We started early today, with Jason diving down around midnight. The dive began similar to our past ones, starting with science objectives. We had our usual deployments and recoveries of tube traps, tilt meters, and sipuncollector. After completing those objectives, we moved on to collecting our mussels. At these mussel patches you could see oil droplets floating through the water like small little pearls occasionally. At these cold seep sites, along with methane, natural oil flows into the overlying water. Around 3am, the scientists had the opportunity to interact with some deep-sea wildlife. While traveling across the seafloor, the Jason watch team came across a giant isopod, of the Bathynomus genus. Jason slowly approached the bug and extended an arm. Here’s a short video of the isopod running off, it wasn’t interested in hanging around with us.
Here’s a video that Avery Calhoun put together on the last cruise highlighting the Bush Hill site:
Once Jason resurfaced around 8am, we had the chance for discovery. During the dive we came across some tubeworms that were covered in white sponges. Dr. Young mentioned an interest in a species of worm that lives on the sponges that live on the tubeworms. The deep-sea seems to have many of these worm-sandwich epibiotic relationships, just like the sabellids on the Acesta on the tubeworms described earlier. This worm species had been described but didn’t have specimens, however. With the tubeworms in our bioboxes, the team was tasked with searching the sponges for these elusive worms. We whisked them away to the microscope table where we removed the sponge and began searching. Dr. Young described them as the same color as the sponge, so we had to search for distinctive textures and worm-like shapes. Confused eyes turned into a big surprise as the two Western REU students, Fiona McBride and Liam Patrick found a few of them! These individuals are going to be preserved and used for further study, potentially they could end up in a museum! They may not be the most charismatic creatures, but finding a novel species is worth the excitement. This is why deep-sea research is so fascinating, these places haven’t been studied extensively and new discoveries are common. Even while searching through these sponges we found some bathymodiolin mussel larvae, which was not expected. Finding them on the sponges indicates the larvae can swim at least as high as the tubeworms, aiding in answering our research questions about larval dispersal.
The Bathymodiolus excitement continued later into the night by finding many live larvae while sorting through the slurp samples. The live mussel larvae have a small foot that sticks out and they crawl around with, but also some of these babies were swimming! We are interested in finding these swimming veligers because they haven’t developed their methane-consuming bacteria symbionts yet and can use them for microbiome and morphometric analyses.
With another sunset, we ended the day by beginning or transit to our last site, Mississippi Canyon, which we detoured earlier in the cruise. We can’t believe we’re almost done!
The days are beginning to feel similar at these sights. Again, we started the day with a short dive with Jason down to the seafloor. On this dive we completed the video transects of the brine pool sight and recovered Lauren’s trees and trampolines. We also deployed the Technicap carousel, a collector that opens a new tube every month to collect larvae.
In the early morning we also had a Sentry recovery, right before Jason went in the water. After sorting for morphotypes over the past three weeks, we’ve gotten fairly good at identifying different larval types in our samples. We can correctly identify gastropods (snails) over pteropods, and bivalves over ostracods. While these imposters are still all over the samples, we were getting fed up with another organism; the nauplius. Nauplii are the larval form of copepods (or barnacles), the crustaceans that make up the majority of individuals in our samples. These tick-looking larvae are not ones we are looking for, but we have been finding them all over the SyPRID samples. To cope with this, we came up with a little nursery rhyme:
“Fatty fatty nauplii
Swimming in a row
Clogging up the SyPRID Sample
From the plankton tow”
Later in the day, the scientists got to work sorting through the sieved water and sediment from the bioboxes on the Jason dive yesterday. While the samples were dense with black, oily, sediment, we had a welcomed surprise. Usually whenever we find a pink Bathymodiolus shell, the team is ecstatic, and the finder calls it out with glee. That’s how sorting these samples began. Each of us would take a sample from our container, immediately find one of these pink treasures, and shout it out. Then we began seeing a few more, until looking more closely. We were finding Bathymodiolus shells everywhere! Using these larval shells for isotope analysis requires a good amount, but we had found over 100 within 30 minutes! What takes us hours on other sites, we had completed in record time here. This makes our job easier and can put a higher priority in searching for live larvae for pictures, videos, and preservation.
