when I was fortunate to be invited to
participate in an expedition to the
McMurdo Dry Valleys at 6,500 square
kilometres the McMurdo Dry Valleys is
the largest ice-free permanently
ice-free area on the continent now for
me as a microbial ecologist this was a
really exciting opportunity because for
the last 30 odd years I’ve been studying
probably the most extreme environments
on the planet and the microbial
communities that inhabit them whether it
be the deep sea hydrothermal vents the
hot springs around the world tops of
active volcanoes or acid mine drainage
sites and the reason I’m doing this is
because I believe that by understanding
how bacteria can operate under extreme
environments we’re better able to
understand how they operate in more
complex ones and you’ll see in a moment
why I believe that bacteria are probably
the most amazing organisms on the planet
now my mom who’s 90 years old asked me
every time that I go seer why of all the
beautiful organisms on the planet I
chose to work on something you can’t see
it’s something that most people really
don’t care about well I’m gonna give you
some reasons why I think these are such
great are organisms first off they’ve
been around for 4 billion years and have
survived multiple extinction events and
multiple climate change events they’re
the most diverse organisms on the planet
in fact we have only been able to
culture about less than 1% of them they
occupy just about every niche on the
planet whether it be man-made or in the
environment and at the same time they
have this capability of evolving
extremely quickly they evolve by
generation times the record being around
about 10 minutes devolve escape ability
they have the ability to acquire
our DNA from the neighboring cell from
the environment or even from a viral
infection giving them an increased and
immediate capability to adapt to an ever
creasing and changing environment around
them they also in my opinion of the
master biosensors on the planet the
cells are covered with receptors each
able to sense various molecules in the
environment so sensitive that a single
molecule can elicit a change of a
response
now that response if we were able to
decipher and decode that response
imagine the power we would have to
understand how the environment is
operating I believe that if we could do
that these would become the most
essential sense sentinels of
environmental change now when I came to
the Dry Valleys in 2001 most of there
was 30 years of really productive
microbiological research have been
conducted out there but most of that
work had been conducted using
cultivation approaches we only really
knew what we could grow and I was
bringing something kind of new to the
table thirty years ago there was a major
revolution in technology taking place
around the world technology very
powerful technology was being developed
to enable us to unlock that cook the
messages hidden in the DNA code now
whilst most of this technology was being
directed towards human and human related
diseases microbial ecologists were
looking at the power of these tools that
we might be able to apply to be able to
understand bacteria in the environment
so when they started to apply these
tools and this is about 25 years ago
what became very apparent was that the
diversity of bacteria that we thought
was out there based on these cultivation
approaches had very much underestimated
the diversity so these tools are so
powerful that they’re now enabling
microbiologists to better to answer
these two questions is how do bacteria
interact with each other and how do they
interact with the environment around
them
four billion years of evolution gives
you a huge amount of clout in terms of
environmental interaction if we could
get into this and be able to decipher
how these organisms are relating to
their environment we would be able to
build a capability to be able to sense
the environment today and hopefully be
able to predict where the environment is
going to be going in the future but to
do this we need a functional ecosystem
you can’t pull the ecosystem out of the
environment and stick it into the
laboratory it’s way too complicated and
you’ll change it so microbial ecologists
of course wanted the first thing they
wanted to do was to move in to complex
systems
well these systems are just way too
complicated the animals and plant
diversity the bacterial diversity viral
and fungal diversity all piled on top of
the chemical and physical environment
it’s just way too too complicated it’s
kind of the proverbial forest for the
trees
what we are in search of was something
way simpler a place where the complexity
of the organisms of the higher-level
organisms was removed and the
microbiology would be able to stand up
and next to the physical and chemical
environment so this brought us to the
Dry Valleys now as I mentioned there had
been 30 years of research that had been
conducted out there and that work had
left us with three beliefs the first was
that the system had low biodiversity
again this is using cultivation
approaches the diversity was low because
the system is extreme this is very
typical of extreme environments the
selective pressures are so extreme that
they are the only organisms that can
survive or those that are highly adapted
to live there the second was that
everything was everywhere
no matter where you went in the dry
valley system you basically grow the
same thing and thirdly is that because
of the temperature in the in the in
Antarctica and in the Dry Valleys the
low temperature and the low availability
of liquid water which is essential for
life these organisms operated very
slowly
so I had mentioned before about a ten
minute turnaround time on a generation
for the fastest these guys if they were
lucky we’re getting two or three during
any given three-month season during the
summer time when conditions might be
appropriate so I went into the valley
and a tent not dissimilar to this I went
in with a generator and a bunch of
equipment sat on my knees and my
objective was to was back in 2001 was to
look at the overarching higher-level
complexity of the system I went in
looking for 12 of the 17 higher level
groups of bacteria at the time there
were 17 there’s around about 60 right
now and I went in with the hope that I
might find one that hadn’t been grown
