Assessing the utility of barium isotopes to trace Eurasian riverine freshwater inputs to the Arctic Ocean
Journal
Marine Chemistry
Journal Volume
236
Date Issued
2021
Author(s)
Abstract
Tracing riverine freshwater transport pathways within the Arctic Ocean is key to understanding changes in Arctic Ocean freshwater inventories. Dissolved Ba concentrations have been used in this capacity but are compromised by non-conservative processes. To assess the potential for Ba isotopes to provide insights into the impact of such processes on Arctic Ocean dissolved Ba inventories, Ba concentration and isotope data for surface seawater samples from the Siberian Shelf and Bering Sea/Strait are presented. These samples capture the mixing of riverine freshwater discharged by the rivers Yenisey, Lena and Ob, with Atlantic and Pacific derived seawater, which are traced by relationships between salinity, Ba concentration and δ138/134Ba. The δ138/134Ba of net river inputs, following modification by estuarine processes, are constrained to be 0.31 ± 0.04?, 0.20 ± 0.06? and 0.23 ± 0.04?, for the rivers Yenisey, Lena and Ob respectively. These values are used to estimate an average δ138/134Ba for Eurasian river freshwater input to the Arctic Ocean of 0.23 ± 0.04?. The Ba concentration and δ138/134Ba of Lena River freshwater transported across the Laptev Sea are modified by non-conservative processes. These non-conservative processes do not result in distinctive modification of dissolved Ba concentration-δ138/134Ba mixing relationships between Eurasian riverine freshwater and Arctic seawater, which unfortunately limits the potential of Ba isotopes to improve tracing riverine freshwater sources in the central Arctic Ocean basins using dissolved Ba inventories. More generally the results of this study help advance understanding of Ba isotope cycling in the environment and their development as an emerging tracer of marine processes. ? 2021 Elsevier B.V.
Subjects
Arctic Ocean freshwater
Ba isotopes
Estuarine Ba cycling
Marine Ba cycle
barium
estuarine chemistry
estuarine ecosystem
freshwater input
isotope
river water
salinity
seawater
tracer
Arctic Ocean
Bering Sea
Pacific Ocean
Siberian Shelf
Type
journal article