Category: EPR Biofilms 4 Larvae

Deep-sea reflections

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By Tanika Ladd

As this cruise and this project are coming to an end, I have been reflecting on what a journey it has been. Three years ago, I had almost no idea what it took to visit and study the deep sea. Now, at the end of almost 30 days at sea, it is routine to wake up and watch Alvin launch. When we are surrounded by all the scientists and Alvin pilots observing first-hand the thriving ecosystems living 2500 m below us, it is important to remind ourselves how extraordinary this all is. Diving in Alvin is one of the most amazing experiences of my life. Like my co-observer, Davide, said during our dive together – landing on the seafloor is an otherworldly experience. The rock features and the unique animal communities found down there in complete darkness are lit up just for us.

pillow basalt
Biovent chimney

Images taken from Alvin during this cruise (AT50-20). Shawn Arellano, Chief Scientist, WWU; Alvin Operations Group; National Science Foundation; @Woods Hole Oceanographic Institution

But we are not just tourists exploring these spectacular places – we have so much work to do during our precious time on the bottom of the ocean. For the science team, planning each dive has taken months of thought and prep. We need to make sure we have the correct tools and sampling boxes to do the work and enough space on the Alvin “basket” (the platform on the front of Alvin that carries all the science gear) for all the deployments and recoveries. In the images below, you can see the many different types of tubes and boxes that we fill with sampling and experimental devices, each with their own purpose, and that we ask the Alvin team to squish onto the basket for us. The “lunchbox” in the middle image is specifically designed for picking up colonization sandwiches and it has 8 separate inserts that allow us to keep them separated during recovery. In the days leading up to dives, the scientists work with the Alvin team to make sure our plan can be executed and that the weather will allow us to dive.

Images of science gear on the basket and a basket diagram that is sent with the divers to record sample collected. AT50-20 Shawn Arellano, Chief Scientist, WWU; Alvin Operations Group; National Science Foundation; @Woods Hole Oceanographic Institution. Photos by Tanika Ladd

Everything that happens during a dive is the responsibility of the 3 people in the sub (usually two scientists and one Alvin pilot), so we definitely do our homework the night before. The Alvin pilots are impressive (they go through some difficult training!) and they can use the Alvin manipulators (or arms) to do some careful and precise work, like picking up mussels or placing all our experimental deployments. For this project, we are asking a lot of the Alvin team and pilots because we have SO MANY things to deploy and recover. In the sub, while the pilot is driving and using the manipulators, the scientists are busy directing the science and taking video and notes of all the work. Doing an experiment at the bottom of the ocean where you need a large submersible with big metal arms to place a bunch of small colonization surfaces and tube traps in precise locations near some really hot hydrothermal fluids is no easy task.

Image of Alvin pilot Tony Tarantino, Tanika Ladd, and Davide Corso during their dive. AT50-20 Shawn Arellano, Chief Scientist, WWU; Alvin Operations Group; National Science Foundation; @Woods Hole Oceanographic Institution. Photo by Tony Tarantino

BUT we did it! Over the course of 3 cruises, we have deployed/recovered a total of 51 tube traps and 140 colonization “sandwiches”. The experiments may seem chaotic while they are happening, but we have gotten some really cool data from some of our first attempts at trying out these experiments! There are still so many samples we have to sift through (literally on a microscope sifting through tiny rocks and animal goo to pull out larvae), but all our hard work, with so much help from the captain and crew of the R/V Atlantis and the Alvin team, has made this cruise and the project a success. I can’t help but come home from an exhausting and non-stop 30-day cruise feeling exhilarated. I don’t think my words can fully describe how this ending feels but I just want to say that I love being a deep-sea researcher and I hope that I can keep exploring, learning, and spending my time surrounded by the ocean.

Image of the R/V Atlantis and Alvin during a dive recovery (left) and and image of a sunset (right). AT50-20 Shawn Arellano, Chief Scientist, WWU; Alvin Operations Group; National Science Foundation; @Woods Hole Oceanographic Institution. Photos by Tanika Ladd

Tanika Ladd is a postdoctoral researcher working at Shannon Point Marine Center (Western Washington University). Her time working with Shawn Arellano has converted her to the dark side (of the ocean, that is) after spending a lot of time thinking about the sunlit ocean. Her research interests include understanding interactions between microbes and animals and how energy and carbon flow through ecosystems, from primary producers to higher trophic levels.

