Day 16: So long, and thanks for all the fish

bow view

95% of the time, all units on the R/V Thomas G. Thompson—the science party, the submersible teams, and the ship’s crew—are either working hard or sleeping (a lot more of the former than the latter).  But on this jam-packed 16-day cruise, we still found a little time here and there to enjoy the experience of being on a ship. As we head back to port and get ready to call it quits, here are a few highlights from life at sea.

 

fishing

Fishing over the side was a popular pastime during the rare calm moments between deck operations. It looked like we might strike out on this cruise, but on Friday night, we finally caught 5 mahi in a combined effort between the ship’s crew and the science party.

Arne fish

mahi poke

This left us with about 35 pounds of fresh fish, which the Thompson’s fantastic mess team whipped up into poke (above) and fillets.

 

 

making eggs more

Thanks to Sarah, the Thompson’s steward, we got to celebrate Easter at sea by decorating eggs. When the ROV Jason had to pull out of a dive earlier than expected, we had a chance to attack egg decorating with the same intensity that we’d been applying to lab work.

jason egg

Arne’s egg featured a sketch of Jason.

egg tray partial

On the last night of the cruise, Sarah and Clara staged an egg hunt in the storerooms below decks. Prizes included a Thompson t-shirt and mug, a hard hat, and, for the person with the least eggs, a deck chair hand-painted with the words “TGT Loser Easter 2013.”

happy easter

 

 

During periods between submersible launches and recoveries when the ship was holding a steady position, the science party was allowed to come up to the bridge (the control center of the ship on the uppermost deck) for a look around. 3rd mate Lucas walked us through the whole set-up: steering controls, radar and navigation monitors, radio systems, signal flags, and an assortment of mysterious buttons and knobs.

bridge long

bridge corner

 

 

The plus side of having to stay up all night processing samples is that you might get to see a beautiful at-sea sunrise. Here are Anna, Sean, and Clara taking a break from lab work to check it out.

sunrise bow

 

 

We finished up our last Jason dive ahead of schedule, which gave us time for a little something extra before returning to port. The Thompson’s crew obliged us with a drive-by past active lava flows on the coast of the Big Island.

watching flows

We couldn’t get close enough to see anything glowing red, but the plumes of rising steam show clearly where the flowing lava meets the sea.

steam zoom out

steam zoomed in

 

It’s been an intense, challenging, and rewarding expedition, with lots of deep-sea exploring, experimenting, microscope staring, electrode polishing, watchstanding, acid washing, all-nighters, teamwork, and more samples than you can shake a nano stick at.  Although we’ll be sorry to say goodbye to the Thompson, everyone is looking forward to getting some rest back on land, and making progress on the exciting projects that got started at Loihi this year.

side view with moon

–Cat Wolner, NSF

 

Photo credits: Jason Sylvan (lava flows), Heather Fullerton (Arne with fish), Arne Strum (poke); all other photos Cat Wolner

Day 15: Captains of the deep

Jimmy control room

We couldn’t let the cruise come to an end without a post about the ROV Jason team, without whom none of this research would be possible. This intrepid crew has taken us from the rugged craters of an undersea volcano to the smooth, otherworldly plains at 5 km below the ocean’s surface, all without ever leaving the deck of the ship.

Our Jason expedition leader and chief pilot is Alberto “Tito” Collasius, Jr., who got his seagoing start as a dishwasher aboard the voyage that discovered the Titanic wreck. Before going to sea, Tito didn’t know that deep submergence tools like ROVs existed—but once he saw the technology in action, he knew he wanted to be involved. After about 15 years as a ship crewmember, Tito made the transition to ROVs, and now he’s pleased to be able to say that his “office” is anywhere from 1 to 5 kilometers below the surface of the ocean.

Tito overseeing a Jason recovery.

Tito preparing for a Jason recovery on the fantail.

