Dark Life II

Here we are in Puntarenas, Costa Rica, anchored about a half-mile from the beach. It is hard to believe that our journey at sea is coming to an end, after all of the months and years of planning, and then actually going on the cruise. We are very proud and satisfied with the science that we accomplished on the cruise. We have become very comfortable on the ship, our home for the last three weeks. Things that seemed awkward or uncertain at the beginning of the cruise are now routine. We have forged new friendships, strengthened old ones, and developed a deeper appreciation for our colleagues’ personal strengths. We have much to be proud of and thankful for. We are very lucky and fortunate to have the opportunity to explore and study the ocean, particularly at deep-sea hydrothermal vents, part of Earth’s rich tapestry of life in the most surprising places!

The Science Party of Dark Life II in front of Alvin.

The cruise has been very productive scientifically, although in ways that we could not have predicted at the beginning of the cruise. Some new projects greatly exceeded expectations and have blossomed over the past few weeks into strong potential for future projects. Carolyn Tepolt, a newly appointed WHOI scientist, was very successful at trapping Bythogreae crabs at the vents. She was able to collect many tissue samples from the crabs, which she plans to use for transcriptome analyses back at the lab to begin to understand specific adaptations of these crabs to hydrothermal vents. François Thomas at the Station Biologique de Roscoff (France) has begun a very promising study during the cruise on bacteria that degrade chitin, a major component of the tubes of Riftia and the exoskeleton of the crabs. He already made several insightful discoveries about chitin-degrading bacteria on the cruise. Kevin Becker, a postdoctoral researcher at WHOI, initiated a new study tracing the fate of chemosynthetically derived carbon up the food chain at vents using lipid biomarkers. Ileana Perez-Rodriguez, starting a new Assistant Professor position at the University of Pennsylvania, obtained a variety of samples to begin a new project examining the role of microbes in degrading asbestos, as vents may be a good place to look for such organisms.

Towards the end of the cruise, a fun lab competition took place, involving performances by the three different labs. Shown here are the members of the Biolab, who gave an artistic performance about how the peaceful life at the dark, deep-sea vents gets interrupted by Alvin and its lights. Shown from left to right are: Carolyn (crab), Tjorven (Riftia), François (chitinolytic bacterium), and Horst (Alvin). The awards were presented by Catie Graver and Alison Heater (SSSG).

Some projects were a continuation of work conducted during Dark Life I in 2014 at 9˚N. Tjorven Hinzke (working with Horst Felbeck) continued collecting Riftia samples for her PhD research focused on interactions between the sulfur-oxidizing bacterial symbionts and the Riftia host. She will analyze her samples using proteomic techniques to provide new insights into the interactions between symbiont and host.

Ashley Grosche and Sushmita Patwardhan are graduate students from the Vetriani laboratory at Rutgers University, and they continued their lab’s study of bacteria that grow on colonizers that we deployed for various times at different vent sites during the cruise. We hope they are able to isolate a new crop of interesting bacteria back at the lab. We also continued the time series of Lauren Mullineaux’s lab at WHOI, studying larval recruitment and colonization at deep-sea vents. Net Charoenpong has been analyzing vent fluid samples for ammonium nitrogen isotopes for four years now for his PhD. He was able to see sites where his samples come from first-hand on his Alvin dive. He was one of 11 scientists that got their first chance to see the vents up close by diving in Alvin.

Jeremy Rich (left) and first time diver Ed Hobart (right) in front of Alvin before their dive.

Andrew Babbin and Ryan Woosely were a great addition to the cruise, maximizing the number of environments and samples that we could collect on the cruise. They were able to sample 9 CTD casts to characterize the unique chemical features of the oxygen deficient zone of the water column above the vents and along our transects from port to port. Andrew participated in the Vent-SID studies working on measuring nitrite in vent fluids.

Atlantis as seen from the water taxi bringing us to shore.

The Vent-SID was the primary motivation for the cruise. What’s the latest with the Vent-SID? The Vent-SID team consisted of WHOI scientists Craig Taylor and Stefan Sievert, WHOI engineer Ed Hobart, Professor Jeremy Rich and Research Assistant Sean O’Neill of the University of Maine and Diana Vasquez Cardenas, currently affiliated with the University of Sao Paulo (Brazil). She has studied chemosynthesis in coastal sediments for her PhD in the Netherlands and it was her first foray to study an environment where chemosynthesis is actually the predominant process.

The Vent-SID during transport at the seafloor by Alvin.

Although getting a successful seafloor deployment proved to be more difficult than anticipated, we learned a lot about the Vent-SID’s limitations and we have good ideas for how to improve it in the future. We are all very much committed to the idea of the Vent-SID and, besides some of the setbacks, are convinced that this is the way to move forward in order to get actual numbers on the productivity of deep-sea vents and to assess their role in biogeochemical cycling of the deep-ocean and beyond.

Jeremy Rich opening a valve to allow vent fluids to be delivered to the incubation chamber during the on-deck incubation.

We did run a successful Vent-SID experiment on-deck of the ship, using vent fluids that were obtained with the Major fluid samplers at the vents. The on-deck incubations demonstrated the full functionality of the Vent-SID and we were able to measure substantial microbial activity in the different incubations, for example based on rapid consumption of nitrate and increases in cell numbers. These results are very exciting as we move closer to measure these processes directly at the seafloor. We anticipate insightful results from these Vent-SID incubations after we get back to our shore-based labs to analyze carbon and nitrogen isotopes as well as the microbial community composition and gene expression.

Members of the Science Party on the fantail of Atlantis.

Overall, our cruise was very successful. The chemistry among scientists was excellent with a great atmosphere of teamwork and collaboration. The Atlantis crew, science technicians, and Alvin team were excellent and extremely hardworking and knowledgeable as always. Without them we would not have gotten the samples that we need for our research and their help is greatly appreciated. As we are now all heading back to our families and friends, we leave this cruise with a sense of accomplishment, wonder, and strong desire to come back in the future to finish what we have started. While this cruise has come to an end, it also marks the beginning of many new chapters waiting to be written.

(Apologies to The Clash.)

