Biological response to coastal upwelling and dust deposition in the area off Northwest Africa     

T. Ohde  H. Siegel 《Continental Shelf Research》2010

Nutrient supply in the area off Northwest Africa is mainly regulated by two processes, coastal upwelling and deposition of Saharan dust. In the present study, both processes were analyzed and evaluated by different methods, including cross-correlation, multiple correlation, and event statistics, using remotely sensed proxies of the period from 2000 to 2008 to investigate their influence on the marine environment. The remotely sensed chlorophyll-a concentration was used as a proxy for the phytoplankton biomass stimulated by nutrient supply into the euphotic zone from deeper water layers and from the atmosphere. Satellite-derived alongshore wind stress and sea-surface temperature were applied as proxies for the strength and reflection of coastal upwelling processes. The westward wind and the dust component of the aerosol optical depth describe the transport direction of atmospheric dust and the atmospheric dust column load.  相似文献   

美国国家公园志愿者服务及机制——以海峡群岛国家公园为例     

王辉  刘小宇  郭建科  孙才志 《地理研究》2016,35(6):1193-1202

具有百余年历史的美国国家公园志愿者服务已成为美国国家公园管理的重要部分,志愿者服务有效实现了美国国家公园的全民管理思路。通过实地考察和访谈记录梳理,就国家公园志愿者服务的相关概念、服务动机、服务决策、服务内容、服务支持和服务机制深入剖析,从庞大有序的服务系统、管理与运行、功能实现三方面分析国家公园志愿者服务机制;提炼出美国国家公园志愿者服务的四个支持：宣传支持、技术支持、学习支持和立法支持。并以美国海峡群岛国家公园为例进行论证。最后提出国家公园志愿者服务和中国国家公园志愿服务尚需研究的诸多内容,任重而道远。  相似文献   

文化生态学视角下的南海诸岛地名文化   总被引：1，自引：0，他引：1  

赵静  张争胜  陈冠琦  南文龙 《热带地理》2016,36(6):1045-1056

地名具有丰富的文化内涵,正日益受到学术界的高度关注。南海诸岛及其附近海域是中国政治敏感地带,多国为主权归属问题摩擦不断,研究其地名文化历史演变问题可为维护中国领土主权提供有力证据。基于南海诸岛地名命名、变更和演变等资料,采用文本分析方法,分析《更路簿》和不同时期公布的南海诸岛命名资料,并利用 GIS 将地名的演变情况进行地理可视化表达,同时对南海诸岛及其附近海域的开发者--渔民和老船长等进行深入访谈。研究发现：南海诸岛的土地名主要依据岛礁的自然地理环境特征而命名,地名的更替、消亡与社会文化环境紧密相关;1935 年公布的地名以音译英文地名为主,1947 年更名以去外国化、美化、纪念地名为主,1983 年对 1947 年所公布的标准地名更改很少,在这 118 个地名中,增加了前几次未公布地名 39 个,这些地名几乎都沿用渔民命名的土地名。  相似文献   

Reciprocality between biology and geology: Reconstructing polar Gondwana     

B. Michaux   《Gondwana Research》2009,16(3-4):655-668

The reciprocal nature of the relationship between historical geology (reconstruction models) and biology (constructing phylogenies) is discussed and the conceptual basis of such a relationship is examined through its historical development. Examples to illustrate aspects of the relationship are drawn from the Cretaceous breakup of polar Gondwana and the Cenozoic history of some of the resultant microcontinental fragments. A new mid-Cretaceous (circa 100 Ma) rift zone, separating the west Gondwanan Campbell Plateau, southern New Zealand, from the east Gondwanan Melanesian Rift is proposed, and biological and geological evidence for it is presented and discussed. It is also suggested that the Bounty Trough, Chatham Rise, and Hikurangi Plateau unit is incorrectly placed in reconstruction models, and it should be fitted outboard of the Melanesian Rift until its mid-Cenozoic attachment to the Campbell Plateau. It is concluded that both reconstruction modelling and phylogenetic analyses have much to gain through ‘reciprocal illumination’.  相似文献   

REGIONAL DEVELOPMENT IN DENMARK     

ROLF GUTTESEN M.Sc.  FRANK HANSEN M.Sc.  BUE NIELSEN M.Sc. 《Geografisk tidskrift / udgivet af Bestyrelsen for Det Kongelige danske geografiske selskab》2013,113(1):74-87

  相似文献   

The Problem of Double Longitudes on Glavač’s Map     

Marina Viličić  Miljenko Lapaine 《The Cartographic journal》2013,50(3):217-234

Abstract

Exploring large volumes of geospatial data is difficult. This paper presents an approach that combines visual and computational analysis to make this process easier. This approach is based on the effective application of computational algorithms, such as the Self-Organizing Map (SOM). These are used to uncover the structure, patterns, relationships and trends in the data, and for the creation of abstractions where conventional methods may be limited. In addition, graphical representations are applied to portray extracted patterns in a visual form that allows for better understanding of the derived structures and possible geographical processes, and should facilitate knowledge construction.  相似文献   

A GIS-based glacier inventory for the Antarctic Peninsula and the South Shetland Islands —A first case study on King George Island     