Once Jason was back on board, we left Brine Pool and moved to the last site in our trifecta: Bush Hill. The site is faithfully named for being a large hill with tubeworm bushes on it. When we arrived, Sentry was expertly deployed yet again, to get the first of our two SyPRID samples at each site.
We ended the day with a beautiful sunset outside. Many of us have been working so hard that some of us have only seen a few, or no sunsets from the entire cruise! The different sleeps schedules also play a role here, with some people typically sleeping while the sun goes to bed itself. While the sun was setting, we were told about a legend at sea called the Green Flash. Apparently, when the sun hits the horizon on open ocean, there is a flash of green visible to those who watch. We all watched closely, hoping to observe this phenomenon, hardly blinking as the horizon met with the sun. But the green light didn’t appear, not at the horizon, nor at the end of the dock. Regardless, it was a beautiful sunset.
The morning began by returning to the tubeworm gardens. This short dive is to deploy and recover Lauren’s trees and trampolines. Due to the size of the equipment we can’t put all our instruments in one basket and need to dive twice. Carefully, Jason has to hover around the deployment sites, avoiding crushing tube worms and stirring up the sediment too much. Time was of the essence however, so we couldn’t spend too long on the seafloor. With the science deployed we quickly resurfaced, and immediately left GC-234 to head to our next site: Brine pool.
What’s a brine pool? It’s a pool of very dense, salty, water at the seafloor. These form throughout the Gulf of Mexico. Our brine pool was formed through salt intrusions called salt diapirs. The diapirs are buoyant and a lower density than the overlying sediment, which forces them through the bottom. Essentially these diapirs dissolve in the water and create these hypersaline pools. The brine pool we are studying is unique to others in that there is a ring of mussels surrounding the pool like a beach. Mussel beach. This break in the seafloor from the diapir is also allowing methane gasses (and oil) to seep into the surrounding water that provide the basis of this methanotrophic community. The brine pool is 120 PSU, with the density high enough that our deep-sea submersibles float on top, and most organisms can’t survive inside. This video is a great introduction to what our site looks like, created by Avery Calhoun on the spring cruise last year.
Tonight, we had a night recovery of Jason. Both Sentry and Jason and their teams work hard around the clock, with the scientists always ready to support. While unloading the ROV and gathering our samples, we all became familiar with the fact of nighttime in the Gulf in June is still very warm. In heat and less light than we’re used to, the scientists were still cracking jokes while we extracted and sieved the water from our bioboxes. We’ve been together for over three weeks and had our limited interactions during quarantine. We’ve become a close group of friends that are supportive, keep the moral up, and are excited to conduct science at sea.
Once we arrived at brine pool, Jason was quickly put back into the water for our first brine pool dive. On top of our usual habits of collecting mussels and carbonate rocks, recovering and deploying tube traps, sipuncollectors, and tilt meters, we were interested in snails! At this site we find snails called Thalassonerita naticoidea (previously Bathynerita naticoidea) living amongst the mussels and even laying egg cases on the mussel shells. While diving we also visited another site called snail mound, where these snails are abundant, and conducted a partial video transect of both sites. Within the Jason van, we have a sonar system called BlueView and here’s a photo that shows the entire brine pool on that radar screen!
Here’s another awesome video that Avery Calhoun put together on the last cruise, showing the famous brine pool site! There was even a Blue Planet episode on this very brine pool!
Today we arrived at the first of our trifecta of sites, Green Canyon (GC-234). GC-234 is a special site for our cruise objectives as it does not actually have any mussels! Instead, we were greeted by a large abundance of tube worm bushes. Tube worms, also known as Lamellabrachia luymesi, are unique to our Gulf of Mexico sites. These tube worms are one of the dominant habitat-forming species found at cold seeps sites in the Gulf, the other habitat-forming species being the mussel species.
Picture showing an overview of all our sites. The far left point (Brine Pool) is where our trifecta: GC-234, Brine Pool, Bush Hill, are all located.