before I went in grabbed some soil this
is in the upper right valley
I grabbed some soil digested the DNA
shot it into the machine did the
analysis and all twelve lit up i
contaminated everything obviously so I
went back which is very typical of me
and I went back and I did it again in 12
hit and then it we did it again in 12 3
other locations all 12 lit up so became
apparent to me that actually like other
places on the planet
we had totally underestimated the
diversity of bacteria in this system so
immediately the questions that came up
an extreme system should be have low
diversity and we don’t have that so why
is it so diverse and what is maintaining
that diversity so over the next four or
five years a program called the New
Zealand terrestrial Antarctic bio
complexity survey began to look at and
undertake a landscape scale analysis it
was the most comprehensive landscape
scale piece of work ever conducted on
the continent the sole purpose of this
was to understand the distribution of
the biota including the microbiology and
specifically to test each one of these
beliefs so the first one belief number
one was this low diversity so in 2001 I
began to see that but when we did a
landscape scale study this entirely
so we have high diversity throughout the
dry valley system the second one is
everything is everywhere so on a
landscape scale study we could run these
comparisons and what we found was
actually each valley has its own unique
diversity which was totally unexpected
and when we began to look at the system
it appeared as though each of the
valleys has their own unique chemistry
and it’s the chemistry that’s driving
the microbiology but that chemistry is a
leftover a fingerprint of the glacial
history of each one of these valleys as
we went on and we started to look at the
distribution in there we also found that
there was a patchiness to this
distribution and that patchiness is
driven by local microclimate so and
everything is everywhere actually each
valley is unique belief number three is
about low activity so the system for all
intents and purposes these organisms
should be operating really slowly what
we did is performed I think a unique is
probably the first time that anybody has
ever done this experiment where we moved
a mummified seal that had been in a
location for 450 years and we moved it
from that location to a pristine
location and we monitored the microbial
communities underneath that seal for
five years and what we found was that
actually the microbial community
completely switched in just two years we
would hope that we might be able to see
some subtle change in five and we saw a
complete switch in to now not only did
we see a complete switch but we also saw
a loss in biodiversity the single
parameter that governed this change with
the availability of liquid water it
marginally went up but significantly and
drove the entire switch in this
community now why is that important well
it’s important because the projections
for the Dry Valleys over the next
hundred years are too warm if they warm
is going to be more glacial meltwater
more glacial meltwater means
wider spread wetting of the system
weiter spirit wedding of the system will
mean that these that there’s a potential
to lose some of the unique biodiversity
we have in the system due to these
wedding events so where are we at today
right now we’ve got this amazing system
is incredibly well characterized
it’s a microbiological system being
driven solely by the the abiotic or
nonliving components the physical and
the chemistry of the system is what’s
driving this now the hope is in the
future that the what we’re understanding
in an unlocking an understanding of the
message that these organisms are
relating to their environment that we
will be able to develop a better roadmap
with which to then move into more
complex systems but does it really
matter
do bacteria really matter I mean you
can’t see them they don’t appear to be
doing anything well I think they really
do matter
bacteria underpin our at the basis of
every ecosystem on the planet they are
the fundamental keystone organisms that
maintain the driving force that brings
organic matter back into nutrients and
those nutrients are then fed back into
the system without them even a healthy
ecosystem if we pull them out or change
them in some way the failure of the
ecosystem is almost certain so to me
these guys are keystone now I’m some of
my key
ecological colleagues my ecology
colleagues would probably disagree with
that word but I believe that these are
the fundamental foundations of most
ecosystems on top of that they’re also
our bio mediators these are the guys
that come to our aid when we screw up
many of you will remember the Deepwater
Horizon disaster in 2010 when 4.5
million barrels of crude oil was dumped
into the Gulf of Mexico what you
probably don’t know is that we didn’t
clean that up we made kind of an effort
but actually this mess was cleaned up by
a small group of unknown organisms at
the time they came to our aid and
bloomed in that situation and took care
of the
problem now the deep water disaster and
itself it was it occurred in a specific
time in a specific place now we have a
much more an important pending problem
in the climate crisis many of you will
feel almost helpless or even wondering
whether your independent actions that
you take place every day are having any
impact on the climate change and maybe
they’re not however I believe after 30
years of work working on the smallest of
organisms on the planet where I’ve seen
them systematically come together and
work together to sustainably and scale
ibly alter the environment around them
in 1959 twelve very brave countries got
together and decided to protect the
fifth largest continent on the planet
Antarctica now they were doing this
because of the most certain degree of
exploitation that might take place in
the future these were in all big
countries they included Belgium Chile
Argentina in Norway and of course New
Zealand but what made them powerful was
their collective effort to focus and the
passion of protecting a continent from
almost certain exploitation I believe
that if we come together as a global
community if we can have that same
passion in that same focus we can turn around this climate issue thank you