自然与人文交互作用下的干旱区典型绿洲耕地动态变化驱动力分析——以新疆于田绿洲为例

 绿洲是干旱区独特的自然景观,是人们生产生活的载体。如何在保持经济发展、提高人民生活水平的基础上保护有限的耕地资源,是关系到干旱区绿洲和谐以及可持续发展的重要问题。选取干旱区典型绿洲——于田县1949\_2004年的自然与人文统计资料,首先分析了五十余年来该县耕地变化的情况。然后从自然与人文两个角度对影响耕地面积变化的因子进行分析,结果表明,自然因素往往构成一定区域绿洲发展的基本限制,人为因素在短时期内,对耕地的变化起着决定性作用,这种作用如果顺应自然因素的限制,则对绿洲发展有利,绿洲稳定性增强;反之,绿洲稳定性减弱,由于新疆绿洲外围多为戈壁及沙漠,因此,对绿洲的利用要遵循自然规律,以保护绿洲为前提,合理利用水等自然资源,否则绿洲的面积随时都有可能缩小。     

胶州湾水母类生态研究Ⅱ.优势种丰度的时空分布

根据2003年5月-2004年9月胶州湾浮游生物浅水Ⅰ型网中水母的调查资料,分析了胶州湾水母类优势种丰度的季节变化及水平分布.结果表明,对于优势度最大的优势种,半球美螅水母一年中有6月和9（8）月两个丰度高峰,2003年6月丰度最高,达29.5ind/m^3,占当月水母总丰度的47.2 %;薮枝螅水母一年中有9（8）月份和4月份两个丰度高峰,2003年9月份的丰度最高,达12.9ind/m3,占当月水母总丰度的17.4%,4月份该种的丰度占水母总丰度的93.1%;五角水母在9月份丰度高达28.8ind/m^3,占当月水母总丰度的38.7%;八斑芮氏水母2、3月份的丰度均很高,分别为64.7ind/m3、118.0ind/m3,分别占水母总平均丰度的99.5%和98.0 %.对于优势度较小的优势种：四枝管水母、日本真瘤水母、四手触丝水母,真拟杯水母和锡兰和平水母,由于在个别月份占优势,其丰度高低随种类的不同及所在月份的不同而不同.就丰度水平分布来讲,不同优势种类的分布不同时间有所不同,但其丰度分布大都倾向于以湾顶区、湾西部、湾东北部、东部港口沿岸、黄岛沿岸为密集中心.     

半干旱地区水资源承载能力研究——以松嫩平原西南部霍林河流域为例

水资源的合理开发利用与否是影响社会经济发展的瓶颈。以霍林河流域为研究对象,对该流域特征及其生态环境问题进行了分析,构建了水资源承载力研究的指标体系,该体系包括水资源形成的自然条件、开发利用及社会经济因素3个方面9项指标。应用因子分析法对流域内各县市水资源承载能力进行定量评价,结果表明,霍林河流域从上游到下游,水资源承载能力主要受水资源形成条件和开发利用强度的影响,水资源承载能力评价是水资源可持续利用的关键。     

青藏铁路沿线不同类型挡沙墙阻沙率

基于风洞试验对青藏铁路沿线不同类型防沙措施防沙效果进行模拟研究,探讨了不同类型挡沙墙的防沙效果。结果表明：挂板式、轨枕式和箱式挡沙墙输沙率随高度基本呈递增缓变型趋势,最大输沙率低于20%;铃铛式和高立式聚乙烯（PE）网挡沙墙随高度呈递减陡降型趋势,距地表6~8 cm处为转折点,转折点以上输沙率随高度增大急剧减小,转折点以下输沙率随高度变化较为平缓,最大输沙率低于50%。随着风速的增大,各挡沙墙的阻沙率呈递减趋势：挂板式和轨枕式挡沙墙对风速的敏感性最弱,整体阻沙效果较优,可大范围推广;箱式挡沙墙对风速的敏感性较弱,建议在风速18 m·s^-1以下的地区使用;PE网挡沙墙防沙效果对风速的敏感性最强,建议在风速10 m·s^-1以下的地区使用。     

升温与硝酸盐加富对鹿角杯形珊瑚幼虫的生理影响

选择三亚鹿回头近岸海域常见的鹿角杯形珊瑚(Pocillopora damicornis)幼虫为研究对象,采用室内连续培养的方法,探究了升温(29℃和31℃)与硝酸盐加富(0、5、20μmol/dm^3)对鹿角杯形珊瑚幼虫共生体的生理影响。结果表明:升温和硝酸盐加富对鹿角杯形珊瑚幼虫存活率与共生虫黄藻叶绿素荧光指数(Fv/Fm)无显著影响,但对幼虫附着率的影响表现为明显的交互作用。升温条件下,各处理珊瑚幼虫附着率均显著下降,且硝酸盐加富加剧了升温对珊瑚幼虫附着率的负面影响。再者,升温对幼虫呼吸速率的影响与硝酸盐的浓度有关,5μmol/dm^3硝酸盐处理抵消了升温对幼虫呼吸的促进作用;与此同时,5μmol/dm^3硝酸盐处理提高了幼虫的净光合作用而且光合呼吸速率比(PG/RD)大于2,表明此时珊瑚幼虫共生体系光合作用固定的有机碳为净累积。综上,适量的硝酸盐加富可以缓解升温对珊瑚幼虫代谢的负面影响,但高浓度硝酸盐加富则会不利于鹿角杯形珊瑚幼虫的附着及种群的本地补充。     