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

Digo’s Nautical Adventures

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By Digo Zúñiga

Our collaborators, the Mullineaux lab group, conducted a HiPPO larval behavior experiment onboard. Released from COVID prison at the beginning of the cruise and no longer on COVID parole, Mullineaux Research Assistant Digo Zúñiga writes:

“No, we are not referring to the terrestrial mammal. Fun fact though (!): the closest living relative to deep sea diving whales isn’t the manatee or the seal, it’s actually the hippopotamus. For our purposes though, HiPPO stands for ‘High Pressure Plankton Observatory’. It’s a pressure chamber that allows us to observe larvae from the deep sea onboard the ship in pressures they naturally live in. Like COVID jail, it’s small and constrained, but unlike COVID jail it keeps deep sea larvae alive and happy long enough for us to record their behavior with a high-speed video camera. How the larvae swim in our HiPPO chamber tells us a little about how they can undergo long journeys to find different hydrothermal vent homes in a dark and vast ocean– currently a mystery to deep sea biologists. In other words, the HiPPO chamber is the closest us land creatures can get to watch deep sea baby animals in their natural habitat.

Digo and Dr. Lauren Mullineaux with the HiPPO. “The larvae go here.”
Copepods and polychaete explore the HiPPO chamber under pressure (3650 psi).

For those curious about what COVID quarantine is like on a research vessel, for me: it was not the worst thing imaginable. Luckily I got the booster vaccine a couple of weeks ago, and my case was pretty mild. The isolation was really the worst of it and each con had its corresponding pro. Though I got stuck in a windowless room for a week, I had it all to myself and didn’t have to share my bathroom with anyone (a rare premium on boats). I didn’t get to socialize with anyone during lunch, but I got room service for every delicious meal. And although I had to find what little energy my body could muster to get the occasional breath of fresh air, the view on the deck was a spectacular one– nothing beats that salty ocean breeze. I’m proud to say that the strict adherence to protocol was all worth it, and that nobody else got sick. I’d argue that the best way to experience COVID (other than to not get it at all), is in the middle of the Pacific with a great group of well-spirited, considerate fellow sea lovers.

Signed – Digo

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

You are connected to the seabed right now

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By Rose Jones, WHOI

Most people, if they thing about the seafloor at all, think about it rather like another planet; a distant, hostile place full of strange creatures. The seabed can be these things, which is why we need a ship and vehicles like Alvin to get to them.

However, the seabed is increasingly seen as a vast source of untapped resources in our resource-hungry era. You are holding some of those resources right now, in the rare metals in your electronics and rechargeable batteries. You have a stake in the future of the seabed.

Image of Alvin working from a lander, Cruise AT42-21 (2019). Jason Sylvan, Chief Scientist, Texas A&M; Alvin Operations Group; National Science Foundation; @Woods Hole Oceanographic Institution

Humans have always had an economic relationship with the sea, from early humans hunting for food through to its use as trade highways and as a source of gas and oil. Whether this is a good thing or not depends on what side of the often-competitive nature of that particular use your personal history falls. Now, technology like ROV’s are putting the seabed within reach of more than just those of us lucky enough to study and participate in it.

Alvin recovery at sunset, AT50-20. Shawn Arellano, Chief Scientist, Western Washington University; Alvin Operations Group; National Science Foundation; @Woods Hole Oceanographic Institution. Photo by Rose Jones

A controversial new use is deep sea mining. Our need for rare metals like cobalt and lithium for your rechargeable batteries is outstripping Earth’s supply. Equally, the way these metals are mined on land can be controversial and cause pollution. Some industries are considering mining the vast, untapped ores on the seabed to avoid the issues associated with land mining. Currently manganese nodules (fields of potato sized lumps of ore formed in some seabed areas) are the primary focus but mining inactive hydrothermal vent deposits is under consideration too. East Pacific Rise won’t be one of the sites mined but other sites like it might be.

Inactive hydrothermal vent chimney sample, AT50-20. Photo by Rose Jones

There are many arguments for and against mining the seafloor, from the debatable renewability of seabed resources to speculation on the extent of pollution and disruption to potentially unique ecosystems, and risking causing the extinction of valuable sources of new bio-technologies. DNA technology and all the medical advances that rely on it being a prime example, as one of the keys to DNA extraction is an enzyme from a hydrothermal vent microbe.

The main problem though, is that much of what we’re basing arguments on is merely speculation. We have at least four thousand years of experience with how land mining can change and damage an ecosystem and humans. However, we have barely any of the data we would need to make informed, evidence-based decisions on how to mine seabed resources. Most sites are barely explored, yet alone understood. We can’t yet even say if mining the sea would create the same disruption it does on land. Although, the laws of chemistry and physics are universal, so there is a reasonable chance that some of the same impacts are very possible. More information on these sites and how they react to disturbance is greatly needed.