Tito spends about a third of his time at sea on expeditions, and the rest of the time at home in Massachusetts working on ways to improve the vehicle and make dives go more smoothly. When he’s at sea, Tito doesn’t just fly Jason—as expedition leader, he’s also responsible for coordinating operations with the science party and the ship’s crew, managing launches and recoveries, training junior team members, and organizing watches (shifts) that work together effectively. Jason dives can last 72 hours or more, so watches in the control van run round-the-clock. Each watch is four hours long, twice a day (e.g., 4 am to 8 am and 4 pm to 8 pm).

A watch consists of a navigator, an engineer, and a pilot. The navigator drives the ship from within the Jason control van, keeping it where it needs to be in relation to the vehicle, and also tracks the position of the elevators. The engineer controls Medea (Jason’s power and information conduit) and the enormous associated cable winch on deck, monitors vehicle systems, and supports the pilot with operating the various compartments and tools installed on the vehicle. The pilot’s main job is to fly Jason and control the vehicle’s two manipulator arms—perhaps the most highly specialized, artistic part of the operation. In addition to the watchstanders, there’s also a data manager tasked with the monumental job of handling all of the event logs, multi-camera video footage, and photos from every dive.

A masterful use of the manipulator arms for undersea sampling.

A masterful use of the manipulator arms for undersea sampling.

There are about 15 people in the Jason team’s pool of seagoers, but only a subset of this number goes on each cruise. The group we have on this expedition runs the gamut of experience. Pilot Jimmy Varnum has been working with ROVs for over 30 years in settings ranging from vehicle design to salvage operations to oil field and military support, and now works exclusively on Jason science cruises. On the other end of the spectrum, Baxter Hutchinson, who’s in his early 20s, pursued his spot on the Jason team after getting a recommendation at a robotics fair a few years ago. But regardless of experience, the team works well together. Jimmy says one of his favorite things about the job is the group of people with whom he gets to go to sea.

Jimmy prepping Jason for a dive.

Jimmy getting Jason ready for a dive.

Jimmy is known for keeping his watch entertained with colorful commentary. Most of what he says is unprintable, but what comes through between all the swear words is that he loves being a pilot. The jobs he finds most satisfying involve using the manipulator arms to install and work on large instrumentation—e.g., CORKs—but he also enjoys scientific sampling in general, and the essential thrill of flying a 9000-pound vehicle around the ocean.

Tito says he knows the Jason team has done its job right when he sees that the scientists are overwhelmed with more samples than they know what to do with. The science party’s current state of sleep deprivation is a testament to just how many samples we’ve had to process, so there’s no question that this expedition meets his ambitious standards.

 

–Cat Wolner, NSF

To see the Jason team in action, check out WHOI’s short video from 2011.

 

Photo credits: Shingo Kato (top), Cat Wolner (2nd), Brian Glazer (bottom); subsurface photos from the Jason control van

Day 14: Charismatic macrofauna

In our search for Zetaproteobacteria, we sometimes come across larger, more conventionally photogenic creatures, dubbed “charismatic macrofauna.” Although our main goal is Zetas, these multicellular organisms provide for interesting discussion and entertainment during our Jason dives. Many fish and small invertebrates swim quickly by Jason’s cameras, so capturing one on film can sometimes be quite a challenge. If the scientists can’t quite capture the macrofauna with the High Definition cameras, Jason is equipped with cameras that take photos every minute. With careful note taking and patience, we can look back through this log to find these strange life forms. Here are some of the better shots we’ve gotten over the past few days.

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Here we see the tadpole-like fish mentioned in a previous post, with another fish that appears to be standing on the seafloor. These two fishes were found at FeMO Deep (4980m depth).

 

crinoid

This flower-like organism is known as the stalked crinoid. Here it perches on pillow basalts at FeMO Deep, feeding on passing particles in the water column. Stalked crinoids have been seen moving from place to place by using their petals to pull their body across the seafloor.

 

anenome

At approximately 5000m deep, this sea anemone is living under high pressure; perhaps that is why it appears so angry.

