Spatial heterogeneity in beryllium isotopic distribution in the Indian Ocean

Abstract

Beryllium-10 (10Be) has proven to be an essential tool for building chronology and understanding millennial-scale surface processes. Measurements in both the water column and authigenic fractions from various archives (such as surface sediments and Fe-Mn crusts) have provided valuable information on processes regulating Be isotopic distribution in the global oceans. Unlike the Pacific and the Atlantic Oceans, Be isotopic measurements in the Indian Ocean are sparse. Here, based on Be isotopic measurements on surface sediments from the central and northern Indian Ocean, an attempt is made to understand the processes controlling spatial Be isotopic distribution. Our data from the northern Indian Ocean suggests that terrestrial input is one of the primary contributors of 9Be. Owing to higher terrestrial flux, the sediment samples from the Bay of Bengal show higher 9Be concentrations and lower 10Be/9Be ratios. Our study suggests that scavenging by sediment particles plays a vital role in the distribution of Be isotopes in well-mixed open ocean water. Between carbonates and clay particles, carbonates are less efficient in scavenging beryllium from the water column.