Mostly the weather out here sucks

Cloudy days, often-as-not rainy nights, high winds, and colder than
most of the clothes I brought. But every now and then we get a nice
sunset...

Snails, part II

Here's another shot at the snails, which didn't seem to display on the last one.

 

Snails!

It just occurred to me that I haven't posted any pictures of the neat little critters we study. Here's a glamour shot of two members of the genus Alviniconcha. These crazy little guys are not like snails you may have met before. First, there's very little calcification of the shell – most of what you see is a tough outer chitinous layer. If you try and dry the shell out, this layer shrinks and literally explodes the thin calcified layer beneath into hundreds of little pieces. Bummer for collectors, but good for the snails: vent water has a lower pH than normal seawater, making precipitation of calcium carbonate more difficult. Think of these guys as a preview of ocean acidification. 

Second, and in large part why we're out here, is that these snails are autotrophs – like plants, they make their own food. In association with their symbiotic bacteria, Alviniconcha takes in CO2 from the environment, then reduces it into sugar. Unlike plants, the snail/bacteria partnership doesn't use light to power this reaction; instead, they use chemical energy from the vents.

In most of the habitats with which we're familiar, the abundance of oxygen means that most of the chemicals floating around are fully oxidized – they've lost their extra electrons – and thus aren't good sources of energy. The exception to this rule is organic carbon, like sugar, fat, and protein. The carbon atoms in these molecules had their electrons restored to them at some point in the past by a photoautotroph, or someone who uses light (photo) to make their own (auto) food (troph). Now all that good reduced carbon is available for chemoheterotrophs like you and me.

At vents, though, there's a ton of extra energy being dumped into the system from the hot mantle. There's also not much free oxygen deep down in the crust. This means that, at vents, there's a lot more reduced chemical species kicking around to take advantage of – stuff like sulfur and hydrogen, which up on the surface, we usually see in its oxidized form, like in sulfate (SO4) and water (H2O). All those extra electrons open the door for chemoautotrophs like Alviniconcha, which oxidizes hydrogen sulfide (H2S) to sulfate (SO4), and uses the energy to make its own food. 

Pretty cool!

Going back to the picture: you may have noticed some subtle differences in the 'hairs' covering the shells of those two snails above. Is this just random variation in the population, or might these represent two closely related species? If they're different species, why are they found at the same sites? What about their bacterial partners – do those differ, too? Their physiological capabilities? 

Lots more to learn...

 

 

Life under pressure, part II

It turns out that Blogger cuts your message after the picture, so
here's the main bit of writing from yesterday:

...

First, let's set the scene. Picture yourself standing just inside the
doorway of your regular, 20 foot refrigerated shipping container.
Throw in a bolted-together green Unistrut steel internal frame (you
can see a horizontal member on the top of the back wall) with
varnished plywood bolted up along the sides. Now throw in some heavy
shelves, a few benches, and a big stainless steel tool chest. Set the
noise from the reefer unit to 'periodically earsplitting.'

The main event here, now that we've got the lab itself built, is the
high-pressure aquarium. These are basically scuba tanks with a
removable lid. There are three such aquaria in this picture, wrapped
in insulation in the left foreground. These particular vessels are
turned from solid titanium and have a pressure rating of around
4500psi. They have an internal volume of about 3L, and thanks to the
Ti, weigh in at a relatively svelte 60 pounds or so.

Next, we need to get water into the aquaria. These are flow-through,
meaning they have a constant supply of clean water coming in to them.
Our water is piped in through a hose from the ship, filtered, and
collected in a reservoir at the back of the van, just off the left
frame of the picture. The seawater is then pumped to the clear plastic
equilibration column in the top center of the photograph. Here, a
mixture of gasses is bubbled through the water to adjust the chemistry
to desired levels -- oxygen, hydrogen sulfide, and so forth. Finally,
the equilibrated water is pumped through the big blue high pressure
pumps into the vessels. A backpressure valve on the outflow keeps
things at a cozy 3500psi.

On the other side of things, we need to measure what's coming out of
the vessels -- things like oxygen consumption, carbon dioxide and
hydrogen sulfide uptake, pH, and so forth. We do this in two ways. The
first is an analytical stream, including pH and oxygen sensors, a
cyclic voltammetry electrode, and a mass spectrometer, to which a
stream selector valve switches each vessel for about 30 minutes at a
time. The analytical stream gives us real-time data on what's going on
with vessel chemistry.

In addition, we take and preserve water samples for later analysis.
That's what the fancy-looking bank of valves above the pressure pumps
is for, allowing us to easily divert water from the waste stream of
each vessel into a test tube or sample vial.

At the end of the day, presuming check valves don't fail, backpressure
valves don't fail, pumps don't fail, motors don't fail, instruments
don't fail, and operators don't fail, all this adds up to some
interesting and unique data about amazing critters from the bottom of
the sea. Pretty neat!