 

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Swimming along the seafloor at FeMO Deep is what appears to be a lobster. Unlike Lō’ihi, FeMO Deep is very flat. In this type of landscape it is very easy to spot movement in the distance.

 

shramp

shramp 2

Back near the summit of Lō’ihi, we see small shrimp. Bresiliid shrimp (Opaepele loihi) are endemic to Lō’ihi Seamount and appear to feed on the microbial mats. These shrimp have been observed walking over baitfish but it wasn’t obvious that any were consumed (Vetter, 2005).

 

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The shrimp are not without predators—here’s one being chomped by an eel.

 

angelina

A rare sighting, two fish in one shot! Here you can see the large anglerfish and a small, sleek eel-like fish. The anglerfish has a fleshy protrusion above her mouth, which is used to attract prey. We’ve nicked named this beauty ‘Angelina’ for her large pouty lips. The smaller fish in this photo has been dubbed the ‘screeching eel’ since it is often seen with its mouth wide open, perhaps screeching at the light.

 

rattail

Another rare sighting at Lō’ihi, the rattail. However, these fishes are some of the most abundant in the benthos.

 

shark

Shark! While Jason is exchanging samples on the elevator, a curious sixgill shark comes looking for its next meal. This species has been recorded at depths up to 1875 meters; so seeing one at 1300m isn’t a big surprise, except to the science crew!

 

Not much is known about the macrofauna of Lō’ihi and FeMO Deep, but us Zetahunters have become amateur zoologists during this research cruise.

–Heather Fullerton, Western Washington University

Photo credits: all photos from the Jason control van

Day 13: Adventures in anaerobia

test tubes close up

We know that Zetas, the iron-oxidizing bacteria that have been our primary focus on this cruise, live at the edge of the oxygen minimum zone in the deep sea. But what happens when you dig below the actively growing surface of the microbial mat, into older, deeper layers of the mat that are cut off from oxygenated water?

Even in the absence of oxygen, microbial life goes on. There may not be any iron-oxidizing Zetas living in the anaerobic (or no-oxygen) zone of the mat, but there are other kinds of microbes in Loihi’s hydrothermal vent communities—some of which don’t need oxygen at all.

Post-docs Joerg Deutzmann and Anne Kaster of Alfred Spormann’s lab at Stanford University are here to search for these anaerobic life forms. They’re working with samples collected where oxygen is absent, as indicated by the electrochemical sensors that we’ve been deploying via the ROV Jason. This usually means that the samples come from the interior of a microbial mat or a hydrothermal venting orifice (below).

An arm of the ROV Jason collecting an anaerobic fluid sample from a deep-sea hydrothermal vent orifice.

Using the ROV Jason to collect an anaerobic fluid sample from a deep-sea hydrothermal venting orifice.

Joerg is interested in isolating anaerobic species that could be used for microbial electrosynthesis. In this process, microbes are “fed” electrons from a cathode. The microbes’ metabolic use of the electrons drives industrially or environmentally relevant chemical reactions—for instance, transforming cancer-causing compounds into harmless substances (i.e., bioremediation), or generating CO2-neutral biofuels.

Joerg is super excited that microbes are growing in one of his tubes.

Joerg is super excited that microbes are growing in one of his tubes.

To isolate the anaerobes, Joerg is using tubes containing different combinations of gases, fluids, and solid substrates that encourage them to grow.

A tube for growing microbes from the anaerobic zone.

A tube for growing microbes from the anaerobic zone, with elemental iron substrate at the bottom.

Anne’s focus is on single cell genomics and metagenomics. Deep-sea anaerobic microbes—which are ancient in origin—share certain genes with land-based microbes used in bioremediation. Anne’s genetic studies of the deep-sea species are aimed at getting a better understanding of how the bioremediators evolved, potentially take us a step closer to being able to engineer them in the future.

What parts of the hydrothermal chemical system are anaerobic microbes using as an energy source? What industrial applications might they have? Do anaerobic microbes exist independently of Zetas, or are there symbiotic relationships among different members of the microbial mat community? The Spormann Lab’s work on this cruise will help to answer these questions, adding a new dimension to our picture of Loihi’s deep-sea microbial ecosystems.

