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101.
Baussant T Ortiz-Zarragoitia M Cajaraville MP Bechmann RK Taban IC Sanni S 《Marine pollution bulletin》2011,62(7):1437-1445
Mussels (Mytilus edulis) were continuously exposed to dispersed crude oil (0.015-0.25 mg/l) for 7 months covering the whole gamete development cycle. After 1 month exposure to 0.25 mg oil/l, the level of alkali-labile phosphates (ALP) and the volume density of atretic oocytes in female gonads were higher than those in the gonads of control females, indicating that oil affected the level of vitellogenin-like proteins and gamete development. Spawning of mussels was induced after 7 months oil exposure. Parental oil exposure did not affect subsequent fertilization success in clean seawater but this was reduced in 0.25 mg oil/l. Parental exposure to 0.25 mg oil/l caused both slow development and a higher percentage of abnormalities in D-shell larvae 2 days post-fertilization; reduced growth 7 days post-fertilization. These effects were greatly enhanced when larval stages were maintained at 0.25 mg oil/l. Similar studies are warranted for risk assessment prognosis. 相似文献
102.
Pacios I Guerra-García JM Baeza-Rojano E Cabezas MP 《Marine environmental research》2011,71(4):275-282
This is the first study describing the crustacean fauna associated to Asparagopsis armata, a non-native, red seaweed widely distributed along western Mediterranean coasts. First found in Australia and New Zealand, it was introduced naturally through the Strait of Gibraltar and rapidly spread out. A one-year spatio-temporal study (Feb 08-Feb 09) was carried out in the Strait of Gibraltar to characterize the spatio-temporal patterns of the associated crustacean fauna. Maximum biomass of A. armata was measured during April-June, whereas the maximum crustacean abundances were registered from June-October. In total 41 crustacean species were identified. The caprellid Caprella penantis, traditionally associated to non-polluted areas, was more abundant on Tarifa Island (higher values of dissolved oxygen and pH) than in Algeciras (lower oxygen and pH). The gammarid Podocerus variegatus was dominant in Algeciras Bay while Hyale schmidti and Apherusa mediterranea were the most abundant on Tarifa Island. Among isopods, Synisoma nadejda was only found on Tarifa Island. When compared with literature of native algae of the intertidal and shallow sublittoral, the species richness of associated crustaceans was similar in A. armata and the natives. Very little is known about the influence of this algae on altering marine communities, so complete faunistic studies dealing with other groups such as polychaetes or molluscs are necessary to properly address biogeographical, ecological and management programmes dealing with this non-native species. 相似文献
103.
The effects of elevated atmospheric carbon dioxide [CO2] on microbial communities in arid rhizosphere soils beneath Larrea tridentata were examined. Roots of Larrea were harvested from plots fumigated with elevated or ambient levels of [CO2] using Free-Air CO2 Enrichment (FACE) technology. Twelve bacterial and fungal rRNA gene libraries were constructed, sequenced and categorized into operational taxonomical units (OTUs). There was a significant decrease in OTUs within the Firmicutes (bacteria) in elevated [CO2], and increase in Basiomycota (fungi) in rhizosphere soils of plots exposed to ambient [CO2]. Phylogenetic analyses indicated that OTUs belonged to a wide range of bacterial and fungal taxa. To further study changes in bacterial communities, Quantitative Polymerase Chain Reaction (QPCR) was used to quantify populations of bacteria in rhizosphere soil. The concentration of total bacteria 16S rDNA was similar in conditions of enriched and ambient [CO2]. However, QPCR of Gram-positive microorganisms showed a 43% decrease in the population in elevated [CO2]. The decrease in representation of Gram positives and the similar values for total bacterial DNA suggest that the representation of other bacterial taxa was promoted by elevated [CO2]. These results indicate that elevated [CO2] changes structure and representation of microorganisms associated with roots of desert plants. 相似文献
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东昆仑哈日扎含矿花岗闪长斑岩LA-ICP-MS锆石U-Pb定年及地质意义 总被引:6,自引:0,他引:6
哈日扎铜钼多金属矿床位于东昆仑成矿带东段,是大型斑岩型铜钼多金属矿床.笔者利用锆石LA-ICP-MS U-Pb法,获得花岗闪长斑岩的成岩年龄为(234.5±4.8) Ma(MSWD=0.24);花岗闪长斑岩为其成矿母岩.对哈日扎花岗闪长斑岩的岩石学和地球化学研究表明,花岗闪长岩富SiO2(70.94%~76.08%)、K2O(4.91% ~6.07%),贫CaO(0.16% ~2.01%)、Na2O(0.24% ~0.78%),属钾玄岩系列及高钾钙碱性系列.稀土元素总量变化较大(124.69×10-6~178.68×10-6),稀土元素配分曲线为平缓的右倾型,轻稀土元素相对富集,重稀土元素相对亏损.δEu变化范围0.26~0.30,具有弱负Eu异常.岩石微量元素相对富集大离子亲石元素(LILE),贫高场强元素(HFSE),即相对富集Rb、U、La和Nd,而亏损Ba、Sr、Nb和Y.花岗闪长斑岩形成于同碰撞构造环境. 相似文献
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内蒙古北山地区小狐狸山钼矿辉钼矿Re-Os年龄
和LA-ICP-MS锆石U-Pb年龄 总被引:2,自引:1,他引:1
小狐狸山钼矿是内蒙古北山地区近年来新发现的一个中型规模的斑岩型矿床。通过对成矿斑岩锆石和成矿晚阶段石英脉型钼矿的同位素研究,获得小狐狸山含矿花岗岩锆石LA-ICP-MS U-Pb年龄216.9Ma±0.5Ma(MSWD=0.41),与斑岩型钼矿化的时间220Ma±2.2Ma在误差范围内基本一致,为该矿床主要为一个斑岩型钼矿床提供了同位素年代学的佐证;晚成矿阶段辉钼矿单矿物Re-Os模式年龄加权平均值为213.2Ma±4.6Ma(MSWD=1.3)。小狐狸山钼矿床成矿岩体的展布受控于沿黑河展布的北东东向构造,该组构造切割了早期形成的北西向区域构造,暗示216~220Ma为北山地区由后碰撞进入板内伸展环境提供了初步的年龄约束,北山地区印支期的成矿作用值得重视。 相似文献