Oxygen dynamics in shelf seas sediments incorporating seasonal variability

Natalie Hicks, Gangi Ubbara, Briony Silburn, Helen Smith, Silke Kroger, Ruth Parker, David Sivyer, Vassilis Kitidis, Angela Hatton, Daniel J. Mayor, Henrik Stahl

Research output: Contribution to journalArticlepeer-review

24 Citations (Scopus)
179 Downloads (Pure)

Abstract

Shelf sediments play a vital role in global biogeochemical cycling and are particularly important areas of oxygen consumption and carbon mineralisation. Total benthic oxygen uptake, the sum of diffusive and faunal mediated uptake, is a robust proxy to quantify carbon mineralisation. However, oxygen uptake rates are dynamic, due to the diagenetic processes within the sediment, and can be spatially and temporally variable. Four benthic sites in the Celtic Sea, encompassing gradients of cohesive to permeable sediments, were sampled over four cruises to capture seasonal and spatial changes in oxygen dynamics. Total oxygen uptake (TOU) rates were measured through a suite of incubation experiments and oxygen microelectrode profiles were taken across all four benthic sites to provide the oxygen penetration depth and diffusive oxygen uptake (DOU) rates. The difference between TOU and DOU allowed for quantification of the fauna mediated oxygen uptake and diffusive uptake. High resolution measurements showed clear seasonal and spatial trends, with higher oxygen uptake rates measured in cohesive sediments compared to the permeable sediment. The significant differences in oxygen dynamics between the sediment types were consistent between seasons, with increasing oxygen consumption during and after the phytoplankton bloom. Carbon mineralisation in shelf sediments is strongly influenced by sediment type and seasonality.
Original languageEnglish
Pages (from-to)35-47
Number of pages13
JournalBiogeochemistry
Volume135
Issue number1-2
DOIs
Publication statusPublished - 29 Mar 2017

Keywords

  • Oxygen consumption
  • Benthic carbon cycling
  • Total oxygen uptake
  • Shelf sea
  • Benthic biogeochemistry
  • Benthic mineralisation

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