–Cat Wolner, NSF

Photo credits: Cat Wolner (top three); subsurface photo from the Jason control van

Day 12: The Emerson Lab–cassettes, cultures, and interconnections

mat sampler close up

Dave Emerson (Bigelow Laboratory for Ocean Sciences) is a Loihi veteran. He and Craig Moyer have been coming here for decades to investigate the microbial ecosystems of the seamount. Over the years, Dave and his collaborators have gotten a pretty good sense of who lives at Loihi (microbially speaking), so now the focus is on getting a more detailed, fine-scale picture to help place the iron-oxidizing Zetas in a functional and evolutionary context.

Anna prepping the mat sampler.

Anna prepping the mat sampler.

The new tool that’s helping to make this possible is the mat sampler (sometimes called the cassette sampler) that we’ve been featuring so much on this blog. Previously, sampling technology was limited to scoops and vacuum slurps (pretty much what they sound like)—techniques that pick up a lot of biomass but don’t allow for any assessment of fine-scale details. Initial attempts to sample microbial mats with syringes revealed that communities could vary substantially on the scale of centimeters—a much finer scale than what a scoop or a slurp could capture. But individual syringes were difficult to operate with the ROV Jason’s robotic arms.

So Dave pursued funding with Chip Breier of Woods Hole Oceanographic Institution to develop the mat sampler, which involves a cassette of 6 syringes, each with a separate nozzle to avoid cross-contamination. The cassettes journey to the seafloor by elevator or in Jason’s science basket.

magnet wand cassette

When it’s time to sample, the Jason pilot picks up a cassette using a magnetized wand gripped with one of the vehicle’s arms (above). The pilot uses the wand to position the nozzles, but the syringes themselves are operated remotely by a tablet computer. The pilot and the tablet user work as a team to get a sample of microbial mat into each syringe.

Emerson Lab post-doc Erin Field is using samples collected in the cassettes for single cell genomics, meaning that she’s isolating individual Zeta cells and amplifying their DNA so that she can sequence it. The results will be tied in with metagenomics from the Moyer Lab in order to relate individual microbe metabolisms to the functional capacity of the whole microbial community—in other words, tying the individual to the group.

slide trap - anna credit

Along with the mat sampler, the Emerson Lab is making use of slide traps (above and below). Inside the plastic housings are glass microscope slides positioned to collect microbes on their surfaces.

Slide traps deployed on a deep-sea ridge.

Slide traps deployed on a deep-sea ridge.

When the slides are retrieved, technician Anna Leavitt views them under the microscope to observe the Zeta-created mat structures in their intact form—something that’s difficult to preserve with other sampling devices.

Micrograph of iron oxide structures produced by Zetas.

Micrograph of iron oxide structures produced by
Zetas.

Post-doc Jarrod Scott is developing node networks that show how different microbe populations found at Loihi are interconnected with one another (below). The node (dot) size indicates the abundance of a given species; the length of the line between two nodes indicates how closely two species are associated.

One of Jarrod’s node networks showing associations between different species of microbes found at Loihi. Individual species are represented by nodes (dots); associations are represented by lines.

The Emerson Lab is also continuing ongoing efforts to culture Zetas. This is a tricky, iterative process that involves creating Loihi-like micro-habitats in the lab and tweaking them to encourage different types of Zetas to grow. The electrochemical data that the Glazer Lab has been collecting on this cruise will help to better define the chemical and thermal niches in which different kinds of Zetas grow best, facilitating the Emerson Lab’s efforts to culture a wider variety of Zeta species.

By understanding Zetas, the Emerson Lab and their collaborators on this cruise are pushing forward our understanding of life on Earth, and maybe even beyond. Zetas are potentially ancient organisms that are highly evolved for using iron as an energy supply, and may be analogues for life in extreme, iron-rich environments on other planets. As Dave says, Zetas may be tiny, but they’re worthy of interest: they’ve been around for a long time and they may once have been among the most dominant life forms on Earth.

