They say all good things must come to an end, and sadly this cruise has an end as well. While we’ve all grown as a family spending a month at sea together, sharing discoveries and seeing awesome sights from the sea floor, it’s time to head home. It’s a bittersweet goodbye. The experiences out here are forever, but we have our lives to return to. It’s sad to leave behind the community of our expedition, but we will cross paths in the future at conferences, in collaborations, and potentially even future cruises. Once a few of us get into writing our own grants and leading our own laboratories, there will be an EPR reunion cruise!

There’s a lot to say about this cruise. I’ve covered the sample processing I was involved with and some sneak peaks of our what we’re finding, but I want to tell you all about the others things we got up to on our expedition (and also have an excuse to share more seafloor pictures).

On this cruise there were two main projects; one looking at the relationship between microbial biofilms and larval settlement at active vents, and another exploring life at inactive vents. This meant that we were able to see a lot of diverse habitats and involved in varied sampling efforts. Hydrothermal vent fields are so exciting as the precipitating vent fluid creates high relief structures: chimneys, chimlets, spires, etc., but also are surrounded by lava flows and pillow basalts. We were able to see diffuse flow, like the shimmering water in the Tica Riftia image, but also erupting black smokers in the surrounding areas. These sites act as oases in an otherwise food-limited deep-sea, teeming with life; whether giant Riftia tubeworms and mussels, or small gastropods and squat lobsters. Knowing that all these photos and videos are of these extreme habitats that typically exist in pitch-black darkness adds to the amazement of the life that survives here.

In addition to our settlement sandwich deployments I’ve talked about, we did many other sampling types throughout this cruise. We would take temperature measurements quite often, enhancing our understanding of gradients throughout the region, and how they change. In tandem with spot-specific and auto-collecting chemistry sensors from Nadine LeBris, these measurements allow us to understand the conditions these animals survive under, and discern any spatial or temporal patterns. We also used MAJOR samplers, and extracted small chimney pieces, to analyze the bacteria living within the super-hot vent fluid, and on the chimneys themselves. On the inactive side, we took rock collections to collect animals, and characterized rock types to understand their habitat better. If you’re interested in what we’ve found so far at inactive vents, check out this paper that came out of our last cruise: Chen et al. 2024.

If this cruise didn’t have enough excitement, we all on board probably got to witness the most insane display of human innovation and connection. A friend of the Chief Scientist Dr. Shawn Arellano (WWU), NASA astronaut Loral O’Hara, video called with the R/V Atlantis from the International Space Station. Loral used to be an Alvin technician and knew many of the ship’s crew. She wanted to connect while on her first deployment to space, and we even managed to get her connected to Susan Mills (WHOI) WHILE SHE WAS IN ALVIN ON THE SEAFLOOR. They were literally talking from space to the seafloor, 2500 meters below. How insane is that. As you can see from the picture on the right above, the entire science party was entranced by the meeting. As we asked Loral silly questions about sleeping and eating in space, she floated through the ISS and even showed us the view of where we were on our planet, from her viewport. A completely surreal experience overall.

As things winded down with our final sample processing and getting started on packing, we were also offered a tour of the ship’s depths. First, we were shown the control panels for all the machines and reservoirs on board that made this all possible. We could see how we get freshwater on board, where the thrusters are located, how waste and fuel are managed, and even the fire suppression systems. After donning our Atlantis™ ear plugs, we were then able to tour through the hot and loud engine room. With pipes running below, overhead and along at the walls, panels with buttons, emergency light displays, valves and levers, it was like stepping into another world. We saw the reverse-osmosis machines that convert saltwater into drinking water, the bilge pumps, the engines themselves, and many other machines. This 274-foot ship takes a lot to keep running for an entire expedition with no access to shore.

After a month at sea we did manage to make it back to land with our port in Golfito, Costa Rica. We hadn’t seen green (besides phytoplankton / bioluminescence) for a while, and this tropical biodiversity hotspot was quite the warm welcome. After celebrating and finishing our demobilization checklists, we were free from the ship. Some of us had to fly back immediately, some stayed a few days, while others decided to take a well-deserved vacation. Golfito was a beautiful place, with scarlet macaws overhead, iguanas and coatis running across the roads, and the tallest palm trees I’ve ever seen. Right next to the town is Golfo Dulce, a gulf between mainland Costa Rica and the Osa peninsula. Some of us were able to go diving during our short time there, seeing moral eels, sail boat shipwrecks, coral farms, and many schools of tropical fishes.

