2018/01/19 by Jack J. Middelburg · 1 citation
Environmental Science · Earth and Planetary Sciences · Chemistry · #Methane Hydrates and Related Phenomena #Microbial Community Ecology and Physiology #Marine Biology and Ecology Research #Bioturbation #Organic matter #Biogeochemical cycle #Microbial loop #Sedimentary organic matter #Total organic carbon #Environmental science #Carbon cycle #Ecology #Biomass (ecology) #Sediment #Ecosystem #Environmental chemistry #Earth science #Chemistry #Geology #Biology #Food web #Paleontology
paper · pdf · doi:10.5194/bg-15-413-2018
openalex created_date 2017/09/15 · openalex publication_date 2018/01/19 · openalex updated_date 2026/07/30
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.