a005  2150  28 Oct 81
PM-Topic-World in a Bottle, Bjt,950
TODAY'S TOPIC: Shrimp and Algae In Little 'Worldlet'
Laserphoto NY3
By ROBERT LOCKE
AP Science Writer
    PASADENA, Calif. (AP) - Biologist Joe Hanson builds tiny,
self-sufficient worlds and seals them in softball-sized bottles to
prove a living community can survive on its own by recycling all that
it has, to produce all that it needs.
    The colonies of shrimp, algae and bacteria - which convert each
other's wastes into oxygen, carbon dioxide, water and food - are
apparently the most complex, fully closed ecosystems ever to survive
more than a year. And they may be the first, tentative step toward
self-contained ecosystems that would allow mankind to venture deep
into space and colonize other worlds.
    ''Eventually, assuming humanity doesn't destroy itself on this small
ball, we're going to want to start moving out into space. That's the
sort of thing humanity does,'' Hanson said. ''That means we're going
to have to support people and possibly colonies for extended space
flights and for extended periods on other planets.''
    A space voyage could take years, even decades, and require huge
supplies of food, water and oxygen. Providing such fundamental
essentials for a full-scale colony in orbit around Earth or on another
world would be a near-impossible challenge.
    So the Closed Ecology Life Support Systems section of the National
Aeronautics and Space Administration is considering another
possibility: sending aloft a whole ecosystem that can handle its own
needs just as the bottled ''worldlets'' on a laboratory shelf at the
Jet Propulsion Laboratory have done for almost 16 months.
    And on a more terrestrial level, Hanson said, ''There's a kind of
moral lesson in there: We don't have to keep throwing all of our trash
away. If we have enough energy ... it is possible to recycle
everything.
    ''These are, in a sense, very small, very simplified analogs of
spaceship Earth,'' he said.
    Still, he added, ''They're extremely complicated, even though all
you see is a little bit of algae and a few shrimp swimming around in a
small bottle.''
    Almost all the fundamental pieces that maintain Earth's natural
balance are working in three cups of artificial seawater inside the
sealed beakers. Plants - microscopic, stringy green algae - produce
oxygen through photosynthesis. The half-inch red shrimp use the oxygen
and exhale carbon dioxide, the raw material of photosynthesis.
Bacteria and other microscopic creatures feed on the shrimp's wastes,
converting it into fertilizer for the algae, which are eaten by the
shrimp.
    ''You've even got a predator-prey loop,'' Hanson said, although
''it's very simplified. The shrimp, I'm sure, are also eating bacteria
and some of the other microscopic organisms.''
    The only thing these little worlds take from outside is light and
heat. Just as Earth feeds on energy from the sun, the driving force in
the microecosystems are fluorescent lights that burn 12 hours a day.
    A totally closed microecosystem could prove a major tool for
scientists studying the effects of such things as pollutants on a much
more complex scale.
    But for now, Hanson said, the beakers ''have pretty much served the
purpose I had in mind. ... The biology community in general believed
that closed ecosystems smaller than the planet probably were not
possible. I think we have now shown ... that they are, in fact,
possible.''
    He did it, he said, with about $200 and odds and ends ''from
somebody's garage.''
    Hanson started with about a dozen beakers, each holding a roughly
identical mixture of artificial seawater, algae and 11 to 16 shrimp.
Then the tops were melted shut so nothing could get in or out. Now
most are thriving, although ''they've all gone off in different
directions.''
    The shrimp died in several jars, a few of which now look like green,
stagnant swamps. Most survived, although the algae appears in several
different forms and is sometimes present only at a microscopic level.
    The diversity probably resulted from ''very small differences'' in
the original mix tht caused each isolated community to follow
different routes to stability, Hanson said.
    ''The same kinds of things happen in nature,'' he said. ''When the
systems survive, that means they have assumed a balance between the
photosynthetic organism (plants) and the consumer organisms.''
    Once that balance is achieved, the system should live until the
shrimp die of old age, which could take years, unless some chemical
calamity wipes out a whole community by depleting some vital
component.
    Hanson said he hopes to develop instruments and procedures to
monitor such systems without breaking the seals. Without that, he
said, ''I don't really know what's going on in there.''
    And he said the next logical step is to mix in new variables and new
species, especially true predators. But if the shrimp are to become
prey, ''You're not making much of a game out of it.''
    And he'll have to figure out how to persuade the shrimp to
reproduce, which probably will require manipulating the intensity and
duration of their artificial sun.
    Without such added components, he said, ''You're not playing the
ecology game fairly and it won't come out right.''
    
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