Bioluminescence Expedition

This ctenophore, Beroe forskalii, is capable of displaying bright bioluminescence when disturbed. But the rainbow colors seen here are an effect produced from diffraction of light on the jelly’s comb rows. Photo by Steve Haddock

MBARI Expedition #467

Expedition goal: During this cruise, we will conduct ROV and scuba dives to aid our research into the biochemical, physiological, and genetic adaptations that midwater organisms have evolved to help them survive and diversify in the deep sea.

Expedition dates: July 9- 17, 2019

Ship: R/V Western Flyer

Research technology:  ROV Doc Ricketts

Expedition chief scientist: Steven Haddock

For the next eight days, the MBARI Bioluminescence Lab, led by Steve Haddock, will be at sea on the research vessel Western Flyer, exploring the organisms that inhabit the midwater of the Monterey Bay and beyond. We will use remotely operated vehicle Doc Ricketts, along with blue-water scuba diving by several members of our team, to observe and collect organisms from the shallow surface waters to the seafloor.

Most organisms in the ocean are bioluminescent, meaning they make their own light from a chemical reaction. We will use our low-light camera on the ROV for observing and recording bioluminescent behavior in the wild, especially bioluminescence from gelatinous organisms such as ctenophores, medusae, and siphonophores. The biochemical mechanisms that different organisms use to produce their light is part of our research under the MBARI Biodiversity and Biooptics of Zooplankton Project. Also as part of that project, we will look at the genetic diversity of several midwater organisms. Our goal is to understand how organisms of different species are related to one another, and how the genetics of a single species varies within a population.

Of particular interest to many of us are ctenophores, also known as comb jellies. Not only are most comb jellies bioluminescent, but various species can be found from the (relatively) warm surface waters with low hydrostatic pressure, all the way down to the low temperature, high-pressure environment of the deep seafloor. How different species of ctenophores have evolved to live and thrive under great differences in pressure and temperature is a focus of investigation for our NSF-funded DEEPC Project (DEEPC stands for “Diversity, Ecology, and EcoPhysiology of Ctenophores”).

Updates from researchers on the R/V Western Flyer:

Tuesday, July 16, 2019
From Lynne Christianson and Steve Haddock

When the Haddock lab is at sea, we use different technologies to explore and collect the many interesting species we hope to study. The main tool is MBARI’s underwater robot, the remotely operated vehicle ROV Doc Ricketts. The Doc Ricketts has cameras, lights, two manipulator

Steve Haddock and Shannon Johnson unload sampling containers from the ROV Doc Ricketts after a successful dive. Photo by Lynne Christianson

arms and sampling chambers that the ROV pilots and scientists operate from a control room on the ship. With the ROV, we can explore and sample delicate organisms in the water column or seafloor, all the way down to 4,000 meters (2.5 miles). The pilots are extremely adept at adding and refining sampling capabilities to this flexible workhorse, giving it incredible ability to capture tiny and delicate ctenophores and other gelatinous zooplankton. Yesterday, using this vehicle the size of a minivan, we caught a ctenophore about the size of a pomegranate seed.

Using our low-light camera on the ROV, we can even image bioluminescence from organisms in the wild in full color—something that couldn’t even be imagined even five years ago.

Another method we use is blue-water scuba diving. Blue-water diving is like an underwater space-walk, and allows us to collect shallow organisms in the upper 25 meters (80 feet). Divers are tethered to a central line and drift among the plankton (and the occasional shark, sea lion, or ocean sunfish). Organisms are collected by hand into jars and brought back to the ship’s lab. So far on this expedition it has been too windy for the divers to get in the water, but we have been able to get in full ROV dives to keep everyone very busy in the lab.

Darrin Schultz and Alex Lapides deploy the trawl net from the back deck of the Western Flyer. Photo by Shannon Johnson.

Midwater trawling is the traditional method of collecting samples, which we also use on our expeditions. The trawl net can capture a broad size range of organisms, from tiny copepods to jellies and small fish, so trawling then gives us a record of the diversity at particular depths. However, many delicate organisms, such as the ctenophores we are interested in, are damaged on collection, so the trawl is best for more sturdy organisms, and the ROV remains the best way to retrieve delicate jellies in perfect condition.