We need to understand these places better before we make the decision on whether to go ahead with mining or not. We’re risking destroying so much before we ever knew it was there.

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

A ship-based jacuzzi for deep-sea invertebrates

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By Stephane Hourdez

All species on Earth are affected by the temperature they encounter in their environment. Ectotherms are especially sensitive to temperature variations as their internal temperature follows that of their environment. As a result, these species’ distribution correlates with latitude on land and in coastal marine environments (e.g. temperate species will not occur in polar or equatorial regions). In the deep-sea, temperatures are much more homogenous, cold, and should not significantly affect species distributions. Deep-sea hydrothermal vents, however, are a notable exception. There, the hot hydrothermal fluid (up to 400˚C) exits the seafloor in focused areas and mixes with the deep-sea, very cold (2-3˚C), water. Depending on the proportion of hydrothermal fluid mixed with the seawater, the whole range of temperature is possible. If some microorganisms can grow at up to 113˚C, metazoans cannot withstand temperatures much higher than 50˚C. Over very short distances, species can experience sharp temperature variations. Other conditions (pH, oxygen concentration) near hydrothermal vents can also be very challenging and affect species distribution. Our observations have shown that there are distinct species assemblages and that their thermal environment is different. What is the role of temperature in the distribution of these species? Are other conditions important as well or is temperature the only driver?

During this cruise, we carried out experiments on a diversity of invertebrate species to determine their tolerance to temperature. We are working with deep-sea species and most would not survive at atmospheric pressure. We therefore need to reproduce the pressure to which they are exposed in situ (250 times the atmospheric pressure at 2500 m). The animals are placed into a pressure vessel (photo) through which sea-water flows to minimize oxygen depletion. We start the experiments at the temperature of the surrounding deep-sea and raise it by 1 ˚C every 10 minutes. The top window allows us to observe the animals and determine when they can no long withstand the conditions. Some species will die at 10˚C while others can withstand at least 20˚C more. These tolerances reflect values for short term tolerances, long term tolerances are roughly 8˚C lower.

Figure legend: Scaleworms (annelids of the family Polynoidae) from the Tica vent site on the East Pacific Rise in a pressure vessel at 250 times the atmospheric pressure.

Overall, the tolerances we measured correlate well with the in situ measurements made near the assemblages where their usually live. Some species, however, have higher tolerances than expected. This could mean that we have not properly documented their natural environment or that other parameters affect these species’ distribution.

Stephane Hourdez is a marine biologist working as a researcher at CNRS (Centre National pour la Recherche Scientifique) in France. He works on the evolution of adaptations to hypoxia (low oxygen concentrations) and variable temperature.

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

Progress on our Polynoid Pilgrimage

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By Jack Gates

This week, the larval lab set out on the final research cruise for our EPR Biofilms 4 Larvae project! We are en route to the East Pacific Rise where the hydrothermal vents lie. While our field experiments on the relationship of microbial biofilms to larval settlement continue, masters student Mel will also be investigating a deep-sea polynoid worm, Branchipolynoe.

A summary of our work for those new to the blog:

Being dotted sometimes miles apart, locating hydrothermal vents on the vast seafloor is a big feat for a small larva. The Biofilms 4 Larvae project aims to understand the role microbial biofilms might play in helping these larvae find a place to settle. Chemosynthetic microbes are characteristic of hydrothermal vents; while plants and algae at the surface create energy from sunlight to support our ecosystems, microbes at hydrothermal vents use the mineral-rich water erupting from vents to create energy through chemical reactions. With these microbes at the heart of hydrothermal vent communities, they could be a cue for the larvae of vent species to settle. The larval lab is investigating how larval settlement is impacted by the presence of microbial biofilms.
(Sunset photo by Mel Lemke)

Our days-long transit gives us time to prepare for our experiments. Rocking back and forth with the waves in the R/V Atlantis’ main science lab, we have been busy constructing tools, measuring preservative chemicals, and reviewing dive plans. This work involves building ‘sandwiches,’ stacks of square polycarbonate plates. See Mel modelling a completed sandwich to the left.

These will be deployed on the seafloor for larvae to settle upon. Sandwiches deployed last year are waiting for us on the seafloor—these are contained in mesh ‘purses’ that keep larvae from entering but allow microbial biofilms to grow. Using the submersible Alvin, we will remove these purses and deploy microbe-less sandwiches, so we can see how larvae settle on biofilms versus on bare surfaces.