Another aspect of this site that’s fascinating is the epibiotic interactions. Epibiotic means things living on other things, like barnacles on a whale. At this site we have a cascading epibiotic relationship with the tubeworms. On top of these tubeworms live a clam called Acesta oophaga, or the egg-eating clam. These clams have a specialized shell that fits over the opening of a tubeworm in order to eat their eggs when they spawn. On top of these clams live another organism, a type of worm called a sabellid worm. These worms bore into the shells of the clams and filter the water flowing around them. One of the graduate students from the University of Oregon on our cruise, Lauren Rice, is interested in these epibiotic interactions. In this picture here, you can see the circular feeding crown of the sabellid worms, on the yellow clams, on the tubeworms with their red heads poking out.
Once ready, Jason began its descent. After passing through nearly 600 meters of deep blue water, with the occasional ctenophore or shrimp floating by, we saw the silty seafloor. A maze of a tubeworm garden appeared before us. The first challenge at every site is locating where our science equipment was deployed on the last cruise. We always save the coordinates of our sites, but they don’t always line up. We scanned the bottom, swerving over and around small and large bushes, searching for our distinctive instruments. Thankfully, we found the target site right next to one of the largest tube worm bushes, larger than Jason. Under the shadow of the worms, we picked up our equipment, placed it within Jason’s basket, and returned to the surface.
Pictured taken by Dr. Craig Young with Johnson Sea-Link 2.
Once back on the surface, Sentry was deployed to collect a new plankton sample for us with SyPRID. Tomorrow we will be doing another quick Jason dive to deploy and recover Lauren’s tables and trampolines. Check out this video that Avery Calhoun put together of this site on the last cruise that highlights these crazy tubeworm bushes, but also some beautiful Gorgonian corals with ophiuroids!
With Florida Escarpment off our stern we started course for our next site: Mississippi Canyon. We had a change of plans however, with a tropical storm developing in the Gulf heading for our most important sites. To avoid losing access to our sites, we took a detour and are heading for GC-234 first and attempting to return later in the cruise to Mississippi Canyon. We should be arriving at the site around 0800 tomorrow morning. Moving from site to site aboard the TGT gives our team time to catch up on our projects, and this round of transit was no exception. Our previous ROV Jason dive from the Florida Escarpment gave us plenty to do all day and all night. To help stay on track, we have a whiteboard to-do list posted in the main lab, where we check off tasks as they are completed. There is no greater feeling than checking off a box that has taken hours to complete.
Our next three sites (Green Canyon, Bush Hill, and Brine Pool) are where many of our graduate students are focusing their research. Today, Young Lab PhD student Lauren Rice constructed her two different types of settlement arrays (pictured here) which will be deployed at the bottom of the ocean for a few months at these sites and recovered in Autumn. These arrays will help determine the variety of epibiotic organisms that like to settle around methane seeps and their preferred locals. The single-tier settlement arrays are referred to by the Alvin Crew as “trampolines” even though they do not bounce (unfortunately). They are a single height above the sea floor with a variety of substrates including rocks, clam shells, mussel shells, and tube worm tubes. These arrays are placed next to healthy bushes of tube worms which are very abundant around methane seeps in the Gulf. We will also be gathering settlement arrays that Lauren placed at these three sites in February of 2020 to see what has settled where.
Meet a Scientist on Board
Hi! My name is Ian Grace. I am a PhD student in Dr. David Eggleston’s marine ecology and conservation lab at North Carolina State University in Raleigh, NC. I worked in the same lab during undergrad and spent two years analyzing DSV Alvin Framegrabber footage to quantify habitat composition and species diversity and abundance at deep-sea methane seeps in the Gulf of Mexico (GOM) and West Atlantic Margin (WAM). I returned to NC State in late 2019 to begin my graduate program. I am investigating if variance in elemental composition of mussel larval shells is sensitive to region, depth, or time, and if results can infer patterns of larval behavior such as demersal drift and vertical migration among methane seep sites in the GOM and WAM- many of which I studied in early undergrad. For instance, if larval shells collected from two groups of sites have significantly different average elemental composition, it may mean that populations at these sites recruit from different larval pools or that those larvae are locally retained and therefore are less likely to disperse to distant sites. Being at sea certainly makes me miss my hobbies- beyond spending time on my research, I enjoy kayaking, composing music, travel photography, and playing disc golf.
