Category: Lau Basin Vent Symbiosis

During our final transit back from our last site, Mata Tolu, we were able to reflect on the cruise as a whole and were impressed by numbers! This 50-day cruise boasted 35 million liters of water filtered from the McLane pump and Sentry’s SyPRID. Within that water we were able to identify over 2,000 larvae that belonged to 72 distinct morphotypes (similar form). While alternating Sentry and Jason dives at our 7 separate sites, each vehicle spent over 200 hours in the water! Jason allowed us to sample over 1,000 snails and opportunistically collect 51 lbs of ash from the recent volcanic eruption of the Hunga Tonga-Hunga Ha’apai volcano. During this time at sea we ended up traveling nearly 7,000 miles across the ocean, which is enough to earn each sailor a sparrow tattoo. During this long time we had many celebrations though, for holidays, birthdays, and even the captain’s promotion!

On the final days of this transit we finally had to organize and pack everything that we can brought out and collected over the past two months. We had samples in every fridge and freezer, at different temperatures and preservation types. We had to plan how we were going to get all of them back, shipping in acceptable quantities, scheduling pick-ups and dry-ice shippers. All our lab gear lay strewn about the ship, where we realized we probably should have been labeling everything each lab brought. I swear as we were packing up we had a lot more things than we came with, but we ended up getting our freight container fully packed! It’s kind of like Tetris, only the shapes are even worse with lab instruments, and if you pack it wrong things will break! Thankfully afterwards we only had a couple extra coolers that could easily be checked with our luggage on the way back. Most of the stuff we brought is staying on the ship until the ship reaches Newport, Oregon around May 20th. This way we don’t have to ship all the way from Hawaii… However, we packed up everything nicely so the team that’s meeting the ship will not have more work than necessary. (We really appreciate the OIMB lab members heading down there).

Alviniconcha boucheti

Our last creature showcase is of our third Alviniconcha species, Alviniconcha boucheti. Although not named after any other punk band members, it is named after Philippe Bouchet, a prominent deep-sea gastropod biologist. This snail has the most diversity in spine height, with an alternating pattern of long and short spines. This photo shows the varying lengths clearly. Fun fact is that these spines are not super hard, they actually feel closer to when you touch the hook end of VELCRO. Boucheti tend to dominate the more northern sites. We even found it at our West Mata site, Mata Tolu! All these snails host symbiotic bacteria that allow them to live at these hydrothermal vents. These bacteria are involved in chemosynthesis – using energy from chemical reactions to create food. Each snail species is typically associated with certain bacterial communities. When these snails acquire them, or why those communities, is another question we are hoping to answer with our results.

On this cruise we are particularly interested in finding the larvae of the Alviniconcha and Ifremeria sp. snails we are studying. This is not an easy thing to do. With the samples collected by Jason, Sentry’s SyPRID, and the McLane pump, our team of sorters pick through water, sediment, and snail bucket dregs searching for them. We work day and night. If any of our deployments come up at 2am, then we sort all morning. We plan accordingly though, taking naps, getting snacks, and playing music to keep us awake and focused. Here’s a photo of 9 different larval snails, gastropod veligers, we’ve found on this cruise that highlight the beauty and diversity of these organisms. The middle veliger has its “velum” out, a lobe covered in small hairs that it swims with. However, we are not confident on which species these veligers belong to. We’ve actually identified 23 different gastropod veligers so far! Unfortunately, we won’t be able to confirm their mysterious identities confidently until we do DNA sequencing on these individuals back on land.

As the next part of our creature feature, I’d like to show you the second of our three Alviniconcha species, Alviniconcha strummeri. This punk rock snail is named after a member of the punk rock band, the Clash, Joe Strummer. Named by: Shannon Johnson (punkrocksnails on Instagram/Twitter) A fitting name for these snails that have adapted to live in one of the most extreme habitats on the planet. This species is easily identifiable by the spines on its shell. This species only has long spines of the same length, while the other species have varying lengths. A. strummeri dominates the more southern of our sites along with A. kojimai from the last post. One interesting aspect about Alviniconcha is that under their periostracum (the outer layer of the shell), their shell is gold! You can see at the apex of this individual a little bit of it sticking out. However, we are only collecting these snails for the scientific wealth they hold. Here’s an article about them if you want to learn more: https://www.npr.org/2014/12/20/372052995/a-snail-so-hardcore-its-named-after-a-punk-rocker