I first heard about the Crab Spa from Stefan about a year ago, during my job interview at WHOI. I’ve studied crabs for the past decade, so the prospect of an entire undersea resort full of crabs “taking the waters” was a singularly delightful prospect. The Crab Spa certainly lived up to its name, with dozens of blind white crabs prowling the Riftia beds near warm-water outflows. Like most crabs they are predators and scavengers, on the hunt for anything, dead or alive, which will stand still long enough for them to eat it. This greed and un-pickiness are characteristics I’ve exploited before in trapping for coastal crabs.

My prior experience with deep-sea crabs, however, consisted solely of watching reruns of Deadliest Catch. Since I am insufficiently grizzled and bearded to go that route, I opted for a different approach: commercial crayfish traps from Amazon. An added complication not faced by the gentlemen of the Bering Sea is that my traps have to fit in an insulated biobox. These are thick plexiglass, sealed watertight with silicone, and keep the deep water cold during the ascent. The one we used most on the cruise is long and relatively thin, and is doing double-duty for my crab traps and Horst and Tjorven’s tubeworms. (Because of its shape and purpose, it is more colloquially referred to as the “worm coffin” by the Alvin team.)

Crab trap and tubeworms in the ‘worm coffin’.

It felt a bit surreal to fish for crabs by submarine, leaving a lone trap under 1.5 miles of ocean. One distinct bonus is that traps in the deep sea are always right where you left them, something that can’t be counted on in coastal waters. It took a few dives to find the right trap (long and skinny), and the right bait (dead tubeworms), but once I did, it worked like a charm. From the sub, we watched the crabs cruise over soon as the traps were down, climbing the mesh in an effort to get to their newfound bounty. Occasionally one claimed my trap as his own, glaring blindly at other approachers from his perch directly on top of the bait bucket.

A crab tries to fight off Alvin’s claw as it reaches for tube worms.

On the cruise, I collected these animals because they’re evolutionarily fascinating. They shuttle between vent outflows and the deep-sea floor, two starkly different environments. The first is full of food and energy, but also hot and toxic and devoid of oxygen. In contrast, the seafloor is cold and largely lifeless, though the water is healthy and oxygenated. Switching between the two is like walking outside on a beastly hot day from an office where the AC is constantly set too low: a shock to the system.

Holding a vent crab up to the light to highlight its translucence.

Back at WHOI, the harder work will begin soon. My next step will be to rifle through the crabs’ DNA and compare it to that of their shallow-water relations, looking for genes which show signs of adaptation to life at deep sea vents. These genetic breadcrumbs will help me walk backwards through the crabs’ history, piecing together their long evolutionary path towards a dark life. With a little luck, it will be the beginning of a new research direction, and more deep-sea crabbing.

My grandfather was sixteen years old the first time he tried to enroll in the Navy. It was a different era, and a time when young men felt it was their duty and responsibility to defend their country during a time of war. For many, that meant taking up arms. Serving in the Navy shaped the values, perspectives, and character of my grandfather in ways I’m sure I will never fully comprehend. That sailor went on to have a family, and became one of the most influential figures of my young life. We were Thelma and Louise with a sixty-year age difference, and however unconventional it may have been, he was my best friend.  He passed down his principles to me, his blue eyes and demeanor, and of course, his love of the sea.

Frederick Carl “Framp” Grosche.

The first time I ever saw the ocean was with my grandfather and brother at Bradley Beach, New Jersey. I remember as vividly as if it had happened yesterday, the smell of the sand and salt as we hurriedly emptied out of the car, rushing over a dune, and looking outwards in anticipation of the notion of what I thought the ocean would be. It was a moment of complete and total awe. I was dumbfounded by the incomprehensible size and magnificence of it all. Crystal blue extended out into forever, reaching up into the sky. How could it be that some people could go their entire lives without seeing such beauty? Now that moment, and my grandfather, live on only in memory. Time and circumstance have shaped me into a person who feels like a distant relative of that girl on the sand dune. But each time I see the ocean, I’m brought back to that day, and the familiar feeling of awe is new again.

The stories I heard of his time at sea were few and often second-hand through other relatives. I suppose war stories were not something my grandfather regarded appropriate for a little girl to hear. The bits and pieces of his adventures planted a seed in my mind that eventually infects the minds of oceanographers, seaman, and lovers of the sea alike. The seed of the plan for my own adventures travelling the ocean. It seemed at first like nothing more than the idle musings of a child to my friends and family, but the seed took root, and the roots expanded and grew stronger with passing time. I had begun graduate studies when my childhood plan morphed into reality. When the opportunity to board the R/V Atlantis came, I did not hesitate to say yes.

I first boarded the Atlantis December of 2013 during my third year of graduate studies. The trip itself was a welcome reprieve from the monotony of school, studying, and the routine of everyday life. Looking back now, the trip was a glorious blur. How is it that time slips by, speeding up and slowing down like a river twisting and turning through the terrain of life? I fell in love with a life of no land in sight, without the distractions of cell phones and indulgence in internet, and with a new aversion towards the excess things in life that were simply unnecessary clutter. The sea felt like home in a way a new place never had before. I found comradery in scientists with the same passions and research interests as my own, and formed friendships with crew members who told stories of their adventures traveling the world. I saw the sun rise every morning and watched as it cast dazzling sparkles across the water, got lost in a new rhythm of exploration, science, friendship and introspection. It was an incredible journey, and when it drew to a close, I quietly accepted it had ended, thankful for the experience, and wondering if it was the last of its kind. I didn’t know then that another spectacular voyage was on the horizon, this time of grander proportions. It was 2017 and I was preparing to finish my graduate studies, when the possibility of another research expedition solidified into a reality. This time, the submersible Alvin was on board, and I was given the opportunity to go into the depths. It was a once in a lifetime opportunity, and of course I said yes.

Riftia tubeworms surrounded by mussels.

A peculiar calm fell over me the day of my first dive in the submersible Alvin. The ocean and sky greeted me with their vast display of blue and choppy sapphire waves licked the sides of the ship, causing it to bob lightly up and down. The Alvin awaited, hanging within the A-frame as the scientists and crew prepped for the dive. Time fast-forwarded and suddenly I was climbing the stairs to the hatch, removing my shoes. Rung by rung, I lowered myself into the Alvin, the smell of metal hung in the air. Light from the switchboards bathed the sub interior in a red glow which intensified as the sub descended into the dark abyss. During the descent, I felt what I can only describe as an intense déjà vu that is impossible to substantiate, and even more impossible to explain to others. It all felt so incredibly and unexplainably familiar.