While this cruise was the end of the EPR Biofilms4Larvae project, the inactive sulfides project will continue to study this site. However the East Pacific Rise is due for an eruption any day now, so a lot of scientists are keeping their eyes out. If you’re interested in learning more about what we did on this cruise, check out Dr Arellano’s Larval Lab Blog that was ran by her current students, and look for upcoming papers about our discoveries!

I want to say a huge thank you to the entire science crew, and the R/V Atlantis crew for making this whole cruise possible. Without the round-the-clock operations by the engineers, oilers, mates, able-bodied workers, and cooks, we never would have survived. Thank you to the SSSGs for working with us to ensure we could effectively conduct our science and adjust to life at sea. Of course, thank you to the scientists on board who made all this possible, worked long hours, shared ideas, and supported each other. Thank you for following along! Keeping following our lab to see what we do next!

EPR Biofilms4Larvae project is a multi-institutional NSF grant: OCE-1948580 (Arellano), OCE-1947735 (Mullineaux), OCE-1948623 (Vetriani).

Also find us on Instagram @larvallab, #Biofilms4Larvae

The Inactive Sulfides project is a multi-institutional NSF grant: OCE-2152453 (Mullineaux & Beaulieu), OCE-2152422 (Sylvan & Achberger).

Also find us on Instagram @jasonsylvan, #LifeAfterVents

The Atlantis Sulfuric Sub Shop has opened for business!

After 4 dives of recovering our deployed settlement sandwiches, we processed them for 8 full days. We sat under the microscope scanning each sandwich plate, looking for any attached animals that had settled on them during the two weeks they’ve sat on the seafloor. Once that is done, we handed off the plates to Dr. Costa Vetriani’s group where they will analyze the microbes and conduct proteomic and metagenomic work on the bacterial communities. This will allow us to tease apart patterns between the animals and bacteria; if the bacteria are sending cues for animals to settle on these surfaces, emulating the natural processes at our vent sites.

In order to keep the plates preserved for microbial analysis, we had to sort all of our samples in a solution called RNA Later. This is essentially a super salty liquid, that crusts over everything, so we wore gloves the whole time. Throughout this week of sorting, all of our clothes, scopes, and utensils became encrusted in salt. I still don’t feel clean days later. We also had to be conscious of cross-contamination and being sterile between each sample, so we sterilized our equipment after each completed sandwich.

We had many candy breaks, played music, and told jokes to make the hours fly by. While it was tedious, we were seeing successional processes similar to the origins of these hydrothermal vent communities, which was awesome. Thankfully we also got some help from fellow scientists like Susan Mills (WHOI) to sort. In total we sorted 45 half sandwiches, and 16 full sandwiches, totaling 231 plates. We scanned each square, every groove and inside each gunk pile on both sides.

Sorting through the sandwiches we saw a lot of variation in the biofilms. We had sandwiches that had been deployed since the last cruise and a new set that we deployed at the beginning of this cruise. The ones deployed longer typically had thicker biofilms, some with white filamentous bacteria, some were completely clean, and a few had this strong orange color. This made the squares look like Cheez-Its. Combing through them felt like exploring the surface of a foreign planet. I think the last picture could be circulated with the title “Life on Mars??” and would fool a good amount of people.

Of course the goal for this process was to collect all the organisms that were attached to the sandwich and categorize them as settlers or colonists. Whether they had attached and grown as exploring larvae looking for cues, or potentially just exploring a new surface and grazing on the biofilms for food. We did see evidence of biofilm grazing, and attachment by adult mussels with byssal threads left behind. There were many animals which had made homes in the grooves of the plates: mostly polychaete worms and limpets. Amphisamytha galapagensis created mucus tubes covered in sediment that we would have to pick them out off, and other worms like the Serpullid worm Laminatubis alvini created calcareous tubes.

We also found many larval snails, known as veligers as they swim with a velum (a sail-like organ covered in cilia), on our sandwich plates. At this size they are very difficult to find during our sorting, and impossible to identify at the dissecting microscope. Seeing veligers is a good sign. These settlers will help us test our hypotheses by observing patterns of bacterial presence on the plates they’ve attached to and if they are preferentially attaching to sandwiches with older biofilms. We take pictures of each one we find, and preserve them for DNA analysis later, to find out what species they are.

