MBARI Expedition #479

Expedition goal: The principal goal of this expedition is to measure oxygen consumption rates of select deep-sea animals using a custom-designed tool, the Midwater Respirometry System (MRS), at both shallow and deep locations. We will also be observing and collecting midwater animals to investigate their ecology, physiology, and behavior in conjunction with onboard collaborators from GEOMAR Helmholtz Centre for Ocean Research in Kiel, Germany, and the Auckland University of Technology in New Zealand. Additional research will include the effects of abrupt seafloor topography on the distribution of midwater species, and the impact of food falls (carrion) on the deep-sea food web.

Expedition dates: November 15-21, 2019

Ship: R/V Western Flyer

Research technology:  ROV Doc Ricketts, Midwater Respirometry System

Expedition chief scientist: Bruce Robison

The Midwater Ecology Group will continue its research into the respiration rates (oxygen consumption) of deep-sea animals using the Midwater Respirometry System (MRS). The MRS allows the group to measure these animals’ metabolic rates where they live as opposed to in the laboratory at surface pressure. Understanding the energy requirements for these animals will allow a clearer understanding of the biological pump and the energy transfer from the surface, through the ocean’s midwaters to the seafloor. The group’s studies over the last three decades have shown the area of the deep ocean where the oxygen level is lowest is growing. The midwater team has documented the vertical expansion of the oxygen-minimum zone by 60-to 80-meters in relation to ocean warming. This expansion has fragmented the midwater community by shifting the distributions of some midwater animals. Long-term studies like this are necessary for first detecting shifts in communities and then predicting how communities will respond in the future to further changes in the environment

Midwater cruises also include exploration of this large habitat, where light does not penetrate from above and the seafloor is not in sight below. Such explorations have led to many significant observations and discoveries about this habitat and the animals that live there—and their behavior.