Good morning John,

(0:01) So last week I went to the Monterey Bay Aquarium which is, from what I can tell, one of the best places on earth. I got amazed by mudskippers, enchanted by otters, amused by mola mola and dumbfounded by cuttlefish. All of these delights and more are on display for all who attend.

(0:18) But, Monterey Bay Aquarium has a secret.

(0:23) First, lets talk about Chicago, where in 1930, Shedd Aquarium opened. At that time, it was the largest aquarium in the world. The only problem: Chicago, as you may have noticed is really far away from the ocean. They solved this problem by sending train tanker cars down to Quay West, Florida, filling them with sea water and sending them back to Chicago. Now, of course, we can make sea water from scratch, which is what they do at Shedd Aquarium today. But, it's a pain. You have to buy huge amounts of something called Instant Ocean which you mix in to fresh water in like, 80000 gallon tanks. And it's expensive, so you have to constantly filter that water and reuse it.

(1:02) Aquariums on coasts do not have this problem because they get their sea water from the sea. And Monterey Bay Aquarium gets its sea water from some of the best sea in the whole world.

(1:33) If you take a look at the west coast of the United States, you'll see, after the coast happens there's that little light coloured bit. That's the continental shelf. Geologically, that bit is part of the continental land mass, it just happens to be under water. But you'll also notice one place where there's a little chink in the armour of the continental shelf. A place where the darker blue goes all the way up to the coast. That is Monterey Bay, specifically, it's Monterey Canyon. Which has cliff faces more than a mile high, and from shelf to base is roughly the depth of the Grand Canyon.

(2:07) That canyon gives researchers access to an amazing variety of ocean depths, and thus ocean ecosystems, without having to travel far offshore. Monterey Bay, and the areas around it all have consistent winds that blow warmer, less nutrient rich waters offshore. Cool, clean, nutrient rich waters from deeper in the ocean then rises to the surface in a process called upwelling. That makes this area of the Pacific coast extremely abundant and it makes the water fantastic.

(2:38) And so the Monterey Bay Aquarium simply pumps 2000 gallons of sea water per minute into its facility, and a roughly corresponding 2000 gallons leaves, headed back into the Bay. The system that manages this is a marvel and I got to walk around in it and learn a little bit about how it works.

(3:09) The system tracks over 33000 data points, making different exhibits different temperatures for different animals, and ensuring that flow is never interrupted for too long. It's built to handle massive earthquakes and has a redundant backup for everything.

(3:24) At the Monterey Bay Aquarium, not only are they guaranteed a perfect match for the chemistry of the sea, they also have a perfect match for the microbiome of the sea. Which turns out to be a benefit to the plants and animals that live there. Just like we are in a healthy relationship with most of the microorganisms that live on and around us, the microbiome of the ocean keeps plants and animals healthy. The greater the diversity of microscopic species, the less likely it is that harmful infections will occur.

(3:52) Now this all sounds very rosy so far, but it turns out that building your whole aquarium around the use of raw sea water opens up a whole other set of engineering challenges. The biggest of which is probably barnacles, in your pipes. Now you might think, like, just put like a barnacle resistant coating on the inside of your pipes, but there is no such thing as a barnacle resistant coating; they can stick to anything. Barnacle larvae are also tiny, too tiny to filter out of the source without the filter constantly clogging, and you can't get the water moving fast enough to keep them from cementing in the pipes.

(4:28) So, you need two sets of pipes, so that several times per year, you can close one off at both ends, starve it of oxygen, killing the barnacles, and then send a rubber plug, called a pig, through the pipe to wash all the dead barnacles into the sea. Apparently, this smells just fantastic.

(4:47) At the Monterey Bay aquarium, they'll filter sea water to get the biggest stuff out. After the filtering, the water heads straight into their Monterey Bay kelp forest tank, so the ecosystem of that tank is as close as possible to the ecosystem of the actual Monterey Bay. From there, it's distributed throughout the rest of the aquarium. That tank serves as a kind of public facing storage so whenever new water isn't coming in, the level of that kelp tank actually starts to drop.

(5:16) And for the exhibits that contain wildlife native to Monterey Bay, you don't even need to filter that water on the way out because all that stuff is already stuff that's in the bay. But while an aquarium native to, like, Atlanta doesn't have to worry about introducing invasive species because it's a pretty long and arduous trip from Atlanta to an ocean ecosystem, the Monterey Bay aquarium discharges water just as often as it comes in, it's a constant cycle. And for their exotic exhibits, they have to filter water out and pass it through what's basically a U.V. tanning bed which sterilises the water before it's discharged to the bay. So think about that next time you're wondering if you should go in for a tan.

(5:53) And finally, anyone who's picked up a five gallon bucket of water knows that water is not light, so pumping water requires a lot of energy. And in the intake gets clogged, like say, by a smack of jellyfish, they giant steel cylinder that keeps big animals from being sucked in gets crushed like a soda can and the water stops flowing.

(6:14) Ocean water, over that last fifty years or so, has gotten warmer and warm water holds less oxygen. That's bad for many animals, but jellies, which have been roaming the world's oceans since before fish even existed, appear to be taking up the slack, so jellyfish blooms are more common, and these steel cylinders need to be replaced more often.

(6:33) So nothing about this place is simple, but all of this hard work and engineering in the basement creates this magical experience for the millions of people who visit here every year. Every person who walks in these doors encounters what, in many ways, feels like another world that we just happen to share this planet with. That world, in a way, walked right up and knocked on the door on Monterey, California, and humans answered. This aquarium is that open door, giving us an appreciation for the oceans and an understanding that this is in fact all one planet and needs to be treated as such.

(7:13) On the surface it looks like effortless magic. Underneath, we see the secret, the work, the engineering, the science, the passion, and the geology and climate that make it all possible. What a fantastic place?

(7:38) Thank you obviously so much to the Monterey Bay Aquarium and the very cool people on the social media team there. Following them on Twitter or Instagram is an absolute joy. They are some of the best in the world as science social media, so I've put links to their socials in the description. Thank you to Andrew Huang for the music in this video, all of the tracks were from his album TV and Video Games.

(7:57) And John, I'll see you on Tuesday.