Bioluminescence peeked in from the portholes, flickering bright green against the inky black surrounding us. We approached the bottom, a barren surface of grey crevices carved out of the seafloor. Who knew how lovely grey could look? We approached a hydrothermal vent field and abruptly, life erupted. Fields of alien-nesque tubeworms spread out in front of us as we floated along the seafloor. Pale yellow mussel beds studded the valleys dipping between. Shimmering fluids streamed through the water, tousling the fauna caught in its reach. The biology was incredible. We approached vent site Bio9 and I was floored yet again by a massive sulfide structure jutting up from the seafloor, spewing scorching black clouds of minerals from its throat. How incredibly beautiful the works of nature really are.

Black Smoker Sulfide Structures at Bio9 Vent tower over the seafloor.

The dive lasted for seven hours, but time mysteriously sped up once again, and before I knew it, I was back on deck being greeted and congratulated with two cold buckets of ice water over the head, customary tradition for first divers.  Many of my friends and fellow divers have written of their time at the bottom of ocean since our first Alvin dives, and it’s apparent that the experience has had a profound effect on us all. Now the cruise is coming to an end, and again I am left wondering if the experience will be the last of its kind. The ship is steadily advancing towards Costa Rica, a life of land, of work to be done, and a thesis to be finished. As the burning sun slowly sinks into the ocean, casting pale hues of pink onto the waves, I have a singular feeling, that there are yet more adventures on the horizon.

The ocean has fascinated me and had a pull over me ever since I was a child. I have always been curious about this magical body of water teeming with life. This love for the ocean coupled with a curiosity to study how life survives in it brought me to Rutgers University, USA all the way from India. I am currently a PhD student in Dr. Vetriani’s lab. As a lab we are interested in studying the physiology, ecology and evolution of microorganisms at vent environments that resemble early Earth’s environment. It wasn’t until I joined Dr. Vetriani’s lab that I realized that going down to the bottom of the ocean and visiting these unique environments was a possibility! When I heard of this opportunity to be able to join the Vent-SID cruise organized by Stefan Sievert and to be out at sea for a month to do science, I was thrilled beyond words. I had been looking forward to this for a long time and it was finally happening. What was even more exciting was that it was an Alvin cruise, which meant there was a slight chance that I would get to dive, but that was just the icing on the cake.

Dusk on R/V Atlantis

Being on this cruise has been one of the best experiences of my life. I have learnt so many new things, met some wonderful people, made some good friends and, most important of all, I have made cherished memories to take back with me. Every single day has been an adventure and a new experience, but the day I dove in Alvin for the first time will always stand out! What made the dive extra special besides the fact that it was my first was that it was an additional dive added to the dive series due to being able to save time during transit back to Puntarenas and that we were responsible for bringing back some very crucial samples from the deep sea. The day before the dive was an emotional roller coaster for the divers and the scientists since there was a lot of uncertainty involved around the dive the next day due to issues with the thruster of Atlantis.  In the end everything sorted itself out and it was decided that dive 4905 would be taking place indeed. The night before the dive was spent in a constant battle between being awake with excitement and wanting to get some rest.

Pilot Jefferson with scientific observers Ileana (left) and Sushmita (right)

Finally the day arrived and surprisingly excitement is all I felt! There wasn’t a trace of nervousness. The dive was piloted by Jefferson Grau, with Ileana Perez-Rodriguez as the port observer and myself as the starboard observer. It felt great to be diving with a fellow woman scientist who also happened to be my academic sister (she got her PhD from the Veriani lab). When the sub first hit the water I admit I had a fleeting feeling of being drowned, but as we slowly continued our descent everything felt normal. It was fascinating to see the changing hues of the water as we descended through the euphotic zone. It started out with being sky blue to a very beautiful teal to a very dark blue and then just darkness! That’s where the bioluminescent life came out to play, resembling thousands of stars in our galaxy. The journey to the bottom of the ocean was remarkably peaceful, calm, and quick. The first thing that I was mesmerized by was the seafloor. It was hard to believe we were still on planet Earth, it looked nothing short of an exoplanet. Our first task was to find the Large Volume Pump (LVP) and position it in the desired fissure at Teddy Bear. En route we witnessed two different types of octopuses, sea cucumbers, sea pigs, anemones, and a number of other fascinating creatures. Next on the list was getting fluid samples with the Majors. For this we travelled to Crab Spa which is a really cool vent site adorned with Riftia, mussels, crabs and fish. If I were a marine creature, I could see myself hanging out at this cool joint! Almost all of the Major Samplers fired beautifully and it was a proud moment for me as part of the Major Team.

A beautiful colony of healthy Riftia.

From there we moved on to collect some dead and healthy Riftia. The Riftia tubeworms were ten times more beautiful in real life than in photos. With their brilliant red plumes and gracefully swaying bodies they were quite a sight! After doing our last task of releasing the LVP, we started our ascent back to reality. These eight wonderful hours of my life had passed by in a heartbeat. To this very day it still feels like a dream…. a dream that came true!

How can I begin to relate the emotions I am feeling as I prepare for a dive to the sea floor, 2500 meters (just over a mile and a half) below the surface? I begin with a caveat and an apology: this post is written for myself to memorialize these feelings, and thus, will perhaps ramble in spots and be mind-bogglingly boring for most. It’s a weird sense, knowing that I am preparing for an expedition that will take me to a world most have never seen. A true explorer, one of the closest humans to the center of the Earth (not that it’ll actually be that close) during the time we’ll be under the water. It feels like I’d imagine an astronaut’s mindset just prior to a launch. Knowing in advance that I will be encapsulated in a small vessel, fully dependent on the structural integrity of the walls, isolated except for a single radio connection from the outside world, is equally off-putting and exhilarating. As an oceanographer, such a dive allows me to truly and literally immerse myself in my research. That in itself is awesome, but not the reason behind my excitement. My work to date has focused on the water itself, not the seafloor underlying this swath of ocean. As a human, rather, testing the limits of our capabilities, pushing ourselves farther than we could have envisioned, I am astounded. I remember seeing submersibles exploring shipwrecks on television and in movies (ahem, Titanic), and thinking how unbelievably cool it would be to go to the bottom of the ocean. I remember being fascinated by 20,000 Leagues Under the Sea, perhaps still one of my favorite novels. I especially adored an adaptive parody for children lovingly purchased by my mother, 20,000 Baseball Cards Under the Sea. Now I get to be that explorer. Not looking for the Titanic or exploring Challenger Deep, but investigating perhaps the most amazing ecosystem on the planet.