–Cat Wolner, NSF

For more on this, see Dave’s essay on orders of magnitude and interconnections in the study of Zetas.

Image credits: Anna Leavitt (top and fourth photo, micrograph), Jason Sylvan (second photo), Jarrod Scott (node network graphic); subsurface photos from the Jason control van

Day 11: The rock is alive!!–or, a day in the life of Brian Glazer

I’m Brian Glazer, an associate professor of oceanography at the University of Hawaii.  My lab group specializes in understanding how chemical cycles influence and are influenced by microbes.   I’m currently on sabbatical this year, on fellowship with the Hanse-Wissenschaftskolleg Institute in Germany, but I’m participating on this expedition because of the exciting opportunity to work with friends and colleagues at an amazing site, and use some cutting edge tools like ROV Jason II and AUV Sentry.  This is my 19th oceanographic expedition, 7 of them with Jason II.  It’s also my 5th expedition to Loihi.

The hydrothermal environments at Loihi Seamount serve as an ideal natural laboratory for studying aspects of geology, chemistry, and biology.  Heat energy from Earth’s interior warms basalt rock that interacts with deep subseafloor circulating seawater, altering its chemistry.  That altered fluid rises back to the seafloor, and microbial communities take advantage of the chemical energy in the fluids, and in the case of iron-oxidizing bacteria, they leave ferric oxyhydroxides behind (bacteria growing & producing rust in the process!). The synergetic relationship between fluids, rock, and microbes that results in such visually striking vents and microbial mats at the seafloor is an expression of subseafloor processes occurring within the rock; the rock is alive!

Ultimately, the rust that the bacteria leave behind may even be preserved in the rock record, helping us learn something about the biology & geology of earlier times on Earth…and it’s really tantalizing to speculate about potential for such geological-chemical-biological relationships on other planets like Mars & Europa.  The active volcanic pit crater at the summit is at about 1100m below the sea surface, which intersects the oxygen minimum zone in this region of the Pacific, and provides optimal conditions for iron-oxidizing bacteria to thrive.  We’ve estimated that between ten million and four hundred million cells per square centimeter per year could be supported by the iron-oxygen energy flux commonly found in the pit crater area. This could equate to about 20 kilograms of biological carbon per day.  Hydrothermal microbe math, yay!

A warm, actively venting site near the summit of Loihi, with one of Jason’s arms gripping a temperature probe in the foreground.

A hydrothermal site near the summit of Loihi, with one of Jason’s arms gripping a temperature probe in the foreground.

In contrast to the warm, actively venting habitats at the summit (shown above), we’ve also located a new ultradiffuse hydrothermal field at the base of the volcano in 5000m water depth.  During a combination of this expedition on board R/V Thompson, and a planned expedition on board R/V Falkor in 2014, we will compare and contrast the geochemistry, microbiology, and geologic settings between summit and deep sites.  We hypothesize that the cold, deep mats found at FeMO Deep are a microbially-controlled genesis of geologic-scale iron deposits similar to umbers found in the rock record.  Over the course of several dives, we’ll use a variety of high-tech and low-tech in situ analyzers, samplers, and data recorders to collect as much physical, chemical, and biological information about our sites as possible.  Days are long, and the schedule is busy, but very rewarding.  Here’s what a typical day at sea is like for me early on in the expedition:

06:00 – wake up, shower, make a double cappuccino

06:30 – check the computer lab whiteboard & the Jason Virtual Van for a quick check of where we are on the current dive plan.  My group has the lead for characterizing the geochemistry of fluids and particles collected from various Loihi sites, so we divide our time between our scheduled shifts in the ROV control van running in situ electrochemical analyses, and preparing for or analyzing discrete samples that are brought up by Jason or elevators.  There’s always lots to do, and it can sometimes be a little confusing to try to get up to speed after catching a few hours of sleep.

