Research

My main research interests are: Biological pump and particle dynamics, utilization of artificial and natural radioisotopes to study environmental process, sediment geochemistry and chemical processes at sediment-water interface, climate change and Carbon dioxide Removal and Sequestration. Listed below are few of the projects that I have been involved in.

US GEOTRACES GP17-OCE (Active) South Pacific and Southern Ocean

The overarching goal of the international GEOTRACES Program is to “identify processes and quantify fluxes that control the distributions of key trace elements and isotopes (TEIs) in the ocean, and to establish the sensitivity of these distributions to environmental conditions” (GEOTRACES, 2006). Since many TEI’s are either bioactive and/or particle reactive, this requires consideration of processes, such as the biological pump, which transfer carbon and associated TEIs to depth via sinking particles. GEOTRACES research cruise from Tahiti to Chile (GP17-OCE) that enables sampling for a broad suite of trace elements and isotopes (TEI) across oceanographic regions of importance to global nutrient and carbon cycling.
Estimating export rates via sinking particles have been hampered by the limited methods available to examine dynamic ocean systems. Thorium-234 is produced by the radioactive decay of 238U (t½ = 4.47 × 109 y) in the water column. Since 234Th is highly particle reactive it is adsorbed onto sinking particles and released when particles are remineralized. The disequilibrium from its soluble conservative parent, 238U, thus provides quantitative information on where particle export (234Th deficiency due to scavenging onto sinking particles; red in and remineralization 234Th excess due to solubilization or fragmentation, i.e. conversion of sinking into non-sinking phases) occurs in the water column.

US GEOTRACES https://www.geotraces.org/geotraces-science-plan/

US GEOTRACES Southern Pacific https://usgeotraces.ldeo.columbia.edu/content/gp17