Dr Josef P. Werne
Dr Josef P. Werne
University of Pittsburgh
Department of Geology & Environmental Science
4107 O'Hara St.
Fields of interest
Organic and Stable Isotope Biogeochemistry in Modern and Ancient Earth Systems: (Paleo)climate and environmental change using biogeochemical proxies and proxy development; impacts of climate change on ecosystems; microbial biogeochemistry; sulfur isotope biogeochemistry, sedimentary sulfur cycling and organic sulfur formation; carbon cycling and carbon isotope fractionation; stable isotope systematics of C, H, O, N, S in natural systems; early diagenesis, especially related to organic matter remineralization; chemical limnology/oceanography; global biogeochemical cycles; black shales; redox geochemistry.
Description of scientific projects
The questions driving research in Quaternary climate and environmental change are important not only for our understanding of how the Earth System has changed in the past, but also because this time period represents the closest analog for what we will be seeing in the near future. My research has gravitated towards understanding climate and environmental change in low latitude systems, in part because they have not been as well studied as high latitudes, but also because I find the questions and teleconnections at the low latitudes intriguing. At low latitudes, temperature changes are measureable, e.g. on glacial/interglacial timescales, but they are quite muted compared to high latitudes. In contrast, significant variability in the hydrological cycle is observed, often resulting in major shifts of arid zones associated with global climate change. Such changes in temperature and hydrology can have a significant impact on both terrestrial and aquatic biota, which can in turn lead to feedbacks to the climate system if the response of biota is great enough, as is predicted for (catastrophic) drying of the Amazon, for example. My own research has focused recently on using biomarkers to reconstruct temperature quantitatively using the developing TEX86 and MBT/CBT paleotemperature proxies, along with molecular isotopic tools such as δ13C and δD of plant leaf waxes to reconstruct relative aridity. Following on this work, I have utilized a variety of biomarkers to reconstruct the response of both aquatic and terrestrial ecosystems to the climate and environmental changes identified. Current research areas include East Africa, Mexico, the southwestern USA, and South America.