Species composition and diversity of pelagic fishes based on a longline fishery catch in the North Pacific Ocean

Evaluation of spatial-temporal variability of species composition and diversity in oceanic ecosystems is not easy because it is usually difficult to obtain sufficient data quantifying such variability.In this study,we examined pelagic species diversity indicators,species richness,Shannon-Wiener index of diversity and Hurlbert's species evenness,for fish assemblages from two areas(north and south) in the North Pacific Ocean(2°±12°N,178°E±165°W) during May±July 2008.The assemblages were based on data collecte...     

中远海综合测量技术设计与实施的合理化探讨

中远海测量具有作业海区远、航次时间跨度长、测区环境复杂、气象条件变化大、测区已知资料少等特点,对作业人员和测量设备都是一个大的挑战。在作业中,综合测量还要充分考虑声学设备之间的信号干扰和作业模式的相互干扰等问题。针对中远海综合测量的特点,对综合测量技术设计、仪器设备的准备、食品的补给、综合测量实施中注意的问题等提出了合理化建议。     

High‐resolution lithostratigraphy and organic carbon isotope stratigraphy of the Lower Triassic pelagic sequence in central Japan

After the severest mass extinction event in the Phanerozoic, biotic recovery from the extinction at the Permian–Triassic boundary required approximately 5 my, which covers the entire Early Triassic. It is important to obtain information on the superocean Panthalassa, which occupied most of the world ocean, to explore paleoenvironmental changes during the Early Triassic at the global scale. In order to establish the continuous lithostratigraphy of pelagic sediments in Panthalassa during the Early Triassic, high‐resolution reconstruction of the Lower Triassic pelagic sequence in Japan was conducted for the first time based on detailed field mapping and lithostratigraphic correlation in the Inuyama area, central Japan. The reconstructed Early Triassic sequence is approximately 9.5 m thick, consists of five rock types, and is divided into eight lithological units. For the reconstructed continuous sequence, measurement of carbon isotopic composition of sedimentary organic matter (δ¹³C_org) was carried out. Stratigraphic variation of the δ¹³C_org value shows large‐amplitude fluctuations between ?34.4 and ?21.0‰ throughout the sequence. In order to establish a higher resolution age model for the reconstructed Lower Triassic pelagic sequence, we correlated δ¹³C_org records in the Inuyama area with high‐resolution isotopic profiles of carbonate carbon (δ¹³C_carb) from shallow‐marine carbonate sequences in southern China based on the similarity in general variation patterns with age constraints by radiolarian and conodont biostratigraphy. The result provides a high‐resolution time scale for the pelagic sequence of Panthalassa during the Smithian and Spathian. The age model suggests a drastic increase in sedimentation rate during the late Smithian, which should have been caused by the increase in terrigenous input to this site.     

Assessing the suitability of commercial fisheries data for local-scale marine spatial planning in South Africa

This study integrates fisheries logbook data with observer and vessel monitoring system (VMS) data in order to assess the accuracy of reported data and to develop high-resolution spatial data suitable for use in local-scale marine spatial planning analyses. Spatial assessments were conducted on five nearshore commercial fisheries to provide baseline information to inform spatial management and conservation planning in Algoa Bay, South Africa. Clear spatial patterns in the distribution of fishing effort were apparent for the linefishery, chokka-squid and inshore demersal trawl sectors. Observer and VMS data confirmed the broad spatial distribution of resource-use patterns of logbook data. Combining these data sources allowed higher-resolution spatial indices of fishing effort to be developed, which are suitable for systematic spatial planning on a local scale and can be used for future spatial management and conservation.     

滇西南牡音河组的沉积特征-环境意义及与之相关的若干地质问题

地处古特提斯域的牡音河组是一套由放射虫硅质岩和凝灰岩组合而成、沉积速率极低的远洋沉积序列。它所包括的４个放射虫组合指示其形成时代为晚二叠世末至中三叠世，从而大大改变了我们以往对古特提斯演化所拟定的时间表。详细的岩相和岩石地球化学分析表明，牡音河组的中、下部与大洋岛弧的火山活动关系密切，上部则有接受更多陆源物质的趋向。这一沉积记录所反映的演化趋可能标志着古特提斯残留海的一次重大构造转折。但是，牡音河组内所有火山碎屑和陆源碎屑仅仅构成若干夹在正常远洋序列中的远源薄层，这意味着古特提斯残留海仍然具有相当规模，距离完全闭合尚远。就牡音河组与相邻一些地层单位的关系，探讨了若干造山带地层学研究中值得注意的基本问题     

Off-scraped Permian-Jurassic bedded chert thrust on Jurassic-early Cretaceous accretionary prism: Radiolarian evidence from le Island, central Ryukyu Island Arc

