This episode is brought to you by EnergySage, the nation’s most trusted online solar marketplace.
Head to Energysage.com to start exploring rooftop and community solar options in your
area.
There are many organisms in nature that are capable of lighting themselves up through
their own bioluminescent means.
But not many have the distinction of having helped guide a future astronaut to safety.
Jim Lovell is perhaps best known for his flights to and around the moon, including the 1970
Apollo 13 mission, which experienced a critical failure that prevented it from actually landing
on the moon.
But in 1954, he was a fighter pilot on a training mission off the coast of Japan when his navigation
systems failed.
With darkness around him and no guide to the aircraft carrier he was meant to land on,
Lovell turned off the lights in his cabin…only to notice a glimmer of green in the waters
below, acting like a trail of glow-in-the dark breadcrumbs left behind by the carrier
as it moved through the water.
That light was the bioluminescence of planktonic life, and fortunately, you don’t have to
be a stranded fighter pilot to see it in action.
That surface oceanic light is most likely attributable to a certain kind of single-celled
eukaryote called a dinoflagellate.
There are more than 2000 living species of dinoflagellates, and while a few are found
in freshwater, most are some form of marine plankton.
Dinoflagellates survive on a mix of diets.
Some are purely phototrophic, consuming food produced by their own chloroplasts.
But most are mixotrophic, meaning that they rely on a mix of photosynthesis and consumption.
In either capacity, dinoflagellates are hugely important for their local ecosystems.
As marine primary producers, they are second only to diatoms.
And when dinoflagellates consume other organisms, they link together various facets of production
and consumption in the ocean, sending energy up the food chain.
But nature is built on balance, and excess dinoflagellates can also become disruptive
to local ecosystems when they accumulate into large toxic blooms, also known as “red tides”.
These can choke off resources to other animals, and sometimes even produce toxins that poison
their neighbors.
Aside from their importance, dinoflagellates are kind of quirky.
For one thing, they have a really weird nucleus.
Like so weird that it has its own name: the dinokaryon.
If “dinokaryon” sounds majestic to you, well… that is apt.
The dinokaryon can hold a truly absurd amount of DNA for a eukaryotic nucleus.
A human nucleus, just for reference, holds about 3 picograms of DNA.
Meanwhile, some dinoflagellates species can hold somewhere from 100-200 picograms of DNA
in their dinokaryon.
And where most eukaryotes pack our DNA into little structures connected together like
beads on a string, dinoflagellate DNA does not have that clear of an architecture.
Even more weird: they have the genes to make that kind of orderly arrangement possible,
they just rarely seem to use them.
Dinoflagellates also swim kind of funny.
It’s part of why we can’t show them too often because they’re always whirling in
and out of focus.
One is held in a structure around the organism’s equator, spinning and moving the organism
forward.
The other flagella, which you can see here coming out the end of the dinoflagellate,
helps the organism steer around.
While most dinoflagellates are capable of photosynthesis, they do not all go about their
chloroplasts the same way.
Yes, some dinoflagellates have their own chloroplasts and use them as you would expect to carry
out photosynthesis.
But others, like the freshwater Nusuttodinium, are a little bit less honest.
They steal their chloroplasts.
These dinoflagellates will start out chloroplast-less and colorless.
But as they begin to consume their favorite meal, some local photosynthetic algae, the
dinoflagellates don’t just consume their nutrients: they steal the algae’s chloroplasts.
These, appropriately enough, are called kleptochloroplasts, and they’ll stay with the dinoflagellate
until they divide and the daughter cells have to steal some new ones.
But of course, the most striking dinoflagellate trait is their bioluminescence.
When the organisms were first described by Henry Baker in the 19th century, he called
them “animalcules which cause the sparkling light in sea water”.
That sparkling light is the product of a molecule called luciferin, which is usually set into
glowing action by some kind of mechanical stimulation.
It could be the breaking of waves, a passing aircraft carrier, or—most relevant to the
dinoflagellates themselves—a potential predator.
Scientists have hypothesized that dinoflagellates flash their lights as a kind of “burglar
alarm” in response to predators, attracting the attention of other organisms that will
eat the dinoflagellates’ own enemies.
So, no, they’re not scaring away their predators.
They are attracting the predators of their predators.
This system of bioluminescence and the molecules underlying it has its parallels across a lot
of other animals, including fireflies.
And whether they are taking in light for photosynthesis or producing it through their own pathways,
dinoflagellates have evolved their own mastery of illumination.
Thank you for coming on this journey with us as we explore the unseen world that surrounds
us.
And thank you again to EnergySage for sponsoring this video.
EnergySage is the nation's most trusted online solar marketplace, used by millions of consumers
every year.
They help people make smart energy decisions and make the process of going solar as easy
as booking a flight online -- leading to (on average) 20% lower prices than you'd find
anywhere else.
Whether you’re a homeowner or business, electricity costs can make up a large portion
of your expenses.
With a solar panel system, you will generate your own power for the system’s 25 year
lifecycle.
Plus, you'll be reducing your carbon footprint in the process!
And with EnergySage’s easy-to-use website, you can compare solar proposals, receive multiple
quotes from pre-screened installers, and talk to their team of expert, unbiased Energy Advisors
who can answer your questions and help you navigate your solar journey.
So head on over to energysage.com today to see how much you can save by going solar.
If you ever think to yourself, “Boy, I sure do like this channel.
I wonder who I can thank for that.”
Well these people on the screen right now, they are those people.
Our patrons on Patreon who make it possible for this whole team to come together to make
this special little show for YouTube.
If you want to see more from our Master of Microscopes James Weiss, check out Jam & Germs
on Instagram, and if you want to see more from us, there’s always a subscribe button
somewhere nearby.