MBARI Conducts Midwater Ecology Fall 2013

In order to document the effects of declining oxygen concentrations on midwater communities, the midwater ecology research group has conducted approximately one remotely operated vehicle (ROV) dive per month, compiling a time series which measures the identity, abundance, and vertical distribution of the constituents of the midwater fauna at specific sites.

The results of the time series demonstrate that several species have already been displaced by the expanding oxygen minimum zone (OMZ). OMZs are depths, typically 300 to 1,000 meters below the surface, where oxygen concentrations are already quite low in many parts of the world’s oceans.

The midwater team will be examining the physiological characteristics of midwater animals relative to the expanding OMZ. This research utilizes the midwater respirometry system (MRS), an instrument which gathers oxygen consumption measurements in situ, to gauge the metabolism of animals without subjecting them to the stresses of decompression during transport to the surface. Data provided by the MRS helps to determine the oxygen level at which each species switches from “regulation” to “compensation.” Once these oxygen levels are known for a number of species, the future of how expansion of the OMZ will change the spatial composition of the midwater community can be predicted, as well as the ecological implications of such changes.

In addition, the MBARI research team will be joined by a group of husbandry staff from the Monterey Bay Aquarium. The Monterey Bay Aquarium is interested in the potential for creating an exhibit of deepwater organisms and will be working closely with MBARI on organisms such as jellies and cephalopods.

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Source: MBARI, November 11, 2013