海南省的环境与可持续发展问题探析

海南岛是中国唯一一个全省位处热带的省份，有得天独厚的环境和资源。到目前为止，海南省的环境一直处于良好的状态，大气环境各项指标基本上符合国家一级标准，全省河流和水库中的水有80%符合国家地面水环境质量Ⅱ类及以上标准。但是，对海南省的环境也不应当地高估计，建省前后的开发过程出现了许多生态和环境问题，例如林业砍伐、橡胶垦殖等。不能只讲开发，不讲保护或是因为开发对环境有影响就不进行开发，要坚持可持续发展的战略，妥善解决实现可持续发展中遇到的各种具体问题，真正把海南省规划建设好。     

海南岛沿岸风暴潮特征分析

本文在统计分析１９４９～１９９４年间影响海南岛的热带气旋特征的基础上,对海南岛沿岸的风暴潮特征进行总结分析,并对海南岛沿岸的风暴潮灾害作了概述。     

Cross-shore separation of adult and juvenile euphausiids in a shelf-break alongshore current

Euphausiids are an important component of the zooplankton in boundary current upwelling regions, including the Pacific Northwest continental margin. Many aspects of euphausiid distribution and ecology in this region are well known. However, some features of their spatial and temporal distribution are less understood:

• How and why euphausiids aggregate near the shelf-break upwelling center.

• How and why there is (within an alongshore band of high abundance of all stages) spatial segregation of adults and larvae.

• Why, despite spatial association with upwelling, euphausiid abundance off Vancouver Island is weakly or negatively correlated at interannual time scales with upwelling intensity.

To address these, we made km-resolution surveys of adult, juvenile, and larval euphausiid horizontal distributions, water properties, and currents across the Vancouver Island shelf break in mid-to-late spring of two successive years. Survey timing was before (1997) and after (1998) the spring transition to upwelling conditions, and near the annual spring reproductive peak. In both years, early developmental stages occupied an alongshore band that was offset from the late juveniles and adults. The direction of the offset differed between the two surveys. Early life history stages (larvae and early juveniles) were shoreward of adults in April 1997 (downwelling-conditions), but seaward of adults in May 1998 (upwelling-conditions). Separation distance (order 5–10 km) was consistent with expected differences in cumulative wind-driven (and vertically-sheared) cross-shore transport of surface-dwelling larvae and early juveniles vs. transport of diel migratory late juveniles and adults. Separation direction was consistent with recent history of winds and Ekman transport—shoreward during poleward winds, and seaward into blue water (and usually into a strong equatorward current) during equatorward winds.     

Back-arc basin assemblages in Kohistan,Northern Pakistan

Abstract

The east central part of the Kohistan magmatic arc is made up principally of the Jaglot Group. From bottom to top it consists of I) paragneisses and schists intercalated with amphibolites and calc-silicates (Gilgit Formation), II) Gashu-Confluence Volcanics (GCV) and III) the Thelichi Formation comprising a volcanic base (Majne volcanics) and turbidites, marble, volcanoclastic sediments and lava flows. Metamorphic grade varies up to the sillimanite zone. The GCV are correlated with the Chalt volcanics and the Thelichi Formation with the Yasin Group. Other lithologies include the Chilas Complex, the Kohistan Batholith and part of the Kamila Amphibolite. Metavolcanics show a broad range in chemical composition. Geochemical parameters used to specify the tecto-nomagmatic regime suggest affinities of both island arc and MORB-like back-arc basin basalts. Kohistan can be divided into three tectonic zones, I) the southern (Kamila) zone comprises amphibolitized basalts, and mafic and ultramafic rocks, II) the central Chilas Complex, and III) the northern (Gilgit) zone i.e., the Jaglot Group. Previous tectonic models considered the southern two zones as the crust of a Cretaceous island arc. This investigation concludes that only the southern zone represents a true island arc. The Jaglot Group derives from back-arc basin assemblages and the Chilas Complex is a magmatic diapir emplaced in the back-arc basin.     

