Plankton prognoses in the North Sea     

Greve  Wulf  Lange  Uwe 《Ocean Dynamics》1999,51(10):155-160

Ocean Dynamics - Our understanding of the marine ecosystem is expressed in our ability to predict ecological processes. Several approaches are compared to make such predictions on plankton...  相似文献   

Nature Conservation versus Scenic Quality：A GIS Approach towards Optimized Tourist Tracks in a Protected Area of Northwest Yunnan,China     

YANG Ming-yu  VAN COILLIE Frieke  HENS Luc  DE WULF Robert  OU Xiao-kun  ZHANG Zhi-ming 《山地科学学报》2014,11(1):142-155

Development of appropriate tourism infrastructure is important for protected areas that allow public access for tourism use.This is meant to avoid or minimize unfavourable impacts on natural resources through guiding tourists for proper use.In this paper,a GIS-based method,the least-cost path（LCP） modelling,is explored for planning tourist tracks in a World Heritage site in Northwest Yunnan（China）,where tourism is increasing rapidly while appropriate infrastructure is almost absent.The modelling process contains three steps：1） selection of evaluation criteria（physical,biological and landscape scenic） that are relevant to track decision; 2） translation of evluation criteria into spatially explicit cost surfaces with GIS,and 3） use of Dijkstra＇s algorithm to determine the least-cost tracks.Four tracks that link main entrances and scenic spots of the study area are proposed after optimizing all evaluation criteria.These tracks feature lowenvironmental impacts and high landscape qualities,which represent a reasonable solution to balance tourist use and nature conservation in the study area.In addtion,the study proves that the LCP modelling can not only offer a structured framwork for track planning but also allow for different stakeholders to participate in the planning process.It therefore enhances the effectivenss of tourism planning and managemnt in protected areas.  相似文献   

The role of climate in the spread of modern humans into Europe     

Ulrich C. Müller  Jörg Pross  Polychronis C. Tzedakis  Clive Gamble  Ulrich Kotthoff  Gerhard Schmiedl  Sabine Wulf  Kimon Christanis 《Quaternary Science Reviews》2011,30(3-4):273-279

The spread of anatomically modern humans (AMH) into Europe occurred when shifts in the North Atlantic meridional overturning circulation triggered a series of large and abrupt climate changes during the last glacial. However, the role of climate forcing in this process has remained unclear. Here we present a last glacial record that provides insight into climate-related environmental shifts in the eastern Mediterranean region, i.e. the gateway for the colonisation of Europe by AMH. We show that the environmental impact of the Heinrich Event H5 climatic deterioration c. 48 kyr ago was as extreme as that of the glacial maximum of Marine Isotope Stage (MIS) 4 when most of Europe was deserted by Neanderthals. We argue that Heinrich H5 resulted in a similar demographic vacuum so that invasive AMH populations had the opportunity to spread into Europe and occupy large parts before the Neanderthals were able to reoccupy this territory. This spread followed the resumption of the Atlantic meridional overturning circulation at the beginning of Greenland Interstadial (GIS) 12 c. 47 kyr ago that triggered an extreme and rapid shift from desert-steppe to open woodland biomes in the gateway to Europe. We conclude that the extreme environmental impact of Heinrich H5 within a situation of competitive exclusion between two closely related hominids species shifted the balance in favour of modern humans.  相似文献   

First evidence of a distal early Holocene ash layer in Eastern Mediterranean deep-sea sediments derived from the Anatolian volcanic province     

Y. Hamann  S. Wulf  O. Ersoy  W. Ehrmann  E. Aydar  G. Schmiedl 《Quaternary Research》2010,73(3):497-506

A hitherto unknown distal volcanic ash layer has been detected in a sediment core recovered from the southeastern Levantine Sea (Eastern Mediterranean Sea). Radiometric, stratigraphic and sedimentological data show that the tephra, here termed as S1 tephra, was deposited between 8970 and 8690 cal yr BP. The high-silica rhyolitic composition excludes an origin from any known eruptions of the Italian, Aegean or Arabian volcanic provinces but suggests a prevailing Central Anatolian provenance. We compare the S1 tephra with proximal to medial-distal tephra deposits from well-known Mediterranean ash layers and ash fall deposits from the Central Anatolian volcanic field using electron probe microanalyses on volcanic glass shards and morphological analyses on ash particles. We postulate a correlation with the Early Holocene ‘Dikkart?n’ dome eruption of Erciyes Da? volcano (Cappadocia, Turkey). So far, no tephra of the Central Anatolian volcanic province has been detected in marine sediment archives in the Eastern Mediterranean region. The occurrence of the S1 tephra in the south-eastern part of the Levantine Sea indicates a wide dispersal of pyroclastic material from Erciyes Da? more than 600 km to the south and is therefore an important tephrostratigraphical marker in sediments of the easternmost Mediterranean Sea and the adjacent hinterland.  相似文献   

The Palaeoproterozoic Kangerluluk gold–copper mineralization (southeast Greenland): Pb and Nd isotopic constraints on its timing and genesis     

Henrik Stendal  Robert Frei  Mike A. Hamilton  Wulf U. Mueller 《Mineralium Deposita》2001,36(2):177-188