View of the Jason control van from the electrochemical (a.k.a. e-chem) operator’s seat. Monitors in the background are live views from Jason of e-chem sensor deployment. Monitor in the foreground shows real-time e-chem data.

View of the Jason control van from the electrochemical (a.k.a. e-chem) operator’s seat. Monitors in the background are live views from Jason of e-chem sensor deployment. Monitor in the foreground shows real-time e-chem data.

An elevator coming up in the wee hours.

An elevator coming up in the wee hours.

06:50 – a quick lesson on the new navigation system from the AUV Sentry team.  While the ship is very maneuverable and can be positioned precisely by using GPS, GPS doesn’t work underwater. Jason and Sentry have to rely on acoustic signals from the ship in order to precisely navigate their positions on the seafloor.  The first task when we arrived on station was to calibrate the ship’s GPS navigation system with the ultra-short baseline navigation system (USBL) underwater acoustic navigation system by dropping a nav beacon overboard and having the ship do figure 8’s back and forth to coordinate the two systems.

USBL (ultra-short baseline) navigation screen showing ship position laid over bathymetry (in meters).

USBL (ultra-short baseline) navigation screen showing ship position laid over bathymetry (in meters).

07:25 – breakfast of fruit, cottage cheese, pancakes, bacon, and, of course, more coffee.

07:45 – fluid sampling team meeting to review objectives, and finalize protocols & subsampling methods.  For this expedition, our fluid sampling and analysis team consists of me and my two postdocs, Angelos Hannides and Arne Sturm, and collaborating scientists, Karyn Rogers (Carnegie Institute of Washington), and Jason Sylvan (University of Southern California).  In addition to the in situ analyses explained below, we have a suite of fluid and particle analyses that we’re targeting in order to better understand the synergy between the Loihi heat source, rocks, hydrothermal fluids, and the microbes that colonize the vents, walls, and chimneys.

09:00 – adapting inline filters for the in situ mat sampler syringes with Dave Emerson and Jared Scott.  In addition to collecting whole samples of a mix of particles and fluid, we’re really interested in sampling just the pore fluids, independently of the particulates.  This will allow us to be sure that the chemistry that we measure on the samples isn’t compromised or contaminated by fluid-particle interactions within the syringe after collection.  This is the first Loihi expedition for the new mat sampler (developed by Chip Breier, WHOI), so we met to work out some possible ways to try it.

The mat sampler in action.

The mat sampler in action.

09:25 – checking the in situ electrochemical analyzer (ISEA) on the ROV Jason science basket and finalizing cabling with Jason pilot and science basket management guru, Jimmy Varnum.  Any instruments that go on the ROV have to be secured, checked, double-checked, and safely and neatly arranged on Jason’s science basket for optimal utilization on the seafloor.  It’s a refined, somewhat miserable, but rewarding art, and Jimmy is the best in the universe at it.  The ISEA is a custom e-chem analyzer designed by Don Nuzzio of AIS, Inc. and optimized for deep-sea operations through years of close communication and collaboration.  We deploy custom, hand-made sensors on every dive that allow us to measure a suite of redox reactive chemicals in real time.  At Loihi, measuring iron concentrations in situ gives us the capability to guide discrete sample collection and decide how/where to make collections or deploy incubation experiments.

The Jason science basket loaded with mat sampler cassettes (right and middle milk crates) and e-chem wand (left milk crate).

The Jason science basket loaded with mat sampler cassettes (right and middle milk crates) and e-chem wand (left milk crate).

Jason pilot Jimmy preps the vehicle for a dive.

Jason pilot Jimmy preps the vehicle for a dive.