风对福建中部沿岸春、夏季水文结构和上升流的影响

本文对台湾海峡西侧海坛岛附近海域风情与附近岸站的风情进行了对比分析,结果表明,海上风情和岸站风情变化基本上是一致的;在不同季风的作用下,海域温、盐度呈现不同类型的分布。风情的短期变化对上升流的强弱变化有一定影响。     

Changes in diatom assemblages in Lake C2 (Ellesmere Island, Arctic Canada): response to basin isolation from the sea and to other environmental changes

Diatoms preserved in the sediments of Lake C2 (82°50 N, 76°00 W), a high arctic meromictic lake, track changes in the lake's salinity which have occurred as the basin was isolated from the sea. An assemblage dominated by marine taxa, such as Chaetoceros species, Nitzschia cylindrus and Diploneis spp., was replaced by a Cyclotella kuetzingiana var. planetophora dominated freshwater flora. A brief brackish period separates the two assemblages. Relatively little floristic change occurred within either the marine or freshwater periods, indicating rather stable environmental conditions, except that rheophilous diatoms fluctuated in relative abundance during the lacustrine phase, perhaps tracking past changes in discharge from inflowing streams. These may reflect periods of warmer, wetter environmental conditions.This is the eighth in a series of papers published in this issue on the Taconite Lakes Project. These papers were collected by Dr R. S. Bradley.     

海洋工程对觉华岛国家级海洋公园海域生态环境影响研究

文章根据2016—2019年觉华岛周边海域生态环境监测结果,并结合期间大规模海洋开发活动,分析了觉华岛国家级海洋公园海域环境变化趋势。结果表明:2016—2019年,觉华岛周边海域水质要素监测结果均符合《海水水质标准》中的二类标准,沉积物要素监测结果均符合《海洋沉积物质量》中的一类标准。水质与沉积物大部分监测要素的平均含量年际变化呈先降低再上升的变化趋势,生物环境状况整体水平变化情况与水质和沉积物的变化趋势有良好的对应关系,说明海洋工程建设对觉华岛国家级海洋公园海域生态环境造成了一定的负面影响,但影响程度不大。     

基于风暴水流能量分布对海南岛小东海珊瑚巨砾成因的分析

波致水流的能量差异有助于风暴和海啸巨砾的区分。本文基于这一思路, 进行风暴波浪和波致水流的能量分析, 给出海岸珊瑚巨砾在风暴潮期间以推移质方式输运的动力学过程表达, 推算出风暴巨砾的理论输运距离。结合海南岛极端事件历史记录, 得出海南岛小东海风暴巨砾在礁坪的分布格局, 并与该海区的巨砾实际分布进行对比。结果表明, 小东海风暴巨砾分布与巨砾的质量、形状及风暴潮能量密切相关。研究区现场观测的大部分巨砾沉积分布符合风暴巨砾的理论空间分布格局, 因而判断其为风暴潮成因堆积。未来经过模拟假设条件的完善, 并构建相应海啸水流输运模式, 可形成用以区分风暴、海啸巨砾的完整判据。     

论海南岛地区志留系

海南岛志留系以往被划分为上、中、下三个统。志留系之上是南好组 ,其层位以往被确定为下石炭统岩关阶 ,并认为它与其下的上志留统足赛岭组呈不整合接触。最近在南好组选层型剖面发现早志留世特里奇期晚期(L ate Telychian)的 Xinanospirifer腕足动物群和三叶虫 L atiproetus cf.latilimbatus (Grabau) ,重新论证了以往被确认为中志留统靠亲山组所产的腕足类、三叶虫和珊瑚化石其实都是特里奇期早至中期的分子。现在以无可争辩的事实证明了久归于下石炭统岩关阶南好组 ,以及其下的、以往被确定为上志留统足赛岭组、中志留统靠亲山组等所谓两个构造层的地层都应改归于下志留统 (L landovery Series)。北区下志留统仅有鲁丹期中期至爱隆期早期的黑色碳质页岩相和泥页岩相沉积 ,未发现任何大化石。南区下志留统发育较全 ,为细至中粗粒碎屑岩相夹碳酸盐岩相沉积 ,产丰富介壳相各门类化石 ;当时该区所生存的动物群与扬子区早志留世的关系非常密切 ,并在早志留世末期与扬子区大部分地区一样上升为陆 ,表明海南岛地区在当时属于扬子地台区范畴。     

上海大金山岛植被资源状况及保护对策

大金山岛是上海海域存留天然植被较完整的海岛,对其现状进行调查和分析有助于制定具有针对性的海岛植被保护策略。文章基于21个样地的调查,将大金山岛植被划分为常绿阔叶林、常绿落叶阔叶混交林、落叶阔叶林、落叶灌丛和草丛5个植被类型14个群落类型。地带性森林群落径级结构和物种多样性特征分析表明,大金山岛森林群落结构相对稳定、物种多样性较高。为进一步完善大金山岛的植被保护措施,需加强植被分类与制图、量化典型植物种群大小和分布特征、跟踪管理大径材树木生长和健康状况、开展植被和动物综合调查以及植被动态长期监测的研究和管理。