水玻璃基淤泥固化土力学性质试验研究     

刘洪涛  梧松  陶东新  陈必权  王利斌  朱钰龙 《中国煤炭地质》2024,(2):58-63

为解决淤泥固化及其资源化利用的问题,以宁波地区淤泥为研究对象,利用水玻璃基淤泥固化剂制备固化土,通过室内试验、固化机理分析和现场试验研究固化土的力学性质。室内试验给出了无侧限抗压强度和压缩模量随固化剂掺入比改变的规律,并指出存在最佳掺入比为7%;固化机理分析表明随着固化剂掺入比增加,固化土颗粒由鳞片状或条块状向团块状变化,团块体积呈增大趋势,固化土孔隙率小幅增大,中值孔径亦小幅增大,固化土由黏性土向粉土化转变;现场试验取心土样无侧限抗压强度约为室内试验值的70%。结果表明,水玻璃基淤泥固化剂加固淤泥土方案切实可行。  相似文献   

赤道印度洋的第四纪碳酸盐记录及其与生产率变化的关系     

Naidu  PD 丰全会 《海洋地质前沿》2000,16(1):8-10

赤道印度洋的自然地理学特征是由３个向北延伸的线状高地（Ｎｉｎｅｔｙｅａｓｔ海岭、Ｃｈａｇｏｓ＿Ｌａｃｃａｄｉｖｅ海岭和Ｃａｒｌｓｂｅｒｇ海岭）分隔的一系列盆地组成。在赤道印度洋西部３０３８ｍ水深处钻探了ＯＤＰ７０９Ａ站位,该站位位于Ｍａｄｉｎｇｌｅｙ中脊顶峰附近的一个小盆地中,而Ｍａｄｉｎｇｌｅｙ中脊则是Ｃａｒｌｓｂｅｒｇ海岭和Ｍａｓｃａｒｅｎｅ高原北部之间的一个区域高地。不规则的基底地貌被厚度从小于５０ｍ至大于４００ｍ不等的沉积物所覆盖。由于印度洋的北部陆地封堵、复杂的自然地理和强的季风,印度洋…  相似文献