Feel free to follow me on Instagram (@ianjgrace) where I post cool research and travel pictures, videos, and blurbs!
The past 24 hours have been focused on sorting through slurp and biobox samples. This process included sifting through sieved sediment and specifically sampled sites with the slurp vacuum. This step is crucial yet extremely tedious to hand pick through particles searching for treasures of target specimens under the microscopes. There are many important things that the scientists have to continually maintain during this process including: keeping organisms on ice, organizing our creatures, facilitating the jams, and taking snack breaks. We are typically sorting all night so it’s important to keep up morale. At the end our sorted critters are consolidated and distributed for various projects and typically photographed and/ or preserved for later. It’s all worth it in the end to answer our scientific questions, and seeing some fascinating organisms. Here’s a picture from our consolidating process where all the ophiuroid (brittle stars) juveniles looked like a bunch of stars in the night sky!
Today was a highly anticipated day. Not only did we arrive at our next seep site after days of travel (plus a few stops to pick up plankton and then to pick up our chief scientist, Craig), but this is the deepest site on our itinerary. At 3300 m deep, Florida Escarpment sits at the base of a sheer underwater cliff. The unique sites We deployed Jason just after midnight. After a two-hour descent down the cliff, we reached a treasure trove of a site. Florida Escarpment contains Bathymodiolus mussels galore, a target species for many of us in the science party, as well as tube worms, sponges, and bacterial mats, spread out over a site which surprised us with its extent. We filled the slurp and the bio boxes full and spent several hours after exploring the site and recording video. At the site were a few indicators of human presence: some trash, which is disappointingly common at the seafloor, and some small collectors left by other science parties. We passed over some ballast weights left at the bottom from an Alvin dive when the vehicle prepared to surface.
When Jason surfaced around 3 in the afternoon, it was all hands on deck to sort and store samples. Mussels and tube worms were brought into the cold rooms in seawater, the sipuncollector and larval traps were recovered, and remaining sediment in slurp chambers and bio boxes were sieved and stored for the long process of larvae sorting. Laura, a WWU master’s student studying hydrothermal vent bacteria, was presented with her own bacterial mat sample for sequencing. During the chaos of unloading Jason, the TGT crew also assisted in deployed Sentry on its second Florida Escarpment dive for yet more larval samples.
Meet a Scientist on Board
Hello blog-goers! My name is Avery Calhoun, a PhD student in Craig Young’s lab at the Oregon Institute of Marine Biology (OIMB), University of Oregon. My background lies in mapping, habitat modeling, and community ecology. I studied Marine Science at California State University, Monterey Bay (CSUMB), and I am excited that the Arellano lab brought along Liam, a current student at CSUMB. It has been great to catch up with him and get updates on my favorite professors (hi Gerick and Alison)! My project in the Gulf of Mexico focuses on species associations and habitat modeling for organisms at methane seep sites with the goal of determining physical conditions that may contribute to distribution of larvae. While I am gathering information for my dissertation, I am also working closely with the Sentry AUV and Jason ROV teams to prepare coordinates for our dive sites and surveys. The Sentry team shares a lab space with our science team which has promoted great networking and social interactions; I look forward to working with them throughout my career! Fun fact: I’ve caught and released 2 stray stowaway birds from our lab this trip.
The rest of the day was spent sorting larvae under microscopes and dissecting bivalves. Both operations take lots of time, so the science party has been keeping busy. This site had a lot of samples, finding ourselves with 18 containers of slurp and biobox sediment to sort through. We hope to have all of our samples processed by the time we reach our next site where we can do it all over again.
The Florida Escarpment site is one of our more charismatic sites, with fascinating topography and communities. Here’s a video that Avery Calhoun put together on the Alvin cruise last spring from the footage at this site!