This tiny ctenophore was collected by the ROV Doc Ricketts. Photo by Steve Haddock

Monday, July 15, 2019
From Alex Lapides

Everyone says you can’t really understand an ecosystem until you’ve experienced it for yourself, but it’s surprisingly true. As a data technician in Steve Haddock’s lab, I work with the existing data in the Video Annotation and Reference System (VARS) database. Because of this, I don’t work hands-on with the organisms I study, electing instead to discover their secrets by leveraging statistics and large datasets.

Alex Lapides and Mari Figueroa in the control room of the Western Flyer. Photo by Lynne Christianson

However, having the opportunity to be on this cruise shaped my understanding of the midwater column and opened new avenues to explore in my research. Yesterday our nightly trawl returned noticeably fewer organisms than usual. PhD student Darrin Shultz explained to me that the trawl was done in the oxygen minimum zone, an area of the water column where very low oxygen makes life sparse. Similarly, going over the daily ROV dive plans has me wondering about community composition on often-dived sites and how they change over time.

I’ve also been spending a lot of time in the ROV control room, sketching animals and trying to understand how they might interact with the world around them. During my shifts as the dive annotator, I’ve had the chance to add my own records to the VARS database. Being on the data creation side of the process has given me a better understanding of where my data come from, and how to approach possible biases that may be present in the records.

Now I’m more excited than ever to get back to the lab and have some fresh data to work with, as well as fresh ideas about how to approach my projects. Having the opportunity to be out here has been inspiring and invigorating, and I’ve been grateful for every moment of it.

Drawings created by Alex Lapides during ROV dives.

Sunday, July 14, 2019
From Lynne Christianson, Steve Haddock, Jacob Winnikoff, and Tiffany Bachtel

Many deep-sea species have never been seen or collected before. Nevertheless, we can learn a great deal by studying them with next-generation laboratory equipment and methods like optical oxygen microsensors, high-pressure instruments, genome-scale sequencing, protein purification, and gene cloning and expression. For the DEEPC project, MBARI Scientist Steve Haddock and collaborator Erik Thuesen, of The Evergreen State College, and their teams, are applying these tools to learn how ctenophores (comb jellies) adapt to a broad range of temperatures and pressures.

Some ctenophores live in the warm temperatures and lower pressures of the shallow waters, while others live in the cold temperatures and high pressures of the deep sea. Proteins tend to be sensitive to extreme temperature and pressure, so our DEEPC project asks: How do the proteins in both deep- and shallow-dwelling species function efficiently under such dramatically different conditions?

These two closely related species of Lampea live in vastly different habitats—one was collected at 15 meters (50 feet) depth and the other at 2,670 meters (1.6 miles).

Years ago, when biologists wanted to characterize a particular protein, they might need to collect thousands of individual animals to obtain enough material for experiments. Now, by analyzing an animal’s “transcriptome.” we can learn a lot about the capabilities of a species using just a small amount of material from a single organism.

The transcriptome is the portion of the genome that an organism is using as blueprints to make proteins. Each gene in a transcriptome, then, reveals the sequence of a protein. Using computational methods, we can compare these protein sequences across a variety of organisms.

For our DEEPC project, graduate students Jacob Winnikoff and Tiffany Bachtel are using transcriptomes and biochemical experiments to compare the metabolic enzymes of deep and shallow ctenophores.

Tiffany Bachtel and Jacob Winnikoff working at sea in the lab of the Western Flyer.

Combined with traditional biochemistry, transcriptomes let them detect subtle differences in the structure of these essential proteins that affect their temperature and pressure tolerance.

Long after the DEEPC project is complete, the transcriptomes themselves will remain useful. We can revisit the data anytime, for example, to compare photoproteins, which are responsible for making bioluminescence. We can also compare sequences of multiple proteins simultaneously, to learn about the evolutionary relationships and diversity of many species. By applying new tools to old questions, we can unlock more of the mysteries of life in the deep ocean.

MBARI cruise participants

Other cruise participants:

Tiffany Bachtel and Erik Thuesen, The Evergreen State College
Maggie Cooper and Marisol Figueroa, MBARI summer interns