Eagerly waiting to submerge beneath the surface!

Hydrothermal vents are primordial systems where life flourishes not due to sunlight but due to chemical energy stored in the unique molecules that exist in abundance as volcanic gases mix into seawater. These organisms, from the bacteria and archaea at the base of the food chain to the tube worms (some longer than I am tall), crabs, and mussels at the top, are all uniquely adapted to living under alien conditions. I am privileged beyond belief to be able to submerse myself first-hand into an environment that seems much more likely to be imagined by Asimov or Wells than one that in fact exists on Earth. I have been warned to pack many layers for my voyage to the deep. It gets cold in the deep ocean, 2ºC ambient temperature causes the inside of the sub to be 6ºC. Given that we’ll be on the seafloor for about 5 hours, odds are we’ll get chilly. But I think that I’ll be so consumed with awe and wonder that I won’t need the wool socks and hat. I guess I’ll know soon.

The crew of Alvin dive 4903: Pilot Phil Forte (center), port observer Stefan Sievert (right), and starboard observer me!

Coming back to the feeling of being like an astronaut, I’m thinking of the engineering that has gone into ensuring the sub can withstand pressures 250 times that at the surface. The titanium sphere must hold. And all of the systems inside, redundant backup after redundant backup to prepare for every eventuality should an emergency arise. Fitted oxygen masks in case a fire necessitates purging the sub from all air (of course I’ve been reassured this has never happened), carbon dioxide scrubbers to reduce the CO₂ concentration inside the sub (I wish the planet had some of these, actually…), and camera after camera. As the novice diver on this trip, my job is really that of videographer and observation logger. I have control over two external cameras to capture the extraordinary world and immortalize my experience for ample reshowings (and unadulterated braggadocio) upon my return home. The cameras are also technically for the scientific record to document how instruments were deployed, where samples were taken, and when activities were conducted. But let’s be honest, if I take a picture of a 6 foot long tube worm or expansive biofilm formation, I will use it for a great many purposes.

Come here little fishies! I’m here for you!

Anyway, before I ramble too far down a tangent, I am going to curtail my anticipatory thoughts. My only fear is that my sense of enthusiasm is so great that the experience be a let down. I have specifically avoided looking at too many photos and videos from the previous dives so as to remain ignorant of the magical world into which I am about to descend. I’ll soon find out whether I’m whisked into preternatural delight upon submergence from the surface and into the dark expanse of the deep.

===

And now for the ludicrous task of distilling my first voyage to the sea floor into a manageable post that captures the wonder of exploring some of the most amazing biological ecosystems, geological structures, and chemical environments on the planet. It is surely impossible to relate the experience properly, and in fact, I’m not entirely sure I can yet comprehend the awesome opportunity I was afforded in being able to transit in a submersible to the bottom of the ocean. Perhaps it is best to not even try and to simply overload the post with image after image, but photos alone cannot convey the feelings of being sent to the bottom of the sea.

The anticipation truly peaked once inside the sub aboard the ship, waiting to be lifted off the vessel and into the sea. As soon as we were dangling in the air, my smile erupted, giddy for what was to come. We waited for a few moments, for the ship’s crew to disentangle us from the lines holding us to Atlantis, and then, with a simple flick of a switch, the air bubble keeping us afloat was purged and we started descending. At first, the portholes only glimpsed what could otherwise have been a pool. Brilliant blue water, clear as can be, that just kept getting darker. Darker and darker the world got as we sank until we reached this ethereal blackness that was entirely alien to a boy who grew up in the suburbs of New York. Then pop! Bioluminescence! The first signs of life deep below the surface. Unknown organisms naturally producing proteins within themselves that emit light, organisms so small that they are invisible except for the tiny photons they produce. And there are tons of them. Flitting around, zigging and zagging as we descend, their movements dictated entirely on the small-scale turbulence of the water as they cannot themselves swim fast enough to escape the flow.

Life along the bottom! Crabs galore!

And then, suddenly, blackness. The unique feature of this vent system is that in order to get to it, we must transit vertically through anoxic patches of water devoid of oxygen. These “dead” zones were visible to the naked eye in their absence of light. Possibly the same bioluminescent organisms inhabiting the shallower depths dare not pass through this region. It’s also certainly possible that the organisms are there, but because there is no oxygen, they are in stasis or living off the oxidative power contained within other molecules besides oxygen (namely nitrate). Regardless of reason, the starkness of this void is intense. As soon as we descend far enough and the oxygen begins to creep up again, the bioluminescent light reappears. First, flickers that fool the eye and then suddenly a deluge as the ballet of lights restarts after a 300 meter intermission.

We continue to descend, at about 30 meters per minute, for another hour until we reach the bottom. This alien world hazy at first but then sharpening as the craggy seafloor appears. Flashes of light act as beacons, but these lights are man-made. There’s a blinker attached to an instrument much like the flickering of a bulb on the tip of an airplane’s wing. And suddenly, we stop. We release steel plates that weighted us down, dragging us to the bottom, and now we’re neutrally buoyant, meaning we can move very similarly as one would in space (just at a much much higher viscosity). We use the thrusters to move up and down, left and right, searching for our instruments deposited from the ship the night before and waiting for us in the murky abyss. The bottom is surprisingly turbid to me, as I did not anticipate the quantities of flocculent material being emitted from the vents, visible motes of solid sulfur and suspended bacterial biofilms that have been sloughed off the surfaces they colonized by the active flows providing the chemical energy they need to survive.

Track of Dive 4903. The end part, to the left of X=4800 is when I took the helm!

We begin to search for the Vent-SID, an instrument developed by some of the scientists aboard the ship that is capable of conducting an incubation directly in these harsh environments at the temperatures and pressures the microbes experience, in an effort to minimize the artificiality of putting microbes in a bottle to see what they do and how fast they do it. The instrument is brilliant, but finicky, as maintaining fully functional electronic and mechanical systems at these pressures and amidst the corrosive power of the elements here is far from straightforward. The instrument, a couple meters tall, suddenly appears ahead of us, ready for us to grapple onto with the sub’s robotic arms and transport to the specific vent of interest, Crab Spa.