Today we arrived on our first Gulf of Mexico site, Florida Escarpment. To round out our transit activities before getting back into science, we had a special celebration at sea! Two members of our science team, Casey Barnard (UO) and Dexter Davis (WWU), are graduating during this research cruise! While both graduations are being delivered online this year, the crew on board wanted to host an unforgettable celebration. Dexter had brought his cap and gown, and diploma placard for photos, but the science crew wanted to amplify the experience. Caitlin and Avery had the great idea to use leftover deep-sea mussel shells to craft a graduation lei signifying the deep-sea research we are conducting. A fun twist on the traditional cords and flowers typically worn for graduations. The ultimate addition came from the Jason team, excited to get involved, and be the one to hand our graduates their diplomas.
The ceremony itself was glorious. The double feature began with walking the “aisle” next to the Jason control van, with “Pomp and Circumstance” playing from a portable speaker. Each graduate walked up to their mentors Dr. Shawn Arellano and Dr. Craig Young while being introduced. After an affirming handshake, solidifying the years of hard work, our graduates approached Jason. The deep-sea vehicle held the diploma with an outstretched limb, beckoning the graduates to accept their degrees. Stopping for photos, the graduates thanked Jason, shook its hand, and joined the audience of supporting crew and science members. This was truly a unique and unforgettable experience for everyone on board, and incredibly meaningful for the graduating scientists. Afterwards the cooks even made celebration cupcakes! Here’s a couple shots from the ceremony!
“Way to Go – Congrats Dexter & Casey”
Meet a Scientist on Board
Dr. Shawn Arellano is an Assistant Professor at Western Washington University in the Biology Department and the Marine and Coastal Sciences Program. She has been based out of WWU’s Shannon Point Marine Center (SPMC) since 2012, but she has been working to understand the lives, movements, and behaviors of the larvae of deep-sea animals since graduate school (at OIMB in the lab of co-Chief Scientist Dr. Craig Young!). In her career, Shawn has been on more than 20 research cruises, had 24 dives in 4 different deep-sea submersibles (20 dives in the Johnson Sea-Links I & II, 1 dive in DSV Pisces V, and 3 dives in DSV Alvin), and has been out working with AUV Sentry and ROV Jason 3 times. She says that one of the best parts about working at Western and SPMC has been introducing budding scientists to research, larvae, and the deep-sea. In fact, Shawn has been able to bring 7 undergraduates and 4 graduate students from WWU on her deep-sea research cruises with her in the past two years.
Fun fact—Shawn has been working with both Dexter Davis (our WWU graduate) and Tessa Beaver (Shawn’s MS student) since just before they started their freshman year in 2017, when they spent two weeks at SPMC for a field course that Shawn taught.
Fun fact 2—Mitch Hebner (Shawn’s other MS student) was an undergrad in Craig Young’s lab before coming to Shawn’s lab for an MS.
Fun fact 3—Shawn is from Kansas and was introduced to marine science for the first time as a confused 5th-year college student when she decided to give a marine science internship a try. That internship was at the Shannon Point Marine Center. Her mentor during that internship? Dr. Brian Bingham—Craig Young’s first PhD student! You might say there is a bit of larval exchange between SPMC and OIMB!
Amidst the celebration for our scientists, there was still science to be done! In the morning Sentry was launched at 7:30 am and was recovered around 8:00 pm. Following soon after, Jason left to explore the escarpment at 10:45 pm, with an hour and half descending time. We’re hoping for a long dive tomorrow to complete our research tasks but also to explore these unique cold seeps further. Of course, we also made many more cups to go down on this site, as the deepest site will shrink them the most! It’s been a day filled with excitement, with joy in the air.
Once we had completed our sampling at our Florida Keys site, we had another important task to do: we had to pick up the other Principal Investigator for our cruise, Dr. Craig Young! He has been quarantining in the Florida Keys for the past week and we had to make a quick pit-stop on our way to our next site. After a short transit to move closer to shore, we were within range of a small boat delivering our chief scientist. As the director of and a professor at the Oregon Institute of Marine Biology (OIMB), Dr. Young was reconnected with his undergraduate and graduate students from his lab on board. His expertise on deep sea invertebrates has been eagerly awaited to assist in identification and developmental biology.
