What ocean microbes reveal about the changing climate Angelicque White
Translator: Joseph Geni
Reviewer: Krystian Aparta
I’m a biological oceanographer.
I have the absolute privilege
of studying microbial lives
in the Pacific Ocean.
So we’ll talk about microbes in a minute,
but I first want to give you
a sense of place,
a sense of scale.
The Pacific Ocean is our largest,
deepest ocean basin.
It covers 60 million square miles.
If you took all the continents
and you put them together
in a little Pangaea 2.0,
they’d fit snug inside the Pacific,
with room to spare.
It’s a massive ecosystem,
from the blues of the open ocean
to the green of the continental margins.
In this place,
I get to study the base of the food web:
plankton.
Now, in my research,
and really in the field
of microbial oceanography as a whole,
there’s a theme that has emerged,
and that theme is “change.”
These microbial ecosystems
are changing in real and measurable ways,
and it is not that hard to see it.
Oceans cover 70 percent of our planet,
so ocean change is planetary change,
and it all starts with microbes.
Now, I have two vignettes
to share with you,
and these are meant to be
love stories to microbes.
But I’ll be honest
that there’s an aspect of it
that’s just a total bummer,
and, beware, focus on the love.
Right? That’s where I’m coming from.
So the first thing to know
is that the forests
of the sea are microbial.
And what I mean by that
is that, by and large,
plants in the open ocean are microscopic,
and they are much more abundant
than we realize.
So I’m going to show you
some mug shots of these organisms
that I’ve collected over the years.
These are the lowest rungs
of the ocean food web.
These are tiny plants and animals
that come in a variety of shapes
and sizes and colors and metabolisms.
There are hundreds of thousands
in a single milliliter of seawater.
You are definitely swimming with them
when you’re in the ocean.
They produce oxygen, they consume CO2,
and they form the base of the food web
on which every other form
of ocean life is reliant.
Now, I’ve spent about 500 days
of my scientific life at sea,
and a lot more in front
of a computer or in the lab,
so I feel compelled to tell you
some of their stories.
Let’s start in the Pacific Northwest.
This place is green. It is beautiful.
These are blooms of phytoplankton
that you can see from space
along the West Coast of the United States.
It’s an incredibly productive ecosystem.
This is where you go to salmon fish,
halibut fish, whale watch.
It’s a beautiful part of our country.
And here, for 10 years,
among other things,
I studied the uplifting topic
of harmful algal blooms.
These are blooms
of toxin-producing phytoplankton
that can contaminate food webs
and accumulate in shellfish and fish
that are harvested for human consumption.
We were trying to understand
why they bloom, where they bloom,
when they bloom,
so we could manage these harvests
and protect human health.
Now, the problem
is the ocean’s a moving target
and, much like some people in our lives,
toxicity varies among the plankton.
(Laughter)
Alright?
So, to get around these challenges,
we combined satellite remote sensing
with drones and gliders,
regular sampling of the surf zone
and a lot of time at sea
in small boats off the Oregon coast.
And I don’t know if many of you
have had the opportunity to do that,
but it is not easy.
[Even oceanographers get seasick]
Here’s some poor students.
(Laughter)
I’ve hidden their faces
to protect their identities.
(Laughter)
This is a challenging place.
So this is hard-won data
I’m about to talk about, OK?
(Laughter)
So by combining all of our data
with our collaborators,
we had 20-year time series
of toxins and phytoplankton cell counts.
And that allowed us to understand
the patterns of these blooms
and to build models to predict them.
And what we found
was that the risk of harmful algal blooms
was tightly linked to aspects of climate.
Now when I say “climate,”
I don’t mean weather day-to-day,
I mean long-term changes.
These oscillations
that you may have heard of –
the Pacific Decadal
Oscillation, El Niño –
they usually bring warm,
dry winters to this region,
but they also reduce the strength
of the California Current,
which runs from the north to the south
along the Pacific Northwest,
and they warm the coastal ocean.
These are the reds
you’re seeing in this plot,
warm anomalies,
strong positive indices of the PDO.
And when we have
these changes in circulation
and changes in temperature,
the risk of harmful
algal blooms is increased,
but also salmon recruitment has decreased,
and we see intrusions
of invasive species like green crab.
So these are ecological
and economic impacts of climate.
Now, if our models are right,
the frequency and severity of these events
are only going to get worse,
right along with these warm anomalies.
And, to illustrate that,
2014 was probably one of the worst
harmful algal blooms in Oregon history.
It was also the hottest year
in the modern climate record at that time,
that is until 2015,
2016,
2017, 2018.
In fact, the five hottest years
in the modern climate record
have been the last five.
That bodes really well
for harmful algal blooms
and poorly for ecosystem health.
Now, you may not care about shellfish,
but these changes impact
economically important fisheries,
like crab and salmon,
and they can impact the health
of marine mammals like whales.
And that might matter a little bit more.
That might resonate.
So, there’s your doomsday tale
for the margins of the Pacific.