We are also building tube traps: upright cylinders that preserve any small critters descending toward the seafloor. These give us an idea of how many larvae in the water column are going toward the benthos to settle. When we arrive on site, Alvin will descend to thousands of meters depth to deploy these, alongside our sandwiches, amidst the hydrothermal vents.

Left: Laura screws the weighted base on to a tube trap. Right: (from left to right) Tanika, Dexter, and Laura build sandwiches.


Alvin will also be collecting samples. Mel is hoping to bring up Polynoids (also known as scaleworms) living inside of deep-sea mussels to investigate their ecology. In addition to studying the adults, we have a worm nursery on board for raising Polynoid larvae. Pressure vessels called HiPPOs allow larvae to be raised in the high-pressure environment they are accustomed to in the deep sea. By observing these little worms, we can better understand their development.

Temperatures are rising as we draw farther south, as is excitement as we near our first dive. We are joined by flying fish, a flock of boobies, and the occasional dolphin, each skimming the surface of the ocean. Soon, we will get to see what lies far beneath. The larval lab is excited to share the rest of our voyage with you!

Jack

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About me: I’m Jack. I’m a WWU student working in the larval lab as an REU intern. As a fan
of creatures and the ocean, I’m excited to share my experience on a deep-sea
research cruise!

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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

Leaving Land Behind

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By Mel Lemke

This week marks the start of the last research cruise for our EPR Biofilms 4 Larvae project. We set sail late morning around 9:15, once everyone was safely onboard WHOI’s R/V Atlantis. Almost immediately, large gusts of wind pushed us along and by 9:30 we really started to boogie.

As per tradition, everyone in the science party gazed into the horizon as we began our transit. Photo credit: Mel Lemke, Western Washington University

Living onboard a ship, even one as incredible as WHOI’s R/V Atlantis, can sometimes be incredibly challenging (in addition to being fantastically incredible). From technical difficulties, to large swells and sea sickness, we began our research cruise troubleshooting, but thats part of life at sea! It’s not always sunshine and rainbows, even when gazing into the beautiful sunsets we witness at sea. Yet, despite a few snaffoos, everyone onboard is buzzing with excitement and optimism as we prep for our missions. We have already begun creating wonderful memories together, including witnessing a small pod of dolphins immediately after departure. They were with us for only a moment before disappearing back into the dark blue pacific ocean, but the positivity they brought was a boost we all felt.

In other good news, this voyage is the first for two members from the Arellano lab! A big congratulations to our REU student Jack (bottom left) and Masters student Laura (bottom right in her safety suit).

Jack (left) and Laura (right) experiencing their first few days at sea. Photo credit: Mel Lemke, Western Washington University

Difficulties faced upon departure are fairly standard for any operation, but such challenges only highlight the incredible strength and resilience of the entire science party, the crew of the R/V Atlantis, and the Alvin team. The crew of WHOI’s R/V Atlantis have been miracle workers and we are so grateful for all of their hard work and dedication to make this trip happen. It’s definitely been an eventful start to the trip, but we are a strong and resilient team dedicated to discovery and exploration. There are no other humans I would rather be out here with, and I cant wait to share what we learn!

Peace, Love, and Larvae

Mel

Laura (left) and Mel (right), bundled up for the windy departure! Photo credit: Mel Lemke, Western Washington University

Mel Lemke is a first year Master’s student in the Biology Program at Western Washington University. This is her second Alvin cruise. Mel likes worms.

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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

Deep-Sea Biology Research Internship Opportunity

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Announcement

The Arellano Larval Lab is currently seeking one WWU undergraduate intern to conduct deep-sea biological research at Shannon Point Marine Center (SPMC) and join on an upcoming research expedition to the East Pacific Rise (EPR) hydrothermal vents. The position is an NSF-funded Research Experience for Undergraduates internship, starting winter quarter 2024 as part a project to explore the predictive nature of microbial biofilms for cuing larval settlement at deep-sea hydrothermal vents. Gain valuable experience both in the lab and at sea while investigating larval and microbial ecology in unique and fascinating hydrothermal vent ecosystems. This position includes a stipend during the academic quarter that the research cruise will take place (winter quarter 2024). During other academic quarters research credits may be earned and development of an undergraduate thesis project is encouraged.

To learn more about the project, visit here to read the overview and here to read the blog posts from our first cruise!

Internship Details

This paid internship will be full time during winter 2024 (ie, you will NOT be able to take any courses at WWU in winter quarter). Please note that this position requires significant time onboard a research vessel at sea (30 days) and international travel (Costa Rica), so a passport is required. All travel to and from the port, all meals and lodging during travel, and all meals on board the ship will be provided. After the research cruise, housing at the SPMC dorms will be provided.

