I am a biogeochemist interested in the interactions between the three major components of Earth system: biosphere, hydrosphere and geosphere. My expertise is chemical oceanography – a branch of oceanography which employs geochemical methods to study biological processes in the oceans. I study how perturbations in environmental conditions, such as caused by climate change, affect structure, composition and biological rates within ecological systems. Using a variety of chemical proxies (concentrations and isotopic composition of different forms of biologically relevant elements) I determine the rates of biological cycling, or “chemical heartbeat” of ecosystems. My area of expertise is in studies of oxygen and nitrogen isotopes, and my current research projects can be classified in two broad categories: 1) studies of biological primary production in the sunlit surface ocean and 2) studies of nitrogen transformations in anoxic environments, deep within ocean abyss. Two of my current projects focus on factors controlling the magnitude of primary production in two radically different ecosystems: 1) Bering Sea Shelf - probably the most productive area in the ocean; 2) Eastern Tropical Pacific, which is considered a biological desert. My work on anoxic nitrogen cycling is mostly focused on sedimentary processes within Oxygen Minimum Zones of Eastern Pacific, including California Borderland Basins

nitrogen isotopes; triple oxygen isotopes; primary production; anoxic sediments

Biogeochemistry Stable isotopes Oceanography