Concentrations of organochlorines in sperm whales (Physeter macrocephalus) from Southern Australian waters

Concentrations of DDTs, PCBs and HCHs were measured in sperm whales involved in two mass stranding events on the west coast of Tasmania, Australia in February 1998. DDTs and PCBs were present in all samples analysed, while only three contained HCHs. The relationships between organochlorines, sex, age and reproductive groups were marked by high variability. Differences in organochlorine concentrations were observed between animals from the two stranding sites and discussed in light of the ecology of this species. Concentrations of all pollutants were stratified throughout the vertical aspect of the blubber and possible reasons for and the implications of this are discussed. Concentrations of compounds were higher than those documented in this species in the Southern Hemisphere previously, although were relatively lower than those documented in the Northern Hemisphere. However, comparisons were confounded by spatial and temporal differences. Continued monitoring of marine mammals throughout this region in a co-coordinated, standardized manner is essential for establishing definite temporal and spatial variations in pollutant concentrations.     

http://www.sciencedirect.com/science/article/pii/S1674987112000655

Four different varieties of charnockitic rocks,with different modes of formation,from the Mesoproterozoic Natal belt are described and new C isotope data presented.Excellent coastal exposures in a number of quarries and river sections make this part of the Natal belt a good location for observing charnockitic field relationships.Whereas there has been much debate on genesis of charnockites and the use of the term charnockite.it is generally recognized that the stabilization of orthopyroxene relative to biotite in granitoid rocks is a function of low aH₂O（±high CO₂）,high temperature,and composition （especially Fe/（Fe +Mg））.From the Natal belt exposures,it is evident that syn-emplacement.magmatic crystallization of chamockite can arise from mantle-derived differentiated melts that are inherently hot and dry（as in the Oribi Gorge granites and Munster enderbite）,as well as from wet granitic melts that have been affected through interaction with dry country rock to produce localized charnockitic marginal facies in plutons（as in the Portobello Granite）.Two varieties of post-emplacement sub-solidus chamockites are also evident.These include charnockitic aureoles developed in leucocratic,biotite.garnet granite adjacent to cross-cutting enderbitic veins that are attributed to metamorphic-metasomatic processes（as in the Nicholson’s Point granite,a part of the Margate Granite Suite）,as well as nebulous,patchy charnockitic veins in the Margate Granite that are attributed to anatectic metamorphic processes under low-aH_O fluid conditions during a metamorphic event.These varieties of chamockite show that the required physical conditions of their genesis can be achieved through a number of geological processes,providing some important implications for the classification of charnockites,and for the interpretation of charnockite genesis in areas where poor exposure obscures field relationships.     

Effects of silt loading on turbulence and sand transport

The transport of bed material and fluid turbulence are affected by many factors,including the fine sediment load being carried in a channel.Current research has focused on sand-sized particles introduced to gravel beds,while the effect of silt load on sand transport has received less attention. Experiments on the effects of silt load,in concentrations 0-26,900 mg l^-1,on sand transport were performed with a recirculating laboratory flume using three different sand bed configurations:ripples （Fr=0.24）,dunes（Fr=0.34）,and dunes（Fr=0.48）.Three Acoustic Doppler Velocimeters were arranged to measure flow and turbulence quantities simultaneously in one vertical.Sand transport did not change in a consistent manner with increasing silt load,increasing up to 4,000 mg l^-1 for dunes （Fr=0.48） and up to 2,000 mg l^-1 for dunes（Fr=0.34） and then declining to near the clear water case with increasing silt concentrations.Silt addition for the ripple case caused a relatively small change in sand transport,decreasing with added silt up to approximately 2,000 mg l^-1 and then increasing as silt went up to approximately 10,000 mg l^-1.Dunes（Fr=0.48） decreased in length and height as silt increased,while dunes（Fr=0.34） did not show a consistent trend.A clear trend of decreasing Reynolds stress with increasing silt concentration was observed in the ripple case,with a 33% reduction in near-bed Reynolds stress caused by an 8,900 mg l^-1 concentration of silt.     

