While the designation of the NACES MPA is a welcome result and helps to safeguard the ecosystems found here, the fact that we know so little about it means we do not understand how effective the MPA is in protecting deep-sea environments. Moreover, we are presently unable to reliably predict the short, medium, and long-term impacts of current and emerging threats on the health and functioning of oceanic food webs in this area. As such, managers do not have the scientific foundations to assess the risks human activities pose, or which precautionary actions they have in their power to mitigate negative impacts. Our ultimate objective for this cruise is therefore to undertake the first deep ocean survey of the NACES MPA to census the biodiversity and ecosystem processes of the deep pelagic, seamounts, and abyssal plain ecosystems found here, and start to quantify the hydrography of the water column, biological carbon pump, and pelagic and benthic food-webs.

We will fully characterize the BCP and water column hydrography in the NACES MPA from multiple CTD casts over seamounts and abyssal plains, and by deploying two sediment trap moorings with current meters from the RV ‘Sarmiento de Gamboa’ for one year, which will allow us to begin to understand the Biological Carbon Pump in the area. These observations will be accompanied by shipboard experiments to document pelagic C-degradation, and dark inorganic C-fixation (an alternative C-input pathway). The sediment trap moorings will be recovered one year later during a follow-up research expedition with the RV ‘Celtic Explorer’.

We will also quantify the biodiversity, abundance, and feeding patterns of dominant organisms at meso- and bathy-pelagic depths (e.g., residing in the deep-scattering layer or DSL) to estimate the potential impacts of the release of predators (e.g., due to pelagic fisheries) that feed on fauna in the DSL.

We will also undertake seafloor respirometer lander deployments to quantify seafloor respiration, and rates of C-cycling by the benthos, as well as baited camera deployments to document the biodiversity and feeding activities of benthic and demersal scavengers. This information will be used together with seafloor image surveys carried out one-year later, which will allow us to document the flux of mesopelagic carrion (e.g., squid and jellyfish) to the seafloor to further parameterize the BCP.