Abstract

The supply and distribution of dissolved silicon (Si) in the oceans is a key factor in the growth of marine diatoms, which precipitate biogenic silica (or opal, hydrated SiO2). Rivers and groundwater have long been considered the major inputs of dissolved Si, which is released during the weathering of silicate rocks. Glaciers are known sources of both dissolved and particulate phases of Si, but the impact on oceanic systems needs further quantification to produce a more robust global budget. The aim of the ICY -LAB project is to investigate the role of high-latitude processes on the Si marine cycle, using isotope geochemistry to constrain the impact of different key processes. I will be presenting some new findings from terrestrial field campaigns, and some preliminary findings from oceanic expedition DY081 (RRS Discovery, July-August 2017) to the Southwest continental shelf region of Greenland. Our findings improve the understanding of the Si cycling between terrestrial sediments, shelf processes and seawater in glaciated regions, which represents an important but understudied component of internal cycling as well as a key input into the oceanic Si budget.