{"name":"climate-driven-ecosystem-succession-in-the-sahara-the-past-6000-years","title":"Climate-Driven Ecosystem Succession in the Sahara: The Past 6000 Years","maintainer":"Christian Schepers","maintainer_email":"christian_schepers@online.de","notes":"Desiccation of the Sahara since the middle Holocene has eradicated all but a few natural\r\narchives recording its transition from a \u201cgreen Sahara\u201d to the present hyperarid desert. Our\r\ncontinuous 6000-year paleoenvironmental reconstruction from northern Chad shows progressive\r\ndrying of the regional terrestrial ecosystem in response to weakening insolation forcing of the\r\nAfrican monsoon and abrupt hydrological change in the local aquatic ecosystem controlled\r\nby site-specific thresholds. Strong reductions in tropical trees and then Sahelian grassland\r\ncover allowed large-scale dust mobilization from 4300 calendar years before the present\r\n(cal yr B.P.). Today\u2019s desert ecosystem and regional wind regime were established\r\naround 2700 cal yr B.P. This gradual rather than abrupt termination of the African Humid\r\nPeriod in the eastern Sahara suggests a relatively weak biogeophysical feedback on climate.","type":"researchdata","resources":[{"description":"","format":"PDF","url":"http://crc806db.uni-koeln.de/data/Phase_1/A/A2/data/000/Kr\u00f6pelin_etal_2008_Climate-Driven_Ecosystem_Succession_Sahara.pdf","created":"2014-09-22T11:54:23.754407","state":"active","package_id":"b5a13793-f8e7-450b-b283-4468bbbe7099","last_modified":"2021-10-23T02:10:32","id":"53cf1fc0-9ea2-4f61-81bf-7ddf667a32f7","name":"Kr\u00f6pelin_etal_2008_Climate-Driven_Ecosystem_Succession_Sahara.pdf"},{"description":"","format":"URL","url":"http://www.sciencemag.org/content/320/5877/765.full","created":"2015-02-01T14:27:01.018289","state":"active","package_id":"b5a13793-f8e7-450b-b283-4468bbbe7099","last_modified":"2021-10-23T02:10:32","id":"738f61f6-38b8-483d-9b86-bbccba6a0d87","name":"http://www.sciencemag.org/content/320/5877/765.full"}],"tags":[{"name":"chad"},{"name":"climate change"},{"name":"climate reconstruction"},{"name":"ecosystem succession"},{"name":"palaeoenvironment"},{"name":"sahara"}],"extras":[{"key":"bibtex:address","value":""},{"key":"bibtex:author","value":"Stefan Kr\u00f6pelin and Dirk Verschuren and Anne-Marie L\u00e9zine and Hilde Eggermont and Christine Cocquyt and Pierre Francus and Jean-Pierre Cazet and Maureen Fagot and Bob Rumes and James M. Russell and Frank Darius and Daniel Conley and Mathieu Schuster and Hans von Suchodoletz and Daniel R. Engstrom"},{"key":"bibtex:booktitle","value":""},{"key":"bibtex:citation","value":"Kr\u00f6pelin S., Verschuren D., L\u00e9zine A.-M., Eggermont H., Cocquyt C., Francus P., Cazet J.-P., Fagot M., Rumes B., Russell J. M., Darius F., Conley D. J., Schuster M., Suchodoletz H. v., Engstrom D. R. (2008): Climate-Driven Ecosystem Succession in the Sahara: The Past 6000 Years. In: Science 320: 765-768"},{"key":"bibtex:doi","value":"10.1126/science.1154913"},{"key":"bibtex:editor","value":""},{"key":"bibtex:howpublished","value":""},{"key":"bibtex:isbn","value":""},{"key":"bibtex:journal","value":"Science"},{"key":"bibtex:month","value":""},{"key":"bibtex:number","value":""},{"key":"bibtex:organization","value":""},{"key":"bibtex:pages","value":"765-768"},{"key":"bibtex:publisher","value":""},{"key":"bibtex:school","value":""},{"key":"bibtex:series","value":""},{"key":"bibtex:type","value":"article"},{"key":"bibtex:key","value":""},{"key":"bibtex:url","value":""},{"key":"bibtex:volume","value":"320"},{"key":"bibtex:year","value":"2008"},{"key":"Spatial","value":"{\"type\":\"Polygon\",\"coordinates\":[[[-15.1,31.2],[40,11.01],[40,11.01],[-15.1,11.01]]]}"}],"groups":[{"image_url":"http://crc806db.uni-koeln.de/fileadmin/template/images/projects/imageA2.png","name":"a2"}],"author":" Christian Schepers","author_email":false}{"help":"Update a dataset (package).