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Do microbes ever feel fear? Or concern? Or trepidation? While they can’t exactly tell us, they probably don’t– at least not in ways that we could understand. But we can tell that they definitely experience stress.

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This series could not exist without the support of our amazing Patreon patrons. So, we want to start this one out by saying a big thank you to those of you who have chosen to support us.

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Or concern? Or trepidation? While they can’t of course tell us, they probably don’t– at least not in ways that we could understand.

But we can tell that they definitely experience stress. Now, that stress is not terribly similar to what we experience when tax season rolls around or a traffic jam makes you late for an important meeting. The microbial world is mercifully free of such troubles.

But at its core, what microbes experience is stress nonetheless - the recognition of, and response to, less-than-ideal circumstances. And when you think about it, of course the microcosmos, can be a very stressful place - from shifts in food availability, to sudden temperature swings, to changes in pH that can begin picking apart a microbe molecule by molecule. All in all, there’s a lot going on that can get in the way of microbes living their best lives.

So maybe it is no surprise that, naturally, stressed microbes are everywhere. Like a bear going into hibernation through a frigid winter, this tardigrade, also known as a water bear, has seemingly given up trying to face the stresses of the world. Instead, it is lying motionless in a state of reduced metabolic activity, almost as if it is simply waiting for all of its problems to disappear.

It has formed a durable and protective cyst, and it will stay in there until more favorable conditions arise. And it can stay encysted like this for months, to be woken up by a change in seasons, perhaps. Microbes from all domains of life have evolved similar abilities to outlast those trying times.

And they do this by entering extended periods of reduced metabolic activity, or dormancy. Because, while microbes can be found everywhere you point your microscope, that doesn't mean they can thrive just anywhere. Each species has its own preferences when it comes to habitat, its own comfort zone that is specific to its biology and way of life.

Holophyra ciliates, for example, prefer non-acidic habitats that have plenty of dissolved oxygen. If these ciliates find themselves in a more stressful acidic environment, they, too, form cysts and sit tight, waiting for the world to change. If they’re lucky, that change might arrive in the form of heavy rains that increase the pH of those puddles and pools that their cysts lie dormant in.

Sensing a more hospitable habitat, they re-awaken, face the day, and go about their ciliate business. Now cysts are not the only way members of the microcosmos can enter the liminal boundary between life and death, though. These bacteria have found another way to cope.

The brighter pockets at their tips are the first stages of their last resort to stress. Maybe it’s a lack of nutrients in the sample, maybe the pH levels don't suit them. Whatever it is that’s left them distressed, their coping mechanism is unfolding.

They’re each building a cellular bunker, a spore, which we can see forming here. Their DNA and essential cellular machinery will be almost completely dehydrated and tightly packaged inside the spore’s thick envelope. Eventually, the spore will abandon the cell altogether, jettisoning like an escape pod as the mother cell undergoes a self-destruct sequence.

In their spore form, with their metabolism at minimum possible levels, they can last for decades or even centuries, protected from the harshest of conditions, biding their time. But until then, they are part of the ecosystem’s microbial seed bank - the repository of dormant microorganisms too stressed out by local conditions to fully live their lives, but also too stubborn to die. Seed banks are a big deal in the microcosmos.

They allow species to enter cold storage when times are tough. In that seed bank, species have tapped out of the stressful game of life or death. They’ve found a temporary third option.

And when they awaken, whole microbial ecosystems can simply pick back up where they left off. You can wake up a seedbank yourself and watch it happen at home. All you need is some food and, of course, a microscope.

If you soak the vegetables and herbs destined for your next meal in water overnight and check the water under your microscope the next day, you are pretty much guaranteed to spot some colpodids swimming around. You have just enticed them out of the seed bank – by providing them with a welcomingly wet habitat, you triggered them to ‘excyst’. Not to exist, ‘ex-cyst’.

Colpodid ciliates can be found in soils around the world and they will often hitch a ride on the surfaces of your food. Now, do not lose any sleep over the idea that you are exposed to and are ingesting dormant microbes throughout your day. That is just part and parcel of life on this planet I promise, like you consume them just breathing- it's just one of many of the bridges between us and the microcosmos.

Encysted colpodids are not dangerous, they’re just sleepy stowaways, making the trip from the soil, to the surface of a tomato, and then, into your mouth. James, our master of microscopes, often tries a few different tricks to coax stressed out microbes back into existence. And using different chemical cues, he can activate the dormant cysts and spores of different organisms.

If he wants to awaken the seedbanks of microbes that have a particular love of sulfur, for example, he might add the yolk of a cooked egg to the sample. For others, the wake up call comes in the form of fertilizer, which provides nitrogen and phosphorus. This stage that we’re looking down at right now can host an endless combination of casts performing an endless number of plays, it all comes down to direction.

It seems wherever you look in the microcosmos, microbes enduring stressful conditions can be found, suspended in a twilight zone between life and death, each species sitting, waiting, holding out hope for their own version of paradise to appear. Thank you for coming on this journey with us as we explore the unseen world that surrounds us. And thank you again to our amazing supporters over at

You’ll be seeing some of their names on the screen pretty soon, look there they are. Like I said at the beginning of the episode, we could not do this show without your support, so we want to thank each and every one of you who have supported this channel over the last almost 4 years that we have been doing it. I am so happy to have been able to be a part of the creation of this show and thank you to everybody who is or ever has been or ever might be a patron.

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