Three Kings Ridge: a west-facing arc

The Three Kings Ridge has been described as a remnant arc or an east-facing arc on the western side of the South Fiji Basin under which symmetric South Fiji Basin magnetic anomaly lineations have been lost. We find evidence of neither arc-trench morphology on the eastern flank of the ridge nor collision tectonism within the adjacent South Fiji Basin that might have obliterated it. We believe there is room for the missing magnetic lineations within the South Fiji Basin and we recognize the distinctive island-arc morphology characteristic of a west-facing arc on the western flank of the Three Kings Ridge. Our interpretation requires that arc volcanism postdated formation of much of the South Fiji Basin and that oceanic lithosphere from the adjacent Norfolk Basin must have been subducted beneath the west-facing Three Kings Arc.     

A seasonal survey of the sterol composition of the cockle cerastoderma edule: A comparison of polluted and non-polluted environments

The sterol composition of a cockle population from an unpolluted environment in South Wales was monitored by monthly sampling over a 12-month period. In spite of the likely variation in dietary sterols during this period, the component sterols of the cockles showed no significant seasonal variation, indicating that the cockle was able to exhibit a high degree of control over the composition of its functional sterols.Dramatic differences were observed in the sterol compositions of a nearby cockle population from a highly polluted environment, near a sewage outfall; only three out of the ten sterols present were common to the unpolluted cockles. Forty-five per cent of the sterols from the ‘polluted’ samples contained fully reduced systems and included three new alkylated C-29, C-30 and C-31 stanols. It is considered possible that these structural changes may affect the stereochemistry of the functional sterols and hence alter the permeability of the animal's membranes. This may reflect a biochemical response to the polluted environment.     

Storm-built sand ridges on the Maryland inner shelf: a preliminary report

Several aspects of the Maryland ridge field are pertinent to the problem of ridge genesis in response to Holocene sea-level rise. There is a systematic morphologic change fromshoreface ridges throughnearshore ridges tooffshore ridges, which reflects the changing hydraulic regime. Grain size is 90° out of phase with topography, so that the coarsest sand lies between the axis of each trough and the adjacent seaward ridge crest, while the finest sand lies between each ridge crest and the axis of the adjacent seaward trough. Finally, analysis over a 43-year period on an outer ridge reveals a systematic pattern of landward flank erosion, seaward flank deposition, and seaward crest migration. These relationships support a model which explains the ridges as consequences of the up-current shift of maximum bottom shear stress with respect to the crests of initial bottom irregularities. The oblique orientation of the ridges with respect to the beach may be at least partly due to the more rapid migration rate of the ridges’ inshore ends.     

A correcting “prism” for underwater viewpoints

The angular field observable in water by an observer in air depends on the configuration of the air-water interface. When the interface is a plane, the absolute limit to observable field is about from the normal to the interface. A practical limit, because of lateral chromatic aberration is considerably less, approximately 30°. A conventionally used configuration in research submersibles, is a polymethyl methacrylate port with inner and outer surfaces parallel. This has the same optical limitations as the plane air-water interface. It is shown that if the inner and outer surfaces are not required to be parallel to each other, there are solutions which permit extending the observable field to nearly a full hemisphere with acceptably small distortion and lateral chromatic aberration.     

Comparison of high spatial resolution trace metal distributions with model simulations for surface waters of the Gulf of Cadiz

A multidisciplinary study in the Gulf of Cadiz is revisited, using additional diagnostic modelling tools. The dissolved trace metal (Cu, Ni, Zn, Co) distributions in the Gulf of Cadiz are analysed using modelled tracer evolutions, field observations and the concept of tracer ages. This study shows that a significant part of the observed metal distributions can be explained by the metal inputs of three river systems (Guadiana, Rio Tinto and Odiel, Guadalquivir) discharging into the Gulf of Cadiz, while the remainder of the signal is most likely associated with the benthic metal remobilisation along the shelf of this coastal region.     

Suspended sediment concentration in a buoyant plume: Fraser River,Canada

A study of suspended sediment concentration in the buoyant plume of the Fraser River, Canada, showed that unstratified flow conditions at the river mouth caused resuspension of sandy bed material and high concentrations of coarse sediment. When flow at the mouth was stratified, sediment was fine-grained and concentrations were low. Application of a multivariate model revealed that suspended sediment concentration along the plume axis was controlled primarily by distance seaward of the river mouth, secondly by tidal height, and least by sediment concentration in the river.     

4-溴苯甲酸-2,3,4,5,6-五溴苯酯的合成(英文)

以苯酚和4—溴苯甲酸为原料,合成一种尚未见文献记载的新化合物——4—溴苯甲酸—2,3,4,5,6—五溴苯酯,用无水三氯化铝催化苯酚的全溴化。此产物可望在阻燃剂方面得到应用。     

三峡工程对长江口区无脊椎动物资源影响的预测

长江大量径流给其河口及邻近海域带来丰富的营养物质,维持了长江河口生态系统的巨大生产力,并使之成为多种重要经济鱼虾类的索饵和产卵场。长江口生态环境的变化,对我国最大、最重要的浙江舟山渔场和江苏吕四渔场的渔业资源有举足轻重的影响。三峡工程的兴建将使长江入海径流量及其季节分配有很大改变,也不可避免地影响到河口和近海的海洋环境、经济动物的组成及资源状况。为研究长江口无脊椎动物资源结构及其分布特征,以及预测三峡工程对自然生态环境的影响,于1985年9月至1986年8月进行了无脊椎动物资源底拖网试捕调查。本文系统整理调查所得资料,结合历史资料进行分析研究。     

Wave group statistics from numerical simulations of a random sea

Two commonly used methods of simulating random time series, given a target power spectrum, are discussed. Wave group statistics, such as the mean length of runs of high waves, produced by the different simulation schemes are compared. The target spectra used are obtained from ocean measurements, and cover a wide range of ocean conditions. For a sufficiently large number of spectral components, no significant differences are found in the wave group statistics produced by the two simulation techniques.     

Proximate Constituents, Biomass, and Energy in Posidonia oceanica (Potamogetonaceae)

Abstract. The proximate composition of the various components of Posidonia oceanica is given in terms of gravimetric and energetic level and amount of plants from 2 depths at Port-Cros (Var. France). The level of proximate constituents differed little between the leaves (regardless of age) and the roots, but the rhizome contained much more soluble carbohydrate and less structural carbohydrate and ash. Because of this, the energy level in the leaves was more in terms of organic material and less in terms of total material than the energy level in the rhizome. The leaves of a P. oceanica shoot at 2 m depth in July contained 1.6 g organic material. 29.0 kJ. The weight and energy of the soluble carbohydrate in the rhizome from the base of the leaves to the 18th sheath scale decreased by ca. 40% from October to March and increased by ca. 100% from March to July.