I want to walk you through some of the sights we’ve seen so far. When we first arrived, the first thing we saw at our sites were not snails, but instead was what we presumed was ash! Since we are so close to the Hunga Tonga Hunga Ha’apai volcano, we are assuming that this could be from the recent eruption. We’re currently communicating with some geologists in Tonga and around the world to collect observations and samples. The depth has varied across and between sites, but at Kilo Moana one of the manipulator hands on Jason disappeared completely into the ash. The ash turned our rocky sites into snow-capped mountains. At first, we were worried that all vent animals were covered. As we further explored our sites, we found concealed refuges of resilient snails. Here’s a photo at ABE, our biggest site, of a group of chimneys covered in Ifremeria nautilei, Alviniconcha sp., and some vent crabs. One thing to notice is at the apex (the smallest whirl / point of the shell) of many of these snails it’s white where the shell has broken off. It’s tough living at the bottom of the ocean on rocky volcanoes!

This next photo takes us to another site, Tu’i Malila that was very mountainous. Throughout the dive we were surrounded by huge walls of basalt with diffuse, weak, flows of vent fluid. These pockets of hydrothermal energy were inhabited by groups of animals, like these Alviniconcha strummeri here. If you look closely towards the center of the image you can actually see the shimmering water that indicates these diffuse flows mixing with the seawater. This site had many patches like this, some snail patches surrounded by groups of Bathymodiolin mussels, creating a nest-like appearance. At this site we also found many creatures peering out from between the rocks like this curious little pink sea toad.

Alviniconcha kojimai

Keeping up with the pattern from the last post, I’d like to introduce another of our study species, Alviniconcha kojimai. This was one of the first of our Alviniconcha sp. that we found on this expedition. As I introduce the rest of the snails from this group, you’ll see they look very similar to each other. There are a few ways to differentiate them, I prefer to do it through the spines on their periostracum (the outer shell layer). On kojimai between each of the tall spikes there are three smaller spikes. They also have the reddest coloration on their snout and cephalic tentacles (those long protrusions). This species is found in our more southern sites, where the geology is more andesitic and hydrogen sulfide concentrations in the vent fluid decrease. Whether these changes are impacting their distribution is one of the questions we are exploring.

April 9th, 2022. It’s been a while, but we made it to the Lau Basin! It’s located just northwest of the Kingdom of Tonga, and near the Hunga-Tonga Hunga-Ha’apai volcano that erupted in February. Within this basin there are a series of hydrothermal vents (underwater volcanoes) along a north-south axis. We will be visiting 6 different sites across it, twice, once to deploy equipment, and a second to recover them.  Currently, we are at our third site. We started at Kilo Moana, a site where there’s no active venting, then we went to Tow Cam, and are now at Tahi Moana. One interesting feature of these sites is that there is a geological gradient transitioning from basaltic rock in the north to andesitic rock in the south. In the samples we’ve been sorting so far there’s been a lot of small pieces of basalt. This gradient has been linked to a gradient in vent fluid geochemistry as well, which we are curious to the impacts on our target snails’ bacterial symbionts.

AUV Sentry works independently of the ship with a pre-programmed course mapped out. As it travels it hovers at a set altitude and filters water through two “plankzookas”, collecting plankton and hopefully our target larvae. It communicates acoustically via “chirps” to a team on board, sending updates on location, vehicle status, and science equipment status. The team can send small messages back altering the mission, small changes to the course, control the science equipment, or even abort the mission.

The McLane pump is within a metal frame and pumps water at a rate of 30 liters per minute for 24 hours over a 60µm sieve. The pump has a weight stack with an acoustic release and a float pack overhead that allows us to deploy it over the side of the ship and release it off the seafloor without guiding it. Once the pump is on the seafloor, ROV Jason will move it next to a chimney to collect more larvae and is programmed to pump during Sentry’s dive. This pump so far has been most efficient at collecting live larvae, that we can try to raise and preserve on the ship.

ROV Jason is attached to the ship with a cable, where it can be controlled from a storage container (“van”) on board. Within this van, members of the science party can watch live footage from the vehicle. They can communicate with the Jason pilot, co-pilot, navigator, and data manager to collect samples, deploy instruments, explore sites, and take videos / pictures. Jason has two manipulator arms that are controlled by the pilot and can use a multitude of tools including scoops, temperature probes, a slurp, mussel pots, and the SuPR sampler. This allows us to collect adult and juvenile target species, deploy / recover other instruments, and sample water for free-living bacterial symbionts in the environment.

