AUTHOR=Lin Feng , Lin Cai , Lin Hui , Sun Xiuwu , Lin Li 

TITLE=210Pb-Derived Bioturbation Rates in Sediments Around Seamounts in the Tropical Northwest Pacific

JOURNAL=Frontiers in Marine Science

VOLUME=Volume 8 - 2021

YEAR=2021

URL=https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2021.701897

DOI=10.3389/fmars.2021.701897

ISSN=2296-7745

ABSTRACT=To evaluate bioturbation coefficients (DB) and mixing depths (L), 210Pb and 226Ra activity was measured in two sediments cores (from water depths of 5398 m and 4428 m), which were collected from seamount areas in the Northwest Pacific. Using a steady-state diffusion mode, we estimated DB values of 16.8 cm2/a and 24.1 cm2/a, higher than those in abyssal sediments and those predicted by traditional empirical equations. Corresponding L values varied between 19.3 cm and 23.1 cm. These high values indicate that seamounts are the area of active bioturbation. A one-dimensional model for the transport of TOC from the surface layer of sediments to the deep layer was developed using the distribution pattern of the specific activity of excess 210Pb (210Pbex) and its relationship with total organic carbon (TOC). The model showed that the TOC flux transmitted downward by bioturbation was 0.09 mmol/(cm2·a) and 0.12 mmol/(cm2·a).