Vent-SID ahoy! Starboard side! Among the Riftia!

Crab Spa is a lively place, chock full of crabs (surprise!) and tubeworms and mussels and fish and the occasional tiny shrimp beating its legs close to the viewport of the sub. Biofilms abound and sulfur particles are emitted with great intensity from this mound that first appeared following an eruption about 10 years ago. It was discovered and named by the very chief scientist of the cruise, Stefan Sievert, who passionately explores this system. We see loads of shimmering water emitted from the crevasse that is the vent, signs that hot vent fluid (at least compared to the 2ºC of the surrounding seawater) is mixing with the surrounding sea. We proceed to position the instrument at the crack, carefully and intently placing the sampling wand that will pump vent fluid into our incubation chamber directly into the flow. The temperature at the tip reads 26ºC, exactly the water we want to capture. Success. The instrument is scheduled to turn on in an hour and begin its sets of incubations to quantify a number of nitrogen and carbon cycling rates and describe the microbial communities responsible for them. And so we move on, to complete the other details of our mission.

Hordes of Riftia! Colonies of tubeworms uniquely accustomed to life in the harsh vent conditions.

The next stop on our agenda is the Bio9 vent and a colony of Riftia. These giant tubeworms are dependent on their microbial symbionts to provide food, and grow in such great abundance and to astounding lengths. They surround themselves with chitin tubes (the same material as crab shells), which they use to hide themselves in if they are disturbed. Watching the worms flick themselves into cover when a fish swims by and then slowly inch themselves back out is wondrous. We were here though for work, to pick up a crab trap deposited a few days prior and deploy a new one. A scientist on the boat studies the crabs and the parasites associated with them, and requires as many samples as she can obtain for her research. The crab trap, however, was more of a fish trap, collecting half a dozen fish and a single crab. Each organism is stark white, selectively evolved to be devoid of pigment, losing color that would be irrelevant in a world that receives no natural light. We further pick up some giant mussels for another scientist, scooping a robotic handful at a time, before moving on to our next stop on this magical journey: another vent, cutely but oddly named Teddy Bear.

Our goal at Teddy Bear was simple: collect as much water as possible so that one of the scientists back on the boat can incubate it to look at how the molecular biology changes with time. We utilize a piston-style sampler called a Major, compressed with a spring that when released allows the chamber to expand and fill with water. They have an elongated metal sampling tube so that they can be positioned precisely to suck in the specific water of choice. We fired 5 Majors here, about one and a half liters each, to bring back to the surface. We move slightly to the Riftia colony close by to collect some of these worms thriving at Teddy Bear. Yet more scientists back shipboard rely on their daily harvest of worms to dissect and characterize. Carefully plucked from their rocky beds, the worms are delicately positioned in the containers secured to the platform attached to the front of the sub so that they will be in good condition upon arrival back at the surface.

Sample baskets are full! But we can’t leave quite yet…

At this point, we have completed our mission’s specific objectives, but we have plenty of time to spare, and so we utilize it to check on a few of the colonizers that were deployed throughout the cruise and will be collected during the dive the following day. These colonizers are a mesh stretched across a stout PVC pipe. They collect the biofilm and flocculent material swirling around and allow the microbes to set root and colonize. The first colonizer we seek, deposited in a deep narrow trench on the first dive of the cruise, is unable to be seen. We bopped around for 15 minutes or so, searching everywhere for the small orange beacon floating suspended from the top, but to no avail. Rather than continue cruising in circles, we move on to see the colonizers at two much more distinct sites, and trust that tomorrow’s dive crew will have better luck in finding it.

The second colonizer to check was placed on a giant mound of Alvinella. Dubbed the Wedding Cake, this biological assemblage of a few inch-long polychaete worms is a sight to behold! The scientific name is Alvinella pompejana, named after the submersible Alvin that discovered them in the Pacific in the late 1970s (an earlier incarnation of the sub I am now viewing them from!) and Pompeii, given their extremophile nature residing only at hydrothermal vents. They are feather-shaped, but the bristles are not the worms themselves but rather filaments of bacterial colonies. We also look at the nearby nascent mound, “Cupcake,” a much smaller Alvinella colony that in a few years can reach the same sizable heft as Wedding Cake.

A colonizer deployed at the vents, designed to collect falling material and promote bacterial biofilm development for culturing and isolation shipboard.

Now we return to Bio9. Easily the most impressive site of the expedition, these black smokers defy gravity. The pillars of sulfur and pyrite, coated in bacterial biofilms, tower tens of meters from the base as billowing black smoke is emitted at temperatures exceeding 300ºC into the deep sea. The alien nature of this world is beyond comprehension. We see the colonizer and it looks good, but truly, the scientific endeavor takes a backseat to the simple astonishment of watching these spindly fingers gushing plumes of buoyant smoke upwards into the ocean. I am glued to the window, anxious as we slowly drift higher and higher in the sub, from the base of the structure to the very tips of the fingers, the newly formed mass that can grow by an inch in a week. Utterly amazing, these smokers far exceeded any of the impressive geological formations I have seen before, from the mountains of Yosemite to the Grand Canyon. Fundamentally different as well, the smokers reflect the turbulent and active nature, formed not over eons as the Colorado River dug out the Grand Canyon but continually made and remade as vents open and close and the fragile columns topple. They look exactly like the drip castles I made in the mud at the Jersey shore during my childhood, but magnified to impressive heights, and constructed not of dried sand but of the precipitated volcanic fluid emitted from the fissures. I keep reflecting on the dozens of smoking pillars and the chaotic marvel they provide.

The towering spires of Bio9! These black chimney smokers are a sight to behold. Nothing short of magic.

The time has come to ascend back to the surface and leave this world beneath the sea behind. Before doing so, however, we must transit off the primary axis of the vent, away from the active spreading center chock full of these wondrous features. We make our way to the pillow lava plains to the east, an area of rolling mounds of cooled lava. The pilot offers to let me take the stick, ignorant of the fact that I haven’t even driven a car in the last dozen years, but happy to show me how to accelerate and decelerate and turn and change the sub’s altitude. For 15 joyous minutes, I drove across the lava plains, meandering about and getting a feel for what is surely the most extreme vehicle I will ever operate. We pass over a huge anemone, but the moment is fleeting and it is gone before I have a chance to stop. A few crabs here and there, but at this point, I am consumed not by the biology, but by the magnificent joy of darting about in a tiny sub at the bottom of the ocean. In no uncertain terms, it was the perfect ending to a most dreamlike day.