10:00 – electrode polishing.  My lab specializes in applying voltammetry to aquatic environmental biogeochemistry.  We make custom solid-state voltammetric microelectrodes for deployment on the ISEA for every ROV lowering.  They consist of a 100-um diameter gold wire, sealed in epoxy, carefully hand polished, and coated in a thin film of mercury.  By applying a voltage to the mercury film, we can measure a current response peak for any detectable chemical species, and the current peak height is proportional to its concentration in the fluid.  Voltammetry is a technique that has been used in a lab environment for many years, but only optimized for in situ applications over the past 10 years or so.  More coffee and good music is critical to the electrode polishing process.

10:30 – temperature logger assembly. Many important biological and chemical processes are influenced by temperature in hydrothermal environments.  At Loihi, we typically encounter temperatures as high as 40-50oC in the more vigorous flowing vents, while the more diffuse flow areas are in the range of ~25 oC.  During this expedition, we’re deploying a combination of temperature data loggers from RBR and Antares.

11:15 – fluid sampling team recap of titanium major samplers (or majors for short).  Titanium syringe samplers were designed especially for collecting hot fluids, up to 400oC, from hydrothermal environments for measuring most major ions.  They are robust and reliable samplers that work well with the ROV manipulator arms, and their somewhat complex cleaning, assembly, and disassembly procedures have been a bit of a right of passage for sea-going hydrothermal scientists for decades.

Jason preparing to fire a major sampler.

Jason preparing to fire a major.

11:30 – lunch

12:00 – prepare & mount helium sampler. Collecting samples from deep hydrothermal fluids for gas analyses is challenging: PV=nRT!  In some cases fluids at deep hydrothermal sites could contain 1000-fold gas concentration, compared with surface waters.  At Loihi, we’re especially interested in measuring helium isotope ratios, and are collaborating with colleagues at the University of Bremen (Dr. Jurgen Sultenfuss) who has developed a prototype gas sampler for in situ collection using the ROV.

12:30 – more coffee, more voltammetric electrode polishing.

Brian preparing an electrode. Photo credit: Clara Chan

Brian preparing an electrode. Photo credit: Clara Chan

13:00 – science meeting.  The whole science party tries to meet every few days or dives to allow for coordination of individual groups’ science plans, go over any concerns or new requests, and plan the upcoming few dives.

14:00 – mount helium sampler on Jason basket.  Again, Jim Varnum is the man with the plan, and fashions a sturdy mount to allow for the gas sampler to be launched, recovered, or carried on the ROV.

15:00 – mat sampler fluid & particle subsampling discussion.  Many different kinds of in situ & lab measurements, and discrete samples are being collected.  Typically, one person is placed in charge of coordinating distribution of fluid & particulate subsamples to each group from each kind of sampler (e.g., mat sampler syringes, scoops, slurps, titanium majors, etc.).

15:15 – elevator & ROV configuration planning.   Both scientists and ROV engineers alike prefer for the ROV to stay on the bottom doing work for as long as possible.  In order to enable cycling certain samplers and samples between the seafloor and the ship, we use an independent elevator like a shuttle between the ship and seafloor.  Various samplers will be mounted on to the elevator on deck, the elevator is dropped over the side, freefalls (after careful weight vs. buoyancy calculations), and lands on the bottom in the general working vicinity.  Jason flies in to the elevator, swaps out samples for empty samplers, releases the elevator to the surface, and then continues working, while the elevator is recovered to the ship and samples are processed in the lab.  For this to work most efficiently, careful diagrams of what samplers are in what containers on which vehicle and at which site have to be coordinated.

15:45 – Jason pre-dive check and science instrumentation check.  Just like a team of engineers and pilots run through a series of equipment and instrumentation checklists before a place takes off, the Jason team tests all vehicle systems before launching in the water.  Likewise, any scientific instruments that communicate through the Jason (like the ISEA) are tested one last time before launch.

Brian checks the e-chem wand in the Jason science basket. Photo credit: Jason Sylvan

Brian checks the e-chem wand in the Jason science basket. Photo credit: Jason Sylvan

16:15 – yes, more coffee

16:25 – resume preparing more voltammetric electrodes with Arne.

17:15 – dinner

17:30 – resume preparing voltammetric electrodes with Arne.

