Midwater Ecology Expedition Spring 2019

This jelly, Solmissus sp., is one of the species the Midwater Ecology group uses to study oxygen consumption in the Midwater Respirometry System (MRS).

MBARI Expedition #458

Expedition goal: The main goal of this expedition is to expand ongoing research into the respiration rates (oxygen consumption) of deep-sea animals using the Midwater Respirometry System (MRS). The MRS will be deployed at a “shallow” (approximately 1,500 meters depth) and a “deep” (approximately 3,000 meters depth) mooring during the duration of the eight-day cruise. The group is also accompanied by MBARI partners from the Monterey Bay Aquarium, who are interested in observing and collecting select deep-sea organisms.

Expedition dates: March 8- 14, 2019

Ship: R/V Western Flyer

Research technology:  ROV Doc Ricketts, Midwater Respirometer System

Expedition chief scientist: Bruce Robison

The Midwater Ecology Group is heading out to continue studying the midwater respiration rates of deep-sea animals. This long-term project aims to investigate deep-sea animals response to changes in the environment (i.e., oxygen or temperature). To date, the Midwater Ecology Group has successfully 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 many 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.

Updates from researchers on the R/V Western Flyer:

Thursday, March 14, 2019
Senior Research Technician Kyra Schlining

A gallery of some of the amazing deep-sea animals we observed during this expedition:

Updates from researchers on the R/V Western Flyer:

Wednesday, March 13, 2019
Senior Research Technician Kyra Schlining

We are fortunate to have two aquarists from the Monterey Bay Aquarium, MacKenzie Bubel and Wyatt Patry, working with us on this expedition. They are busy collecting an array of new deep-sea animals and have been able to keep several animals alive longer than we ever have before. They are hoping to successfully culture several key species. The cold room in the wet lab is filled with an elaborate set up of seven aquaria of various shapes and sizes. The room is dark and the water is kept at a chilly five to six degrees Celsius. The researchers typically use red light when working in the cold room as the deep-sea animals are less sensitive to it.

Updates from researchers on the R/V Western Flyer:

Tuesday, March 12, 2019
Senior Education and Research Specialist George Matsumoto

The Midwater Ecology Group is out here studying a layer in the water column called the oxygen minimum zone, or OMZ. The OMZ is a layer where the oxygen levels are lower than the waters above. In the Monterey Bay area the OMZ is typically 600 to 900 meters below the surface. OMZs form where large amounts of organic material (marine snow) sink down from the sea surface. When bacteria break down this organic material, they remove oxygen from the water. Above the OMZ, this oxygen is replaced by oxygen-rich seawater that mixes down from the sea surface. Below the OMZ, oxygen is replaced to a lesser extent by deep-ocean currents. But seawater within the OMZ doesn’t mix very much with the waters above or below it, so oxygen concentrations are often very low. Many animals cannot live in or even swim through the OMZ, but a few species have adapted to survive in this challenging environment.

MBARI researchers are very interested in knowing more about how sensitive deep-sea organisms are to changing oxygen levels which requires knowing how much oxygen they use to survive. While the deep Midwater Respirometry System collects data (this last deployment was a 48-hour deployment at 2,900 meters), Kim Reisenbichler is hard at work in the lab measuring the respiration of other animals collected on earlier dives. He also is the person with the most experience with net deployment, thus he also assisted in the deployment of the midwater trawl last night.

And, while all of this is going on, you never forget that the deep-sea is full of amazing organisms like this incredible whalefish that gathered the attention of the everyone aboard as it slowly posed for us before swimming away into the darkness.

Updates from researchers on the R/V Western Flyer:

Monday, March 11, 2019
Senior Research Technician Kyra Schlining

We steamed for just over four hours until we reached our first dive site at approximately 3,000 meters (almost two miles). The first few hours of the dive were spent filling the Midwater Respirometry System (MRS) sample buckets with mysid shrimp for a deep deployment. According to Research Specialist Kim Reisenbichler the shrimp are “good guinea pigs” because they are common at this depth and give reliable respiration results.

Chief ROV Pilot Knute Brekke hung the MRS on a cable at a depth of 2895 meters. The instrument includes eight sample buckets, six contain shrimp and two are kept as controls. We will leave the equipment hanging at depth for 48 hours then come back to retrieve it. During the experiment period Kim will remotely adjust the pH (acidity) of the water in the chambers and measure the reaction of the mysids. These efforts help the researchers understand how the animals will respond to future conditions as the ocean shifts in acidity.

We found hitchhikers! As we explored with the ROV we observed a pycnogonid spider living parasitically on a midwater jelly (Pandea rubra) at 700 meters. Although we have seen this before, it was still a surprising sight because pycnogonids are typically spotted on the seafloor and we were a very long distance (over 2,000 meters) off the bottom. We also filmed the large and unusual medusa Deepstaria reticulum with a parasitic isopod, Anuropus, tucked inside.