We found plenty of other tiny things while sorting too. Some we knew, others we didn’t. Deep-sea research is time-consuming, and expensive, so we try to make the most of every sample we collect, or organism we find. It’s a highly opportunistic field, which is part of why I love this work, there’s always something new, and so many unanswered questions. Every unknown organism we take pictures of on the compound microscope, and bring it back to the lab where it can be analyze it later.

These are just some of the organisms we’ve found through our shipboard sorting, but there is much more sorting to be done back at the main lab. I will not be part of that process, but I’m hoping for many more larvae! In my next, and last post about this cruise, I will share some more pictures of the deep-sea, and what’s next for this project.

EPR Biofilms4Larvae project is a multi-institutional NSF grant: OCE-1948580 (Arellano), OCE-1947735 (Mullineaux), OCE-1948623 (Vetriani).

Also find us on Instagram @larvallab, #Biofilms4Larvae

The Inactive Sulfides project is a multi-institutional NSF grant: OCE-2152453 (Mullineaux & Beaulieu), OCE-2152422 (Sylvan & Achberger).

Also find us on Instagram @jasonsylvan, #LifeAfterVents

With our cruise-long experiments fully deployed, we had two weeks before they would be recovered, but there was still much to be done. We explored inactive vents, sorted larval collections from a high-volume pump, and dissected mussels for worms.

My favorite part was looking through the animal collections and “slurp” canisters for baby mussels and scaleworms with the bonus of all the beautiful macrofauna from our study site.

It all starts with the Alvin launch in the morning. Where a pilot and two scientists descend to the seafloor to conduct research and collect samples. A whole orchestra of engineers, led by the deck coordinator, roll out the submersible on its sled, preparing the machine for its journey. Sensors are checked, cameras attached, window covers removed, and weight stacks attached. The pilot is called first, then the observers. The hatch is sealed and the A-frame swings Alvin over and into the water.

We wait patiently on board, hoping for a successful dive as we usually have a lot of objectives to complete. Around dinner time the submersible returns, with the bucket brigade ready to jump into action. It’s important to keep the samples cold so the animals stay alive and in good condition. Surprisingly most of these animals are seemingly unaffected by the pressure difference, even though their home is 250 atmospheres of pressure deeper.

Once the sub rolls back into the hanger and is secured by the team, we are given the go ahead. Larger animals, slurp containers and rocks are transferred into buckets and transported to the cold room. Meanwhile the bucket brigade siphons out the remaining water, sieves it through a 100-um filter, and rinses the macrofauna into a container chilled on ice, before running that to the cold room too. After a quick bite, the sorting under the microscope begins.

Large worms and snails are taken out for Dr. Stephane Hourdez, who is running thermal tolerance experiments under pressure, while the Arellano Larval Lab sorts for baby Bathymodiolus thermophilus mussels. It’s a game of eye-spy. Only around half a millimeter in size, we must sort through all the fluff, in the shells of every limpet, and even the mussel mucus, to find them. These tiny, orange, round, bivalves are easily confused with reddish benthic copepods, ostracods, and baby limpets. Every time one is found, a cheer echoes around the microscope table. With these we hope to do some microbiome work, and FISH (Fluorescent In Situ Hybridization) to see what they’re eating and when they acquired their bacterial symbionts. These bacterial symbionts allow the adult mussels to survive the sulfide-rich hydrothermal vent fluids.

While we search for these there are plethora of other animals we come across which I want to share with you all.

Polychaeta (Worms)

First are the worms, or members of the class Polychaeta. These come in many forms, boasting iridescent colors by their layers of muscles and scales (elytra). Some, like Archinome rosacea and Hesiospina vestimentifera are grazers, scraping biofilms off the substrate, while others like the Lepidonotopodium scaleworms are predators with extendable jaws. Alvinella pompejana and Paralvinella grasslei live on the super-hot sulfide spires where the hydrothermal vent fluid erupts. While Paralvinella are deposit feeders, Alvinella are truly something special. They are some of the most thermally tolerant marine animals, living up to 50°C (or 122°F) and hosting symbiotic bacteria (those white filaments on their back). The final worm, Branchipolynoe symmytilida, are also unique. These are commensal worms that actually live inside of the Bathymodiolus thermophilus mussel. We’ve been finding quite a lot of them as one graduate student onboard, Mel Lemke (WWU), is dissecting mussels to study them. Whether they are parasitic or not is something she is exploring.