A ritual full of buckets and buckets of icy seawater await each diver after his first dive… Omg it was cold. Thanks to senior scientists Stefan Sievert (left) and Jeremy Rich (right) for a momentous 10 gallon finale. Payback will come.

Alvin launch

Alvin coordinators, swimmers on Alvin, and pilot of Avon in a morning deployment.

Our dive series with Alvin consisted of 13-days, 13-dives, no days off! The daily launch of Alvin (and recovery) provides a rhythm and flow to the cruise that is unique among oceanographic cruises and something very special about Alvin cruises. I find the whole routine comforting and adrenaline pumping, making me want to jump out of bed in the morning regardless of how little sleep the night before working.

Alvin getting a scrub down after its last dive of the series, showing Alvin’s hangar and the Doghouse above.

Alvin deployments are the ultimate example of teamwork between the crew of the ship and Alvin team, involving individuals or teams of 2-4 people. The teams each have their names: the Bridge, Doghouse, Alvin coordinator, and Avon. The Bridge oversees operations, Doghouse runs the A-frame that lowers Alvin into the water, Alvin coordinator is on deck with Alvin, and Avon consists of crew that deploys and operates the 18-foot zodiac boat that picks up two swimmers, who ride along on the outside of Alvin as it is lowered into the sea, releasing the giant rope holding Alvin to the A-frame. Once Alvin is in the water, the swimmers put the finishing touches on Alvin for the dive, releasing Alvin’s arms and thrusters. Hearing all four teams over the radio when in the sub for a dive is one of the many welcome routines that I’ve grown accustom to during my four dives on this cruise. The team members’ rotate positions, so that someone new is doing a particular job on any given day. Every deployment is run like it is the only deployment that matters, with crew and Alvin team being extremely vigilant and careful, running through their checks so that deployments go smoothly and safely.

Alvin coordinator Josh Sisson with scientists Sushmita Patwardhan (left) and Ileana Perez Rodriguez after a successful dive.

The crew and Alvin team make everything look seamless. Us scientist have the thrill and honor to watch this daily routine play out over and over again during the dive series. We really appreciate all the hard work of the crew and Alvin team in deploying not only Alvin but in many other important jobs on the ship.

Sunrises at 9˚N

Sunrises are part of my morning routine on Alvin dive days. I naturally fell into this routine on my last Alvin cruise at 9˚N in 2014. On this cruise, I made a point of catching every sunrise on each day of our 13 dive series. For me catching the sunrise is an important part of my routine, giving me a moment to contemplate the excitement of the day to come and marvel at the endless horizon and raw beauty of the ocean. There is a sense of wonder, of sky, intense color, and blue water that is unique to being so far from land. We are in the middle of nowhere at 9˚N, with not a single airplane, contrail, or any other vessel in site during our dive series. All the troubles in the news media are far away. Our focus is on the moment, taking in the beauty of the ocean in between long hours of work and focus on our research objectives. After sunrise, there is breakfast and then wishing our colleagues good luck and happy farewells as they embark on their trip to the seafloor. And of course watching the awesome crew and Alvin team at work as they launch Alvin!

Sunrises during our dive series, with date and dive number corresponding to each day of the series. Our 13th dive (4905) on May 8 is not shown.

Maybe you are asking how we all got here, 2.5 km below the ocean surface. If not, it is certainly one of the first questions that pops to my mind when I look around the lunch tables and the lab benches on the Atlantis. I asked around, and got one of two answers; either they arrived driven by passion for the deep sea, its microbes and animals, or they had perfect timing, they were at the right place at the right time. For me, this has been a journey of passion for the eccentric microbial world.

Alvin in the water in the middle of the Pacific Ocean ready to go for a dive.

Since I learned about hydrothermal vents and the fascinating microbes (chemoautotrophs) that maintain these primitive environments I was hooked. I knew I would one day study how they grow, where they grow, and who they are. Nonetheless, seeing the videos of deep sea vents and pictures of the Riftia worms seemed light years away siting in my parents apartment in the middle of the Andes mountains 2.6 km above sea level. However, I was determined to try. I started building up a career as a marine microbiologist jumped back and forth over the Atlantic, to study chemosynthetic metabolisms like sulfur oxidation and nitrification in marine environments. Today, less than a year after finishing my PhD, I find myself on the Atlantis research vessel a few days after meeting the great hydrothermal vents of 9°N face-to-face on the 4900th Alvin dive.

The Alvin dive starts with a soothing 2 hour descent, enough time to settle into your new reality: ‘there is a 2+ km thick column of water above your head! there is no quick way out anymore’. I am a scuba diver and practiced some free diving in the past, so I know what it feels like to immerse yourself and stay underwater. The idea of the wall of water above my head is thus simultaneously terrifying (because it can crush you) and exhilarating (because who knows what you might see this time out).  Once underwater I always focus on the little organisms in the water column to forget the terrifying part and enjoy the dive. The same occurred during my Alvin dive. Going down I was feeling uneasy so I stared out my window and was delighted by the silent dance of the many bio-luminescent lifeforms streaming by.

First time diver glued to the viewport as Alvin descends.

When we finally approached the bottom, Alvin’s lights were on and I found myself peaking into the dark ocean, hovering above a majestic submarine lava field, filled with anticipation of what was to come (not caring anymore about the cubic meters of water above). During our 4 hour dive we visited several sites: Crab spa, Bio 9, P vent, Teddy Bear, and M vent which gave me a birds (or rather fish) eye view of the diverse landscape you can find at 9°N.

Hairy rock samples covered with filamentous bacteria.

We saw meter high chimneys with warm (and thus denser) fluids pouring out, black smokers that cast a “shadow” over the Alvin, juvenile fish bathing in the vent fluids, and white snowy flocks shooting into the black ocean. I also saw a variety of rock formations: black, orange, white, furry (covered with microbial growth), shinny, opac, sharp, and round silently waiting for the next eruption. We glided over a field of collapsed gas domes as big as the Alvin and sailed through the central axis that serves as a highway between the different vent outflows. Immersed in this incredible environment we set out to collect samples for the entire science team. First we positioned the nossel of the large volume pump into the vent fluids at Crab spa to collect samples for chemical and microbial analysis. Secondly we re-deployed a microbial colonizer on Alvinella mound (alias “wedding cake”) that had fallen down.