In the morning after a very wet and bumpy 7-mile transfer, Craig came aboard from a small orange boat to welcoming scientists and crew! After allowing Craig a chance to change into some dry clothes and gather his belongings, we held a science meeting to loop Craig in about life at sea. We summarized our shifts schedules, who’s in charge of various tasks and data organization, science plans, and how the cruise has been going for everyone, science and otherwise.
The rest of the day was transit, and while some of the science team rested, others indulged in their creative sides. After Sentry’s makeover with larval tape art, we decided Jason needed a new look too. The Jason team obliged and allowed us to decorate the front face and the bioboxes with designs of our choice. Again, we aimed for depictions of larvae where Fiona McBride took the lead and fabricated a tape gastropod veliger front and center.
Meet a Scientist on Board
Craig is a professor of biology at the University of Oregon and the director of Oregon Institute of Marine Biology, a marine laboratory on the rugged Oregon Coast. Craig began working on larval invertebrates in graduate school and has been obsessed with these babies ever since. Also, in graduate school, he was given the opportunity to make several submersible dives in a fjord in British Columbia. He discovered three new species of sea squirts (ascidians) on his first dive in 1980 and was hooked! Eventually, he found a way to combine his diverse interests by pioneering the field of deep-sea larval ecology and embryology in his lab on the east coast of Florida. Using eight different submersibles and six different ROV’s, his lab has investigated deep-sea reproductive processes throughout the world for more than 40 years. Craig was one of the scientists who initially recognized the usefulness of a precision larval collector devise that could operate near the sea floor. He worked as a science advisor to the WHOI engineers who designed and built the SyPRID sampler that we are using on this cruise.
On a personal level, Craig and his wife Robyn (married 45 years) live in a house in the forest with a cockatoo, an Indian ring-neck parrot, a lop-eared bunny and a badly behaved bernedoodle puppy. They have four children and three grandchildren. Craig also has more than 60 academic progeny (graduate students and postdocs) that include Shawn Arellano, our co-chief scientist.
With this departure we are entering the second leg of our cruise, shifting our focus onto the Gulf of Mexico sites. The first site is Florida Escarpment, our deepest site, at 3300 meters deep. With the shift in sites, comes some new, exciting species, like tubeworms and clams. Additionally, many of the graduate students’ projects are focusing within the Gulf, bringing new tasks and science to conduct. To summarize our Western Atlantic sites, here’s a video made by Avery Calhoun on last spring’s Alvin research cruise. This is from out last site, Blake Ridge, and highlights a lot of the work we do on the seafloor.
After two days of transit, rounding the Florida peninsula and coming out of the Atlantic, we arrived at the Florida Keys around 11:30 am. In studying larval dispersal between our Gulf of Mexico and western Atlantic sites, the presence of our target species in these water columns would solidify the possibility of larval transport between sites. This channel is the shallowest area the larvae would need to cross, being the ultimate hurdle in their journey between cold seeps.
The waves seemed to be just as excited as we were to be in the Keys. When we arrived, the weather was not cooperating, and the waves were high. We hesitated to deploy Sentry to conduct a SyPRID plankton tow and we attempted to wait out the weather to no avail. Instead we decided to pursue alternate methods and use a more typical plankton tow. Deployed at 200m deep, we retrieved it around 3pm and the scientists were ready to explore this exciting sample. How full of exciting larvae this sample was! We found many larvae types unseen the rest of the cruise including, plutei (sea urchins and brittle stars), asteroid and ophiuroid juveniles (small sea stars and brittle stars), brachiolaria (sea stars) and auricularia (sea cucumbers), cydippids (comb jellies), and a pilidium (nemerteans).
Ophiuroid juvenile
Brachiolaria
Pluteus
Meet a Scientist on Board
Hi Everyone,
My name is Mitchell Hebner. I am originally from Albuquerque, NM, and a first year Graduate student at Western Washington University. I am working with Shawn Arellano on a project involving vertical migration modeling of deep-sea snail larvae. I did my undergrad at the University of Oregon, and that is how I got involved in the SALT project.
