Journal cover Journal topic
Biogeosciences An interactive open-access journal of the European Geosciences Union
Journal topic
Volume 15, issue 2
Biogeosciences, 15, 413-427, 2018
https://doi.org/10.5194/bg-15-413-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
Biogeosciences, 15, 413-427, 2018
https://doi.org/10.5194/bg-15-413-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.

Reviews and syntheses 19 Jan 2018

Reviews and syntheses | 19 Jan 2018

Reviews and syntheses: to the bottom of carbon processing at the seafloor

Jack J. Middelburg Jack J. Middelburg
  • 1Earth Sciences, Utrecht University, P.O. Box 80 021, 3508 TA Utrecht, the Netherlands
  • * Invited contribution by Jack J. Middelburg, recipient of the EGU Vladimir Vernadsky Medal 2017.

Abstract. Organic carbon processing at the seafloor is studied by biogeochemists to quantify burial and respiration, by organic geochemists to elucidate compositional changes and by ecologists to follow carbon transfers within food webs. Here I review these disciplinary approaches and discuss where they agree and disagree. It will be shown that the biogeochemical approach (ignoring the identity of organisms) and the ecological approach (focussing on growth and biomass of organisms) are consistent on longer timescales. Secondary production by microbes and animals is identified to potentially impact the composition of sedimentary organic matter. Animals impact sediment organic carbon processing by microbes in multiple ways: by governing organic carbon supply to sediments, by aeration via bio-irrigation and by mixing labile organic matter to deeper layers. I will present an inverted microbial loop in which microbes profit from bioturbation rather than animals profiting from microbial processing of otherwise lost dissolved organic resources. Sediments devoid of fauna therefore function differently and are less efficient in processing organic matter with the consequence that more organic matter is buried and transferred from Vernadsky's biosphere to the geosphere.

Publications Copernicus
Download
Short summary
Organic carbon processing at the seafloor is studied by geologists to better understand the sedimentary record, by biogeochemists to quantify burial and respiration, by organic geochemists to elucidate compositional changes, and by ecologists to follow carbon transfers within food webs. These disciplinary approaches have their strengths and weaknesses. This award talk provides a synthesis, highlights the role of animals in sediment carbon processing and presents some new concepts.
Organic carbon processing at the seafloor is studied by geologists to better understand the...
Citation
Share