Good morning. My name is Julie Huber,
and I'm a microbial oceanographer at the Marine Biological Laboratory
in Woods Hole, Massachusetts.
Today, I want to tell you about some of the work I do studying microbes in the deep sea,
why I think it's important, and what it's like to be a field-going, ocean-going scientist.
I wear a lot of different hats as a scientist,
but I think this cartoon illustrates the core of what I do,
which is I use cutting-edge technology to go to strange places
at the bottom of the ocean
to look for microbial life.
In fact, the surface of our planet is covered in water.
About 70% of Earth is covered in water,
but beneath the surface, some pretty amazing things are going on.
This is a topographic map, where we've taken away all the water
so you can see the depth or the height of everything on the planet,
and particularly, in the blue parts, where our oceans are,
you can see there's a lot of interesting relief.
In particular, things like this, where you can see mountain ranges beneath the sea floor.
This is the world's longest mountain range. It's about 55,000 kilometers long,
and it represents places on the sea floor where tectonic plates are moving apart.
When tectonic plates move apart, volcanism results,
and that's illustrated in this slide.
When tectonic plates either spread apart, you get things like mid-ocean ridges.
When plates are subducting beneath one another, you get volcanic arcs.
In fact, volcanism is pervasive underneath the ocean,
and about 70% of the volcanism on our planet occurs within the water.
However, until recently, we didn't know much about it
because we didn't have the ability to study it and observe it.
Here's one example, however, when we were able to.
This is a deep-water eruption, occurring at about 4,000 feet depth
from an expedition I participated in near Samoa in 2009.
Until we took this footage, just a few years ago,
no one had ever witnessed this fundamental Earth process occurring,
despite the fact that it's probably been going on
since our planet formed about 4.5 billion years ago.
So, we had little understanding of how new ocean crust formed,
what types of volatiles were being pushed out of volcanoes,
and how and if life could survive in this type of environment.
So, with this footage, and with these types of expeditions,
we're able to make amazing strides in our understanding in both life and Earth processes.
This volcano is emitting all sorts of volcanic gases,
which serve as very good food for microbial life.
That includes things like hydrogen sulfide
that microbes, bacteria, and archaea can exploit.
So, at deep sea hydrothermal vents, microbes are forming the base of the food chain.
This is footage from the Galapagos ridge.
That's where hydrothermal vents were first discovered in 1977.
These are giants tube worms, and the only reason
these tube worms are able to survive in this environment
is because their gut is packed full of bacteria that are oxidizing hydrogen sulfide
from the vent fluid and creating organic carbon that the worms use to live.
This is in contrast to photosynthesis, where you have light providing the main energy
source and supporting the base of our food chain on land.
Until the discovery of these hydrothermal systems in 1977,
no one even knew chemosynthetic life was possible.
So, the discovery of hydrothermal vents completely changed
the way view biology on our planet.
And it's a very good example of how not everything is hypothesis driven.
This was not explained, or not hypothesized,
and was a complete surprise to all of biology.
So, it isn't just hydrothermal systems that are dominated by microbes.
In fact, we live on planet microbe.
You might feel like it's a eukaryotic world because
we're surrounded by trees, animals, and humans,
but in fact, microbes mediate all the major biogeochemical cycles on our planet.
Carbon, oxygen, nitrogen... these are the things that make Earth habitable for higher life.
In addition, microbes were the only form of biological life
on our planet for about 3.5 billion years.
Remember, our planet is about 4.5 billion years old.
So, they're the dominant form of life for most of Earth's history.
That's in contrast to modern humans.
We've only been around for a few hundred thousand years.
So, in that time, microbial communities have had time to evolve,
and they occupy nearly every corner of our planet, even the human body.
And if we look at the universal tree of life,
with all the known realms of life put on to the same tree,
we can see that most of life on this tree is, in fact, microbial.
They belong to two different domains: the bacteria and the archaea.
These are single-celled organisms. They divide by binary fission.
They don't have any membrane-bound organelles, but you can see
they occupy a huge amount of diversity
because they've had so long to evolve on our planet.
And just in contrast, we are right here, at the very tip of the tree.
So, you can see that most of the life on our planet is microbial.
So, all of the work in my lab, here at the Marine Biological Laboratory,
focuses on understanding these microbes.
And we use a variety of tools to do that.
We want to understand what they eat, how quickly they grow,
what are their genes doing? How do they evolve?
How are they interacting with and impacting the local environment?
So, we use molecular tools that involve looking at DNA and RNA from these organisms.
We try to culture them in the laboratory, which is shown down here.
And we then use microscopy and geochemical tools to study them.
I'm particularly interested in microbes that are specifically adapted
to the volcanic habitat. So, this includes organisms that don't use oxygen
and are using these volcanic gases to make a living.
So, this is one example. These are methanogens.
These belong to the domain Archaea.
Methanogens use carbon dioxide and hydrogen to generate methane,
and they're very successful in these ecosystems.
Another group that belongs to both bacteria and archaea are sulfur reducers.
Sulfur reducers again use sulfur coming out of the vent system,
combine it with hydrogen, to produce hydrogen sulfide.
So, both of these organisms... neither of them use oxygen,
and the discovery of organisms surviving like this, in deep sea systems,
often at high temperature,
led a number of people to hypothesize that maybe
they are remnants of Earth's earliest life forms.
So, remember that I told you, hydrothermal systems are very ancient on our planet,
and so if we've had volcanism going on for a very long time,
these types of organisms are potentially some of the earliest life forms
that we've had on our planet.