Gastropoda (Snails)

Next are the snails in the phylum Gastropoda. This phylum also encompasses the land snails you find eating the tomato plants in your garden. These are generally grazers and deposit feeders, although there are predatory snails as well, such as whelks, and deep-sea chemosymbiotic species like Alviniconcha sp. and Ifremeria nautilei. The Lepetodrilus limpet species are extremely common at our sites, clogging our sieves and covering our deployments, mussels, and tubeworm collections. While cute, they’ve turned into a nuisance when sorting samples. Many of our baby mussels have been found stuck to their feet, or wedged in the side of their shells. Pachydermia laevis is one of my favorite because it looks like a little macaroni pasta. You can see clearly the clear operculum that many snails have, which act as a door they close themselves inside their shells with. I don’t know much about Provanna snails, but they have the coolest shells, with pronounced sculpturing. Eulepetopsis vitrea is another favorite for their mirror-like shells. Made of lathic calcite, small sheets of calcium carbonate refract light to create a transparent shell, hence the name vitrea for vitreous.

Solenogastres and Ophiuroidea

Some other organisms I found were an aplacophoran in the class Solenogastres and a brittle star in the class Ophiuroidea. Aplacophorans are known for not having a shell, but what stands out to me is that they look like a piece of candy. Yes, that is the whole organism. I can’t decide between a Mike and Ike or a Sour Punch straw; either way I would probably eat a whole box in one sitting. These ophiuroids are also pretty common, with legs twisting all over the place, they can also make sorting into a detangling relay. I actually have a tattoo of a larval ophiuroid so I’m partial to them, but I think they are so alien and cool. This close of up its mouth looks like a snowflake.

Of course these pictures are not a full composition of the seafloor macrofauna at the East Pacific Rise, but these are the ones I found frequently, in good condition, and had time to take pictures of. I never thought I’d spend time combing the hairs of deep-sea polychaetes to remove gunk for their photoshoots, but here I am. I hope these pictures have shown you a glimpse of the amazing diversity in the deep-sea, even at just one site. Stay tuned to see what we find on our settlement experiments, hopefully larvae of many of these macrofauna.

EPR Biofilms4Larvae project is a multi-institutional NSF grant: OCE-1948580 (Arellano), OCE-1947735 (Mullineaux), OCE-1948623 (Vetriani).

Also find us on Instagram @larvallab, #Biofilms4Larvae

The Inactive Sulfides project is a multi-institutional NSF grant: OCE-2152453 (Mullineaux & Beaulieu), OCE-2152422 (Sylvan & Achberger).

Also find us on Instagram @jasonsylvan, #LifeAfterVents

On Thursday, January 18th, I was granted the opportunity to dive in the HOV Alvin to one of our study sites, Tica, 2500 meters below the surface (about 1.5 miles deep). I would be diving with one of the Principal Investigators (PI) of the project, Dr. Costa Vetriani from Rutgers University, and Alvin pilot Tony Tarantino. As the second dive of the cruise, I was excited to be one of the first to see how the area had changed since we were last here in December of 2022, and help set-up our cruise-long experiment. The first dive was completed by the chief scientist Dr. Shawn Arellano from WWU and Rutgers PhD student Matteo Selci, where they had seen a huge expansion of the animal communities at Tica. Hearing that, I couldn’t wait to get down there and see how it compares to the last time I dove there. Our goal for this dive, AL5217, was to deploy our sandwiches and tube traps in the Alvinellid and suspension zones of this site, and collect time-series sandwiches from the mussel and suspension zones.

We enter the sub, and moved to our respective sides. I go to the starboard (right) side, and Costa goes to the port (left) side, with Tony between us. The hatch is sealed, the pilot coordinates the launch procedure with his team, and we are lifted up by the a-frame. As we are slowly lowered into the water, the submersible rocks slightly and the view out our portholes transitions from the ship to the air to ocean blue. We disconnect from the ship, and the Alvin swimmers prepare us to dive. With the permission of the launch coordinator, the bridge of the ship, and our pilot, we begin our descent. The light blue tropical water turns a deeper blue, then a dark blue, until finally, it’s pitch black. The darkness is alive though. Small flickers of bioluminescent plankton and gelatinous animals pass by, signaling their presence to us. Hunched over the starboard porthole, I hope to get a glimpse of something bigger.

During this hour and a half descent we go over the dive plan: the order of operations, the data to collect, where our samples are being stored on the science basket, and the division of labor between the scientists. We familiarize the pilot with our confusing science terms of “sandwiches”, “pursewiches”, and “paired sandwiches”, and how we plan to recover them. Then, Costa and I get comfortable with the video systems, controlled by iPads, and entering data into Alvin’s logging system. Throughout the descent the pilot communicates with top lab, his team on the ship, relaying our depth; a reminder of how deep we are diving, further traveling away from the known and into the unknown.