With the aid of all these instruments and vehicles, we’ve begun to explore our study sites, filled with excitement and anticipation. For many of us this is the first time really seeing hydrothermal vents, habitats many of us have dreamt of seeing since childhood. An unrivaled experience is driving up to a massive rock chimney jutting out of the seafloor, spewing hydrothermal fluid. Covered in sea stars, crabs, and snails. The sheer size of it towering over the ROV, understanding this fluid sustains unique ecosystems. After over an hour and a half descent to get to these 2600m deep sites also instills a sense of how remote and hard to reach these vents are. The vent fluid shimmers in the water, highlighting the hot temperatures and chemical richness spewing out. Even though we are still on the ship, within the van surrounded by screens with different cameras and vehicle information, it feels like we are in the ROV seeing these sights firsthand.

One amazing experience happened at 2am at our dive in Tow Cam. After we placed the McLane pump down, we realized we were within a ring of hydrothermal vents, surrounded by rocky peaks. We began to explore the surfaces up and down, searching for our target snails, and surveying the area. As we exited the center, we came face to face with a brilliant orange dumbo octopus. The van erupted into excited gasps and panic to get the cameras rolling. It was a rare sight to see, and one that will stick with all of us in the van forever.

Another cool creature came to us not during a dive, but during the recovery of Jason. When ascending, sometimes fish will get caught on the vehicle and during our Tahi Moana recovery, we accidentally snagged this majestic dragonfish. With an iridescent body and long pointy teeth, it’s certainly nothing like the fish we’ve seen before. We all gathered around to observe it, a deep fish that’s made it to the surface, in relatively good condition for a 2.5km pressure change (about 255 atmospheres!). Unfortunately, we are not here for fish and do not have a permit for keeping them, so we couldn’t hold on to it, and said our goodbyes.

Ifremaria nautilei

I want to end this post by highlighting one of the snail species we’re studying on this cruise, as we’ve been collecting a lot of them, and have been spent a lot of time on their processing. Ifremaria nautilei is a species of deep-sea provannid snail that can be found across all our active sites in this arc-basin, and even in other vent sites like the North Fiji Basin. Here are some headshots of some models collected from Tahi Moana. The bigger ones are about the size of a baseball! What makes these snails so interesting is their unique reproduction. Within their foot (the muscle they crawl around on) they have a brood pouch to raise the embryos. However, these embryos are transported along a ciliated groove (ciliated = moving hairs) into the pouch that expose them to the environment prior to development. They then develop into unique “Waren’s larva”, which have only recently been described. As all of our study snails at these sites have bacterial symbionts that allow them to survive on vent fluid, we are interested to explore when Ifremaria get their symbionts. Whether or not symbionts are acquired during this external movement of embryos to the brood pouch, or during their free-swimming larval stage is something to be explored. Little is known about the Waren’s larva as well, and we hope to learn more about them and potentially culture them on this cruise.

The science party participated in another sailing tradition, or ritual, when crossing over the Equator. To earn the shellback title, graduating from a pollywog, there’s typically a crossing event that takes place. These events can be fairly traumatic and are more like hazing events. Crew members being taken from their berthing rooms, food waste dumped on them, or physically abused. We did not do this, instead, we did a voluntary ceremony to be cleansed with “equator water”. No hazing here. We filled up a bucket for each scientist, with some members of the Jason and Sentry parties joining, lined up against the side of the ship, and baptized ourselves under King Neptune. As we dumped the water, we were welcomed across the boundary separating the North and the South, granting access to the Southern Hemisphere. After the ceremony we received certificates noting the time and place we crossed, 167 25.0 West on March 28^th, and our place of respect within the realm of Neptunus Rex. It was a bonding moment for the family of scientists, taking lots of photos and videos of the event. To the right is a lab group photo, it was all of our first times sailing across the Equator.