由EUROBRIDGE’97地震剖面的P波与S波速度模型和重力数据得到的岩石层上部密度—速度关系

传统的折射与广角反射地震和重力数据的联合解译是基于大量地壳岩石弹性性质实验室研究证实的地震P波速度和密度之间众所周知的相关性。与这一方法相矛盾的一个问题是富含钙长石的岩石具较高的P波速度,而不满足常规密度—VP关系。这说明基于常规密度—VP关系的联合反演不适用于横跨大的非造山带环斑-辉长-斜长岩地块的广角地震调查,因为其组成成分富含斜长石。同时使用VP和VS计算密度模型就可解决这一问题。岩石属性的实验室结果表明密度与VS相关性很强。此外,各向同性VS与密度的相关性较VP更强,且受高斜长石含量的影响更小。即便如此,利用这一已知的密度与VS或者密度与VP及VS的相关性进行地震和重力数据的联合反演仍然十分少见。其重要原因在于暴破地震学中S波波至的质量低,因而难以得到可靠的S波速度模型。本文阐述了在乌克兰地盾EUROBRIDGE’97广角反射和折射剖面所做的地震和重力数据联合反演的结果。该区缺失厚沉积体,使我们可以得到P波和S波速度模型。通过重力反演得到EUROBRIDGE’97剖面密度模型,我们利用密度和VP、VS模型的关系,将密度模型参数化。这样参数化后,经重力数据转换,可以获得密度和地震波速的关系。结果显示EUROBRIDGE’97剖面的密度与地震波速之间呈非线性和离散的关系。对相关性的分析表明,造成离散是缘于横跨该剖面的大的地质构造单元的差异。为解释这一差异,我们对比EUROBRIDGE’97剖面上3个主要地质单元中地震速度和密度的关系和来自乌克兰地盾及另一个前寒武纪地区的岩石学资料。可见与平均密度—速度关系的偏移量是岩石的特殊矿物组合的反映,包含了不同的岩石时代和地壳形成环境。论述了如何通过密度—速度图分析,来限定地壳成分,尤其是下地壳的成分和变质程度。     

加拉帕戈斯三联点北部岩石层的开裂

加拉帕戈斯三联点是由科科斯板块、纳斯卡板块和太平洋板块在加拉帕戈斯微板块处汇聚形成的脊-脊-脊型三向连接构造。在科科斯—纳斯卡裂谷的大部分内斜坡以北区域,长约250km、宽约50km的西北—东南向的火山岩裂谷横插在东太平洋海隆的南北向海山上。在过去的4百万年中,东北—西南向的东太平洋海隆为一系列的较小裂谷提供了条件,使得那些小裂谷通常与东太平洋海隆共同形成三联点,而且与正在扩张的科科斯—纳斯卡裂谷有50～100km的距离。本文假设该裂谷的位置是由压力控制的,并且压力与占主导作用的科科斯—纳斯卡裂谷相关,随着与东太平洋海隆的距离增大而增大。我们推测,在科科斯—纳斯卡裂谷的南侧也曾有类似的短暂性的裂谷发生,并且曾有助于旋转的加拉帕戈斯微板块的初期形成(大约是1.5百万年)。     

东海陆架盆地南部中生界分布特征与油气勘探前景

在充分利用前人对东海陆架盆地中生代油气勘探成果的基础上,对最新处理的地震剖面和重磁反演剖面进行了精细解释和综合研究,结合海陆中生界对比结果认为:东海陆架盆地南部中生界分布广、厚度大,平均厚度可达6 000 m,而且具有“东厚西薄、南厚北薄”的特征。侏罗系主要分布在闽江和基隆凹陷,厚度分布稳定,w(TOC)平均值>1.0%;而白垩系在整个陆架盆地南部均有分布,具有向基隆凹陷加厚的趋势,w(TOC)平均值<1.0%。东海陆架盆地南部的基隆凹陷是下一步油气资源战略选区的首选目标,而台北低凸起很可能具有良好的油气远景。     

