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排序方式: 共有196条查询结果,搜索用时 46 毫秒
1.
A local positive feedback of the tropical Pacific ocean-atmosphere system on interdecadal timescales
LI Chunhui WANG Dongxiao LIANG Jianyin GU Dejun LIU Yun 《科学通报(英文版)》2006,51(5):601-606
SINCE THE 1990S, THE CLIMATIC VARIABILITY ON INTERDE- CADAL TIME SCALES BECAME THE FOCUS OF THE INTERNATIONAL CLIMATOLOGY RESEARCH MISSIONS[1―3]. ON TIME SCALES OF A DECADE OR MORE, THE OCEAN CIRCULATION PREDOMINATEDHEAT BALANCE AND HYDROLOGICAL CYCLE, S… 相似文献
2.
LIUZhifei TUOShouting ZHAOQuanhong CHENGXinrong HUANGWei 《科学通报(英文版)》2004,49(20):2190-2197
The most prominent cooling event of the Earth surface during Cenozoic in the long-term transition from a non-glaciated planet, or “green-house world”, to a polar, glaciated planet, or “ice-house world”, is the Earliest Oligocene Glacial Maximum (EOGM) above the Eocene/Oligocene boundary at about 33.7 Ma. Planktonic and benthic foraminiferal oxygen and carbon isotopes, carbonate content, and coarse fraction, along with high-resolution color reflectance and magnetic susceptibility records during 35-30 Ma, from deep-water Sites 1262 and 1265, Ocean Drilling Program (ODP) Leg 208 in South Atlantic, reveal the global cooling event occurring in both surface and deep oceans. The results show that the earliest Oligocene δ^18O values during 33.5-33.1 Ma represent the magnitude of continental ice sheets on east Antarctica and indicate the large decrease in both surface and deep water temperatures of worldwideoceans. The δ^13C records show the large excursion during the period of EOGM event and indicate some types of shift in global carbon reservoir, probably demonstrating the sudden increase in organic carbon burial rates and the changes in the distribution and timing of production. At the same time, lithologic composition, carbonate content, color reflectance, and coarse fraction brought about significant changes close to the Eocene/Oligocene boundary, reflecting the abrupt deepening in the carbonate compensation depth (CCD). Changes in carbonate content were revealed from the color reflectance identify periodicities associated with eccentricity of the Earth‘s orbit (100 and 400 ka), further indicating orbitally forced global climate variations in the Early Oligocene. 相似文献
3.
《Journal of Natural History》2012,46(11):1597-1615
Over 8000 amphipods were examined from coastal (primarily intertidal) and anchialine pool habitats of Ascension Is. Twenty-seven species, of which 14 are undescribed, were identified. Comparison of species from Ascension with amphipods found in possible source areas suggests that most colonization of the island by these animals has been via the Benguela Current. Possible western Atlantic faunal contributions are significantly lower than for other marine taxa that have been studied at Ascension, all of which are generally characterized by having dispersive larval stages. The high proportion of apparently endemic species, which exceeds that described for amphipods of other oceanic islands, is probably due to both the island's isolation and incomplete faunal surveys in possible source areas. Amphipod species diversity is low, a probable consequence of the size, isolation, youth and low habitat variability of Ascension Is. Consistent with other Atlantic islands that have been studied, nestlers predominate (56% of the species), with tubicolous species (33%) of secondary importance and inquilines (11%) making only a minor contribution. Three species occur in the anchialine pool habitat. Rather unexpectedly, caprellid amphipods are absent. 相似文献
4.
《Journal of Natural History》2012,46(2):471-488
The following digeneans are described, recorded or figured from South African waters: Enenterum kyphosi and E. mannarense from Kyphosus vaigiensis; E. elsti, E. prudhoei, E. stinkvis sp. nov. and E. tongaatensis sp. nov. from Neoscorpis lithophilus; Pseudozakia hatampo from Pempheris oualensis; Opistholebes cotylophorus from Amblyrhynchotes honckenii; and Pleorchis sciaenae from Argyrosomus hololepidotus. The other taxa discussed are: family Enenteridae; genus Enenterum (including a key); and genus Opistholebes (syn: Pseudoheterolebes). 相似文献
5.