Actually, these are really
resilient ecosystems.
They can absolutely bounce back
if we give them a chance.
The point is not to ignore
the changes that we’re seeing,
which brings me to my second vignette.
I have since moved to the most remote
island chain on our planet,
the Hawaiian Islands,
where I’m the new lead of a program
called the Hawaiian Ocean Time-series.
And this is a program that for 31 years
has made this monthly pilgrimage
to a spot called Station ALOHA.
It’s in the middle of the Pacific Ocean,
in the center of this vast,
swirling system of currents
that we call the North Pacific
Subtropical Gyre.
It’s our largest ocean ecosystem.
It’s four times the size
of the Amazon rain forest.
It is warm, in a good way.
It is blue water,
it’s absolutely the type of place
you want to dive in and swim.
You cannot do that off of research boats,
because, you know, sharks. Google it.
(Laughter)
This is a beautiful place.
And here, since October of 1988,
generations of researchers
have made these monthly pilgrimages.
We study the biology, the chemistry,
the physics of the open ocean.
We’ve measured the temperature
from the surface to the seafloor.
We’ve tracked the currents,
traced the waves.
People have discovered new organisms here.
People have created vast genomic libraries
that have revolutionized
what we think about the diversity
of marine microorganisms.
It’s not just a place of discovery,
but the important part about time series
are that they provide us
a sense of history,
a sense of context.
And in 30 years of data,
it’s allowed us to separate
the seasonal change
and see the emergence
of humanity’s fingerprints
on the natural world.
There’s another iconic
time series in Hawaii,
and that is the Keeling Curve.
I hope you have all seen this.
This time series has documented
the rapid increase in carbon dioxide
in the atmosphere.
It’s not just the number,
it’s the rate of increase.
The rate of carbon dioxide
increase in our atmosphere
is unprecedented for our planet.
And that has consequences for our oceans.
In fact, oceans absorb about 90 percent
of the heat that’s generated
by greenhouse gas emissions
and about 40 percent
of the carbon dioxide.
And we have been able
to measure that at Station ALOHA.
Each one of these dots is a cruise.
It represents people’s lives over 30 years
trying to make these measurements,
and it took 30 years
to be able to see this.
CO2 rises in the atmosphere,
CO2 rises in the ocean.
That’s the red line.
A consequence of that
is a fundamental change
in the chemistry of seawater,
a decline in pH –
pH is on a log scale,
here’s your blue line.
So we’ve seen a 30 percent decline
in pH in the surface ocean
in this time series.
Now that has impacts for organisms
that need to feed, build shells,
that changes growth rates,
metabolic interactions,
and it doesn’t just impact plankton –
it impacts ecosystems
as large as coral reefs.
Now one of the things we’ve been able
to show in this time series
is this is just skimming the surface.
Increases in CO2 and a decline in pH
are measured over the top 500 meters
of the water column.
I really find that to be profound.
This is genuinely one of the most
remote places on our planet,
and we’ve impacted the top 500 meters
of the water column.
Now, these two things –
harmful algal blooms,
ocean acidification –
that’s not all, of course.
You’ve heard of the rest:
sea-level rise, eutrophication,
melting of the polar ice caps,
expansion of oxygen minimum zones,
pollution, loss of biodiversity,
overfishing.
It’s hard for me to get a grad student –
you can see this pitch
is a difficult one, right?
(Laughter)
(Sighs)
Again, I think these systems,
these microbial ecosystems,
are immensely resilient.
We just cannot go too far down this path.
I personally believe that sustained
observation of our oceans and our planet
is the moral imperative
for our generation of scientists.
We are bearing witness
to the changes that are being inflicted
upon our natural communities,
and by doing so,
it provides us the opportunity
to adapt and enact global change,
if we’re willing.
So the solutions to these problems
are multitiered.
It involves a portfolio of solutions,
local change,
but all the way up to voting for people
who will protect our environment
on a global scale.
(Applause)
Let’s bring it back to the love.
(Laughter)
Microbes matter.
These organisms are small,
abundant, ancient,
and they are critical to sustaining
our population and our planet.
Yet we are on track to double
our carbon dioxide emissions
in the next 50 years,
so the analogy that I use for that
is like we are eating
like we’re still in our 20s,
assuming there will be no consequences –
but I’m a woman in her 40s,
I know there are consequences
for my fuel consumption. Right?
(Laughter)
These oceans are very much alive.
These ecosystems have not collapsed.
Well, except for the Arctic,
we can talk about that.
(Laughter)
But the sustained observations
that I’ve shared with you today,
the work of generations of scientists,
are pointing us to take
better care of our oceans
and to nurture the microbes
that sustain us.
And on that note,
I want to end with a quote
from one of my heroes,
Jane Lubchenco.
And this slide is appropriate.
Jane has said that the oceans
are not too big to fail,
nor are they too big to fix,
but the oceans are too big to ignore.
Thank you.
(Applause)