The time seems to fly by as we quickly approach the seafloor. We drop a set of weights to slow our descent and watch as the bathyal depths appear into view. Reflective basalt rocks from a previous eruption stretch as far as I can see, with a few shrimp, reddish sea cucumbers with snout-like heads, and some sea squirts populating the rock. We pinpoint our location, find the heading to our target site, turn, and bobble eastward. We enter the axial spreading center, where Tica lies at it’s heart, and open up to an awesome sight.

An inundated jungle of Riftia tubeworms lay before us. Growing up to 9 feet long, they had created overlapping mounds, filled the valleys below, and stretched around the sub. With mussels around the base, eelpouts and squat lobsters swimming within, the site was teeming with life. The same general structures from our last visit were still visible but new patches of Riftia obscured the view of markers we had deployed or made sections less accessible. There also seemed to be an increase in other fauna, more anemones and Calyptogena clams. New diffuse flow in the basalt also hinted at the expansion of the site. Tica seemed to be thriving, it was beautiful.

We came here to do some science however, so we shifted into gear to find our past deployments, which could be a challenge. We had a sketched map from an Alvin pilot, Bruce Strickrott, which detailed our markers in relation to major landmarks of the region and our deployments. We also had coordinates and heading of the vehicle from last time, but the adventurer in me was excited to follow the treasure map in our hands. We were searching for marker “DKA 12”, in honor of the late Diana K. Adams, to identify our first station, the Alvinellid zone. These Alvinellid worms inhabit the hottest parts of the vent system, building tubes within the active sulfide rocks that precipitate out of the venting fluid. We had deployed our sandwiches at a small spire inside the valley, but we weren’t finding what we remembered. We triangulated our location from finding the “30” bucket-lid marker, and the “AT50-06” marker from our last cruise, but all that was below us was this huge sulfide spire that couldn’t have been the same one. Until we saw it, two bright yellow polypropylene loops that extended from our purse deployments near the base.

Not only had the Riftia in this area exploded in ground cover, but the sulfide spires had grown taller and wider, crafting larger chimneys expelling hydrothermal fluid. It was covered in Alvinella worms, their smaller red crowns dotting the white rock. We couldn’t believe how fast it had grown. We had deployed our purses at the top of the spire last year, it must have been at least a few meters taller. Our pilot Tony expertly lowered us down, careful of the life and rock faces we were sandwiched between. Out my starboard viewport, I saw the siphons of feeding Bathymodiolius thermophilus mussels, and the cute faces of Thermarces cerberus eelpouts, whom I’ve all named Rufus as they all look like little old men (or perhaps a subconscious reference to Kim Possible). Out Costa’s port viewport, the basalt rockface nearly pressed against the submersible. “Small movements” our pilot directed. We were perfectly positioned.

We worked quick. First, taking temperature measurements of our deployments, to capture the conditions our biofilms had formed under. We recovered and redeployed the sandwiches within the purses, and then deployed new paired sandwiches and tube traps close by. We took notes on their positions, and video recordings of the deployments and new spire, then inched our way out, to move to the next station.

We moved into the suspension zone, away from the high biomass and warm temperatures of these vent communities, to clear basalt mostly inhabited by scavenging crustaceans, white Serpulid worm tubes and other suspension feeders. This area had more ambient deep-sea temperatures, closer to 2°C.

This area was much easier to work in, with space to sit the sub down, and stretch the manipulator arms out. It looked the same as we had left it, and we located it immediately. We collected the time-series sandwiches into our “lunchbox” on the science basket, then opened our purses, and again deployed sandwiches and tube traps to set up our new experiment. We’ll be back to pick those up in about two weeks.

All this sandwich talk reminded us that we too needed to eat lunch. We opened our packed lunches – peanut butter & jelly, ham & cheese sandwiches, and a KitKat. Out the window I notice a small octopus,Vulcanoctopus hydrothermalis, slinking past the sub, observing us but keeping a safe distance. It was a reminder that we were the aliens visiting their habitat, typically cloaked in darkness, and were quite the presence.