The day before, we crossed the International Date Line on March 27^th / March 28^th where we only changed our time, not the day. We went back one hour but we were supposed to move forward a day, instead deciding to keep the day the same to avoid mix-ups in our continuous tracking of days and events at sea. This caused some confusion among the science party, as now when we are connected to the internet all our messages and notifications are coming from the future, telling us we posted in 20 hours, or our messages from yesterday, are actually today. Some of us entered a philosophical state, joking about the human constructs of time, entering a state of temporal limbo. It was nice to get an extra hour of sleep though! Time at sea already feels so different, none of us can remember what day of the week it is, and soon when sampling starts it will only get more difficult to keep track of time. We will all be on different ROV Jason watches, 6 4-hour shifts for round the clock science as well as having separate responsibilities to be available for the different instruments. This will inevitably set us all on different sleeping schedules, and time will become meaningless to us. It doesn’t help that while we are all coordinating with “ship time”, the ROV Jason operates under UTC time. Today we’ll be finally reaching our first site, Kilo Moana. We’ve been split into our respective teams of dissecting and microscopy, to divide and conquer all the snails we will be collecting for this grant. Now all the instrumentation we brought will be put to the test and after 10 days of transit, we’re ready to start the science.

We crossed the gangway with all of our luggage to friendly crew members welcoming us on board. To some, the Thompson is an old friend, participating on another cruise just last May, but to many this was a new introduction. We made our way to the main lab where we began to familiarize ourselves with our new home. We learned where we would be sleeping, our berthing rooms, where we would eat, the galley, our meeting spot, the library, and other amenities on the ship including a small gym, the laundry room, and a movie lounge.

Once we were moved in, the first step was to set up the lab. Before heading to sea it’s important to ensure everything is tied down properly, avoiding any expensive crashes resulting from the rocking of the waves. We set down grippy shelf liner, drilled holes into the tables and secured equipment with rope, and ratchet strapped larger bins and technologies under tables and to the walls. We also set up our respective lab spaces for the different processing we’d be doing, and organized our equipment to avoid future headaches of digging through our various deep containers.

Now at sea, with such a long transit time to our study sites, it begs the question, what are our scientists up to? Here’s a list of what we’ve been doing to keep ourselves busy:

• Science meetings – informal presentations about the various project goals from the inter-institution science party.
• Writing proposals and preparing for post-cruise presentations.
• Setting up our equipment and running tests.
• Many board and card games including Rummikub, Ligretto, Egyptian Rat Screw, King’s Corner.
• Lab group photos.
• Movie nights – “Nausicaa of the Valley of the Wind”, “O Brother, Where Art Thou”, “The Goonies”, “Ghostbusters”.
• Stargazing out on the bow.
• Lifting weights and running on the treadmill in the gym (getting off a treadmill on a rocking boat is a very disorienting feeling).
• Curling up with a good book (I’m currently reading The Shining, maybe not the best book when being *voluntarily* trapped somewhere remote).
• Drawing analog and digital art.
• Journaling and reflecting on times in Hawaii and life at sea.
• Getting to know each other – sharing stories and comparing the different regions we’re from.
• German lessons from Livia.
• Texting and calling our friends and family (yes we have internet all the way out here!).
• Sunset watching.
• Searching for whales and watching flying fish off the boat. Apparently humpback whales are currently migrating to Alaska from Hawaii.
• An intense hula hooping contest (current record of 303.74 seconds held by Melissa Betters of Temple University).

We will be collecting many different types of samples, and we’ll go into depth about what all these will tell us later in the cruise blog. The focus of this cruise will be on two main groups of snails found at our sites; Alvinoconcha sp., and Ifremaria nautilei. Relying on symbiotic bacteria that feed off the vent fluid, their distributions follow patterns throughout our sites, and we want to find out why. To explore this question we will be dissecting adult snails to retrieve gill tissues, we will sort through plankton samples searching for larval and juvenile snails, and we will collect and filter water samples. Additionally, we will take lots of photos and videos of our sites and the organisms that inhabit them.

For many of us this is the longest cruise, or the first cruise we have been on. Spending a total of 51 days on the ocean, without stopping at any ports, we will put to the test our dedication to unraveling the mysteries of the deep-sea.

Before we head out on our expedition, with long nights and hard work, we’re enjoying the Hawaiian experience, much different than our home towns. Staying COVID conscious, and avoiding people, we are delving into the tropical natural world around us.

Many of us are spending time at the beach where we read, draw, swim, and tan (actually more like burn..) in the 82 °F sun. This tropical climate also allows us to experience all sorts of different flora and fauna, exciting for a group full of biologists and nature lovers. Hiking through forests of palm trees and large fronds, volcanic craters, along the coast with cerulean waters and sandy beaches, Oahu is full of fantastical habitats to explore.