Pollution history and recovery of a boreal lake exposed to a heavy bleached pulping effluent load

We examined the effects of heavy pulp mill discharges on the Lake Lievestuoreenjärvi ecosystem and the later recovery of diatom and chironomid communities from age-dated short core samples. Beginning in 1927 the lake received a heavy effluent load from a sulphite pulp mill. Except for the recession during the Second World War and the temporary closure of the mill from 1967 to 1971, the industrial load, containing large quantities of nutrients, organic matter and toxic compounds, increased continuously. In the early 1980s, laboratory documents were falsified by the directors of the mill and the systematic illegal effluent overload led to a collapse of the whole lake ecosystem. In 1985, the outdated plant was finally closed down. Based on the assessment of chemical properties and biological remains of the sediment, we distinguished five developmental phases in the ecological state of the lake. In the pre-industrial phase, the pelagic and profundal benthic communities were dominated by species preferring ultraoligotrophic or oligotrophic lakes. Concomitant with the increasing discharge and deposition of chlorine compounds, resin acids, and mercury, as well as strong acidity and hypolimnetic and epilimnetic anoxia, the ecological status changed in a short period from excellent to bad. Finally, in the early 1960s, the majority of the lake was virtually dead and the aquatic life survived only in the uppermost littoral zone. Since 1985, a fast recovery in the water quality has led to a strong, but temporary eutrophy in pelagic communities. The main peak of eutrophication was caused by the invasion of a species new to the lake,Aulacoseira granulata var.angustissima. Later, the pelagic communities shifted towards oligotrophy, but the original, pre-industrial status has not been re-established. The profundal benthic communities have not achieved the pre-industrial structure, but at present indicate mesotrophy.     

A discrete particle representation of hillslope hydrology: hypothesis testing in reproducing a tracer experiment at Gårdsjön,Sweden

Despite the long history of the continuum equation approach in hydrology, it is not a necessary approach to the formulation of a physically based representation of hillslope hydrology. The Multiple Interacting Pathways (MIPs) model is a discrete realization that allows hillslope response and transport to be simultaneously explored in a way that reflects the potential occurrence of preferential flows and lengths of pathways. The MIPs model uses random particle tracking methods to represent the flow of water within the subsurface alongside velocity distributions that acknowledge preferential flows and transition probability matrices, which control flow pathways. An initial realization of this model is presented here in application to a tracer experiment carried out in Gårdsjön, Sweden. The model is used as an exploratory tool, testing several hypotheses in relation to this experiment. Copyright © 2011 John Wiley & Sons, Ltd.     

浅议矿业权转让市场建设与地勘行业改革的关系

笔者从地勘单位由事转企改革的角度,分析论证矿业权转让市场建设的迫切性,并对矿业权转让市场建设中有关的交易对象、矿业权价值认定、矿业权利益取得以及市场的启动与运作等问题,提出了一些具体的意见,使该市场真正对地勘改革和社会主义市场经济建设起到积极地促进作用。     

Overview of the KwaZulu-Natal sardine run

This paper provides an introduction to, and overview of, the natural phenomenon known as the KwaZulu-Natal sardine run. Previous literature on this topic and hypotheses about the reasons why, and the mechanisms how, the run occurs are briefly synthesised and described. Papers contributing to this suite that detail more recent work on a variety of aspects of the sardine run, ranging from physical oceanography through sardine biology and ecology to socio-economic and ecological consequences, are outlined. Such studies will lead to improved understanding of the factors that regulate the timing and intensity of the run, which may permit predictions of whether it will occur, when fish will arrive on the KZN beaches, and how long it will persist. Such predictions would have substantial benefits for this ecologically and economically important event.     