\n\n You must be authorized to edit the dataset and the groups that it belongs\n to.\n\n Plugins may change the parameters of this function depending on the value\n of the dataset's ``type`` attribute, see the ``IDatasetForm`` plugin\n interface.\n\n For further parameters see ``package_create()``.\n\n :param id: the name or id of the dataset to update\n :type id: string\n\n :returns: the updated dataset (if 'return_package_dict' is True in the\n context, which is the default. Otherwise returns just the\n dataset id)\n :rtype: dictionary\n\n ","success":false,"error":{"message":"Unable to add package to search index: Solr returned an error: 500 Lock obtain timed out: NativeFSLock@\/var\/lib\/solr\/data\/index\/lucene-d6f7b3bf6fe64f362b4d45bfd4924f54-write.lock org.apache.lucene.store.LockObtainFailedException: Lock obtain timed out: NativeFSLock@\/var\/lib\/solr\/data\/index\/lucene-d6f7b3bf6fe64f362b4d45bfd4924f54-write.lock \tat org.apache.lucene.store.Lock.obtain(Lock.java:85) \tat org.apache.lucene.index.IndexWriter.init(IndexWriter.java:1562) \tat org.apache.lucene.index.IndexWriter.(IndexWriter.java:1418) \tat org.apache.solr.update.SolrIndexWriter.(SolrIndexWriter.java:191) \tat org.apache.solr.update.UpdateHandler.createMainIndexWriter(UpdateHandler.java:98) \tat org.apache.solr.update.DirectUpdateHandler2.openWriter(DirectUpdateHandler2.java:173) \tat org.apache.solr.update.DirectUpdateHandler2.addDoc(DirectUpdateHandler2.java:220) \tat org.apache.solr.update.processor.RunUpdateProcessor.processAdd(RunUpdateProcessorFactory.java:61) \tat org.apache.solr.handler.XMLLoader.processUpdate(XMLLoader.java:139) \tat org.apache.solr.handler.XMLLoader.load(XMLLoader.java:69) \tat org.apache.solr.handler.ContentStreamHandlerBase.handleRequestBody(ContentStreamHandlerBase.java:54) \tat org.apache.solr.handler.RequestHandlerBase.handleRequest(RequestHandlerBase.java:131) \tat org.apache.solr.core.SolrCore.execute(SolrCore.java:1317) \tat org.apache.solr.servlet.SolrDispatchFilter.execute(SolrDispatchFilter.java:338) \tat org.apache.solr.servlet.SolrDispatchFilter.doFilter(SolrDispatchFilter.java:241) \tat org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157) \tat org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388) \tat org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216) \tat org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182) \tat org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:766) \tat org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418) \tat org.mortbay.jetty.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:230) \tat or - \n\n\nError 500 Lock obtain timed out: NativeFSLock@\/var\/lib\/solr\/data\/index\/lucene-d6f7b3bf6fe64f362b4d45bfd4924f54-write.lock\n\norg.apache.lucene.store.LockObtainFailedException: Lock obtain timed out: NativeFSLock@\/var\/lib\/solr\/data\/index\/lucene-d6f7b3bf6fe64f362b4d45bfd4924f54-write.lock\n\tat org.apache.lucene.store.Lock.obtain(Lock.java:85)\n\tat org.apache.lucene.index.IndexWriter.init(IndexWriter.java:1562)\n\tat org.apache.lucene.index.IndexWriter.<init>(IndexWriter.java:1418)\n\tat org.apache.solr.update.SolrIndexWriter.<init>(SolrIndexWriter.java:191)\n\tat org.apache.solr.update.UpdateHandler.createMainIndexWriter(UpdateHandler.java:98)\n\tat org.apache.solr.update.DirectUpdateHandler2.openWriter(DirectUpdateHandler2.java:173)\n\tat org.apache.solr.update.DirectUpdateHandler2.addDoc(DirectUpdateHandler2.java:220)\n\tat org.apache.solr.update.processor.RunUpdateProcessor.processAdd(RunUpdateP","__type":"Search Index Error"}}