Life under pressure, part I

So what exactly do I do all day out here?

A big piece is running experiments on live deep-sea animals in our
mobile high-pressure laboratory, a 20-foot refrigerated shipping
container we call the 'pressure van.' (For some reason, shipping
containers on research vessels are called vans. Not sure why.)

Below I've attached a picture of the experiment I just set up today.
It happens to include a lot of what goes into these experiments
(including baffling amounts of tubing).

Crazy nature

Can Blogger handle pictures as email attachments? Let's see!

This is Roxie and I at the too-insane-for-words blowholes on the west
coast of Tongatapu, the Tongan capital island. (Or at least the island
with the capital city. I'm not sure how it works.) As you can see, I
am assuming a characteristically reserved and respectable demeanor.
Unlike previous, lesser blowholes you may have seen, this is not one
meager sea-puff brought about by chance erosion of the rocky cliffs;
no, this is _several_kilometers_ of noisy awesomeness spurting forth
from the cracks between vertical ramparts of lava tubes. A solid
southwestern swell impacts with a string of
*crash*pfft*pfft*pfft*BOOM*s zooming up the coast in righteous,
natural mega-surround stereophonics.

Shipside update: despite all of our animals dying in port due to an
unfortunate accident involving power supply to the reefer unit, things
seem to be going unnaturally well. We've had time and fresh energy to
put together several key improvements to the van, which should greatly
increase the efficiency of our experiments once we get some fresh
critters.

The flipside of this is that I now seem to have a small amount of
mysterious 'free time,' in which I can actually choose to do
non-work-related activities, like yoga or sleeping. I have to admit
that I find this to be somewhat unnerving.

Under way

Here we go again.

As I type, Jason is 1800 meters below the boat, looking for the Kilo
Moana vent site. Pumps are cranking away in the pressure van. Our
bench is a colossal mess. All is right -- or at least what passes for
nomal -- in the world of cruise.

I should probably go to bed, to get in at least one symbolic
pre-midnight sleep in. There are about 800 things I feel like I need
to be doing, though. Not less than 24 hours ago I was thinking, "Ahh,
great, this time we can back off and do an amount of work only
marginally likely to make us want to jump overboard." Ha. Despite the
fact that the last few days in Tonga feel like they lasted for weeks,
the next 28 -- possibly my last at the Lau basin in my graduate career
-- seem terrifyingly short. There's so much to get done!

Ah, well. Might as well get up early as do them late. I am optimistic;
this list seems at least marginally less impossible than the one we
started with on the last leg. Neither Roxie nor I seem to be feeling
motion sick. The van is already set up. The seas are calm. The galley
has been restocked with snacks.

Perhaps a few snacks then, and then to sleep. Catch you again soon.

A moment on land

The four-day port call in Tonga has turned my thoughts back to solid
ground. It's sort of a mixed blessing, getting off the ship for a few
days -- on the one hand, if I didn't have a chance to sit out on the
beach and sleep for a few hours before the next leg, I would probably
lose my mind; on the other, walking under trees and riding around in
taxis makes for a potent reminder of what's waiting for me back home.
My roommate Carrie just wrote to tell me that my hops are eighteen
feet tall. Imagine that! They were two-inch little twigs when I left.

Here in Tonga, Roxie and I took a cab up the coast to a nice little
beach resort for a day. I hit the sand hard, and stayed there. Roused
myself a couple times to go for a swim, get a bite to eat, and talk to
interesting strangers; but mostly I spent my 24 hours of freedom
laying on my towel and reading.

Then it was back to the boat. When we got to where we were supposed to
meet our professor for a nice bite to eat and final wrap-up
conversation before he flew home, we found not Pete, but a message
that something had gone wrong in the van, and we needed to head back
to the wharf instead. You could hear our stomachs hitting the floor.

Fortunately, it wasn't a huge deal, and we still got to go out to
dinner. It was one of those 'cultural dance' nights at a local hotel,
the third I've been to on this trip -- and, incidentally, the third at
which I've been selected to be the foolish tourist invited up on stage
in the middle of the performance. You'd think I had a sign on my
forehead that read "mock me" or something (and the tattoo artist
_assured_ me that it means "dignity"). Fortunately, this time I wasn't
the only one, and could thus avoid the epic antics demanded by the
previous occasion.

But now I'm back on board, and have but a brief foray into town
tomorrow to acquire supplies (including, gods willing, tofu) between
me and the open ocean. Ah, well. It's not often you get a chance to
implement all those improvements you thought of right away...

More blogging should hopefully be one of those improvements, through a
combination of more sleep (the #1 goal of the second leg!) and my
discovery that I can post via email. Miraculous!