Greetings from Magrathea

Written record, found by Kevin Pang, Santosh Srivastava, Robert Keston, and Hung-hsiang, recorded in Voyage to Atlantis.

Introduction

A few articles ago, I wrote about the Year Without a Summer. I chose that event because it was well recorded. However, there are other volcanoes. One of the exciting ones was the Thera eruption. It had the explosive force of the Tambora eruption, but it happened mid-2nd century BCE, so there are fewer reliable eyewitness accounts. That's the bad news. The good news is, according to some theories (and you should note that "according to some theories" is equivalent to "this is complete nonsense"), the Thera eruption caused the destruction of Atlantis. My go-to book for this is James W Mavor's Voyage to Atlantis: The Discovery of a Legendary Land. Half of this book reads like a one of those travelogue pieces; Mavor went to the Mediterranean for hands-on work. If he is a bit lax on describing the surroundings, the prose is engaging in how he interacted with it, climbing cliffs and sailing on the research vessel. Mavor also consults with proponents of this theory, most notably Angelos Galanopoulos. The other half of the book is an attempt to weave biblical and mythological accounts to this real life explosion. While this does ping my Casti list of things not to trust, the book is entertaining.

Of course, this isn't the only theory. From National Geographic comes this quote: "Pick a spot on the map, and someone has said that Atlantis was there," says Charles Orser, curator of history at the New York State Museum in Albany. "Every place you can imagine." Is there a single place besides Wikipedia that can make sense of all these theories? And what did Atlantis look like (not the attempts of the ?real' Atlantis, but the fictional Atlantis described by Plato)? One of the best sources for Atlantis is an RPG ? GURPS Atlantis. Other sources include the aforementioned Voyage to Atlantis and the Dictionary of Imaginary Places. Pre-sinkage, Atlantis was an island, 533 kilometers by 355 kilometers. The capital was circular, bordered by a wall made of oricalcum, a magical reddish alloy that glowed. Canals circled around and through the capital, and the canals were large enough that harbors inside the capital held huge tremeries. The buildings inside the capital overshadowed anything in the known world. Plato wrote that Atlantis (the island) had an empire that reached Greece itself; Athens was one of the few city-states that repelled the Atlantean empire.

After it sank to its watery grave, what happened? One of the early stories was by Sir Arthur Conan Doyle: The Maracot Deep, first published in 1929. In this, the protagonist, Professor Maracot, and his team go by bathysphere to one of the deepest trenches in the Atlantic. They end up stranded in Atlantis. Air was created using some unexplained machinery and the natives use a chemical reaction to create coffee, tea, and flour. What about the water pressure? I'll let the author explain. "Where was that terrific pressure which had exercised the imagination of so many scientists? We were no more affected by it than were the dainty fish which swam around us. It is true that, so far as our bodies were concerned, we were protected by these delicate bells of vitrine, which were in truth tougher than the strongest steel, but even our limbs, which were exposed, felt no more than a firm constriction from the water which one learned in time to disregard." You need to remember that this is early science fiction. Anyway, transparent strong material is used to shield us airbreathers from the nasty effects of water.

And this isn't the only depiction. Both Marvel and DC Comics used Atlantis as a source of superheroes. Both could breathe underwater, and both were immune to water pressures of deep sea diving. If you remember the Justice League TV comic, the DC Atlantis was portrayed with a dome over it, which seems silly if everyone could breathe water. A few TV series (Stargate Atlantis and the BBC Atlantis) pulled the myth in even more directions.

Marine Zones

Anyway, why do I bring all this up? First, it's cool. I ran a 1930's pulp-campaign where the characters found themselves stranded in Atlantis, and the goal was to get back alive. Having miles and miles of ocean in between the characters and the rest of civilization was a nice isolating factor. It was a nice contained environment, and I populated the city with dinosaurs, flesh-eating insects, natives, and a murderous crew from a previous expedition that went all Apocalypse Now. They ended up finding a spacecraft and separating it from Atlantis, probably altering WWII in the process. The other reason is because adventuring in marine environments have their own peculiarities. Let's go through those, focusing on salt-water environments. There are four main zones:

• Intertidal: I was hesitant to include this zone in "marine" environments. Technically, it is a marine environment (and technically correct is the best kind of correct). But, this zone covers that area of land that is underwater in high tide, and land at low tide. You can find this anywhere there's a coast; we used to explore the Point Reyes tide pools in California. Obviously, organisms that can move just avoid this area. Plants and animals that cannot move need to be very resilient. There is usually enough water to support seaweed and mussels, and even at low tide, the area is usually wet and slippery. An adventure in an intertidal zone is nice because it provides both timing ("we need to wait until midnight") and countdown ("after ten rounds, the area becomes difficult terrain") until the area is submerged. And when the area is submerged, you can introduce more monsters to challenge the player characters.
• Pelagic: This is the open water zone. It doesn't include areas near the coast, nor does it include the sea bottom. Ecologically, this starts at the surface of the sea, with photosynthetic plankton and floating seaweed producing most of the energy here. Sunlight penetrates this layer. As the plankton dies, it settles down to the lower layers, where fish feed on it. Sunlight penetrates about 1000 meters, and if you go down past this point, there's no light and little oxygen. Pressure becomes an issue at this area. For every 100 feet you go down, pressure increases by 43.5 psi. This is a linear increase, so the pressure difference is highest closest to the surface (this means that the most damage to the human body is done closest to the surface). If you have a higher pressure in the outside atmosphere than in the body, then the air inside the body compresses. This causes a partial vacuum, which means that membranes like the ear drum get sucked into the body, and possibly ruptured. The increased pressure means that nitrogen is absorbed in greater rates. Resurfacing with this level of nitrogen causes the bends, which means joint and limb pain, blurred vision, confusion, and unconsciousness.
• Benthic: The benthic zone is the ocean floor, not including the intertidal zone. Like the pelagic zone, there's a distinction between areas where sunlight can penetrate the ecosystem, and areas in darkness. Most of the animals attach themselves to the sea floor, or move across it like crabs and lobsters. The coral reefs, one of the most diverse areas, are included in this region. The fish around the coral reefs have evolved specifically in this environment. Unlike typical fish that are streamlined for quick movement, coral reef fish are flat for maneuverability. These fish are also brightly colored with patterns that allow them to blend in with the coral. A good example of a coral reef carnivore is the moray eel, which has both two sets of jaws, thick skin, and toxic mucus. It's funny ? when I think of underwater adventurers, I envision something similar to flight, where characters can swim to change their position on the Z axis. And you can do this, but many animals treat the ocean floor as ground, not trying to swim.
• Abyssal: The abyssal zone is cool. Seriously, it is cold, reaching only 35 to 37 degrees Fahrenheit. This consists of the very, very deep areas, and the animals here are very weird. Fish here are usually blind because there isn't anything to see. What little heat is found through chemical-rich geothermal vents. There's something called Deep Sea Gigantism, where invertebrates who dwell in this area grow to larger sizes than their shallow water relatives. For example, the giant squid reaches a size of 46 feet. Animals here have evolved to deal with pressure, mainly by having fewer bones and more flexible cartilage. They also are more efficient, pulling what little oxygen there is from the water. We only know about this because of unmanned submersibles like this.

Conclusion

Next month, I'll be talking about domestication and the wonderful ways we've created animals for our use. And I want to end with a shameless plug of a different story, Dread Lord Bob. Until next month.