Utility of trace element studies for improving our understanding of geochemical processes within the arctic ocean environment

Abstract

The Arctic Ocean is a dynamic region undergoing rapid change. Sea ice and meteoric water are intrinsic components of the Arctic environment that play key roles in its ecosystem, including the distributions and cycling of trace elements throughout the pan-Arctic Ocean. Meteoric water (e.g., rivers and snow deposition) contributes to the input of trace elements to surface waters, while sea ice dynamics contribute to the transport of these constituents across Arctic basins. Trace element distributions can provide insights into Arctic processes. The focus of Chapter One is on particulate (>0.2 μm) trace elements in Arctic pack ice, associated snow, and underlying surface waters collected from September-October 2015 during the US GEOTRACES Western Arctic cruise (GN01). This late-season pack ice provides a snapshot of sea ice characteristics in regions near the North Pole, within the Makarov and Canada Basins, and can estimate the impact melting sea ice may have on particulate trace element inputs to Arctic waters. Chapter Two presents on the utility of dissolved barium (dBa), a bio-intermediate element of lithogenic origin, as a tracer of meteoric water throughout the Siberian Arctic Ocean. Samples for Chapter Two were collected during the 2018 Nansen and Amundsen Basin Observatory System. The distribution of dBa in this region may provide useful insights into important shelf processes, such as tracing shelf waters along continental slopes. In Chapter 3, additional spatiotemporal geochemical parameters (δ¹⁸O and salinity) are considered alongside dBa to model how Arctic water mass fractions (meteoric, sea ice melt, and Atlantic waters) changed between 2013, 2015, and 2018 within the Siberian Arctic Ocean. This dissertation contributes to the understanding of Arctic Ocean processes through the application of trace element studies and highlights the usefulness of combining tracers to better understand this dynamic environment.