The Ketilidian Mobile Belt (KMB) in South Greenland is dominated by the Palaeoproterozoic Julianehåb Batholith (1,850–1,770?Ma) and is bordered by supracrustal sequences. The batholith is composed of granite, granodiorite, tonalite, diorite and subordinate gabbro and appinite and formed in a juvenile magmatic arc. The supracrustal rocks consist of psammites, pelites and subordinate, interstratified mafic volcanic rocks. A Rapakivi granite suite (1,755–1,735?Ma) intrudes them. Gold is an important metal in the KMB and occurs in various settings and element associations. Here, emphasis is placed on the Kangerluluk Cu–Au mineralization in the eastern part of the mobile belt. It is hosted within a remnant supracrustal succession dominated by redundant pillowed basalts. Structurally, a syn-volcanic association with gold can be distinguished from one that is clearly related to crosscutting quartz veins. In between, calc-silicate formation in the volcanic rocks occurred contemporaneously with a pervasive sericitization (bleaching) of leucocratic granitoids that are intrusive into the volcanic sequence. Bulk rock and mineral (sulfide) Pb isotope data are comparable in the Pb isotope space. The data define two groups of mineralization where one group is characterized by relatively higher ²⁰⁷Pb/²⁰⁴Pb at given ²⁰⁶Pb/²⁰⁴Pb ratios than the other. Pb stepwise leaching (PbSL) dating experiments performed on garnet and epidote associated with both groups of mineralization confirm the offset in the Pb isotope data. With the geochronological information from PbSL, the results indicate: (1) the initial gold mineralization was genetically related to metalliferous fluids associated with the emplacement of late intrusive stages of the Julianehåb Batholith (1,800–1,770?Ma); and (2) local remobilization of the initial mineralization (1,700–1,750) involved a Pb isotopically evolved fluid, which tentatively can be correlated with the intrusion of the Rapakivi granites in the area. Radiogenic Pb was not only found in altered host rocks but also in various sulfides, suggesting that fluids may have percolated through and/or originated from uranium-bearing graphitic schists which are abundant in the sedimentary package of the KMB. Lead isotopic results suggest that the Rapakivi granites may have supplied heat for renewed circulation of fluids within the supracrustal rock pile.  相似文献   

On the phenology of North Sea ichthyoplankton   总被引：2，自引：1，他引：2  

Greve  Wulf; Prinage  Sabine; Zidowitz  Heike; Nast  Jutta; Reiners  Frank 《ICES Journal of Marine Science》2005,62(7):1216-1223

  相似文献   

Identifying global synchronies in marine zooplankton populations: issues and opportunities   总被引：4，自引：1，他引：4  

Perry  R.Ian; Batchelder  Harold P; Mackas  David L; Chiba  Sanae; Durbin  Edward; Greve  Wulf; Verheye  Hans M 《ICES Journal of Marine Science》2004,61(4):445-456

  相似文献   

Evolution of sandstone peak‐forest landscapes – insights from quantifying erosional processes with cosmogenic nuclides          下载免费PDF全文

Jan‐Hendrik May  He‐Qing Huang  Toshiyuki Fujioka  David Fink  Alexandru Codilean  Guo‐An Yu  Yuanxu Ma  Gerwin Wulf  Jing Gu 《地球表面变化过程与地形》2018,43(3):639-653

The sandstone peak‐forest landscape in Zhangjiajie UNESCO Global Geopark of Hunan Province, China, is characterized by >3000 vertical pillars and peak walls of up to 350 m height, representing a spectacular example of sandstone landform variety. Few studies have addressed the mechanisms and timescales of the longer‐term evolution of this landscape, and have focused on fluvial incision. We use in situ cosmogenic nuclides combined with GIS analysis to investigate the erosional processes contributing to the formation of pillars and peak‐forests, and discuss their relative roles in the formation and decay of the landscape. Model maximum‐limiting bedrock erosion rates are the highest along the narrow fluvial channels and valleys at the base of the sandstone pillars (~83–122 mm kyr^?1), and lowest on the peak wall tops (~2.5 mm kyr^?1). Erosion rates are highly variable and intermediate along vertical sandstone peak walls and pillars (~30 to 84 mm kyr^?1). Catchment‐wide denudation rates from river sediment vary between ~26 and 96 mm kyr^?1 and are generally consistent with vertical wall retreat rates. This highlights the importance of wall retreat for overall erosion in the sandstone peak‐forest. In combination with GIS‐derived erosional volumes, our results suggest that the peak‐forest formation in Zhangjiajie commenced in the Pliocene, and that the general evolution of the landscape followed our sequential refined model: (i) slow lowering rates following initial uplift; (ii) fast plateau dissection by headward knickpoint propagation along joints and faults followed by; (iii) increasing contribution of wall retreat in the well‐developed pillars and peak‐forests and a gradual decrease in overall denudation rates, leading to; (iv) the final consumption of pillars and peak‐forests. Our study provides an approach for quantifying the complex interplay between multiple geomorphic processes as required to assess the evolutionary pathways of other sandstone peak‐forest landscapes across the globe. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献