During the last few terms of my undergrad, I volunteered in Craig Young’s lab at the Oregon Institute of Marine Biology, the University of Oregon’s satellite campus on the Oregon coast. It was here that I finally got some hands-on experience working with organisms in my preferred field of study – marine biology. Craig was gracious enough to allow some undergrads the chance to embark on a research cruise around the end of February to the middle of March 2020. I had just finished all my undergraduate classes in December 2019, and this opportunity to attend a research cruise was too great to decline, so I jumped at the chance to do deep-sea research out in the field. The cruise was aboard the R/V Atlantis and it was the experience of a lifetime.
The Atlantis was my personal maiden voyage into the realm of deep-sea biology, and the time I spent on board was wonderous. There was always work and things to do, but it really did not feel like work because it was so much fun. It was on this cruise too, that I met Shawn Arellano for the first time. She would end up becoming my advisor. The time spent on the Atlantis was laying the groundwork for my current experience aboard the R/V Thomas G. Thompson.
All of us, some old and new friends, have come full circle – one COVID pandemic later – we are back at sea on the R/V Thomas G. Thompson, picking up the sample collectors and things we left on the bottom of the ocean a little more than a year ago. The tube collectors and other things we set down at various cold seep sites in the Gulf of Mexico and Western Atlantic Ocean with the HOV Alvin submarine, are returning to the surface and the lab here on the Thompson with the help of ROV Jason. As part of the science party, I am processing and collecting samples for various projects including my own here on this cruise, and it feels good to be back out in the field doing science.
Conducting research at sea for a month inevitably overlaps with large milestones. It’s common that on research cruises there’s a birthday on board! We’ve had two birthdays on board so far, Matt the Jason pilot, and today one of our own, Carmen! Today she turned 22, with the science and ship crew helping to celebrate. Sorting larvae all day may not have been the ideal birthday party, but the cake our wonderful cooks made, and some decorations made it unforgettable.
“This was the most memorable birthday I’ve ever had. Everyone helped make it so special and I loved every moment. My favorite part was stargazing and watching bioluminescence with all the incredible friends I’ve made while at sea.”
Today is a full transit day with a day of catching up and enjoying the sun for our science crew. This is the perfect opportunity to take time to highlight one of the incredible vehicles we are using on board for science: Sentry.
Sentry is an Autonomous Underwater Vehicle (AUV) that’s a member of the Woods Hole Oceanographic Institute (WHOI) National Deep Submergence Facility (NDSF). Sentry first launched in 2006 and can dive as deep as 4,500 meters. This vehicle works completely independently once deployed from the vessel, following a predetermined mission, and consistently communicates with the Sentry team on board. We have attached the SyPRID (Sentry Precision Robotic Impellor-Driven) sampler that allows Sentry to control discrete plankton collections at target sites. These samplers funnel water, collecting larvae within a mesh net and consolidating at the end of the tube into a container for us to sort though, as we’ve talked about many times!
Sentry does not always work with SyPRID. Sentry is most commonly used for seafloor mapping and sonar projects all over the ocean. For example, Sentry has worked nearby to Washington, mapping seafloor features on the Juan de Fuca tectonic plate using its onboard multibeam sonar.
How Does Sentry Work?
As an AUV, Sentry is given a mission before each dive that contains lines of code telling Sentry where to go, what to expect, and a timeline for the dive. The expedition leader works with the science leads to create maps and plans for sampling. With four rotating fins each with a propeller, Sentry has a wide range of motion that allows it to traverse the deep sea. Throughout each dive, Sentry communicates with the vessel using an Ultra Short Base Line (USBL) system and a WHOI Micromodem for acoustic communication. Sentry sends acoustic messages (“squawks”) relaying data relating to position, velocities, charge, and error messages to a receiver, the USBL pole, that sticks through the ship from the deck to under the vessel (you can hear these squawks from the ship!). Sentry also has a camera on the underside with a strobe that takes pictures consistently throughout the dive, which are retrievable once recovered. Sentry follows a rectangular path back and forth, “mowing the lawn” around sample sites, and when ready to surface, follows a denser path to provide an accurate resurfacing location where the research vessel may retrieve it.