Student Expectations

In collaboration with Dr. Arellano, the intern will develop a guided, individual research project related to the goals of the described research topic. During the research cruise in January- February 2024, the intern may start developing their research project so that sampling or experimental work can be conducted. Besides working on their own research, the intern will be expected to participate in general cruise objectives, such as sample logging, dive video editing, and sample processing. To get an idea of what it is like to be on a research cruise, take a look at the larval lab blog posts from recent cruises: EPR, SALT, Lau Basin.

This internship is designed in coordination with WWU’s research participation courses (see below) to integrate undergraduates in every aspect of research, from proposal development to communication of results. Besides participation in the cruise and conducting the independent research project, we will encourage student interns to enroll for credit through their majors (e.g., MACS 494 Independent Research Project, MACS 496 Communicating Marine Science Research, ESCI 498A Senior Thesis, ESCI 498B Internship, ESCI 498C Senior Project; OR via and Independent Study in Biology). 

Enrollment in one of the above MACS, ESCI, or Biology research courses will be encouraged in the quarter after the cruise activities. During this time students will work one-on-one with Dr. Arellano as they finish developing their independent project and process samples and data from the cruise. Further research credits may be earned in future quarters depending on research and academic goals.

Students will gain valuable scientific skills working on this project, including molecular techniques, microscopy, and data analysis. They will also get the opportunity to learn first-hand about deep-sea research assets and cruise logistics. Additionally, students will be encouraged to present their research at scientific conferences and on campus (for example, during WWU’s Scholars Week) to enhance their communication skills, network with scientists, and get experience presenting scientific research to a variety of audiences.

Eligibility

Open to WWU undergraduate students in MACS, ESCI, Biology, or other related science major programs.

Preference for students that have at least one-two years remaining (after this year) as an undergrad at WWU.

Students supported with NSF funds must be citizens or permanent residents of the United States.

The Arellano lab is committed to supporting students with diverse backgrounds, experiences, and needs.

How to apply

Application package includes responses to the following prompts, CV, and unofficial transcripts. These will be submitted through a google form here.

Responses to the following should conform to character limits and be submitted through the google form.

  • Describe the areas of marine science that most interest you and your personal goals for the internship and beyond. (4000 character limit maximum, ~1 page, 12pt font, single spaced)
  • What qualities and characteristics will you bring to the program because of your work/activities/other life experiences? (2000 character limit maximum, ~1/2-page, 12pt font, single spaced)
  • Write about an experience of overcoming adversity or an obstacle in your life. (2000 character limit maximum, ~1/2-page, 12pt font, single spaced)
  • The name(s) of 1-2 professors here at WWU who could speak to your interests, motivation, work ethic, and accountability.

Important Dates

Application due date October 20, 2023 

Awardees notified November 5, 2023

Cruise information: 30 days at sea on the RV Atlantis during winter quarter 2024 (Depart from San Diego, CA January 10; Return to Golfito, Costa Rica February 10).

If you have any additional questions, please contact Dr. Shawn Arellano (arellas@wwu.edu)

Funding provided by: NSF Award # 1948580

Pacific Passage Postcard

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Welcome back everyone. It is time to wrap up the posts about this cruise, about a month after we returned from the East Pacific Rise (EPR). For many of us this expedition was life changing, seeing hydrothermal vent communities in person that we had always dreamed about. We had teams and scientists from all over the world helping on this project, providing new perspectives, and diverse skills that led to our success. We were able to complete our main objectives, conduct every dive we planned, prepare for the next cruise, and keep spirits high while being away for the holiday season.

First, I want to say a big THANK YOU to the crew of the R/V Atlantis, as well as the Alvin submersible team for all their help, feeding us, and attending to our scientific or personal needs. We faced very little technical difficulties, but for the issues we did face, the teams were able to remedy them quickly to get us back on schedule. We are very impressed with the Alvin team changing out the main batteries of the sub in the middle of the ocean, when they’ve only done it on shore before! Of course, I also want to thank all the scientists on board who worked diligently, and the film crew for including everyone in their story telling and involving the crew into our science.

The end of the cruise went well. We finished all our sample processing on December 31st, just in time for the new year. To celebrate, Vanessa Jimenez (WWU) took charge and decorated the aft deck and under the A-frame with lights strewn across the various platforms. She created a disco ball out of a Styrofoam ball and aluminum foil and had Alvin’s measurement lasers pointed at it while we danced and had a limbo competition until the clock struck midnight. An unorthodox new year, but one we will never forget.

