近2600年神农架大九湖泥炭的气候变化记录

神农架大九湖沼泽泥炭柱状样提供了分辨率为25a的约2600a来的气候变化记录。对样品进行了环境磁学参数测量、X射线荧光分析(XRF)、孢粉鉴定和统计建模，结果表明，大九湖气温的变化曲线与竺可桢中国东部的物候温度曲线以及格陵兰氧同位素变化曲线大体一致，与青藏高原东部希门错湖泊沉积物温度代用指标的变化曲线也十分相似。特别是550—1300AD间的相对温暖期，与竺可桢首次提出来的中国东部隋唐温暖期(约600-1000AD)和欧洲的中世纪暖期(930-1240AD)在时间跨度上大致对应。可划分为4个阶段：(1)600BC—550AD，气候相对冷湿；(2)550—1300AD，气候相对凉干；(3)1300—1900AD，气候又转变为冷湿，其中最冷期1400—1900AD可与欧洲的小冰期对应；(4)1900AD至今，气候又开始转向相对凉干。同时发现低频磁化率χlf与铁元素含量之比(χlf／Fe)的变化曲线与利用孢粉分析数据恢复的大九湖气候变化曲线对应得很好，特别是二者都清晰地显示了500—1300AD为一相对暖期。这预示着χlf／Fe可能是泥炭剖面的一个更好的气候记录代用指标。     

Response of the barrier island coastal region of southwestern Nigeria to climate and non-climate forcing

Despite threats emanating from the influence of climate and non-climate forcing on the barrier island coastal region of southwestern Nigeria, the extent of the coastal erosion is poorly understood. We report evidence of coastal erosion and sediment accumulation in the region over a 34-year period (1973–2017), using Landsat imagery at intervals of approximately six years. Landsat image corrections and various water-extraction algorithms were used to systematically delineate coastal erosion and accumulation in the area. The region was subdivided into western and eastern subregions separated by Lagos Harbour. In the west, erosion took place during the periods 1973–1979, 1979–1984, 1990–1999 and 2005–2011, whereas in the east, erosion occurred during 1973–1979, 1990–1999 and 1999–2005. Coastal sediment accumulation occurred in the east during 1979–1984, 1984–1990, 2005–2011 and 2011–2017, whereas gains in the west occurred during 1984–1990, 1999–2005 and 2011–2017. The study revealed substantial net erosion of 1 228.1 ha in the region as a whole, over the full period. Sediment accumulation accompanying the coastal erosion appears to be linked to longshore drift. Erosion between 1973 and 2011 was probably attributable to climate change (storms and tidal conditions), longshore drift, the inflow and outflow of water at Lagos Harbour, coastal morphology and, possibly, human impacts. However, the coastal changes between 2011 and 2017 were more obviously associated with human activities, such as development of the Eko Atlantic construction project. Coastal surveillance, together with the use of environmentally sensitive protective measures, could possibly help to reduce coastal erosion in the region. Careful coastal management practices, including artificial nourishing and the installation of resilient structures (e.g. seawalls), should be undertaken to protect human settlements that are already at risk from sea-level rise.     

Trichodesmium erythraeum (Ehrenberg) bloom along the southwest coast of India (Arabian Sea) and its impact on trace metal concentrations in seawater

The incidence of a large scale Trichodesmium erythraeum bloom along the southwest coast of India (Arabian Sea) observed in May 2005 is reported. Around 4802 filaments of T. erythraeum ml⁻¹ seawater was observed and a colony consisted of 3.6 × 10⁵ cells. The bloom was predominant off Suratkal (12° 59′N and 74° 31′E) with a depth of about 47 m, covering an area of 7 km in length and 2 km width. The concentrations of Zinc, Cadmium, Lead, Copper, Nickel and Cobalt were determined in samples collected from the bloom and non-bloom sites using stripping voltammetry. The observed hydrographical and meteorological parameters were found to be favorable for the bloom. The concentrations of Zinc, Cadmium and Nickel were found to be higher at bloom stations, while the concentrations of Lead, Copper and Cobalt were found to be very low at bloom stations. Elevated concentrations of Cadmium and Cobalt were observed at Valappad mainly due to the decomposition of detrital material produced in the bloom. Statistically significant differences (P > 0.01) in metal concentrations between the bloom and non-bloom stations were not observed except for Copper. Metals such as Lead, Copper and Cobalt were removed from the seawater at all places where bloom was observed. Cadmium was found to be slowly released during the decaying process of the bloom.     