Abstract The pre-Neogene basement of the central Ryukyu Island Arc shows zonal structures analogous to those of the outer belt of southwest Japan. The innermost terrane (Iheya Zone) consists of isoclinally folded beds dipping northwestward; the anticlinal cores are composed mainly of Permian chert, whereas the synclinal parts are represented by Jurassic to Cretaceous sandstone-rich alternating siliceous shale and chert, bearing appropriate radiolarian fossils. At the east-central area of Ie Island, the basement rocks are exposed as a 172 m high peak, Tattyu. The flank area of Tattyu is composed of latest Jurassic to Berriasian siliceous shale and chert as part of an accretionary prism, while most of Tattyu is composed of a continuous and very compact sequence of Norian through Kimmeridgian (?) bedded chert which is rather gently inclined. Beyond an unexposed part below the Norian chert, Guadalupian chert is recognized. It is inferred that this pelagic chert (Tattyu sequence) was off-scraped and thrust on to the accretionary prism which developed on its flank area in an accretion process after the Early Cretaceous.     

Reexamination of Radiolarian Biostratigraphy in Permian in Pelagic Chert Sequences at Dachongling Section, South China

Permian radiolarian biostratigraphy was reexamined in the bedded chert section in Qinzhou area of southeast Guangxi Zhuang Autonomous Region, South China. On the basis of the analyses of characteristic radiolarian composition, six radiolarian zones are recognized, namely, Pseudoalbaillella longtanensis Zone, Pseudoalbaillella globosa Zone, Follicucullus monacanthus Zone, Follicucullus scholasticus Zone, Follicucullus charveti Zone and Neoalbaillella ornithoformis Zone, in ascending order. Correlation of these radiolarian zones with those in Japan is presented. The Neoalbaillella ornithoformis Zone was firstly discovered in Dachongling Section, which may indicate that pelagic chert of the late Permian existed there, according to the co-occurring conodonts.     

Magnetostratigraphy of Early Cretaceous Maiolica sections of the Southern Alps (Cismon and Pra da Stua, Italy)

The bottom part of the Cretaceous Cismon section in the Southern Alps was sampled for high-resolution magnetostratigraphy. Although the almost pure pelagic nannofossil limestones ( c. 90 per cent CaCO₃) of the Maiolica/Biancone Formation are extremely weakly magnetized, stepwise thermal and alternating-field demagnetization removed overprints and isolated a characteristic remanent magnetization which is interpreted as a primary magnetization. The dominant magnetic carrier mineral is magnetite; a small fraction of haematite may be present. A clear reversal pattern can be correlated unambiguously with Mesozoic polarity chrons CM10N to CM8. A less well-constrained magnetostratigraphy from the Pra da Stua section could not be directly correlated with the global polarity scale, but biostratigraphic information allows its assignment to the interval CM10-CM5. A counterclockwise rotation of 56 and a northward translation of 28 latitude for the Cismon locality since the Early Cretaceous are derived from the palaeomagnetic data, consistent with previous results from the Southern Alps. The high-resolution magnetostratigraphy of the Cismon section is used in an effort to refine the Cretaceous timescale by the combination of magnetostratigraphic and cyclostratigraphic results from the same section. The cyclostratigraphic duration estimates of chrons CM10N to CM8 are compared to their equivalents in a number of traditional timescales and found to be shorter by a factor of 1.26-2.58.     

赤道东经90°海岭3.5Ma以来远洋记录反映的重大环境事件

通过对东经90°海岭ODP758钻孔岩心3.5Ma以来的浮游有孔虫远洋记录的研究,结合岩性地层、稳定同位素地层、碳酸盐地层等资料,探讨了喜马拉雅山加速隆升、"中更新世气候转型"、"中布容溶解"事件等重大构造、环境事件在研究区的表现及相关机制。通过对各项指标的分析和对比,根据ODP758岩心的有孔虫组合面貌、古温度、古盐度和古温跃层的变化情况,推断研究区在1.4～0.7Ma期间的气候变化可能是在"中更新世气候转型"条件下发生的。碳酸钙、碳酸钙沉积通量和非碳酸钙沉积通量曲线在1.7Ma时快速增长,与现有资料显示的青藏高原的隆升历史相符,分别与青藏高原隆升过程中的青藏运动A幕、B幕、C幕(1.7Ma)和昆仑-黄河运动(1.2～0.6Ma)相当。碳酸钙含量、大于150μm的粗组分含量、浮游有孔虫沉积通量和浮游有孔虫生物地层揭示出在0.5～0.4Ma期间研究区深海碳酸盐遭受了强烈溶解。此事件与大西洋、太平洋、印度洋及南沙海区沉积记录中的"中布容溶解"事件一致。