Photo by Dr. Tanika Ladd (WWU)
Left: Tanika and Vanessa (WWU) packing up the lab. Right: Tanika and Stephane putting freight box in science hold.

On the next day, we arrived in port, and spent most of it packing up all our equipment. We did our favorite game of science equipment Jenga back into our storage containers and freight boxes, and divvied up equipment between lab members that we wanted back at the lab. The R/V Atlantis is not returning to the United States until June, so we had to store most of our equipment in the science hold to avoid being in the way of other scientists on the next cruises. The costs associated with shipping internationally, especially with large and heavy science equipment, meant it’d be easier to wait until the ship returns.

The Larval Lab likes to put together these graphics after each of our cruises to remind us of the journey and our achievements during our time at sea. On this cruise we spent 30 days at sea, where we travelled around 2,460 nautical miles (2,831 miles for you landlubbers!) from Puntarenas, Costa Rica, to the EPR, between our study sites, and back to Puntarenas. We had 20 dives with the Alvin submersible, where 12 scientists got to dive for the first time. During these dives we reached a maximum depth of 2553 meters (1.59 miles) and measured the hottest vent fluid to be 353.9°C (669°F)! It got so hot that we actually melted a bit of Alvin’s basket from touching a chimney. We were able to collect many vent fluid, water, microbial colonizer, rock, and animal samples, in addition to sensor readings and successful recoveries and deployments of most our scientific equipment. These tricky sites sometimes made it impossible to locate or reach our old deployments without destroying the habitat, which we are trying to impact as minimally as possible.

The Larval Lab was able to process the 42 settlement sandwiches that we recovered and with the McLane pumps were able to filter 187,856L of water to search for larvae. With the MISO camera and the cameras mounted on Alvin, we were able to take 139,267 pictures and are bringing back a whopping 46 Terabytes of video and data that will assist us for years to come. These images and videos will help us reference any changes in our study sites, and conditions surrounding our deployments and recoveries, as well as provide beautiful shots and animals that we can share with you all. Spending this much time at sea, we end up hitting milestones on the water as well. We had multiple birthdays in addition to the holidays over December, and we even had one scientist, Lauren Dykman submit her PhD and officially become Dr. Dykman.

Top left: limpet, top right: nectochaete, bottom left: gastropod veliger (GV), bottom right: Ophiuroid juvenile (OJ).
Top left: GV, top right: nematode, bottom left: limpet, bottom right: GV
Top left: Amphisamytha polychaete, top right: bivalve veliger (BV), bottom left: polychaete, bottom right: slit limpet.

I’ve talked a lot about our settlement sandwiches and how we’re using them to assess the influence of bacterial biofilms on larval dispersal, but what are we actually finding? When we recovered these sandwiches that we had deployed on the seafloor for two weeks, we split them in half so we could sort through some of the plates for larvae and hand them off to Costa Vetriani’s lab to analyze the biofilms. We put half of the sandwiches in RNA later and the other half we put into ethanol to process back on land. It took us about 10 days of sorting sunup to sundown to get through these 42 sandwiches. We were mostly finding adult polychaetes and gastropods as we sorted, but we did find some larvae! A majority of them were gastropod veligers, which look like teeny, little snails with few whirls, or nectochaetes, which look like small polychaetes with cilia. We found one bivalve veliger and one ophiuroid juvenile. Surprisingly, we did not find the larvae of the abundant Riftia that dominated our sites. However, we still have a lot of samples to sort through on land, so these results are incomplete. Once all our samples are processed we will compare the bacterial communities on the plates to our larval results and see if there are any patterns we can see. We are especially interested in how the sandwiches that developed biofilms first compare to the sandwiches we placed down during this cruise. These photos were taken by Vanessa Jimenez (WWU) and arranged by Dexter Davis (WWU).

Remembering Dr. Diana K. Adams

As we wrap up this series of posts from this cruise, I wanted to take a moment to acknowledge Diane K. Adams (née Poehls) who was pivotal to this project but passed away in 2017. Her doctoral thesis work at WHOI under Dr. Mullineaux titled: “Influence of Hydrodynamics on the Larval Supply to Hydrothermal Vents on the East Pacific Rise” inspired many of the ideas of this EPR Biofilms project. She realized we were studying how larvae were dispersing away from vents, but not how larvae find suitable vent habitats.  Her work was groundbreaking at hydrothermal vents, discovering surface winds as a novel potential mechanism for larval dispersal.

