Isla Castañeda’s research mainly focuses on using multiple organic geochemical and isotopic proxies to address questions in paleoceanography, paleolimnology and paleoclimate. Her main research interests include tropical paleoclimate, reconstructing past sea and land surface temperatures, and examining relationships between climate change and human history. She is currently involved with marine and lacustrine paleoclimate reconstructions from sites spanning from SE Africa to Siberia and covering timescales from the present to the Upper Cretaceous. A current research focus is on using proxies based on glycerol dialkyl glycerol tetraethers (GDGTs) to reconstruct past land and sea surface temperatures. Another main research interest is proxy development, and in particular, further testing and validation of temperature proxies. (Personal Website)
Jeff is the manager of the UMass Biogeochemistry and Stable Isotope Laboratories.
Earth’s sedimentary basins record the story of its climatic and biotic evolution. Today, understanding this history is critical as we realize and begin to deal with the effects of our participation with the carbon cycle. Knowing how the coupled climate-biosphere will respond to the human release of greenhouse gases requires knowing something about how it has responded to similar events, if they exist, in the past.
Recent advances in stable isotope and organic geochemistry now allow us to investigate multiple facets of Earth’s history recorded within single samples. Building on these advances, my research focuses on the application of elemental, isotopic, and organic geochemical techniques to ancient and modern ocean, coastal, and lacustrine sediments and waters in order to reconstruct past environments and ecosystems within a framework of modern processes. (Personal website)
Thomas C. Johnson
Tom Johnson was trained as a geological oceanographer with a focus on deep-sea sedimentation and paleoceanography, having worked in the tropical Pacific, the western North Atlantic, and the Arctic Oceans. He transitioned to applying oceanographic techniques to the study of great lakes of the world, publishing on physical sedimentary processes, geochemical systems, stratigraphic relationships, and paleolimnology/paleoclimatology on the great lakes of North America, Central America, Central Asia, and East Africa. His focus in recent years has been on the climate history of tropical East Africa, based on various geochemical signals archived in sediment cores recovered from Lakes Malawi, Victoria, Edward, Kivu and Turkana. Tom retired from the Large Lakes Observatory, University of Minnesota Duluth in 2015, and then moved to western Massachusetts. He now has an adjunct appointment in the U Mass Department of Geosciences where he continues his paleoclimate research part-time in collaboration with Prof. Castañeda and her lab group. (Personal Website)
Steven Petsch’s research addresses fundamental questions of carbon cycling over large scales of time and space. On the broadest level, these questions include: controls the carbon dioxide and oxygen content of our atmosphere; the composition of the atmosphere varied over geologic time; the relations exist between evolution of the atmosphere and biosphere. He also investigates the rates and mechanisms of organic matter remineralization and the microorganisms involved. Current research includes studies of the isotopic and molecular biological signatures of gas (CH4, CO2) generation in ancient sedimentary rocks from active subsurface microbial communities, and isotopic and molecular diagnostics of ancient sedimentary rocks as sources of aged organic matter in modern river systems. (Personal Website)