Event

Dark oxygen production at the manganese nodule-covered aphotic abyssal seafloor

A seminar delivered by Prof. Andrew K. Sweetman from the Scottish Association for Marine Science

  • Thu 18 Jan 24

    13:00 - 14:00

  • Online

    Zoom

  • Event speaker

    Prof. Andrew K. Sweetman

  • Event type

    Lectures, talks and seminars
    School of Life Sciences Seminar Series

  • Event organiser

    Life Sciences, School of

  • Contact details

    Michelle Taylor

Deep-sea benthic organisms consume oxygen as part of a global balance between photosynthesis and respiration, but direct observations of oxygen consumption rates from the abyssal seafloor are scarce relative to its areal extent and the diversity of seafloor habitats. Since 2013, a total of 54 in-situ benthic incubations have been carried out at the abyssal seafloor in 6 manganese nodule regions of the equatorial Pacific Ocean. In 94% of the incubations undertaken, we have found that more oxygen is being produced at the abyssal seafloor than is being consumed, with oxygen levels rising to more than 3-times background levels over 48 hours. Dark oxygen production (DOP) rates measured from the change in oxygen concentration between the initial and peak oxygen concentration has been found to be 11-53 times greater than estimates of demand within the sediment based on in-situ oxygen micro-profiles and occurs exclusively in the presence of manganese nodules and is unresponsive to experimental abiological treatments. This talk will present these results plus identify some possible mechanisms for the DOP found. If DOP occurs consistently across the seafloor, it could play an important role in biogeochemical cycles and ecosystem function in manganese nodule-bearing environments.

Speaker

Andrew K. Sweetman is the leader of the Seafloor Ecology and Biogeochemistry research group at the Scottish Association for Marine Science (SAMS), UK. He holds a PhD in deep-sea ecology from the Max Planck Institute for Marine Microbiology (Germany). Andrew is an expert on seafloor biodiversity and ecology and has a strong focus on the impact of anthropogenic stressors on shallow and deep-sea benthic ecosystems. Over the last 12 years, he has generated > 10 million GBP of research funding and led/ co-led a total of 28 research projects (funded by National Oceanic and Atmospheric Administration[USA], the Norwegian Research Council, the European Union, the Malaysia Research Council, UK Seabed Resources LTD/ Lockheed Martin, Gordon and Betty Moore Foundation [USA], The Metals Company Inc, Natural Environment Research Council [UK], Engineering and Physical Science Research Council [UK], Global Challenges Research Fund [UK]) on diverse topics including assessing the effects of

  1. invasive species (and their removal) on benthic biogeochemistry and ecosystem functioning
  2. aquaculture on deep-sea fjord ecosystems,
  3. carbon dioxide release from carbon capture and storage (CCS) reservoirs on continental shelf ecosystems
  4. mine-tailings deposition, massive sulphide and polymetallic nodule mining on deep-sea ecosystems
  5. global warming on polar ecosystems
  6. synergistic climate change stressors on shallow and deep-ocean systems

He has also been leading projects to assess the importance of jellyfish blooms in the biological C-pump, and the effect of dead jellyfish (from jellyfish blooms), wood and kelp material on deep-sea benthic environments.


Andrew K. Sweetman

Professor

Scottish Association for Marine Science