She was fearless and determined in her research. She was never daunted by difficult problems and in fact was drawn to them. She did the equivalent of two thesis projects – one deep sea and one coastal during her time at WHOI. She immediately embarked on a cruise to the EPR in 2006 right after an eruption and jumped at the opportunity to be a student star in a James Cameron documentary on the mid-Atlantic Ridge. She approached her science the same way she approached life – with exuberance and joy. An amazing and tireless scientist, but also a strong mentor and advocate for bringing students into STEM. Her students described her as a life mentor who stressed curiosity and work ethic as the foundations of successful science. They are scattered around the field as living proof of her influence.

To remember her legacy, endowment funds are in place at WHOI and Rutgers. Additionally, on Nov 5th, 2021, a plaque was deployed in her memory at a hydrothermal vent site in the Pescadero Basin, Gulf of California during an E/V Nautilus cruise. We wanted to recognize her as part of this project as well, and dedicated our site markers in her name. Her influence on studying the East Pacific Rise hydrothermal vents will continue. Photo of Dr. Diane K. Adams from Rutgers University https://marine.rutgers.edu/team/diane-k-adams/

Diane K. Adams Plaque in the Pescadero Basin.
  • DKA Marker 9
  • DKA Marker 12
  • DKA Marker 17

Thank you to excerpts from Dr. Lauren Mullineaux, Dennis McGillicuddy (WHOI) and Mark Miller’s (former director of EOAS at Rutgers U.) obituaries for assisting in this acknowledgement and telling the story of Diane.

I appreciate the readers for following along this journey with us to further our understanding of hydrothermal vent systems. For now the deli is closed, but more sandwiches will be made when we return to these sites next year and do it all again one more time! Hope to see you there.

If you enjoyed my blog and want to follow me or connect:

Instagram @djdavis123 | Twitter @dexterity_no

Or the lab:

Instagram @larvallab | Twitter @LarvalLab

Subsurface photos taken with MISO camera, WHOI Dan Fornari. Shawn Arellano, chief scientist, Western Washington University; Alvin Operations Group; National Science Foundation; ©Woods Hole Oceanographic Institution.

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

The Wonderful World of Worms

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Happy New Year! I hope everyone is starting the year with a new appreciation for the world around us and the science being conducted to understand it further. While the cruise is over, there are still some things I’d like to share with you all.

This post I want to introduce to you the abundance and diversity of worms at hydrothermal vents. In the deep-sea, worms rule. Filter feeding, recycling nutrients and sediment, grazing, parasitizing, and even ambushing prey; you can find worms in many roles and ecosystems with vents systems being no exception. I’ve already introduced a few of these worms, but first I’d like to delve further into the largest of them, Riftia pachyptila, the large red tube worm that dominates our study sites.

A spawning Riftia pachyptila. If you look closely you can see the cream-colored gametes in the tube before released.
Basic anatomy of Riftia pachyptila.
Eggs on the Riftia’s vestimentum.

These worms are particularly interesting because they are chemosymbiotic, meaning they have a relationship with bacteria that use chemicals for energy, that live inside them. These bacteria consume the chemicals in hydrothermal vent fluid and create byproducts that the host worm can use. These worms have three main segments. The first is their large red plume. This allows the worm to take in the nutrients in the venting fluid, as well as their bacterial symbionts. This is the only part of the worm that sticks out of its tube, and it has mechanoreceptors that sense when it is touched, so the worm can retract to safety. Often, we see crabs and eelpouts eating the tubes and trying to nip the worms. The second segment is the vestimentum, a muscle that anchors the worm into its tube, and houses the animal’s heart, and reproductive organs. The third section is the trophosome, instead of having a stomach and gut like most animals, once their bacterial symbionts are acquired, they transition from a gut into having essentially a bag of bacteria, a powerhouse for turning sulfide into food. (I think it looks like a blood sausage.) The scientists on board received a private lesson from Dr. Stéphane Hourdez (CNRS) and Dr. Shawn Arellano (WWU) through a dissection of a Riftia we collected. Once we dissected it, we could see the white eggs located on the vestimentum, and Vanessa Jimenez (WWU) extracted them to look at them under the microscope. These worms are fascinating not just because they are uniquely adapted to hydrothermal vent habitats, but also uniquely adapted to the relationship with their specific bacterial symbionts.

Riftia aren’t the only chemosymbiotic worms that live at these hydrothermal communities. Another worm called Alvinella, also called “Pompeii worms”, live in the hotter, sulfide mounds and spires of these venting systems. The ends of these worms have been found in tubes up to 80C (176F)!