After our short break, we had one more task, to recover our last time-series sandwiches in the mussel zone. We had seen the “AT50-06” marker earlier where these experiments were deployed last year, so we could quickly get back. As we reached the marker, the Riftia had made it a little trickier to get back, and the Alvinellid spire jutted from below. Nothing Tony couldn’t handle. He talked us through his thought process as he decided the best way to approach without disturbing the ecosystem. He pivoted the sub, with micro adjustments to the heading and depth, so he could reach around the mound with a long-hooked tool and scoop up the sandwiches by their looped handles. In this moment I imagined Alvin pilots must be incredibly good at the arcade crane games I can never seem to win. We loaded the sandwiches, which were covered in anemones and animals, again into the lunchbox and had completed our objectives for the dive. We backed out, as a swarm of amphipods swirled above, with tubeworms passing out port holes, and began to explore with the little time we had left.

We soared over the ever-growing sulfide spires, along walls of more Riftia, and appreciated the complexity of the trough we were just within. Before we knew it, it was time to return to the surface, back to where humans are supposed to be. We moved away from the main site, communicated with top lab to commence our journey, and dropped our weights to begin our ascent.

After reminiscing on past expeditions and old friends between Costa and Tony, we began to see the bright blue waters of the shallows. I don’t feel anxious being so deep in the ocean, but the light is comforting and familiar. We were welcomed by some decent waves, though. As the sub heats up in the tropical water, coupled with being in a lower-oxygen sphere and rocking in every direction, I was starting to feel a little seasick. Tony hands me a plastic bag “just in case”, which I tuck under my clipboard as I try and focus my body and mind. After about 20 minutes, the hands of the a-frame pull us in and set us gingerly on the deck. We’ve returned. The hatch above is opened, along with a pressure difference that pop our ears, and we are able to climb out. Welcoming us is our science team aboard the R/V Atlantis, cheering and eagerly awaiting our report of how the dive went.

Underwater photographs belong to Shawn Arellano, Chief scientist, Western Washington University; Alvin Operations Group; National Science Foundation; © Woods Hole Oceanographic Institute.

EPR Biofilms4Larvae project is a multi-institutional NSF grant: OCE-1948580 (Arellano), OCE-1947735 (Mullineaux), OCE-1948623 (Vetriani).

Also find us on Instagram @larvallab, #Biofilms4Larvae

The Inactive Sulfides project is a multi-institutional NSF grant: OCE-2152453 (Mullineaux & Beaulieu), OCE-2152422 (Sylvan & Achberger).

Also find us on Instagram @jasonsylvan, #LifeAfterVents

Hello! My name is Dexter Davis and I’m a new master’s student in the Cold Dark Benthos Lab at OSU. While I’ve just completed my first quarter at OSU, I’ve been invited to join a research expedition to the 9°N East Pacific Rise (EPR) hydrothermal vent field with my previous advisor and friend of Dr. Thurber, Dr. Shawn Arellano with Western Washington University. I could not pass up on this opportunity and I want to highlight the work we’ll be doing as we study the deep sea.

We will be traveling aboard the R/V Atlantis (find our current location by clicking here) from January 11th to February 12th along with scientists from the Centre National de la Recherche Scientifique (CNRS), Rutgers University, Sorbonne University, Texas A&M University (TAMU), University of Naples, and Woods Hole Oceanographic Institute (WHOI). The goal of this project is to explore the relationship between microbial biofilms and potential cues for settling invertebrate larvae at hydrothermal vents.

Shawn Arellano, Chief scientist, Western Washington University; Alvin Operations Group; National Science Foundation; © Woods Hole Oceanographic Institute.

This is the last cruise of this project, with the last expedition occurring in December of 2022. Here are a few pictures taken with WHOI Dan Fornari’s MISO Cameras on the last cruise, showing the high biomass and biodiversity at our study sites. The nature of hydrothermal vents are ephemeral however, with the potential for eruptions or redirected flow to alter the site. As we travel on our 5-day transit from San Diego to the EPR, we do not know what the region will look like until our first dive.

During our transit there are plenty of activities to keep us occupied. We have many deployments to assemble that will collect larvae and settlers from the seafloor. Above on the left we are assembling tube traps that will be filled with formalin and accumulate passing larvae to measure the larval supply in the area. On the right we are assembling “sandwiches” and attaching “sliders” that will be deployed at the start of the cruise. These will be paired with sandwiches in mesh bags that have been on the seafloor since the last cruise, to develop older biofilms, and be colonized by larvae and settlers. These sandwiches will then be retrieved after two weeks and any attached animals will be sorted and imaged.

