中国红树林资源状况及其药用研究调查 Ⅱ.资源现状、保护与管理   总被引：2，自引：0，他引：2  

傅秀梅  王亚楠  邵长伦  王长云  李国强  刘光兴  孙世春  曾晓起  叶振江  管华诗 《中国海洋大学学报(自然科学版)》2009,39(4)

对中国红树林物种组成、资源状况和分布特征进行了调查和评价.结果表明,中国红树林天然分布南界为海南三亚(18°12′N),北界为福建福鼎(27°20′N)(人工引种北界为浙江乐清28°25′N).中国红树林区系有红树植物20科26属37种.广东、广西和海南沿海是中国红树林的主要分布地区.近50 年来,红树林面积先是锐减(1950年,48 266 hm2;1997年,14 877 hm2),2000年后略有回升(2002年,22 024.9 hm2;2008年,23 081.5 hm2).合理评估红树林湿地生态效价,完善红树林保护区制度,推进红树林湿地生态修复工程,构建红树林湿地保护网络系统,是中国红树林资源保护性开发利用的可行对策.  相似文献   

Glacial and periglacial floodplain sediments regulate hydrologic transfer of reactive iron to a high arctic fjord          下载免费PDF全文

Andrew Hodson  Aga Nowak  Hanne Christiansen 《水文研究》2016,30(8):1219-1229

The transport of reactive iron (i.e. colloidal and dissolved) by a glacier‐fed stream system draining a high relief periglacial landscape in the high Arctic archipelago of Svalbard is described. A negative, non‐linear relationship between discharge and iron concentration is found, indicative of increased iron acquisition along baseflow pathways. Because the glaciers are cold‐based and there are no intra‐ or sub‐permafrost groundwater springs, baseflow is principally supplied by the active layer and the colluvial and alluvial sediments in the lower valley. Collectively, these environments increase the flux of iron in the stream by 40% over a floodplain length of just 8 km, resulting in 6 kg Fe km^?2a^?1 of reactive iron export for a 20% glacierized watershed. We show that pyrite oxidation in shallow‐groundwater flowpaths of the floodplain is the most important source of reactive iron, although it is far less influential in the upper parts of the catchment where other sources are significant (including ironstone and secondary oxide coatings). Microbial catalysis of the pyrite oxidation occurs in the floodplain, enabling rapid, hyporheic water exchange to enhance the iron fluxes at high discharge and cause the non‐linear relationship between discharge and reactive iron concentrations. Furthermore, because the pyrite oxidation is tightly coupled to carbonate and silicate mineral weathering, other nutrients such as base cations and silica are also released to the stream system. Our work therefore shows that high Arctic floodplains should be regarded as critically important regulators of terrestrial nutrient fluxes to coastal ecosystems from glacial and periglacial sources. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

福清湾及附近海域浮游动物的数量和分布   总被引：3，自引：0，他引：3  

林君卓 《台湾海峡》2008,27(1):58-63

本文分析了2005年10月和2006年5月在福清湾及其附近海域采集的浮游动物样品,结果表明,福清湾已鉴定的浮游动物有64种,10类浮游幼体.分为4个生态类群,包括河口低盐类群,近岸暖温类群,近岸暖水类群和广布外海类群.浮游动物物种多样性指数春季高于秋季.春季浮游动物总个体数均值为(161ind/m3)高于秋季的(83ind/m3),春季生物量均值为(67.7mg/m3)低于秋季的(87.7mg/m3);浮游动物总个体数的平面分布,春季湾内西部水域最高,海坛海峡最少;秋季福清湾东部水域最高,湾内西部水域最少.浮游动物生物量和总个体数的平面分布趋势基本一致.另外还对浮游动物的分布与环境因子的关系进行了分析.  相似文献   

Iron geochemistry under mussel rafts in the Galician ria system (Galicia-NW Spain)     

Xosé L. Otero  R.M. Calvo de AntaFelipe Macías 《Estuarine, Coastal and Shelf Science》2009

The intensive mussel culture carried out in the past 40 years in the Rias of Vigo and Arousa (Galicia-NW Spain) has led to substantial changes in the ecology and geochemistry of the seabed in these areas. Organic C enrichment of the seabed has generated strongly reducing conditions that directly affect the geochemistry of Fe and S. In the present study a total of six sediment cores were collected from the seabed under mussel rafts, and two different layers were distinguished: the biodeposit generated by the mussels, and the sediment situated immediately below this. Samples of each were analyzed to determine the pH, redox potential, sulphate and chloride in the interstitial water, as well as total percentage of organic C (TOC), N and S. Sequential extraction of the samples differentiated six fractions of Fe: exchangeable, carbonate, ferrihydrite, lepidocrocite, goethite and pyrite. The contents of total Fe, Fe associated with silicates, Fe soluble in 1 M HCl and AVS-Fe were also determined. In general, both the biodeposit and the sediment were anoxic (Eh < 100 mV) and there were no significant differences between the two in the total Fe or in the Fe associated with silicates, which appears to indicate that the input of Fe to the system did not vary greatly. However, there were significant differences between the sediment and the biodeposit in terms of the forms of Fe in each layer. The concentrations of pyrite in the biodeposit (0.37 ± 0.25 μmol g⁻¹) were high but significantly lower than in the sediment (1.10 ± 0.20 μmol g⁻¹), and there remained large quantities of reactive-Fe that were susceptible to pyritisation. In contrast, in the sediment, the reactive-Fe was intensively pyritised, and judging from the ratio of TOC–DOP, it limited synthesis of pyrite. Furthermore, a plot of the concentration of pyrite-S against TOC revealed an excess of ∼15% of pyrite-S, which is explained by the partial decoupling of pyrite formation from organic matter accumulation, caused by the formation of pyrite from the H₂S generated by the anaerobic oxidation of methane. The latter process also appears to favour, although to a lesser extent, the precipitation of Ca carbonate, with incorporation of Fe.  相似文献   