There are two species at the East Pacific Rise; Alvinella pompejana, and Alvinella caudata. The most noticeable part of Alvinella are four petal-like gills that stick out of their tubes for gas exchange.  Unlike Riftia, they still have a functional gut, where they can consume bacteria that they grab with their feeding tentacles. Their symbiosis is a little different. Instead, the backs of these worms are covered in white hairs, which are actually bacteria, that eat a mucus the worms produce. It’s hypothesized that these bacteria could help insulate the worms against the hot temperatures. Alvinella are fascinating as one of the most thermally tolerant animals in the world, living on the edge of when the mitochondria in their cells begin to break down.

A sulfide spire with orange/red Alvinella and Paralvinella plumes.
An exploring Alvinella is attacked by a Paralvinella.
Stéphane’s pressure vessel full of vent animals.

Along these sulfide spires, these worms are intermixed with other tube-dwelling worms called Paralvinella. As you can guess, both Paralvinella and Alvinella are named after the very Alvin submersible we’ve been using on this cruise! They look very similar to Alvinella, but to the trained eye (mostly Stéphane) there are noticeable differences. The major identifying difference is which segment their chaetae (crawling legs) begin.

Crawling amongst all these tube-dwelling worms are a type of polychaete worm called Polynoids, or scaleworms. These animals have scales covering their backside for protection from predation. They come in many colors, but the ones around here are a pink to purplish color. Dr. Stéphane Hourdez on board is particularly interested in these organisms, experimenting on the thermal tolerances of scaleworms, and other organisms collected opportunistically. The first challenge with this experiment is that he must keep these organisms at a pressure similar to their natural environment in order to ensure they are reacting properly to temperature changes without additional stress. To do this, he has a pressure chamber, that with using an HPLC (High-Performance Liquid Chromatography) pump, pressure can be set to 250 bar, equal to 2,500 meters deep. Once the pressure is set, he observes how the animals react to increasing temperatures. Since they live at these hotter than normal habitats, we’re curious about their thermal adaptations and the limitations.

Are you tired of worms yet? Well, I still have a couple more I would like to introduce to you!

There’s one more symbiotic polychaete that is commonly found at these sites, although very different from the previously introduced ones. These Polynoids, genus Branchipolynoe, are actually found inside another animal. The large mussels at the EPR called Bathymodiolus thermophilus, can often be found to host one of these large Polynoids. While the other symbiotic relationships both parties benefit, only the Polynoids are benefitting from this relationship. They receive a safe habitat to develop and reproduce and the mussels just have a roommate that pays no rent. Each mussel only has enough room for one large female though, while there could be multiple smaller males. These females are very fecund, meaning they have a lot of eggs. These eggs are also very large for a polychaete. With a quick cut on the underside, the eggs erupt out of the females. These worms are found in other deep-sea habitats as well, where we’ve found them in the Bathymodiolins at methane seeps in the Gulf of Mexico. I still remember how surprising it was to open a mussel and find a giant worm inside!

  • Bathymodiolus thermophilus.
  • Branchipolynoe inside!
  • Large eggs of Branchipolynoe.

The final worm I wanted to mention is another type of polychaete called Achinome. This fluffy looking worm has no protective scales like the scaleworms, or a tube like the other worms. Instead, just little nubbin-looking parapodia (legs). These were found to be the most abundant polychaete we were finding on our sandwich deployments. Nestled into the grooves, we’d often have to pry them off the surfaces. To do this we made use of my favorite larval biology tool. My eyelash, glued onto the end of a coffee stir stick or dissecting tool. Metal points of forceps or needles can often be too hard, so the flexibility but firmness at the base of an eyelash or cat whisker is perfect for moving around larvae or scraping animals off surfaces without casualties. We were hoping to find less adults and more larvae of these polychaetes, but more on our sandwich results on the next post.

A sandwich plate with an Achinome within the plate groove.
Zoomed in photo of the Achinome in the groove.

I hope this gives you a little more appreciation for worms. While these live in relatively extreme habitats, they are found all over the marine world, and can often be found if you just dig in the sand at your local beaches. They can be quite beautiful with iridescent scales reflecting rainbows back, or swirling feeding crowns of tubeworms. If anything, I hope you appreciate the diversity of these worms more. They come in all colors and sizes and can play many roles within an ecosystem. I want to leave you with a fantastic drawing that second mate Kenny Beaver of the R/V Atlantis drew about the Riftia tube worms we studied.

Subsurface photos taken with MISO camera, WHOI Dan Fornari. Shawn Arellano, chief scientist, Western Washington University; Alvin Operations Group; National Science Foundation; ©Woods Hole Oceanographic Institution.

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