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Perhaps the most interesting (or the only interesting) job I have had, was working as an intern at Smithsonian’s Marine Systems Laboratory in Washington DC in 1993. The Smithsonian Natural History Museum employed an ecological engineer named Walter H. Adey (?) who had built a synthetic mangrove ecosystem in a spare greenhouse amidst the national orchid collection. The fake everglades ecosystem (which I described more thoroughly in an earlier post) had been built decades earlier and it was starting to fail in some critical ways. However in a larger sense, the failures were the point of the project, since they elucidated the innumerable fragile connections which make living systems possible.

The only picture I could find of this place seems to have been kept because it featured Robert Redford not because of the synthetic ecosystem, which says a huge amount about humankind (although it has raised my esteem for Robert Redford).

All told, the terrarium world was about the size of a large suburban home and, at its heart was a miniature ocean built out of a calcium carbonate pit filled with thousands of gallons of salt water. The water was continuously filtered over algal mats which cleared out the ammonia and nitrogenous waste (and other waste products too). The ocean itself was filled with many tiny cnidarians, copepods, and suchlike micro-invertebrates, however larger animals were scarce (indeed animals larger than a small paperclip were dying out of the entire habitat). The only large fish were a pair of venerable striped sea bass who were definitely not reproducing.

It turns out that ray-finned marine fish almost all go through an extensive (and rather poorly understood) “larval” stage where the infinitesimal and quasi-transparent fish hunt the zooplankton while being hunted by innumerable ocean predators. This phase is nearly impossible to reproduce in captivity (although any ichthyologists or aquaculturists out there should feel free to jump in with additional information). Think of how depressing that is! Almost all of the 20,000 species of exquisite ocean fish are tied inextricably to the ocean! They can’t be conserved or preserved in some zoo or time capsule or artificial paradise, because we have no idea how to do that. If we broke through every sort of technological barrier and built an ark ship to blast off to Alpha Centauri, we wouldn’t have tuna or triggerfish or basking sharks with us.

Hollywood Lies from “Snowpiercer”!

The tiny fake sea (and the brackish mangrove swamp) were not empty though. There were species of small live-bearing fish which lived there and had managed to reproduce. Generations of these robust little minnows lived and died in the ersatz ocean and their delicate stripey shadows could be seen flitting about in bait balls in the depths. I should have asked what species they were–however the fascinating Wikipedia entry on Mangrove killifish should give you an idea of what sort of survivors these characters were.

I have written before about my own terrible childhood experiences keeping aquariums, and (although I still regard myself as a profoundly ineffectual failure on nearly every level), I think the sorts of problems I encountered reveal bigger issues than my jejeune fishkeeping skills. This is a long-winded way of reminding Elon Musk (or whoever else) that Earth’s oceans keep the planet alive and are the defining feature of our world. We would need such things anywhere else–but we know next to nothing about synthetic ecology. It doesn’t seem like a field where just adding more metal tubes and freaky machines actually helps all that much…

A Wild Mangrove

My first job was an unpaid internship at the Smithsonian Institution’s Marine Systems Laboratory in Washington DC during the summer of 1993.  The Smithsonian was operating and monitoring a partially closed synthetic ecosystem within a large greenhouse—in effect they had built a huge terrarium.  This ecosystem was built to mimic a tidal mangrove swamp: tiny locks allowed small amounts of saltwater to flow out of a central “ocean” and back into a multi-staged brackish mangrove swamp in imitation of natural tidal flux.  The highest part of the system was a reservoir of fresh water.  This was allowed to continuously trickle down a creekbed through a little deciduous freshwater forest.  There were then several multiple stages of mangroves varying from true mangroves, which practically had their roots in the “ocean”, to brackish trees, to trees which were only exposed to a tiny amount of saltwater on the highest Proxigean Spring Tide (the system of locks was ingeniously constructed to mimic these rare occurrences ), to the sweetwater trees around the “creek”.

I can’t find any pictures but here is a tiny mangrove tank at the Oklahoma Aquarium

The system had been in operation for many years and a lot of strange things had happened.  All of the egg laying fish in the ocean (actually a large deep saltwater pool) had died out except for a couple of strong-willed sea bass who acted as apex predators.  The fish which remained were all small live-bearing fish which reproduced viviparously and did not require vasty oceans for their eggs to hatch and for their fry to grow up in.  The Florida lizards, turtles, and insects had all vanished (although there were unconfirmed lizard sightings).  The animals which did flourish were tiny sea anemones, tube worms, sponges, and hydras.  These little invertebrates could be found sticking to everything in the ocean and the brackish pools.   The biologists assured me that an even greater number of microscopic invertebrates were reproducing themselves.  Two large rock crabs were still on the scene dominating the oyster shell beach.  I believe there were a handful of mollusks left but I never found out.

The habitat was not closed.  Scientists added water when necessary and the greenhouse windows were opened albeit screened.  Additionally, human visitors–including the wacky bio grad students who ran the place–had free access.  This meant that a whole host of invasive species had showed up.  The most dangerous outsiders were scale insects which came from the giant greenhouses next door (where the immense national orchid collection was housed).  Occasionally sparrows would get in.  Somebody had put some African cichlids in the fresh water reservoir–where they were thriving.

My favorite job at the mangrove was to impersonate tropical storms.  I would run around and squirt everything with a high-pressure hose and kick and shake the plants (it was discovered that the trees and plants started having troubles if not routinely abused).  I would spend whole afternoons pulling up sawgrass and plucking scales from mangrove trees.  More prosaically, I cleaned up algae from the ocean and freshwater filters—which basically consisted of water running over large beds of algae.  It was a fun job with fun people but it was tinged with sadness to record an ecosystem slowly and gradually declining.

What was the purpose of the giant terrarium you might ask?  It was built to observe the small flora and microfauna of a tropical mangrove ecosystem.  It was also a precursor and prototype to Biosphere 2 (the principal scientist/engineer behind the Smithsonian synthetic mangrove pulled out of Biosphere 2 when it was revealed that the oceans would not be built of limestone!).  The whole system was an early attempt at creating a large scale contained ecosystem.  Ecologists hoped to better understand the wildly complicated nature of real ecosystems through looking at these controlled microcosms.  Closed ecosystems were also coming to the attention of NASA and space scientists who were starting to think about building synthetic ecologies for space stations (or even other worlds).   The complexity, scope, and failures of that miniature mangrove swamp were a first taste of how complicated such a project truly is.

Torus Space Colony! It, um, might take a while though…

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