The barnacle Balanus amphitrite as a bioindicator for Cd: Development and application of a simulation model     

Eduardo Teixeira da Silva  David Klumpp  Michael Ridd 《Estuarine, Coastal and Shelf Science》2009

The efficacy of the barnacle Balanus amphitrite as a bioindicator for Cd in the environment was investigated through simulation exercises in an ecotoxicological simulation model based on field data. The study showed in general that B. amphitrite is a good bioindicator to record mean trends of the Cd bioavailability in the environment. The model correct reflected differences between high and low patterns of Cd concentrations in the barnacle in the field, but it did not accurately reflect short-term temporal variations. A model investigation pointed out three issues that must be taken into account when using B. amphitrite as bioindicator for Cd bioavailability in the environment: (1) variations in the mean weight of the sampled population may affect the barnacle's Cd concentration determination, specially if a size effect for the metal concentration in the organism is not detected; (2) a sampling effort approximately 5 times greater than that of usually applied in such studies would be required to detect an environmental change that caused a realistic increase in the main source of Cd to the barnacle; and (3) barnacle tissue better responds to long-term changes in the Cd level of its sources.  相似文献   

山东惠民凹陷东营组尾花介科化石的发现及其意义          下载免费PDF全文

费安玮 《地质论评》2001,47(6):596-601

在山东惠民凹陷渐新统东营组二段发现了浪花介超科尾花介科Recticytherura ualisicosta gen.et sp.nov.－－U形脊直尾花介（新属、新种），化石产于该段近底部含生物砂质灰岩中。这是本区乃至渤海湾盆地下第三系尾花介科化石的首次发现。对该新属、新种进行了描述并据铰合构造、尾突、放射毛细管及壳壁构造等特征判断其为海相介形类。与之共生的介形类的组合特征、壳壁的元素组成特征及围岩的碳、氧同位素特征反映了微咸－半咸水的沉积环境，并由古湖泊的扩张和古气候分析认为东营组二段沉积期在惠民凹陷发生了一次短暂海泛。  相似文献   

湖北大冶铁山矿床钠化蚀变与成矿关系的探讨   总被引：6，自引：0，他引：6  

杨峰华 《地质与勘探》2001,37(6):20-24

对于大冶铁矿内接触带钠化蚀变的岩石特征、钠质来源、动力机制、形成机理等作了比较系统的阐述。并着重指出了钠化蚀变是铁矿化的重要指示标志之一。  相似文献   

宁芜莺子山地区硫铁矿找矿研究          下载免费PDF全文

姚超美  熊先孝 《地质找矿论丛》2001,16(1):62-66

莺子山地区与著名的向山硫铁矿有着相似的成矿条件，成矿作用主要集中在大王山旋回中，硫铁矿体的形成和分布受穹窿构造，NE向断裂，辉石闪长玢岩体等控制，具有褐铁矿化－黄铁矿化－绢云母化－高岭土化蚀变组合，重力异常显著，激电极化率一秀＞15％，并伴有低电脑经异常，具有S异常，并伴有P,Mo元素组合异常等，是莺子山地区硫铁矿的找矿标志，地质，地球物理，地球化学，遥感特征表明和尚岘，龙庵凹一带为找矿一级远景地段，竹园山，老蚊山等地为找矿二级远景地段。  相似文献   

Fossil caddisflies (Insecta: Trichoptera) from the Early Cretaceous of southern England II     

I. D. Sukatsheva  E. A. Jarzembowski   《Cretaceous Research》2001,22(6):685

The following new fossil trichopteran insects are described or revised from the Purbeck Limestone Group and Wealden Supergroup of southern England: Pteromixanum inviolatum gen. et sp. nov., P. ruderatum gen. et sp. nov., P. purbeckianum (Handlirsch) gen. et comb. nov. and P. poxwellense gen. et sp. nov. (Necrotauliidae);Purbimodus minor gen. et sp. nov., P. medius gen. et sp. nov., P. rasnitsyni gen. et sp. nov. and P. saxosus gen. et sp. nov. (Vitimotauliidae);Palaeoludus popovi gen. et sp. nov. (Dysoneuridae);Palaeotarsus desertus gen. et sp. nov. (Plectrotarsidae);Eucrunoecia ridicula gen. et sp. nov. (Lepidostomatidae);Palaeocentropus placidus gen. et sp. nov. (Calamoceratidae) and Helicophidae gen. et sp. incertae sedis. The general composition of the fauna is compared with Early Cretaceous faunas of Asia. The early appearance of several living families is noted.  相似文献   

Pedodiversity: a controversial concept     

CHEN Jie  ZHANG Xue-lei  GONG Zi-tong  WANG Jun 《地理学报》2001,11(1):110-116

The concept of pedodiversity and its measurement methodology proposed and developed by Ibá?ez research term is introduced. An attempt to apply pedodiversity to analyze spatial soil variation and distribution patterns on the global scale is briefly demonstrated. Furthermore, constructive comments and criticisms on pedodiversity and its measurement from the noted pedologists and ecologists are outlined. Finally, potential applications of pedodiversity in soil science and other relevant disciplines are discussed.  相似文献