What Does the Sentry Team Do on Board?
Before deployment the Sentry team does a deck test – making sure all the fins and propellers are moving properly, the SyPRID collectors open and close, verify times are synched, acoustic communications are working. In addition, before deployment, the new mission is uploaded to Sentry, the navigation system is set up, weights are attached, and data from the last dive is extracted and cleared. Once checked, the Sentry team detaches all cords, pulls off covers, and makes sure Sentry is ready to be in the water. Then, with the ship’s crew, Sentry is hoisted off the deck with a crane, ropes and taglines, and expertly transferred into the ocean. During deployment, the Sentry team has 4-hour shifts watching and communicating with the AUV. During these shifts the watch listens to Sentry and notes positions and velocities regularly, while staying alert for error messages and ensuring systems are working properly. While Sentry drives itself, manual movements can be inputted including slight changes in positions, noting areas to avoid, or when to abort the missions and resurface. Once resurfaced the team helps recover Sentry on board, unload the SyPRID samplers, ensures Sentry is supported properly, and conducts another deck test.
How Are We Using Sentry?
On this cruise we have attached the SyPRID samplers that allow us to take plankton samples at different depths on and off-site. Sentry takes two samples per dive, one just above the bottom, and another at a predetermined depth. We conduct two Sentry deployments per site, one on-site and one off-site to compare larval compositions near our seep sites to a control. Sentry has been programmed to open one of the SyPRID samplers, “plankzookas” at each depth, which closes before moving to the next depth. This ensures we have an accurate sampling of only the target depth and site.
Meet the Crew
Top Row: Mike Skowronski, Amanda Sutherland, Joe Garcia. Bottom Row: Sean Kelley, Isaac Vandor
Mike Skowronski
Jack of all trades for Sentry, assisting with mechanics, software, electronics, or where necessary with the team. He studied optical physics and quantum mechanics at Concordia University in Montreal. Mike was an organic farmer before working at WHOI, where he has been an Alvin pilot, works occasionally with Sentry and Jason, and works various engineering jobs around the institute.
Amanda Sutherland
Mechanical engineer for Sentry, studied engineering with a concentration in robotics at Olin College of Engineering. Amanda interned with Bluefin Robotics in college where she worked with other AUVs. She joined the team in 2020 after growing up in Boston and being familiar with the marine robotic work of WHOI.
Joe Garcia
Software engineer for Sentry, studied engineering physics with a concentration in electrical and computer engineering at the University of Maine. Joe previously worked in private sector robotics and joined the team in 2020 after an interest in WHOI with Alvin’s assisted discovery of the Titanic.
Sean Kelley
Sentry program manager and expedition leader. In addition to leading the operations of Sentry for science missions, Sean also manages operations support, hiring, budgeting, engineering projects for upgrading Sentry, as well as teams of engineers. Sean studied electrical engineering at Wentworth Institute of Technology. After graduating Sean spent time working on electric light rail trains in Boston and joined WHOI during the Alvin overhaul in 05/06 and clocked in over 100 dives as an Alvin pilot. He joined the Sentry team in 2014 and took on his current role in 2019.
Isaac Vandor
Software engineer for Sentry, studied robotics at Olin College of Engineering where he focused on marine robotics projects. He interned with the Naval Undersea Warfare Center in Newport, RI, and joined Sentry right out of college in 2019.
We love Sentry and their team, not only for assisting with our scientific endeavors and being fantastic lab mates, but also for allowing us to personally interact with Sentry. Sentry usually adds characters to the sides of Sentry using electrical tape, and the team allowed us to get involved on this cruise! As the glorious SyPRID plankton collector is named after the barnacle cyprid larva, we decided to decorate Sentry with larvae! Flip through our process here and the finished product! Sean ended up making the cyprid, while our team created the pluteus, bathymodiolus, and pelagosphera depictions.
