A comparison of plastic and plankton in the north Pacific central gyre

The potential for ingestion of plastic particles by open ocean filter feeders was assessed by measuring the relative abundance and mass of neustonic plastic and zooplankton in surface waters under the central atmospheric high-pressure cells of the North Pacific Ocean. Neuston samples were collected at 11 random sites, using a manta trawl lined with 333 u mesh. The abundance and mass of neustonic plastic was the largest recorded anywhere in the Pacific Ocean at 334 271 pieces km² and 5114 g km², respectively. Plankton abundance was approximately five times higher than that of plastic, but the mass of plastic was approximately six times that of plankton. The most frequently sampled types of identifiable plastic were thin films, polypropylene/monofilament line and unidentified plastic, most of which were miscellaneous fragments. Cumulatively, these three types accounted for 98% of the total number of plastic pieces.     

Magnetic properties and heavy-metal contents of contaminated seabed sediments of Penny's Bay, Hong Kong

Magnetic properties and heavy-metal concentrations of vibrocore samples were found to be potential indicators of shipping contamination in seabed sediments in Hong Kong Harbour. Geochemical results of 74 vibrocores located off Penny's Bay on Lantau Island revealed an enrichment of heavy metals in the upper 1-2 m of the cores within the eastern part of the study site. Whole-core magnetic susceptibility measurements also showed a greater concentration of magnetic particles in the surficial layer of these cores. A significant correlation exists between the magnetic susceptibility and the concentrations of Pb, Zn and Cu, as well as the Tomlinson pollution load index (PLI). The proximity of these cores to a major navigation fairway and an anchorage site suggests probable contamination of the surficial seabed sediments by shipping-related wastes. A study of the magnetic properties of one of the cores, VT60, revealed a difference in the magnetic properties between the contaminated and the uncontaminated sediments. Samples from the contaminated zone exhibited relatively stronger magnetic remanence and susceptibility. The two groups of samples also formed distinct trends on the hysteresis ratios plot. A level of unusually high magnetic susceptibility within the contaminated zone was attributable to the presence of strongly magnetized granules, which were probably refuse from shipping-related activities. Geochemical and magnetic results were also conducted on samples of different size-fractions from this core. The < 63 microns fraction was found to contain a relatively higher magnetic susceptibility and greater heavy-metal content.     

A comparison of neustonic plastic and zooplankton at different depths near the southern California shore

Previous studies of neustonic debris have been limited to surface sampling. Here we conducted two trawl surveys, one before and one shortly after a rain event, in which debris and zooplankton density were measured at three depths in Santa Monica Bay, California. Surface samples were collected with a manta trawl, mid-depth samples with a bongo net and bottom samples with an epibenthic sled, all having 333 micron nets. Density of debris was greatest near the bottom, least in midwater. Debris density increased after the storm, particularly at the sampling site closest to shore, reflecting inputs from land-based runoff and resuspended matter. The mass of plastic collected exceeded that of zooplankton, though when the comparison was limited to plastic debris similar to the size of most zooplankton, zooplankton mass was three times that of debris.     

Benthic changes during 10 years of organic enrichment by McMurdo Station, Antarctica

A benthic habitat along the coast of McMurdo Station in the Ross Sea, Antarctica is enriched by sewage from the station and altered by hydrocarbons and heavy metals in an adjacent historic dumpsite. We report on 10 years of change in the benthic communities from 1988 to 1998 and compare enrichment effects at Australia's Casey Station, East Antarctica. Despite being 14 km apart, reference communities upcurrent and downcurrent of McMurdo Station remained closely similar over time, dominated in all years by a tube building polychaete, Spiophanes tcherniae. The community bordering McMurdo Station was generally a third as abundant as communities at the reference sites over the decade of sampling, although diversity was as high or higher, except in the most contaminated areas. In 1992, organic enrichment of the outfall community intensified and within the year, the opportunistic polychaetes Aphelochaeta sp., Ophryotrocha notialis, Capitella perarmata, and Leitoscoloplos kerguelensis became dominant. Since 1996, two of the three enriched communities have increased in resemblance to the reference communities. Given the observed responsiveness of the benthos to the outfall so far, further changes are anticipated within the year following implementation of sewage treatment in 2003. Organic enrichment by McMurdo Station has had a greater impact on benthic community structure than at Australia's Casey Station.     

高温高压下岩石波速与地壳深部的物质组成

通过对高温高压下岩石波速实验资料的综合研究得出：岩石波速及速度各向异性可用于确定地壳深部各层的组成和界面性质;岩石波速随构造环境而变化；同一波速层由成分和成因上不同的岩石组合而成利用统计分析后的高温高压波速数据，建立了42组ρ-Vp（密度-速度）关系式及深部岩石判别图解     

山东省筑港工程处简介

山东省筑港工程处,历史渊源,原本是东北人民政府的一支施工队伍,中华人民共和国成立之后,归属到中央交通部。六十年代初,下放到了山东省。自那时起,近三十年来,它转战在占我国漫长海岸线六分之一的齐鲁沿岸,建成港口二十余处,码头数十座,岸线总长近万米,特别是党的十一届三中全会之后,在筑港