Contribution of Tides to Sea Level Variations Along Visakhapatnam,India

The sea level variations along Visakhapatnam coast are governed by astronomical tides and nontidal oscillations including atmospheric pressure, winds, coastal currents, Ekman Pumping, and river influx. Tidal and nontidal sea level oscillations are usually studied separately because of the vastly different ways in which they are forced. In this study the tidal oscillations along Visakhapatnam are analyzed using GOTIC2 tidal model. The correlation between monthly mean sea level and monthly mean tides is 47% (r = 0.68) and increases to 54% (r = 0.74) when applied for inverse-barometric effect. The major six partial tides are computed and presented. The tidal variations from Neap tide to Spring tide are studied.     

Quantification of Spatial and Thematic Uncertainty in the Application of Underwater Video for Benthic Habitat Mapping

This study presents an analysis of the application of underwater video data collected for training and validating benthic habitat distribution models. Specifically, we quantify the two major sources of error pertaining to collection of this type of reference data. A theoretical spatial error budget is developed for a positioning system used to co-register video frames to their corresponding locations at the seafloor. Second, we compare interpretation variability among trained operators assessing the same video frames between times over three hierarchical levels of a benthic classification scheme. Propagated error in the positioning system described was found to be highly correlated with depth of operation and varies from 1.5m near the surface to 5.7m in 100m of water. In order of decreasing classification hierarchy, mean overall observer agreement was found to be 98% (range 6%), 82% (range 12%) and 75% (range 17%) for the 2, 4, and 6 class levels of the scheme, respectively. Patterns in between-observer variation are related to the level of detail imposed by each hierarchical level of the classification scheme, the feature of interest, and to the amount of observer experience.     

Short-Term Morphological and Shoreline Changes at Trinkat Island,Andaman and Nicobar,India, After the 2004 Tsunami

The tsunami waves generated during the Sumatra-Andaman earthquake of 26 December 2004 devastated the coastal area along Trinkat Island, causing sudden changes to the morphology of the landforms. This study uses a series of satellite images to record the short-term morphological response and shoreline changes as well as the recovery of coastal land after its destruction. Results indicate that the island experienced substantial erosion and a significant reduction in land area. Shoreline erosion is more prevalent than accretion at an average linear regression rate of ～?9 m per year between 2004 and 2013. The major morphological changes at Trinkat Island were observed in coastal inlets, beaches, and bay head-lands. Straight beaches had almost recovered eight years after the tsunami; however, erosion is continually observed in other areas. Our study will help understanding the response and recovery of shorelines in Indian Ocean regions after the 2004 tsunami.     

Deep Seabed Mining: Past Failures and Future Prospects

The first attempt to exploit deep-sea manganese nodules ended in failure as a result of the collapse of world metal prices, the onerous provisions imposed by the U.N. Convention on the Law of the Sea (UNCLOS), and the overoptimistic assumptions about the viability of nodule mining. Attention then focused on Co-rich manganese crusts from seamounts. Since the mid-1980s, a number of new players have committed themselves to long-term programs to establish the viability of mining deep-sea manganese nodules. These programs require heavy subsidy by the host governments. Au-rich submarine hydrothermal deposits located at convergent plate margins are now emerging as a more promising prospect for mining than deep-sea manganese deposits.     

以哈维氏弧菌(Vibrio harveyi)为重点的鱼类细菌病原的诊断与控制(英文)

作者对鱼类细菌病原的诊断与控制作了较全面的综述。细菌病原诊断技术包括酶联免疫吸附技术（ＥＬＩＳＡ）及蛋白印迹法（Ｗｅｓｔｅｒｎｂｌｏｔｉｎｇ）。细菌病原控制技术包括化学疗剂的应用,有益微生物的应用,营养添加剂,β－葡萄糖苷增强免疫抗病力,及免疫保护作用等。     

Regional setting of Håkon Mosby Mud Volcano, SW Barents Sea margin

The Håkon Mosby Mud Volcano (HMMV) is a seafloor mud volcano, having a 1-km-diameter circular shape and a relief of 8–10?m. HMMV is located within a slide scar on the Bjørnøya glacial submarine fan on the SW Barents Sea slope, and is underlain by a >6-km-thick Cenozoic sequence. Multichannel seismic data reveal a 1- to 2-km-wide disturbed zone, which extends to a depth of >3?km below the HMMV. We relate the zone to the presence of free gas. The seismic data are compatible with an intrasedimentary sourced mud volcano related to the glacial sedimentation history and mass movements.     

North Brazil current: vertical structure

On the basis of the data ofin situ measurements of the velocities of currents and basic hydrophysical parameters (such as temperature and salinity) carried out during Cruise 41 of the R/VAkademik Vernadsky, we analyze the structure of the North Brazil Current near the continental slope and in the equatorial abyssal part of the ocean in winter, establish the regularities of changes in the current velocity with depth, and compare the structures of the North Brazil and Guiana Currents. Translated by Peter V. Malyshev and Dmitry V. Malyshev     

A Recent Full-Depth Survey of the Alaskan Stream

We examine results from a cruise in May 1997. CTD casts to near the bottom were made south of the Aleutian Islands, across Amchitka Pass, and north of the islands. We computed a westward geostrophic speed of 123 cm s^–1 at 173.5°W in the Alaskan Stream. The computed volume transport there, referred to the bottom, was 25×10⁶m³s^–1. On other similar sections, transports were 8–15 × 10⁶ m³s^–1. Various complex variations in geopotential height along the Stream apparently altered the cross-stream gradients, and hence the transports. Rotational tendencies were also present. Northward inflow through Amchitka Pass was quite strong (6 × 10⁶ m³s^–1). Data north of the islands supported the existence of a zero-velocity reference level of variable depth.     

Cenozoic tectonics of Amazon Mouth Basin

 The Cenozoic shelf margin of the Amazon Mouth Basin is characterized by a thick prograding prism of siliciclastic sediments. This prism, composed mainly of Upper Miocene and younger sediments, overlies a Lower Tertiary carbonate shelf. Two tectonic–sedimentary models for the area were developed with the aid of new deep-reflection seismic data. Gravitational tectonics dominate the regional geological framework. Tensional stresses are created near the shelf margin, and compressional features dominate at the base of the slope. The morphology of this compressional zone is closely associated with the St. Paul Fracture Zone and the boundary between continental and oceanic crusts. Received: 20 August 1996 / Revision received: 11 June 1998     

Ultraviolet absorption/salinity correlation as an index of pollution in inshore sea waters

Ultraviolet absorption spectra of fresh and marine waters along the southern coast of Viti Levu, Fiji, are recorded. Variations in the magnitude of the absorption from streams deyoid of human influence limit the use of such measurements as a sensitive index of organic pollution. However, where there is a significant difference between the absorption magnitudes of adjacent streams, these can be individually identified in coastal waters by concurrent absorption and salinity measurements. Such measurements characterise water masses in inshore waters, and indicate the origin of their freshwater components. Consequently the method has particular relevance in sea areas influenced by fresh waters with enhanced ultraviolet absorbance due to organic pollution.