Sökning: "climatic and environmental changes"

Visar resultat 21 - 25 av 102 avhandlingar innehållade orden climatic and environmental changes.

1. 21. Infrared spectroscopy as a tool to reconstruct past lake-ecosystem changes : Method development and application in lake-sediment studies

   Författare :Carsten Meyer-Jacob; Richard Bindler; Hendrik Vogel; Jan Karlsson; John F. Boyle; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Fourier transform infrared spectroscopy; visible-near infrared spectroscopy; PLS regression; biogenic silica; climate change; carbon cycling; lake-water quality; geochemistry; paleolimnology; Holocene; Lake El’gygytgyn; Torneträsk;

   Sammanfattning : Natural archives such as lake sediments allow us to assess contemporary ecosystem responses to climate and environmental changes in a long-term context beyond the few decades to at most few centuries covered by monitoring or historical data. To achieve a comprehensive view of the changes preserved in sediment records, multi-proxy studies – ideally in high resolution – are necessary. LÄS MER

3. 22. Environmental Effects of Agricultural Expansion in the Upper Amazon : A study of river basin geochemistry and hydrochemistry, and farmers' perceptions

   Författare :Lina Lindell; Mats Åström; Marianne Henningsson; Pasi Peltola; Tommy Claesson; Michael E McClain; Linnéuniversitetet; []
   Nyckelord :tropical humid forest; deforestation; land-use change; slash-and-burn agriculture; spatial variation; vertical distribution; multielement analysis; sustainable development; rural livelihoods; bosque húmedo tropical; deforestación; cambios de uso de la tierra; agricultura de tala y quema; variabilidad espacial; distribución vertical; análisis multielemental; desarrollo sostenible; cambio climático; sustentos rurales; Miljövetenskap; Environmental Science;

   Sammanfattning : In this thesis natural science is combined with environmental psychology in order to determine how deforestation and subsequent agricultural expansion in the Peruvian highland jungle has affected the natural environment and rural livelihoods. This region is part of one of the most biodiverse areas on Earth and is also exposed to high pressure from deforestation that threatens the ecosystems as well as the well-being of local populations. LÄS MER

4. 23. Stormy records from peat bogs in south-west Sweden : implications for regional climatic variability and vegetation changes during the past 6500 years

   Författare :Rixt de Jong; Kvartärgeologi; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Holocene climate; south-west Sweden; aeolian activity; humidity changes; vegetation development; REVEALS vegetation modelling; atmospheric circulation changes; peat sediments;

   Sammanfattning : This thesis aims to reconstruct and explain variations in storm activity, humidity, vegetation composition and land cover in south-west Sweden during the past 6500 years. Two ombrotrophic bogs, Store Mosse and Undarsmosse, situated on the coastal plain of Halland, were selected for this purpose. LÄS MER

5. 24. Late Miocene to Pliocene orbital and climatic forcing on marine productivity

   Författare :Boris-Theofanis Karatsolis; Jorijntje Henderiks; Thomas Stevens; David De Vleeschouwer; Clara T. Bolton; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

   Sammanfattning : The late Miocene to Pliocene was a geological time interval of global cooling, albeit in a warmer-than-present world, which is commonly used as a past analogue for future anthropogenic climate change. The investigation of marine sediments recovered by the International Ocean Discovery Program (IODP) sheds light on different paleoclimatic, paleoceanographic and paleobiological characteristics of this period. LÄS MER

7. 25. Paleoenvironmental and paleoclimatic changes in northeast Thailand during the Holocene

   Författare :Sakonvan Chawchai; Barbara Wohlfarth; Richard Bindler; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Paleoenvironment; paleoclimatic; sediment; peat; multi-proxy; Asian monsoon; the Holocene; Marine Geology; maringeologi;

   Sammanfattning : The long-term climatic and environmental history of Southeast Asia is still fragmentary. This thesis therefore aims at studying lake sediment/peat sequences using a multi-proxy approach to reconstruct the environmental history and the impact of past changes in monsoon variability and intensity on lake ecosystems in Thailand. LÄS MER