18:30 – prepare two more temperature data loggers for deployment on Jason.

18:45 – final check of elevator configuration before elevator launch.

19:30 – mount electrochemistry wand to ROV.   The ISEA runs the voltammetry, but the voltammetric (and temperature) sensors have to reach out away from the vehicle basket to the sites of interest.  The ROV manipulators are very strong, and anything that gets held, moved, or operated by the ROV needs to be robust and anything cabled to the vehicle needs to also have a well-designed cable management strategy.  We typically mount 4 replicate voltammetric electrodes along with a high-resolution temperature sensor on an electrochemistry wand with a T-handle that the Jason pilots can then position using the manipulators.  But, the voltammetric sensors are vulnerable to dirty on-deck conditions, as well as air, so we make every effort to keep them clean & enclosed in deionized water until right before vehicle launch.

The e-chem wand in action over a chimney

The e-chem wand in action over a chimney

20:00 – ROV Jason launch, descent, finding the elevator, and finally, conducting super cool science at 1300m (or more) below the sea surface!

Jason glowing below the surface after being launched from the fantail of the ship. Jason’s power source, Medea (hoisted in foreground), will follow Jason into the water shortly. Photo credit: Shingo Kato

Jason glowing below the surface after being launched from the fantail of the ship. Jason’s power source, Medea (hoisted in foreground), will follow Jason into the water shortly. Photo credit: Shingo Kato

02:00 – off to bed for a few hours, …then repeat various tasks, …for a couple weeks…

aloha,

Brian

Photo credits: subsurface photos from the Jason control van; other photos Brian Glazer unless otherwise specified

Day 10: Bugs + rocks

Jason (the person, left) helps prepare Jason (the vehicle) for a dive.

Jason (the person, left) helps prepare Jason (the vehicle) for a dive.

So far we’ve heard a lot about the ROV Jason, but not so much about Jason Sylvan, our geomicrobiologist collaborator from University of Southern California. Like many of the members of the science team, Jason is a veteran of several Loihi cruises. The excitement of new discoveries and new tools has kept him interested, and experience has given him a focused approach. He’s here to do 2 things.

An incubation experiment with hydrothermal vent samples.

An incubation experiment with hydrothermal vent samples.

Thing #1: investigating nitrogen cycling in hydrothermal environments. Water flowing from hydrothermal vents contains a lot of nitrogen in the form of ammonium. Although a major focus of this cruise has been iron-oxidizing microbes, not all microbes in hydrothermal environments use iron as an energy source; some use ammonium. Ammonium can be traced in the hydrothermal plumes of water rising up over Loihi, which is why Jason is interested in CTD samples collected in the water column, as well as near the vents. “Hydrothermal plumes are sort of like incubators,” he says. He’s running an incubation experiment that involves adding isotopically labeled ammonium to vent and plume water samples, then checking periodically to see how quickly it’s disappearing—or in other words, how quickly the microbes are oxidizing it.

The rate of oxidation indicates how fast the microbes are accumulating, which in turn reveals how much new biological carbon they’re contributing to the deep sea. There’s a broader implication here: a better quantification of carbon production in the deep sea means better-constrained models of the global carbon budget, and thereby perhaps even better-informed models of climate change.

Jason prepares some seafloor basalt for age dating.

Jason prepares some seafloor basalt for age dating.

Thing #2: taking a close look at the rocks. One of the robotic arms on the ROV Jason has rock-crushing capabilities, allowing us to snap up chunks of rock and bring them to the surface. Jason (the person) breaks apart some of these rocks for age dating and looks at others under the DEBI-pt, a laser scanner that uses deep UV native fluorescence to detect the presence of microbes at extremely fine scales (tens of nanometers). The DEBI-pt delivers a very exact picture of where microbes colonize rocks, a first step in addressing the question of why we find life where we do. This kind of work is helping to groundtruth the techniques that we could use to look for microbial life on other planets.

–Cat Wolner, NSF

 

Photo credits: Cat Wolner