ENCORE: the effect of nutrient enrichment on coral reefs. Synthesis of results and conclusions

Coral reef degradation resulting from nutrient enrichment of coastal waters is of increasing global concern. Although effects of nutrients on coral reef organisms have been demonstrated in the laboratory, there is little direct evidence of nutrient effects on coral reef biota in situ. The ENCORE experiment investigated responses of coral reef organisms and processes to controlled additions of dissolved inorganic nitrogen (N) and/or phosphorus (P) on an offshore reef (One Tree Island) at the southern end of the Great Barrier Reef, Australia. A multi-disciplinary team assessed a variety of factors focusing on nutrient dynamics and biotic responses. A controlled and replicated experiment was conducted over two years using twelve small patch reefs ponded at low tide by a coral rim. Treatments included three control reefs (no nutrient addition) and three + N reefs (NH4Cl added), three + P reefs (KH2PO4 added), and three + N + P reefs. Nutrients were added as pulses at each low tide (ca twice per day) by remotely operated units. There were two phases of nutrient additions. During the initial, low-loading phase of the experiment nutrient pulses (mean dose = 11.5 microM NH4+; 2.3 microM PO4(-3)) rapidly declined, reaching near-background levels (mean = 0.9 microM NH4+; 0.5 microM PO4(-3)) within 2-3 h. A variety of biotic processes, assessed over a year during this initial nutrient loading phase, were not significantly affected, with the exception of coral reproduction, which was affected in all nutrient treatments. In Acropora longicyathus and A. aspera, fewer successfully developed embryos were formed, and in A. longicyathus fertilization rates and lipid levels decreased. In the second, high-loading, phase of ENCORE an increased nutrient dosage (mean dose = 36.2 microM NH4+; 5.1 microM PO4(-3)) declining to means of 11.3 microM NH4+ and 2.4 microM PO4(-3) at the end of low tide) was used for a further year, and a variety of significant biotic responses occurred. Encrusting algae incorporated virtually none of the added nutrients. Organisms containing endosymbiotic zooxanthellae (corals and giant clams) assimilated dissolved nutrients rapidly and were responsive to added nutrients. Coral mortality, not detected during the initial low-loading phase, became evident with increased nutrient dosage, particularly in Pocillopora damicornis. Nitrogen additions stunted coral growth, and phosphorus additions had a variable effect. Coral calcification rate and linear extension increased in the presence of added phosphorus but skeletal density was reduced, making corals more susceptible to breakage. Settlement of all coral larvae was reduced in nitrogen treatments, yet settlement of larvae from brooded species was enhanced in phosphorus treatments. Recruitment of stomatopods, benthic crustaceans living in coral rubble, was reduced in nitrogen and nitrogen plus phosphorus treatments. Grazing rates and reproductive effort of various fish species were not affected by the nutrient treatments. Microbial nitrogen transformations in sediments were responsive to nutrient loading with nitrogen fixation significantly increased in phosphorus treatments and denitrification increased in all treatments to which nitrogen had been added. Rates of bioerosion and grazing showed no significant effects of added nutrients. ENCORE has shown that reef organisms and processes investigated in situ were impacted by elevated nutrients. Impacts were dependent on dose level, whether nitrogen and/or phosphorus were elevated and were often species-specific. The impacts were generally sub-lethal and subtle and the treated reefs at the end of the experiment were visually similar to control reefs. Rapid nutrient uptake indicates that nutrient concentrations alone are not adequate to assess nutrient condition of reefs. Sensitive and quantifiable biological indicators need to be developed for coral reef ecosystems. The potential bioindicators identified in ENCORE should be tested in future research on coral reef/nutrient interactions. Synergistic and cumulative effects of elevated nutrients and other environmental parameters, comparative studies of intact vs. disturbed reefs, offshore vs. inshore reefs, or the ability of a nutrient-stressed reef to respond to natural disturbances require elucidation. An expanded understanding of coral reef responses to anthropogenic impacts is necessary, particularly regarding the subtle, sub-lethal effects detected in the ENCORE studies.     

Holistic environmental assessment and offshore oil field exploration and production

According to UK Government surveys, concern for the environment is growing. Environmental regulation of the industry is becoming wider in its scope and tougher in its implementation. Various techniques are available to assess how the industry can drive down its environmental impact and comply with environmental regulation. Environmental Assessments (EA) required by European law do not cover the whole life cycle of the project that they are analysing. Life Cycle Analysis (LCA) was developed to assess the environmental loadings of a product, process or activity over its entire life cycle. It was the first technique used in environmental analysis that adopted what was described as a holistic approach. It fails this approach by not assessing accidental emissions or environmental impacts other than those that are direct. Cost Benefit Analysis (CBA) offers the opportunity to value environmental effects and appraise a project on the basis of costs and benefits. Not all environmental effects can be valued and of those that can there is considerable uncertainty in their valuation and occurrence. CBA cannot satisfactorily measure the total environmental risk of a project. Consequently there is a need for a technique that overcomes the failures of project-level EA, LCA and CBA, and assesses total environmental risk. Many organizations such as, the British Medical Association, the European Oilfield Speciality Chemicals Association, the Royal Ministry of Petroleum and Energy (Norway) and Shell Expro now recognize that a holistic approach is an integral part of assessing total risk. The Brent SPAR case study highlights the interdisciplinary nature required of any environmental analysis. Holistic Environmental Assessment is recommended as such an environmental analysis.     