Part of being on a ship also means learning the safety protocols, emergency procedures, and how to interact with the instrumentation we will be using. Practice fire and abandon ship drills, alternate exits from berthing spaces, and wearing survival suits made us feel prepared for any emergency.

Additionally, on board this ship is the HOV Alvin, a deep-sea submersible that can take 1 pilot and 2 scientists to the seafloor per dive. We were introduced to the external and internal structure of the submersible including cameras, manipulator arms, the science basket, viewports, thrusters, safety and weight systems. Then we were given a walkthrough of how to access the multitude of data collected on each dive, including videos, temperature, dive tracks, timestamps, depth, among many other types. Each dive exports terabytes of data that we will can use during and after the cruise for our analyses, outreach and records.

Tomorrow we begin our first Alvin dive, an engineering dive, and then the science begins! With 20 dives planned for this cruise, there are many chances for every scientist on board to get the opportunity to experience the deep-sea first-hand. Stay tuned to see what we find, life at sea, and to learn more about these unique habitats we are studying.

EPR Biofilms4Larvae project is a multi-institutional NSF grant: OCE-1948580 (Arellano), OCE-1947735 (Mullineaux), OCE-1948623 (Vetriani).

Also find us on Instagram @larvallab, #Biofilms4Larvae

The Inactive Sulfides project is a multi-institutional NSF grant: OCE-2152453 (Mullineaux & Beaulieu), OCE-2152422 (Sylvan & Achberger).

Also find us on Instagram @jasonsylvan, #LifeAfterVents

I have been so glad to share my experiences with you in Antarctica and show imagery of the bizarre and incredible life under the ice. To show you this strange world, the first — and perhaps most crucial step — is finding a way under the Antarctic ice sheet. This requires a dive hole.

While a dive hole generally carries the same definition in Antarctica, the methods of making one vary widely. I have experienced two during my time here.

The first dive hole that I participated in making was an impressive feat of a large team of people with a range of specialties. This included heavy machine operators, carpenters, a sea ice profiler, divers, and scientists all working together to place a hole in the right spot and in the most efficient way possible. During this task, the biggest problem we had to overcome was moving large equipment over a crack in the sea ice, taking a number of ice thickness profiles to ensure the safety of everyone involved.

Once we found thick ice that could be driven over, the rest was relatively quick. The location of the hole was determined by GPS coordinates along with local expertise by Andrew and the Divers, and the machine operators drilled a hole in the sea ice that was 4 feet across and about 8 feet deep in less than 10 minutes.

The carpenters then towed a dive hut on top of the hole, and voila! We had a dive site and a great deal of gratitude.

The second dive hole I participated in making took place in New Harbor, a remote field camp on the edge of Antarctica’s Dry Valleys. Both ourselves and our equipment were dropped off by helicopters.

In this scenario, we were more resource-limited and therefore required more physical labor, time, and patience. This hole began with a jiffy drill — a large drill used to drill through ice to make fishing holes. Using the Jiffy drill, we drilled around 20 times through the first 3 feet of ice, making a large start. We then connected flights to the drill, or ~3-foot extensions to the drill bit, until we hit the water.

After hitting the water, we placed a continuously heated element down the jiffy drill hole for about 20 hours, and waited for the ice to melt into a divable hole!

For every dive hole, so much expertise and support is required from McMurdo station. I couldn’t be more thankful to all the people who made our work possible. Their work made our entry to the other world beneath the Antarctic ice possible.

I have three leggy locals to introduce you to today:

Dr Amy Moran finds a crinoid!

1) Crinoid Promachocrinus kerguelensis

This crinoid is found throughout Antarctica from 10 to 2100 meters depth! It has 20 arms, each of which is edged with feathery pinnules which contain sensory and reproductive organs. Promachocrinus uses its arms to trap drifting plankton. The arms have grooves down the middle along which trapped food particles travel towards the upwards-facing mouth. It changes its feeding posture/shape depending on the ocean currents to maximize the amount of food it captures! Underneath the arms, it has legs (cirri) which it uses to walk along the seafloor and cling to objects.

2) Scale worm Eulagisca gigantea

This might be the coolest animal I found this year! I was just blown away with how big this animal was! This GIANT worm has been observed in Antarctica at depths between 30 to 920 meters. It grows up to 22 cm long and 10cm wide! The eversible proboscis mouthpart bears a pair of extra large jaws and is about a quarter of the length of the whole worm! Translation: I wouldn’t want to pick a fight with this critter!