黄河三角洲造陆速率对夏季风强度变化和人类活动的响应

以夏季风强度指数和年均气温作为反映气候变化的指数,以人类净引水量和流域水土保持面积作为反映人类活动变化的指标,并以黄河流域为例,研究了三角洲造陆对气候变化和人类活动的响应.研究表明,夏季风强度指数的变化可分为三个阶段:(1)在1951~1963年夏季风强度指数呈持续增强的变化趋势;(2)在1963~1965年夏季风强度指数呈突变式减弱;(3)在1966~2000年夏季风强度指数保持在较低的水平上,且呈缓慢减弱的趋势.年降水量变化与夏季风强度指数有同步关系.从1950到1970年的年均温度在波动中略呈降低趋势,然而从1970年开始年均温度在波动中具有持续上升的趋势.气候变化会导致入海泥沙通量的变化,并可能进一步导致三角洲造陆速率的变化.黄河三角洲造陆速率、入海泥沙通量在1952~1964年均呈增大的趋势,1964年后则呈减小的趋势,在总体上与夏季风强度指数的变化趋势相同.除了气候变化以外,流域水土保持和引水对三角洲造陆也有影响.多元回归分析表明,三角洲造陆速率随夏季风强度指数的减弱而减小,随年气温的升高而减小,随梯田林草面积的增加而减小,随年净引水量的增加而减小,同时还表明,夏季风强度指数、年均气温、水土保持措施面积和人类净引水量对三角洲造陆速率变化的贡献率分别为34.94%,3.80%,53.82%和7.44%.表示气候变化的两个变量的贡献率之和为38.7%,说明气候变化对黄河三角洲造陆过程的影响是不容忽视的.     

斜带髭鲷幼鱼生长和生态转换效率的研究

在实验室内, 22. 5±0. 5℃条件下以去头去骨去鳞片去皮的金色小沙丁鱼的纯肉糜为饵料饲养斜带髭鲷幼鱼,测定体重范围在 4. 6~6. 5g的斜带髭鲷的体重、体长的生长曲线及其生态转换效率和特定生长率.实验结果表明,斜带髭鲷的体重、体长在实验期间直线增长,体重、体长的生长曲线分别为Wt(w.w.湿重,下同 ) =0. 391 7t 5. 766 2(R=0. 999 6)和Lt=0. 105t 6. 265(R=0. 989 9).用胃含物法测定斜带髭鲷的胃排空率、日摄食量、日生长量、生态转换效率和特定生长率.实验得到斜带髭鲷消化道的瞬时排空率Rt= 1. 23 4×10-3 (m/m) /h,日摄食量Cd= 1. 342 9g(w.w. ),生态转换效率Eg=29. 50% ±2. 77% [m/m(w.w. ) ],特定生长率SGR=4. 71%±0. 69% [m/m(w.w. ) ].     

基于GIS的柘林湾生态信息系统

柘林湾生态信息系统以ArcGIS为开发平台，采用客户端／服务器的体系结构，基于ArcObjects的组件式二次开发而成，实现了柘林湾的三维实景模拟、生态数学模型与GIS的有效集成、分析评价结果与地理空间数据相结合等功能，具有可视化、智能化、易扩展、安全实用等特点．该系统的建成．极大地提高了柘林湾生态信息的现代化管理水平，并为制定柘林湾的污染防治与生态环境保护策略提供了强有力的支持．     

罗氏沼虾育苗用水中Mg2+与Ca2+含量及Mg2+/Ca2+对出苗率的影响

１９９１年３－６月和１９９２年３－６月在南汇县东海水产养殖公司对罗氏沼虾育苗用水调配原则与不同基础水的调配方法进行试验研究。结果表明，育苗用水中Ｍｇ＾２＋与Ｃａ＾２＋含量及Ｍｇ＾２＋／Ｃａ＾２＋必须达到一定的范围，这是调配的基本原则。以鱼塘水作基础水时，需添加６种化学药品，其中Ｍｇ＾２＋与Ｃａ＾２＋含量可适范围分别为３００．０－４４０．０ｍｇ／Ｌ与１７０．０－２４４．０ｍｇ／Ｌ，Ｍｇ＾２＋／Ｃａ＾     

Action of Cnoidal Waves on Vertical Walls

Based on the 2nd order cnoidal wave theory, the characters of shallow water standing waves and their action on vertical walls are studied in this paper. The theoretical expressions of the wave surface elevation in front of and the wave pressure on the vertical wall are obtained. In order to verify the theoretical results, model tests were made in the State Key Laboratory of Coastal and Offshore Engineering at DUT. For the wave surface elevation in front of the wall and the wave forces on the wall at the moment when the wave surface at the wall surface goes down to the bottom of the wave trough, the calculated results coincide quite well with the experimental results. For the wave forces on the wall at the moment when the wave surface at the wall surface goes up to the top of the wave crest, the theoretical expressions are modified by the experimental results. For the convenience of practical use, calculations are made for the wave conditions which usually occur in enginering practice by use of the inves     

青岛地区的环境水文地质问题及其防治对策

随着工农业的发展,围绕水资源的开发利用而产生的环境水文地质问题,日益向广度和深度发展。青岛地区近年来产生的环境水文地质问题主要有:地下水超采造成的区域性水位下降、海水入侵及地下水污染。另外,部分地区存在原生环境水文地质问题之一——地方性氟病。本文试就这些问题出现的原因、发展程度、防治措施及进一步的研究方向,作了一些有益的探讨。     

胶州湾海域水质预测

在已建潮流模型的基础上,用ADI法建立了胶州湾扩大域变动边界的平流—扩散输运模型,以COD为指示因子,预测了胶州湾海域1995年、2000年的水质、青岛环海公路海上段、沧口区北半部污水截流、北水南调、集中排放以及胶州湾西部经济开发对海域水质的影响等。为青岛市环保部门制定环保规划提供决策依据。