一种适宜安全信息挖掘的地下管线时空数据组织方法

本文针对地下管线关联信息孤立、管理分散无法进行数据挖掘的现状,深入分析了影响地下管线安全的各项外部因素数据,设计了一种适用于地下管线安全信息挖掘的地下管网时空数据组织方法。本文按照该时空数据组织方法对区域范围内的多种管线相关数据进行改造与融合,并进行直观快速地分析,挖掘出了地下管线可能存在的隐患。实际应用表明,本文提出的方法对地下管线信息集成管理、挖掘应用具有一定的指导意义。     

Zooplankton community structure,abundance and biovolume in Jiaozhou Bay and the adjacent coastal Yellow Sea during summers of 2005–2012: relationships with increasing water temperature

Zooplankton abundance, biovolume and taxonomic composition in Jiaozhou Bay and the adjacent coastal Yellow Sea were evaluated using ZooScan measurement of samples collected by net towing every August from 2005 to 2012. Zooplankton abundance and biovolume ranged from 1 938.5 to 24 800 ind./m~3 and 70.8 to 1 480.1 mm~3/m~3 in Jiaozhou Bay and 73.1 to 16 814.3 ind./m~3 and 19.6 to 640.7 mm~3/m~3 in the coastal Yellow Sea. Copepods were the most abundant group in both regions, followed by N octiluca scintillans and appendicularians in Jiaohzou Bay, and chaetognaths and N octiluca scintillans in adjacent coastal Yellow Sea. Over the study period, the most conspicuous hydrographic change was an increase in water temperature. Meanwhile, a general decrease in zooplankton abundance was observed, particularly in copepod populations. Based on redundancy analysis(RDA), the warming trend was the key environmental factor influencing to decrease of copepod abundance. The proportion of small-sized copepods increased while the mean size of all copepods decreased, in significant correlation with water temperature. Our results indicate that zooplankton, particularly copepods, are highly sensitive to change in water temperature, which is consistent with predicted impacts of warming on aquatic ectotherms. Due to their dominance in the zooplankton, the decline in copepod size and abundance could lead to an unfavourable decrease in energy availability for predators, particularly planktivorous fish.     

Distribution patterns of chlorophyll <Emphasis Type="Italic">a</Emphasis> in spring and autumn in association with hydrological features in the southern Yellow Sea and northern East China Sea

Two field studies were conducted to measure pigments in the Southern Yellow Sea (SYS) and the northern East China Sea (NECS) in April (spring) and September (autumn) to evaluate the distribution pattern of phytoplankton stock (Chl a concentration) and the impact of hydrological features such as water mass, mixing and tidal front on these patterns. The results indicated that the Chl a concentration was 2.43±2.64 (Mean ± SD) mg m^?3 in April (range, 0.35 to 17.02 mg m^?3) and 1.75±3.10 mg m^?3 in September (from 0.07 to 36.54 mg m^?3) in 2003. Additionally, four areas with higher Chl a concentrations were observed in the surface water in April, while two were observed in September, and these areas were located within or near the point at which different water masses converged (temperature front area). The distribution pattern of Chl a was generally consistent between onshore and offshore stations at different depths in April and September. Specifically, higher Chl a concentrations were observed along the coastal line in September, which consisted of a mixing area and a tidal front area, although the distributional pattern of Chl a concentrations varied along transects in April. The maximum Chl a concentration at each station was observed in the surface and subsurface layer (0–10 m) for onshore stations and the thermocline layer (10–30 m) for offshore stations in September, while the greatest concentrations were generally observed in surface and subsurface water (0–10 m) in April. The formation of the Chl a distributional pattern in the SYS and NECS and its relationship with possible influencing factors is also discussed. Although physical forces had a close relationship with Chl a distribution, more data are required to clearly and comprehensively elucidate the spatial pattern dynamics of Chl a in the SYS and NECS.     

2014年春末黄海中华哲水蚤(Calanus sinicus)的呼吸率与油脂积累

春末是黄海冷水团中华哲水蚤(Calanus sinicus)度夏种群形成的关键时期。在此期间,中华哲水蚤C5期桡足类幼体(简称C5期)的油脂积累程度关系到种群能否顺利度夏。本文从呼吸率、油囊体积以及种群组成等角度,对春末黄海冷水团内外以及冷水团区表、底层的中华哲水蚤进行比较研究。结果表明,2014年5月底黄海冷水团初步形成,此时冷水团区中华哲水蚤C4和C5期幼体丰度占总体的62%—93%,种群处于度夏前的准备阶段。冷水团区C5期的平均呼吸率是近岸C5期的68%,同时冷水团底层C5期的油囊体积百分数是近岸种群的2.4倍。由此推测,冷水团区次表层较厚的温跃层(19—25m,0.3—0.5°C/m)以及冷水团的低温环境有利于C5期幼体降低呼吸消耗,进而增加油脂的积累。此外,冷水团区表、底层C5期的呼吸率相近,但底层C5期油囊体积百分数为表层的1.9—4.2倍,积累大量油脂的C5期偏向在冷水团底部活动。