Experimental study of ERT monitoring ability to measure solute dispersion

This paper reports experimental measurements performed to test the ability of electrical resistivity tomography (ERT) imaging to provide quantitative information about transport parameters in porous media such as the dispersivity α, the mixing front velocity u, and the retardation factor R(f) associated with the sorption or trapping of the tracers in the pore structure. The flow experiments are performed in a homogeneous porous column placed between two vertical set of electrodes. Ionic and dyed tracers are injected from the bottom of the porous media over its full width. Under such condition, the mixing front is homogeneous in the transverse direction and shows an S-shape variation in the flow direction. The transport parameters are inferred from the variation of the concentration curves and are compared with data obtained from video analysis of the dyed tracer front. The variations of the transport parameters obtained from an inversion performed by the Gauss-Newton method applied on smoothness-constrained least-squares are studied in detail. While u and R(f) show a relatively small dependence on the inversion procedure, α is strongly dependent on the choice of the inversion parameters. Comparison with the video observations allows for the optimization of the parameters; these parameters are found to be robust with respect to changes in the flow condition and conductivity contrast.     

A method of accelerating transport simulation when groundwater pumping is simulated

In solving groundwater transport problems with numerical models, the computation time (CPU processing time) of transport simulation is approximately inversely proportional to the transport time-step size. Therefore, large time-step sizes are favorable for achieving short computation time. However, transport time-step size must be sufficiently small to avoid numerical instability if an explicit scheme is used (and to guarantee enough model accuracy if an implicit scheme is used). For a transport model involving groundwater pumping, a small transport time-step size is often required due to the high groundwater velocities near the pumping well. Small grid spacing often specified near the pumping well also limits the time-step size. This paper presents a method to increase transport time-step size in a transport model when groundwater pumping is simulated. The key to this approach is to numerically decrease the groundwater seepage velocities in grid cells near the pumping well by increasing the effective porosity so that the transport time-step size can be increased without violating stability constraints. Numerical tests reveal that by using the proposed method, the computation time of transport simulation can be reduced significantly, while the transport simulation results change very little.     

Biofiltration of fishpond effluents and accumulation of N-compounds (phycobiliproteins and mycosporine-like amino acids) versus C-compounds (polysaccharides) in Hydropuntia cornea (Rhodophyta)

The biofiltration capacity, biomass-yield and accumulation of N- and C-compounds of Hydropuntia cornea were analyzed. Algae were grown in different conditions for 28 d: outdoor and indoor, with or without fishpond effluents. N-uptake efficiency of these effluents was higher than 95% after 7 d both outdoors and indoors. N-enriched conditions reduced the extent of photoinhibition and increased the maximal quantum yield in H. cornea. The biomass-yield was higher in outdoor grown-algae after 7 d and decreased independently of the treatment after 28 d. N, acid polysaccharide (AP) and mycosporine-like amino acid (MAA)-yields decreased throughout the experiment in all conditions. The highest MAA-yield was observed in fishpond effluent outdoor-grown algae, indicating a positive effect of increased radiation on MAA accumulation. However, APs were higher under N-depleted conditions. The use of MAAs as UV-screening and antioxidants, and the use of AP as immunostimulants are discussed.     

Satellite imaging coral reef resilience at regional scale. A case-study from Saudi Arabia

We propose a framework for spatially estimating a proxy for coral reef resilience using remote sensing. Data spanning large areas of coral reef habitat were obtained using the commercial QuickBird satellite, and freely available imagery (NASA, Google Earth). Principles of coral reef ecology, field observation, and remote observations, were combined to devise mapped indices. These capture important and accessible components of coral reef resilience. Indices are divided between factors known to stress corals, and factors incorporating properties of the reef landscape that resist stress or promote coral growth. The first-basis for a remote sensed resilience index (RSRI), an estimate of expected reef resilience, is proposed. Developed for the Red Sea, the framework of our analysis is flexible and with minimal adaptation, could be extended to other reef regions. We aim to stimulate discussion as to use of remote sensing to do more than simply deliver habitat maps of coral reefs.