《Journal of Natural History》2012,46(6):1451-1460
A new genus of cirolanid isopod Atarbolana, and two new species, Atarbolana exoconta and Cirolana manorae, are described. Atarbolana is distinguished from related cirolanid genera by having a projecting clypeus, pleon with three free tergites, and cylindrical uropod exopod. Cirolana manorae is most similar to Cirolana bovina Barnard, and new figures are given for that species. 相似文献
6.
《Journal of Natural History》2012,46(16):1211-1282
In this study of flabelliferan Isopoda from the Indian Ocean, 19 species are described as new, in 11 genera and two families: family Cirolanidae, Baharilana koloura, B. lira, Cirolana aldabrensis, C. mimulus, C. somalia, C. undata, Eurydice paxilli, and Metacirolana chemola; family Sphaeromatidae, Cassidinidea clarkae, Cymodoce fuscina, C. lirella, Dynamenella alveolata, D. remex, Heterodina (new genus), H. mccaini, Oxinasphaera brucei, O. furcata, O. tetrodon, Paracilicaea stauros, and Sphaeromopsis sulcifera. Diagnoses of the genera and species are provided, and keys to the Indian Ocean species of most of the genera are provided. The material comes primarily from Aldabra Atoll, the granitic Seychelles islands, Zanzibar Island, and Phuket in Thailand. A few miscellaneous samples from the South African Museum collections, and from the International Indian Ocean Expedition carried out in the mid‐1960s are included. 相似文献
7.
ShuangXi Chen TieGang Li Zheng Tang XiaoHua Qiu ZhiFang Xiong QingYun Nan ZhaoKai Xu FengMing Chang 《科学通报(英文版)》2011,56(24):2628-2634
The deglacial δ~13C minimum events that originated from the ventilation of the deep Southern Ocean around Antarctica, have been recorded in a range of marine sediments from the southern to tropical oceans in late Pleistocene. However, the broad δ~13C minimum event was also reported as far as to the northern middle latitudes, in northwestern Pacific marginal sea areas, during the last deglaciation. In the northwestern Pacific, forcing from the northern high latitudes is strongly expressed, while the records of in- fluence from the southern high latitudes are few. The Kuroshio Source Region (KSR) forms a boundary between the northwestern Pacific and the southern, tropical Pacific. So, high-resolution planktonic foraminiferal records in core MD06-3054 from the KSR are well positioned to identify signals from the southern hemisphere in the northwestern Pacific. Planktonic foraminiferal tests from the upper 1030 cm of the core were subject to AMS14C, carbon and oxygen isotopic measurements. A negative excursion was found to occur from about 20.0-6.0 ka BP in δ~13C records of both surface (Globigerinoides ruber) and subsurface (Pulleni- atina obliquiloculata) dwellers, but the overall trends of the two curves have reversed since 26.5 ka BP. Moreover, the δ~13C rec- ord of G. ruber (the surface dweller) shows a robust link to the record of atmospheric CO2, and its changes precede the records of P. obliquiloculata (the subsurface dweller). According to the hydrologic conditions, the broad δ~13C minimum event recorded in the KSR is also a response to the increasing ventilation of the deep Southern Ocean around Antarctica during the last deglaciation. The inconsistency between the records of the surface and subsurface dwellers was possibly caused by the ways that the low δ~13C signal was transmitted. Subsurface water primarily received the low δ~13C signal from the Antarctic Intermediate Water (AAIW), whereas the surface water was probably mainly impacted by atmospheric CO2 in the KSR. The records from the KSR confirm the deduction that the broad δ~13C minimum event in the Okinawa Trough was due to the impact of tropical Pacific surface water dur- ing the last deglaciation, and suggest that signals from the southern high latitudes also can be delivered to the northern middle latitudes. 相似文献
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