Matthias Braun  F. Rau  Jefferson Simões 《地球空间信息科学学报》2013,16(2):15-24

The aim of the international project “Global Land Ice Measurements from Space (GLIMS)” headed by the US Geological Survey is to establish a world wide glacier inventory based on satellite imagery. This data set will form a first digital baseline study for future glacier monitoring. The presented GIS-based glacier inventory for King George Island is a case study for the area of the Antarctic Peninsula. In the database of the glacier inventory topographic information, specific glaciological parameters as well as metadata will be included. The topographic data consists of drainage basin limits, basin areas, altitudinal ranges, perimeters and mean lengths. Glaciological data sets should comprise information on glacier retreat in different periods, glacier velocities, ice thickness and bedrock topography as well as derived parameters. Modelled and measured mass balance parameters could be included as additional data layers. In particular, these metadata records must comprise background information on data accuracy and data sources and should be compatible with a future data model for the King George Island GIS (KGIS). Three examples illustrate that the GLIMS database will not only contain information valuable for glaciological applications, but also other environmental studies on the island will benefit from this standardised remote sensing data sets. Therefore, a very close link between the data models of KGIS and GLIMS has to be established to enable these synergisms. Finally, better access to historic aerial photography would enable a continuous record of glacier retreat from the beginning of the 1950's onward.  相似文献   

Recent macroids on the Kikai‐jima shelf,Central Ryukyu Islands,Japan     

DAVIDE BASSI  YASUFUMI IRYU  MARC HUMBLET  HIROKI MATSUDA  HIDEAKI MACHIYAMA  KEIICHI SASAKI  SHINYA MATSUDA  KOHSAKU ARAI  TAKAHIKO INOUE 《Sedimentology》2012,59(7):2024-2041

Sandy and gravelly carbonate sediments found off Kikai‐jima, southern Japan, a coral reef‐related island shelf, represent the northernmost sub‐tropical, carbonate deposits in the Central Ryukyu Islands (Ryukyus). On the Kikai‐jima shelf, at water depths of 61 to 105 m, these sediments are characterized by macroid pavements. Since the abundance of very small and of exceptionally large macroids may indicate specific hydrodynamic controls regarding constraints on growth and taphonomy, the detailed analysis of recent and fossil macroid pavements is meaningful ecologically and environmentally. Macroids, ranging in size from ca 25 to 130 mm in diameter, are spheroidal and sub‐spheroidal in shape and consist mainly of the encrusting foraminifer Acervulina inhaerens and subordinate thin encrusting and lumpy coralline algae. Accessory components include bryozoans, serpulids and, to a lesser extent, encrusting arborescent foraminifera (Homotrema and Miniacina). Low sedimentation rates and occasional movement due to current action are indicated by sizes, shapes and growth‐forms of the studied macroids, the Entobia–Gastrochaenolites–Trypanites–Maeandropolydora ichnocoenosis and the ‘Bioerosion Index’ for coated grains (introduced herein). The deep‐water tidally induced current energy was sufficient to maintain multi‐directional growth (spheroidal shapes) of the larger macroids and to initiate macroid growth using the diverse biogenic remnants as nuclei. The asymmetrical inner arrangement suggests possible periods of stability for the macroids. The residence time of the coated grain in its original environment determines the size and morphology of the macroid and the selection of coating organisms. The composition of the coating community is mainly a consequence of component growth rates in relation to turnover time and residence time. Long‐term studies are needed to assess the spatial and temporal resolution of present‐day encrusting communities across biogeographic provinces and shelf to slope regions.  相似文献   

U/Pb dating of detrital zircons from late Palaeozoic deposits of Bel’kovsky Island (New Siberian Islands): critical testing of Arctic tectonic models     

《International Geology Review》2012,54(2):199-210

Detrital zircon U/Pb ages provide new insights into the provenance of Upper Devonian–Permian clastic rocks of Bel’kovsky Island, within the New Siberian Islands archipelago. Based on these new data, we demonstrate that Upper Devonian–Carboniferous turbidites of Bel’kovsky Island were derived from Grenvillian, Sveconorwegian, and Timanian sources similar to those that fed Devonian–Carboniferous deposits of the Severnaya Zemlya archipelago and Wrangel Island and were probably located within Laurentia–Baltica. Detrital zircon ages from the lower Permian deposits of Bel’kovsky Island suggest a drastic change in provenance and show a strong affinity with the Uralian Orogen. Two possible models to interpret this shift in provenance are proposed. The first involves movement of these continental blocks from the continental margin of Laurentia–Baltica towards the Uralian Orogen during the late Carboniferous to Permian, while the second argues for long sediment transport across the Barents shelf.  相似文献   

Probabilistic risk assessment of common booster biocides in surface waters of the harbours of Gran Canaria (Spain)     

Sánchez-Rodríguez A  Sosa-Ferrera Z  Santana-del Pino A  Santana-Rodríguez JJ 《Marine pollution bulletin》2011,62(5):985-991

The presence of booster biocides in the aquatic environment has been associated with a risk to non-target species due to their proven toxicity. The aim of the present study was to determine the spatial and temporal distribution of common booster biocides in different harbours of the island of Gran Canaria (Spain) and evaluate, by means of a probabilistic risk assessment (PRA), the ecological risk posed by these compounds. With these objectives, a monitoring campaign was conducted between January 2008 and May 2009, collecting a total of 182 seawater samples. Four common booster biocides (TCMTB, diuron, Irgarol 1051 and dichlofluanid) were monitored. Diuron levels ranged between 2.3 and 203 ng/L and Irgarol 1051 between 2.4 and 146.5 ng/L. The ecological risk associated with these levels was always low, however, with probabilities of exceeding the 10th percentile of autotroph toxicity below 3.5%.  相似文献