3) Sea Spider Colossendeis megalonyx

Found throughout Antarctica at depths from 3 to 4900 m. They are often 20 to 30 cm in diameter! They feed on soft corals, small hydroids, sponges, and pelagic invertebrates, including the gastropod Clione antarctica, jellyfish, and ctenophores. Later in the dive, I found another one feeding on something gelatinous (as shown in the photo below). The giant Antarctic sea spiders might be my favourite animal here!

1. Odontaster validus

This species of sea star lives throughout Antarctica at depths up to 915 meters! It grows to be about 7cm in diameter and takes ~9 years to reach the population average weight of 30g. It is estimated to live for up to 100 years! This sea star is near the top of the food chain in the Antarctic seafloor ecosystems and is a voracious predator akin to the lions of the Serengeti! It eats many things including, but not limited to detritus, small crustaceans, other sea star species, scallops, bryozoans, sponges, sea urchins, and worms.

2. Acondontaster conspicuous

This species of sea star lives throughout Antarctica at depths up to 760 meters! It grows to be about 14cm in diameter. This species eats many species of sponges. They often aggregate and gang up on a single sponge, eventually killing it. The previous red species of sea star (Odontaster validus) gang up to feed on the Acodontaster species (as shown below in Norbert Wu’s photo), and by doing so keep the population in check. Otherwise, this yellow species would get out of control and decimate the sponge populations.

3. Diplasterias brucei

The yellow sea star Diplasterias bruceii lives throughout Antarctica at depths up to 752m and grows to be about 24 cm in diameter. This is a specialized predator of molluscs including bivalves and gastropods.

Also in the image above:

• The featherduster worm (AKA: a sabellid polychaete worm) belongs to the genus Perkinsiana. It is found throughout Antarctica at depths ranging from 3 to 800m. It grows up to 20 cm long. It possesses a crown of feeding appendages (radioles) and uses these to filter seawater for food. They can be tricky to photograph because if you get too close or spook them, they retract their radioles down inside their protective tube which is made of calcium carbonate.
• The proboscis worm Parborlasia corrugatus lives throughout Antarctica at depths up to 3590m and grows to lengths of one to two meters, a diameter of two centimeters, and weighs up to 100g! Parborlasia corrugatus is a scavenger and a predator with a voracious appetite, and will eat almost anything; its diet includes sponges, jellyfish, diatoms, seastars, anemones, polychaete worms, molluscs, crustaceans, and fish. It can detect food at a distance with an efficient chemotactic sense. It has a large mouth and can consume prey almost as large as itself! Finally, they produce a lot of slime

Everywhere around here the landscapes are astounding. It is unique to have underwater landscapes where you can see far in the distance. Above you can see Rowan filming the seafloor near Rob and Amy doing some oxygen measurements. The distance is deceiving in many ways. They are strangely close to me but seem far away (and my dive buddies were Jacob and Steve who are just out of the frame to my left and right).

Even the surface of the ice is surreal. You can see my bubbles but the rest of the features are just how it looks.

But it really doesn’t stop at the ice surface. All of the views are as grand as one can get. Its inspiring to be surrounded by ice and stone on a scale that defies imagination.

So far this season, we have shown you some of the incredible fauna present under the ice in Antarctica. A lot of animals in Antarctica are significantly larger than their global counterparts because of the extremely high oxygen content in the cold waters here. Although the large fauna is incredibly unique and endlessly photogenic, I spent the last week capturing images of the smaller under-sea animals to show you how amazing the little things in Antarctica are as well.

To capture images of the smaller animals in McMurdo, I used macro photography, which uses a magnified lens to show very small living organisms. As someone who studies microbiology, I appreciate any chance to show small, yet incredibly important life. Although not microbes, these creatures are fascinating and beautiful.

An anemone of the Clavularia genus. These anemones are an average of 8 mm tall, and were probably around that size in this picture. Antarctica has an abundance of anemones, including Edwardsia beds at our very own Cinder Cones Seep! 

A sabellid polychaete, or feather duster worm (yes, it’s a worm!) filter feeding with its feathery radioles. The radioles of a feather duster worm have combs that pick up food from the environment. Sabellids are tubeworms, using the substrate from the environment to encase itself.

Likely an isopod from the Arcturid genus. Arcturid isopods are commonly found on sponges of the Homaxonella genus, which is exactly what you’re seeing here! They perch and filter feed on detritus passing by.  

A little sea spider hiding in the crook of an anchor ice bed. This sea spider was small, but sea spiders in Antarctica can be bigger than a dinner plate!