Midwater Ecology Expedition 2018

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

MBARI Expedition #452

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: November 9- 16, 2018

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:

Friday, November 16, 2018
Senior Research Technician Susan von Thun

Learning about the respiration and metabolism of deep midwater animals is a priority of the Midwater Ecology Group. Studying an animal’s respiration (how much oxygen it consumes), helps us better understand how much energy (food) it needs to live. Understanding this relationship between oxygen consumption and energy requirements for different organisms gives scientists a better overall view of the midwater ecosystem and some insights on how this ecosystem may change with a changing climate.

The Midwater Respirometry System is a tool designed by scientists and engineers at MBARI to measure the respiration rates of midwater organisms under the natural conditions in which they live (at depth) instead of in the lab back on surface, where they may be stressed by conditions to which they aren’t adapted. Each day, we fill the MRS samplers with animals and then “hang” the system at various depths on a mooring over one or two nights. The system logs the oxygen consumption and other environmental data, which are downloaded when we retrieve the MRS.

When we aren’t filling the MRS with samples, we can explore the deep midwater above Monterey Canyon and collect animals for further research in the lab. The science team takes turns in the control room, spotting animals of interest, controlling the main science camera, taking frame grabs, and making observations using MBARI’s video-annotations system VARS. We also have husbandry staff from the Monterey Bay Aquarium onboard collecting animals for possible display at the aquarium.

This eight-day expedition has been successful thanks to the collaborative efforts of the science and ship’s crews as well as the ROV pilots. We’ve been lucky with the weather, diving the ROV all day every day, and studying some really amazing deep-sea animals in their natural habitat. Each expedition brings new discoveries and new questions and adds to what we know about this largely unexplored, but extremely diverse and productive, slice of ocean life.

Thursday, November 15, 2018
Senior Research Technician Susan von Thun

As mentioned in the first log entry of the expedition, the midwater contains much of the ocean’s biodiversity and MBARI’s use of ROVs to study this huge and unknown habitat has led to many discoveries.

Some of the most surprising discoveries made by MBARI’s midwater biologists involve giant larvaceans (Bathochordaeus). These pelagic tunicates thrive in waters about 50 to 300 meters deep in Monterey Bay, where they build large mucus houses that they use to filter food. These houses are discarded daily. The Midwater Ecology Group published findings that the discarded larvacean houses provide a massive transport mechanism for carbon to sink from the sea surface to the seafloor. Recently, MBARI researchers discovered that the sinking houses can transport microplastics to the deep sea as well.

Learn more about how larvaceans transport carbon and microplastics to the deep seafloor.

Wednesday, November 14, 2018
Senior Research Technician Susan von Thun

We got these stunning close-up shots of this viperfish, Chauliodus macouni, this week with ROV Doc Ricketts. This fish is over 500 meters (1,640 feet) below the surface and no longer than your forearm. The fact that we can fly a large underwater robot in the deep midwater, spot and zoom in on an amazing deep-sea fish, watch it breath and see its skin glisten in the ROV lights for over 5 minutes is a true testament to the talent of our ROV pilots and crew. We challenge them to give us this kind of view of the deep-sea world and they meet the challenge every time we get to work with them!

The viperfish has teeth so large, they don’t fit in their mouth! Their huge jaws allow them to open wide, engulf prey (like shrimp and fish),  and then the teeth trap its meal in its mouth!

Tuesday, November 13, 2018
Senior Research Technician Susan von Thun

Exploring the midwater with a remotely operated vehicle (ROV) gives us a unique perspective of the communities living there. Traditional methods for studying the midwater involved trawling—dragging a net behind the boat and then sorting through the haul. That haul can be filled with fish, squid, crustaceans, and LOTS of jelly parts. Due to their delicate structure, it can be challenging to accurately count the many gelatinous animals from a trawl. But with an ROV, we can see these creatures easily in their fluid environment. We can often identify and even count them as we cruise through the water column.

ROV Doc Ricketts gives us a window into their world—in the relative comfort of a control room on the ship. Operating the ROV involves a coordinated effort among the entire crew and the ROV pilots. During deployment and recovery of the ROV all hands are on deck, two pilots are in the control room, and everyone is communicating with headsets with the captain on the bridge who is moving the ship to position the ROV for a safe deployment and recovery.

During the dive, the pilots in the control room are constantly talking to the crew on the bridge to ensure the ROV tether has just the right amount of slack in it. A tight tether will cause the ROV to be tugged by the ship, while a slack tether could lead to a loop in the tether. This synchronized operation helps lead to a successful dive. We couldn’t do our research without our crew and ROV pilots!

Monday, November 12, 2018
Senior Research Technician Susan von Thun

Between the ocean surface and the seafloor lies a vast, fluid universe, Earth’s least-known environment. That habitat, commonly called the midwater, contains much of planet Earth’s biodiversity. Using remotely operated vehicles (ROVs) to study the animals living there gives us a unique perspective of this ecosystem. Regular investigations of midwater ecology with ROVs has led to many of MBARI’s most stunning discoveries.

You may be familiar with the submarine canyons’ coral-covered walls or sediment-laden meanders, but the vast majority of the life here never touches the seafloor. On this expedition, we’re exploring the deep waters above the Monterey Canyon. This canyon—in MBARI’s backyard—has given us opportunity to thoroughly survey the community that thrives there and discover new animals, behaviors and ecological linkages on every dive!

As a member of MBARI’s video lab with expertise in midwater animals, I spend much of my time watching ROV video in the lab. So, it’s always fun to join this group at sea and spot animals in real time. While sitting in the control room all day, not only do we discuss current research, personal observations, and ideas for future work, we also get to learn from each other. One of my favorite things is when I spot a fish we rarely see and Bruce Robison and I get to geek out over how cool it is! Many fish have some on the most stunning adaptions to life in the deep sea.

Here are some highlights from today’s dive, cruising slowly down from the surface all the way to 3,000 meters on the seafloor. As Bruce says, sometimes we go to the bottom “just to make sure it’s still there.” But seriously, there are many animals that live just above the seafloor called “benthopelagic organisms” that we are also interested in while we explore Monterey Canyon’s ecological treasures.