My viewport during lunch, Riftia forest just out of reach.

Afterwards we moved to Bio 9 to set a crab trap filled with Riftia and mussel bate, and then settled next to a field of Riftia to enjoy our lunch. This was probably the most memorable part of my trip, since we were able to just sit and observe, take a couple of minutes to pretend we belong. During this pause I saw orange shrimps and white lobsters rowing in front of the Alvin, numerous crabs marching towards the crab bate, little tube worms waving in the water, nervous meter long red Riftia (worms) popping in and out of their tubes, and oblivious white fish hanging out in the Riftia colonies (just to mention a few).

Iconic black smoker.

After lunch Phil and Stefan took me for a tour of Bio 9, a black smoker that spews out hot black vent fluids, what a sight! I had seen similar images in almost every article I read about deep sea vents, and now I was here taking the pictures, just priceless. Then we flew over to Teddy bear to take vent fluid samples for incubations on board and collected a crowded crab trap that had been placed in a previous dive. Finally we collected three hand fulls of Riftia in the biobox attached to the front of the Alvin and strolled along to M vent to see the impressive structures. By then it was 15:15, it was time to go back to the surface, what a sad thought. I would prefer to stay and have dinner with the Riftia colonies.

Back on board the Atlantis, I stared out over the vivid blue ocean and think of the magical world that lies (way) below. What an adventure this was! I will definitely return to continue studying my chemoautotrophs. Thanks to all the Alvin and Atlantis crew for making this odyssey possible and special thanks to Stefan Sievert for inviting me along and making my wildest dream come true.

The view from the Atlantis at 9°N 50′ and 104ºW 17′.

Spending most of my childhood summers near the mangrove swamp, I find the smell of sulfide in the water sample coming up from the abyss on each Alvin dive strangely familiar.  On this cruise, I perform a number of on-board chemical analyses on the vent fluid samples (including concentrations for ammonia and sulfide) and collect samples to bring to the lab back in Woods Hole.

Major Sampler Team striking a pose in front of Alvin.

On most days, the routine is more or less the same.  Alvin surfaces in the late afternoon and we retrieve the Major samplers (which we use for collecting vent fluids) after the submersible is on deck.  My Hydro Lab teammates and I carefully sample from these samplers one by one.  We keep good notes on the white board for the parameters we measure like pH and salinity.  These two measurements, despite sounding seemingly basic, can tell us so much about the water we sample.  In most low-temperature samples (like those of less than 30°C in situ temperatures), they have very similar salinity to that of the bottom seawater (35-37 parts per thousand: 35-37 gram of salt in 1kg of seawater solution) simply because they have a lot of seawater mixed in it.  Their pH values ranges between 5 and 6 (like those of black coffee or milk) On the other hand, the high-temperature vent fluids from the black smokers which have in situ temperature as high as 360°C tend to have lower salinity and also a lower pH of 3-4 (like those of tomato juice or vinegar).

Keeping track of the measurements done on vent fluid samples.

After the pH and salinity measurements are made we proceed with taking samples for other analyses including sulfide and ammonia.  Hydrogen sulfide is the chemical that gives the vent fluid a distinctive rotten egg smell, which permeates the entire Hydro Lab.  Disgusting to most of us, this smelly sulfide however is a good source of chemical energy for many microbes inhibiting around the hydrothermal vents.  They can harvest the energy stored within sulfide for their growth and metabolisms.  Similarly, some microbes can also utilize ammonia in the similar manner.   As a PhD student, I am particularly interested in the production and fate of ammonia in the hydrothermal vent fluids by looking at the nitrogen isotope ratios in different nitrogen-bearing ions and compounds.

Prior to participating on this cruise, I had worked with the water samples collected by other scientists.  So I had very limited knowledge of the processes and hard work that go into the sample collection.  Of course, getting to work in the Major Sampler team and getting a dive in the famous Alvin changed all that.  I was a starboard observer on Dive#4901 on May 4, 2017.  I first learned about Alvin in my undergrad Biological Oceanography class many years back, so it was unimaginable that I would get a chance to ride in it as a PhD student.  All that I learned about light in the ocean was experienced first hand as we made a descent down.  Looking out of the porthole, I observe the water turned from the light shades of blue to the darker hues as we exit the photic (i.e., well-lit) zone of the water.  Jellies are everywhere until we hit the layer called oxygen minimum zone, which at least in this part of the ocean is completely devoid of oxygen. Once we made it out of those depths, the dark water was decorated with the sparkles of bioluminescence (an absolute sight to see).

Major sampler intake nozzle inside of the black smoker chimney during sampling at Biovent.

We had a long list of what we needed to accomplish on this dive including releasing our large volume pump back to the surface, deploying our Vent-SID, taking water samples with Major Samplers, and investigating the crab traps and microbial colonizers; all of which were masterfully executed with ease by our seasoned Alvin pilot, Pat Hickey.  We spent quite a bit of time around black smokers at the sites called Bio9 and Biovent.  I had seen the photos of these stunning structures numerous times before, but nothing remotely compared to what I observed with my own eyes from Alvin; truly a spectacle they are.  The sheer number of animals around the vents is also amazing.  It was such a stark difference seeing merely a couple of them here and there off axis compared to vast expanse of mussel beds and giant tubeworm patches.

Big hollow space in the ground at Hobbit Hole.

As a bonus to our dive since we managed to accomplish all tasks on the list relatively early, we decided to travel further north to a site called Hobbit Hole.  Yes, the site has a structure similar to those you have probably seen from the Lord of the Ring movie: a big hole in the basaltic rock.  We scouted around for a little bit for some warm spots of diffuse flows before we made our way back to the surface.

Before I sign off, I would like to thank the Alvin Team, the crew of R/V Atlantis and of course our Chief Scientist, Stefan Sievert, for such an amazing experience to be on this cruise and of course to be an observer in an Alvin Dive.  My oceanographer’s dream had come true.

Monday, May 1, was the day for my first Alvin dive. I was full of excitement and should not get disappointed. It even exceeded all my expectations and was truly an experience of a lifetime.