中国西南天山山前的晚新生代构造与地震活动

天山是研究现今陆内造山作用及过程、陆内变形、陆内强震及其预测等大陆动力学问题的理想实验场。西南天山和塔里木之间的新生代褶皱－逆断裂带基本上由一南冲弧形推覆构造系统和一向北反冲的构造系统组成，由北而南主要由以下4个运动学单元组成：（1）新生代复活的喀拉铁热克山－天山南脉古生代造山带，其快速变形和抬升可能起始于23－26Ma前，持续至13－16Ma前。（2）向南逆冲的西南天山前陆薄皮主冲断带，包括木兹杜克弧形薄皮推覆体和依柯冲断带，前者代表了向南薄皮逆掩的天山型岩系，地表主要表现为一系列的飞来峰群，在14Ma前曾有过大规模活动，最小缩短量约为20－35km，最小缩短速率为1．4－2．8mm/a；后者代表了向南叠瓦状薄皮逆冲推覆的前陆古生代基底（塔里木地台型沉积岩系）卷入构造，其西段在距今14Ma时曾有过强烈活动。两者共同组成了一复杂的双重构造；新生代地层也卷入变形。（3）喀什－阿图什弧形反冲褶皱－逆断裂带，由3排向北（天山）反冲的左阶雁列展布的第四纪地表滑脱褶皱组成，仅在大山口以西发育。该构造带形成于距今约1．4Ma以后。依什拉克喀拉乌尔断裂以南，博古孜河剖面的最小缩短速率约为5．8mm/a，翁库尔剖面的最小缩短速率约为8．6mm/a。（4）塔里木克拉通下盘块体，向北西方向缓倾，内部变形较小。里木块体西北存在明显的不均匀性，其学问基底高角度逆断裂和走滑断裂控制了盆地新生代沉积的厚度，导致西南天山前陆冲断带的地形地貌、地层、构造变形样式、变形时间以及变形缩短量沿走向的巨大差异性。迈丹－喀拉铁克断裂和阿图什断裂带均为岩石圈规模断裂，研究区的中强地震主要发生在这两条断裂带以及它们之间的西南天山前陆冲断带上。     

天山南缘北轮台断裂库尔楚段晚第四纪的最新活动和滑动速侣

使用全站仪实测了天山南麓北轮台逆断裂库尔楚段阿克艾肯-喀腊萨喀腊阿塔木冲洪积扇断层崖地形地貌,采用10Be测年方法测定了该冲洪积扇的形成年龄,得到该断裂段垂直位移滑动速率为0.48 mm/a、0.85～1.0 mm/a和1.52 mm/a,并对该断裂段的水平缩短速率和天山第四纪水平缩短量进行了讨论.     

华南地区栖霞组菊花状天青石的交代及其地质意义

本文在收集大量菊花石标本的基础上，通过岩石薄片镜下鉴定及X射线衍射分析，识别了华南地区栖霞组菊花石假象内矿物的成因类型，建立了矿物交代序列，并通过对菊花石假象内各种矿物成分的电子探针分析和对交代方解石，脉方解石及其围岩的氧，碳同位素分析，探讨了菊花石交代过程中的成岩环境,合理地解释了菊花石内正延性玉髓和栖霞组内海泡石的成因。     

华南栖霞组菊花石假象内正延性玉髓的成因及其地质意义

正延性玉髓常被视为干旱蒸发沉积环境的标志。正延性玉髓亦广泛分布于华南地区栖霞组菊花石 (目前绝大多数为天青石假象 )内。本文在天青石后期矿物交代序列识别的基础上,通过对菊花石内各期次碳酸盐交代矿物的电子探针分析,发现菊花石内正延性玉髓形成于富含硫酸根离子和镁离子的成岩介质条件中。结合已有的正延性玉髓研究报道和栖霞组的沉积、成岩作用环境特征分析,认为华南地区栖霞组菊花石内正延性玉髓的形成环境与高蒸发沉积环境或高盐度成岩环境无关。因此,仅根据正延性玉髓的出现不足以确定沉积或成岩环境的盐度条件。     

加固滑坡时作用在桩上的应力

桩已被广泛地用来稳定滑坡，因此，预测桩周土可能引起的效应和最大应力在加固设计中起着重要的作用。本文论太以地基反力系数概念依据的一种数值分析，在此概念中，桩上的荷载与土桩相对位移之间用了一种非线性的双曲线性关系。介绍一些实体观测对比结果，以便证实该模式的可靠性并估计移动土的承载力系数，对桩土相互作用的极限条件以及可能出现的破坏模式也作了研究。     

加拿大东海岸冬季风暴的分析

利用加拿大大气环境局第二次冬季风暴观测（简称ＣＡＳＰⅡ）的部分资料，对加拿在东海岸冬季风暴的发生，发展情况进行了分析，结果表明，大多数风暴能达到爆发性发展程度，并对其中一个形成眼区的强风暴例子做了进一步讨论。     

CHARACTERISTICS OF MESOSCALE FLOOD-MAKING TORRENTIAL RAIN SYSTEM SIMULATED BY HIGH RESOLUTION LIMITED AREA MODEL—NUMERICAL SIMULATION OF A HEAVY RAIN PROCESS DURING MEIYU SEASON IN 1991*

An experimental work on the transplant of high resolution limited area model(HIRLAM) isfirstly introduced into China.For the implementation,first of all is to adjust a new geographicalcoordination and to remove the instability caused by the Tibetan Plateau,the roof of the world.Then,we have applied this model to simulate a flood-making torrential rain process which occurredin the Changjiang-Huaihe River Valley in July 1991.That revealed the formation,development andmovement of a mesoseale heavy rain system which had made a disastrous flood event in the middleand lower reaches of Changjiang River Valley.The result encourages us to use the HIRLAM for the researches on the Meiyu belt,the salientfeature of precipitation of East Asia,and the numerical prediction of heavy rains in China.