The KwaZulu-Natal sardine run: shoal distribution in relation to nearshore environmental conditions, 1997–2007

The nearshore presence of sardine Sardinops sagax on the KwaZulu-Natal (KZN) coast was investi-gated using sightings data collected by the KZN Sharks Board from 1997 to 2007. The spatio-temporal distribution of sardine was described in relation to that of their predators and to environmental conditions, and subjected to generalised linear model (GLM) and generalised additive model (GAM) analyses. Variables describing spatio-temporal conditions performed best in the models (r² = 0.52) with seasonal effects, specifically June and July, making the greatest contribution towards sardine presence. The contribution of the years 2003, 2006 and 2007, and the KZN North Coast, was signif-icantly lower. The predator variables were highly significant (r² = 0.48) with Cape gannets Morus capensis, followed by the sharks/gamefish and common dolphins Delphinus capensis, being most closely associated with sardine presence. Environmental variables were not as influential in the GLM models (r² = 0.23), but some variables were useful in describing conditions favouring sardine presence, namely calm current conditions, light north-westerly land breezes and stable atmospheric conditions. Increasing sea surface temperature (SST), moderate north to south currents, large swells and turbid water had a negative impact upon sardine presence. North-easterly and north-westerly winds and north to south currents had a cooling effect upon nearshore SSTs, whereas south-easterly winds and increasing air temperatures caused nearshore warming. Results are discussed in the context of developing an understanding of the mechanisms that govern fine-scale movements of sardine shoals during the KZN sardine run, with a view to predicting such movements.     

Hooker's sea lions in southern New Zealand

The discovery at Stewart Island of a hauling‐out ground regularly used by Hooker's sea lions (Phocarctos hooked) is described, and recent sightings of sea lions in southern New Zealand are reported. An attempted copulation between a male Hooker's sea lion and a dead female fur seal (Arctocephalus forsteri) is also described.     

浮游植物化学分类法—CHEMTAX运算在南中国海应用的改进和优化

In order to determine the phytoplankton community composition, the modification and optimizing of the CHEMical TAXonomy (CHEMTAX) running was carried out through samples grouping, successive run and ev...     

高速摄影对散体振动的研究

以现代高速摄影技术和图像分析以及数据处理方法，针对高效振动磨机中弹性散体工质（如钢棒、球体等）的振动力学进行了深入的探讨和分析，为研究散体动力学和振动超细粉碎过程中的能量分布和传递规律以及能量与物质的相互转换机理奠定了基础，也为相关学科的发展提供了一种可以借鉴的方法。     

中国对虾(Penaeus chinensis)消化系统发生的研究

本文对中国对虾消化道和中肠腺的发生进行了研究。完整的中肠管形成于Ｎ３期，它是由幼虫腹面的内胚层板向背中线上卷合拢而形成。在Ｚ１期消化道完全贯通。至Ｍ１期，胃分化为贲门胃和幽门胃两部分，中肠前盲囊和中肠后盲囊也在此期出现，同时胃磨的雏形发生，但完整的胃磨形成于Ｐ期。另外，中肠腺始于Ｎ４－５期中肠前端突出的两对中肠腺盲囊。第一对中肠腺盲囊于Ｍ３期退化消失，而第二对中肠腺盲囊则发育为成体的中肠腺。中肠腺小管由４种不同类型的细胞（胚性细胞、吸收细胞、纤维细胞和泡状细胞）所组成     

川藏铁路3000 m水平定向钻井技术方案

川藏铁路设计多条超长深埋隧道,且多处于高海拔、高陡斜坡及雪线以上的无人山区,地形险峻,起伏大,交通条件差。沿隧道轴线的水平定向钻井为隧道勘察提供了一种有效的勘察手段。结合工程及地层特点,从钻井设备、工艺等方面,为超长隧道勘察提供了一种3000 m级水平定向钻井技术方案。方案明确了井身结构、全面钻进和长钻程取心钻进工艺、钻井液措施及部分复杂情况应对措施。以较少的钻探工作量,为隧道勘察提供更加详细的实物地质资料,真实反映隧道内的地质情况。