After climbing into the submarine at 8:00 in the morning, we were lifted off the deck of the R/V Atlantis and lowered into the ocean. Support swimmers, sitting on top of the sub while being lifted into the water, detached the lines that were connecting us to the ship and did the final safety check. Then the journey began, to the deep, dark, bottom of the ocean. I could hardly wait.

Stefan and Kevin onboard Alvin

On-board of dive #4898 were the experienced pilot Pat Hickey (more than 680(!) dives), starboard observer and chief scientist Stefan Sievert and myself. The sphere of Alvin is actually quite spacious and provided enough room for stretching legs – one person can even stand at a time. On each side of the sub, mine was the starboard side, are two small round windows to look out of and another out front, overlapping with the pilot. We could control cameras that allowed us to look around and record what we were seeing.

On the way down with a speed of ~30 meters per minute, we were first moving through sunlit, clear, and blue water. Some smaller jelly fish and zooplankton were passing by the viewports, but there were not too many organisms to see due to the oligotrophic conditions in this area. But then, below the illuminated zone, as darkness descends, the water became alive with displays of bioluminescence – tiny flashes of lights produced by organisms using a chemical reaction. It felt like moving through an ocean of stars and it was more beautiful than I had expected. Suddenly, when we entered the oxygen minimum zone, we were enveloped by nothing but darkness until we reached the deeper oxygenated waters, which revealed a dazzling display of bioluminescence again. I kept starring outside the little windows almost the whole way down and was seldom so calm and full of joy.

Collecting rock samples at Crab Spa, a vent emitting vent fluids with a temperature around 25ºC.

At the bottom (~2500 m below sea level), the lights of the sub were switched on and the work began. Equipped with giant robot arms, which were controlled by Pat as they were his own, and a number of samplers and sensors, fluid, rock and biological samples can be collected. For safety reasons, we landed off-axis on a relatively plain pillow lava field. Here, we picked up a previously deployed instrument, the large volume pump, which allows to filter a large amount of vent fluids in situ, and made us on the way to our first station named Teddy Bear. When we entered the hydrothermal vent field, the landscape became rough with ridges of basalt, small chimneys, and cracks in the basaltic crust. It was like flying through a canyon in walking speed. White vent crabs were sitting on the black basalt and although they are blind, it seemed they were staring at us just like I was staring at them.

Sampling of hot vent fluids at Q Vent.

At the vent sites, hydrothermal fluid discharges are seen as shimmering water. Armed with a handful of water samples, we were after these fluids. Reduced chemical species that are vented at deep-sea hydrothermal systems support diverse microbial populations that are independent of sunlight and participate in important biogeochemical processes. Back in the lab, chemical and molecular analysis will provide insight about microbial identities, microbial metabolisms as well as adaptation to this extreme environment. So we basically aim to answer the questions: Who is there, how many, and what are they doing? These chemosynthetic organisms provide the basis of the food web at deep sea vents, which are often surrounded by flourishing life, including white crabs, Riftia tubeworms, vent mussels, vent shrimps, and long white fish.

The top of P vent, a towering black smoker that’s about 13 m tall.

I was really astonished by the abundance and diversity of life that we saw at several of the visited sites and now fully understand why hydrothermal vent fields are often called oases on the ocean floor. At the end of our dive, we made our way to a vent field named Bio9 and P Vent. Here, we explored black smokers – more than 10 m high, roughly cylindrical chimney structures that emit a cloud of black, superheated (we measured 366 °C at Bio9) material. These are probably the most impressive deep-sea vent features and it was just amazing seeing these structures with my own eyes.

After five hours on the seafloor and with all science objectives completed, we ascended to the surface and Alvin was craned backed onto the ship. Our colleagues were already waiting and I received the traditional ice water bucket bath for first-time Alvin divers. I have enjoyed every single minute and would not hesitate a millisecond to go on another dive. I am very grateful for this opportunity.

Since their discovery 40 years ago, deep-sea hydrothermal vents have attracted a lot of interest in understanding how life can thrive in the absence of sunlight. If you have been reading this blog, you probably know by now that this is supported by chemosynthetic microorganisms that can harness the energy from reduced chemicals in the vent fluids and fix carbon, which in turn fuel an amazingly diverse fauna. But this is only one side of the carbon cycle story. Once the carbon has been fixed into biomass, the fate of all this organic matter is still largely unknown.

For example, take the beautiful and dense patches of Riftia tubeworms. With a little help from their chemosynthetic symbiont friends, these animals can grow at the impressive rate of about 1 m per year. Notably, they can produce tubes up to 2 meters long and 4 cm in diameter, made of up to 30% of a sugar polymer (i.e. a poly-saccharide) called chitin. Additional sources of chitin at deep-sea vents include other tubeworms such as Tevnia or Ridgeia as well as the shells of the numerous crabs, squat lobsters and shrimps that thrive down there. However, there is no massive long-term accumulation of tubes and crab shells… Now what happens to all this sweet chitin?

A colony of Riftia pachyptila tubeworms near Teddy Bear, one the sites under investigation during this cruise. Note the patch of dead animals on the right.

As a microbiologist studying polysaccharide-degrading bacteria, this question has piqued my curiosity since my first cruise in 2014. Indeed, numerous studies on soil, coastal and freshwater environments have led to the conclusion that bacteria are major mediators of chitin degradation in nature. Yet, very little is known about who can recycle chitin at deep-sea vents, and how they do it. So, here am I aboard the Atlantis for this cruise, embarking on a treasure hunt for chitin-degrading microorganisms from different vent sites.

Riftia-associated bacteria (dark rods, about 3-5 µm in length) feasting on a chitin particle.

Every day, the submersible Alvin comes back from the deep world with new material for me to search for these unknown degraders: tubes of live or dead Riftia, crab shells, vent fluids, etc. Then, the strategy is simple. I use these samples as inoculum in a seawater-based culture medium containing only chitin as a carbon source, in hopes of “enriching” for chitin-loving microbes. After a few days of suspense, I check the cultures for growth using a microscope (quite a funny task on a moving ship!). I am very excited that my efforts so far have been rewarded with several growing cultures, showing multiple types of deep-sea vent bacteria feasting on chitin particles!

Back in my lab at the Station Biologique de Roscoff (France), I will further characterize these new isolates, to find who they are (i.e. their “taxonomy”), evaluate their abundance in the environment, study their physiology and understand how they degrade chitin. So, this cruise is the beginning of many more scientific adventures to come!