Influence of oxygen exposure time on organic carbon preservation in continental margin sediments

Hilairy E. Hartnett, Richard G. Keil, John I. Hedges, Allan H. Devol

Research output: Contribution to journalArticlepeer-review

538 Scopus citations

Abstract

Today, over 90% of all organic carbon burial in the ocean occurs in continental margin sediments. This burial is intrinsically linked to the cycling of biogeochemically important elements (such as N, P, S, Fe and Mn) and, on geological timescales, largely controls the oxygen content of the atmosphere. Currently there is a volatile debate over which processes govern sedimentary organic carbon preservation. In spite of numerous studies demonstrating empirical relationships between organic carbon burial and such factors as primary productivity, the flux of organic carbon through the water column, sedimentation rate, organic carbon degradation rate, and bottom- water oxygen concentration, the mechanisms directly controlling sedimentary organic carbon preservation remain unclear. Furthermore, as organic carbon burial is the process that, along with pyrite burial, balances O2 concentrations in the atmosphere, it is desirable that any mechanism proposed to control organic carbon preservation include a feedback buffering atmospheric oxygen concentrations over geological time. Here we compare analyses of sediments underlying two regions of the eastern North Pacific Ocean, one which has oxygen-depleted bottom waters and one with typical oxygen distributions. Organic carbon burial efficiency is strongly correlated with the length of time accumulating particles are exposed to molecular oxygen in sediment pore waters. Oxygen exposure time effectively incorporates other proposed environmental variables, and may exert a direct control on sedimentary organic carbon preservation and atmospheric oxygen concentrations.

Original languageEnglish (US)
Pages (from-to)572-574
Number of pages3
JournalNature
Volume391
Issue number6667
DOIs
StatePublished - Feb 5 1998
Externally publishedYes

ASJC Scopus subject areas

  • General

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