For decades, scientists have speculated that there is a link between ocean microbes, cloud formation,
and ultimately, climate. But the logistics of studying marine microbes in their
native environment is hard. So an ambitious team of scientists at UCSD is trying to crack
that problem by bringing the ocean into the lab to study its biological, physical, and
chemical complexity like never before. "So, if you were out over the ocean in a ship,
as we have been, the chance of actually detecting these gases is very small, because they're
they react and they're gone before you can detect them.
Whereas when we move the ocean into the lab, this is where the power of that system really
stands out." This “ocean-in-a-lab” at the Scripps Institution
of Oceanography, is a 33-meter long pool that mimics the action of real waves. The tank
is enclosed and clean air is pumped in over the channel, allowing the isolated study of
aerosol spray and gases, which could include viruses, bacteria, and phytoplankton.
"It turns out that they're the phytoplankton blooms that happen all over our oceans produce
over half of the oxygen we breathe. And those processes actually changed the composition
of the ocean, which in turn can change the composition of
the atmosphere, which then changes the clouds." This is exactly what the team is studying
with their most recent project, “Sea Spray Chemistry and Particle Evolution”, or SeaSCAPE.
"So seascape is an experiment that was designed to try and understand how biology that happens
in the ocean affects our atmospheric composition and our clouds and our climate."
The first way marine aerosols form is through sea spray. When waves break at the ocean’s
surface, bubbles burst, and sea spray containing salt and all those little microbes go airborne.
These marine aerosols can affect the formation of clouds over the ocean. They act as “seeds”
that water vapor and ice can cling to, condensing into tiny droplets that can eventually become clouds.
For instance, some types of aerosols can make clouds that are bright and white,
cooling things down. So aerosols can have a really big impact on
the temperature of the planet. It’s one of the reasons the ocean is known as the planet’s
thermostat, because it plays a large role in regulating climate.
"And the question was, why, you know, how is the ocean changing the properties and the
cooling ability of clouds? That was the big question."
The team first needed to establish a baseline of how ocean microbes were impacting climate
on their own... without any influence from humans.
“So, we spent, I'd say 10 years sort of trying to understand that looking
at the spray what we call sea spray aerosol, and we couldn't even with the bloom... we could
not make the cloud properties change.” So with SeaSCAPE, they started to look at
the second way marine aerosols form which is through the production of gas from marine
microbes. This gas rises into the air above the ocean and reacts with other gases to form
new particles. The scientists added some reactive gases, like hydroxyl radicals, to the wave
tank to replicate human influences on the atmosphere.
"And now we started to see the changes in the cloud properties. And the simple answer
is that it's more than just the biology, it's the biology plus the chemistry, the chemical
reactions that actually lead to the changes that ultimately change the clouds."
One day, the team hopes to identify which pollutants pose the greatest threat to the environment.
The information could help revise inadequate climate models and help shape public
policies that address climate change. Another application of their work is understanding
how marine microbes in aerosols could directly affect us. Knowing which disease-causing microbes
in pollution runoff can become airborne through sea spray could help improve our understanding
of the potential risks to human health. In fact, the “ocean-in-a-lab” has proved
so useful they’re already building a facility that improves on the concept. The
new project, called the Scripps Ocean Atmosphere Research Simulator, or SOARS should be completed
in 2021, paving the way to a better understanding of the ocean’s exact role in climate.
So, you know, healthy planet, healthy microbes, healthy people, like it goes hand in hand,
and we're all working together to keep the health of everything together, as best we can.”
If you want to learn more about the state
of our oceans, make sure to check out The Swim, a film that documents long-distance
swimmer Ben Lecomte’s epic journey across the Pacific Ocean to highlight plastic pollution.
The documentary is available to watch on Discovery Plus, so please go check it out. If you have
science you’d like to see us cover, let us know in the comments below. And as always,
thanks for watching Seeker.