In addition, the discovery of hydrothermal systems
opened a whole new way of looking at life beyond our own planet.
So, the field of astrobiology involves looking at the
origin and evolution of life beyond Earth.
And this is Mars and Europa shown here,
two very promising candidates for either current or past life.
For example, we know that there's a history of volcanism in the past on Mars,
and we believe that there's a salty ocean beneath the icy shell of Europa,
one of Jupiter's moons.
Could there be hydrothermal systems beneath that icy shell?
Could there be life beneath that icy shell?
So, this whole combination of interesting reasons to study hydrothermal systems:
the fact that they're ancient, the fact that we can understand
very fundamental Earth processes going on beneath the ocean's surface,
and the fact that we could potentially learn more
about the origin and evolution of life beyond Earth,
really led me down this road as a young undergraduate student.
I went off to college and thought, like many kids,
I was going to be the next Jacques Cousteau.
I was going to study dolphins and coral reefs and sharks.
But I became really engaged by this possibility of studying microbial life,
not only as powering our own planet, but planets beyond our own.
So, most of the work in my laboratory takes place... it looks very normal,
like what you're probably used to seeing in any biological laboratory.
We have PCR machines, we have culturing, we have all sorts of basic laboratory things.
But to have anything to work with, we have to go to a very different laboratory.
In this case, it's the bottom of the ocean.
So, this is a shot of me diving in the man submersible, Alvin.
I'm sitting at about 4,000 feet beneath the surface,
collecting microbes for our study.
So, in this case, our laboratory becomes a ship,
and our field site, the bottom of the ocean.
This is the Atlantis, which is the mothership for Alvin,
and we usually go out to sea for 2-4 weeks at a time to collect our samples
and then eventually bring them back to the laboratory for further study.
So, I already mentioned Alvin, which is the deep sea submersible that we use
for some of our collections, but often that isn't practical or safe.
For example, that exploding volcano that I showed you at the very beginning.
That's not the type of place that you would want to bring
humans at the bottom of the ocean.
So, in that case, we use remotely operated vehicles.
This one is Jason. It's operated out of the Woods Hole Oceanographic Institution,
and it's tethered up to the ship by a power cable. There's no people on board the vehicle,
but instead, we are all back up on the ship, in a dark room,
with about 14 different monitors
that are showing us what's happening on the sea floor.
And we work with a team of pilots and engineers that run the ROV,
and they help us collect our samples,
make our maps, and make good decisions about how
best to do our science on the sea floor.
We also use something called autonomous underwater vehicles.
This one is called Nerius,
and this is a vehicle that allows us to completely set the vehicle free from the ship,
and it can run a map, for example. It has sensors on it.
And then we can use the ship to go do other things.
And, the final thing we have to do, which is perhaps
one of the most challenging parts is design very specific samplers
for the types of samples that we're after.
And, we're always sort of constrained by the vehicle we're using,
the study site, the depth we're operating at,
and often I walk off a ship and just think,
"Wow, that was 50% of my job, simply getting those samples,"
and then I have a whole layer of another work to happen in the laboratory.
So, working at sea is a pretty unique place to do your job.
It's very challenging. It's very humbling sometimes,
particularly to be sitting in the middle of the ocean
and not really see anything for days at a time.
We run a lot of different safety drills because, of course,
we are on our own, in most cases.
So, this is a shot of me off the coast of Hawaii, running through our weekly safety drill
to make sure if I had to abandon ship that I would know how to do that.
And another particular challenge is that we're working on a moving platform,
and so, we're dealing with chemical... needles in this example,
on a moving platform, and sometimes just keeping your balance,
keeping your breakfast down...
Things can be particularly challenging, just doing basic lab work at sea,
which is why when we're at sea, we mostly just focus on getting the samples,
and we do most of the analysis when we get back home.
We figure a lot of things out.
And, I like to say that being at sea is sort of like being at camp in some ways,
except you're with grown-ups.
So, here I am making coffee. We play ping-pong. We do laundry.
There's a gym. We eat all our meals together.
So, it's a very ... bunch of grown-ups on a 280 foot vessel,
hanging out for a few weeks, working a lot,
but we also manage to find some creature comforts.
And all of this is really for the privilege of doing things like diving
to the bottom of the ocean and observing things
that very few people get to observe in first person.
This is me diving ... going into Alvin at sunrise one morning
before heading to the bottom of the Pacific Ocean.
But, perhaps, my favorite thing about going to sea
is the fact that I don't work in isolation.
So, a lot of people think about a scientist working in their laboratory
late at night, by themselves, making discoveries.
In fact, some of the most remarkable discoveries we've made have been as a team.
About 50 of us strong, including scientists, crew members, from everybody --
from the guys working in the engine room to the people washing dishes,
to all of us operating the vehicles and doing the science.
And I think it was this interdisciplinary nature of oceanography
that drew me to it. I'm not a very lonely person, and I like working with other people
and to be at sea with a bunch of people who have left their families,
who have left their desk job to come out
and really focus on a particular system or question for me
is incredibly exciting.
And there's still a lot to do.
I showed you that map of the ocean. It's a big ocean.
We have very few studies of deep oceanic volcanic systems.
And so, I figure, as long as volcanoes continue to thrive on our planet
and life finds a way to study them,
I will have a job.
And, I think I still have plenty to do to drive many careers ahead of me.
So, I hope I've given you a taste of why volcanic systems are important,
why the life there is so interesting,
and a little bit of what it's like to be a sea-going scientist.
Thank you.