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iLabs: Catch of the Day — The First Settlers

August 30, 2014

In this latest “Catch Of The Day!” post, Micro World Staff member Nancy Locquet discusses our Lab’s “First Settlers,”  the Pioneer Protists of the iLab’s micro-ecosystem.

Pioneer Protists

When scientists talk about ecosystems, they define it as a community of living organisms (biotic factors) such as plants, animals and microorganisms in a specific area where these living organisms function as a unit and interact with one another and with the physical environment (abiotic factors).

The latter are the non-living components such as the local atmosphere, type of soil or water, the temperature, air, humidity, salinity… Ecosystems can be big, such as the Atlantic Ocean, or they can be so tiny you need a microscope to see what’s going on in that “micro-ecosystem” such as a drop of pond water.

The interesting fact is, ecosystems change constantly and are dynamic entities susceptible to the impact of human activities—logging, for instance—or natural disasters, such as earthquakes, avalanches, wildfire, floods, landslides, erosion and many other natural and human interventions.

These natural and environmental catastrophic events are perceived as life-changing; devastating even, but, once in a while, they can bring a positive spin to things. Some ecosystems are born out of the ashes of volcanic eruptions or may be “reborn” through the clearing effects of wildfires. Think about North Carolina’s Long- Leaf Pine Savannas for instance. This ecosystem would simply disappear along with the many endangered plants and animals if fire didn’t occur periodically.

You might ask, what does this have to do with the microorganisms in the pond water samples in the Micro World iLab?

Well, we were wondering if micro-ecosystems follow the same natural laws as their macro counterparts. Can a new micro-ecosystem be created and will it be a suitable habitat for protozoans and algae?

To examine this possibility, we introduced a clean unused synthetic sponge to our fish tank. Since we don’t use chemicals to treat the fish tank, it resembles natural pond water. The sponge is about 1×1.5×2.5 inches and was attached to a rock with a clear fishing line. This bright green synthetic sponge became a “hot-spot” for our Pouch snails and our Ramshorn snails that inhabit our fish tank. The color didn’t seemed to bother them and they seemed to like the texture of the sponge.

Pouch snails exploring the surface of a synthetic sponge in a pond water aquarium

Pouch snails exploring the surface of a synthetic sponge in a pond water aquarium

Soon, debris from the fish tank and some droppings from fish and snails were covering the sponge. We left it in the tank for about 3 weeks until we had to remove it to treat the tank for possible parasites. The filter was replaced and the algae were scraped from the sides of the fish tank. This seemed the perfect time to check what was in our synthetic micro-ecosystem.

Would we see the first settlers of the green sponge? Water was squeezed from the sponge with a set of tweezers and collected in a clean petri dish. A wet-mount was made using a plastic disposable pipet to collect a drop of the water…the slide was placed under the microscope and set to 10 x magnification and we all watched eagerly to see what happened… A familiar life form was dashing over the screen, clearly healthy, happy and super-fast…it was a Euplotes.

Euplotes in pond water

Euplotes in pond water.

These were not the only unicellular protists that we encountered. Some of the other pioneer protists were beautiful delicate Vorticella clustered together on some pieces of green algae. They were small and were only visible at the highest magnification (40x).

Vorticella in pond water

Vorticella in pond water.

Some Colpidium were very active as well, dashing like busy bees over the slide.

Colpidium in pond water

Colpidium in pond water.

Last but not least, we saw our most common protists Paramecia and Rotifers.

Paramecium in pond water

Paramecium in pond water.

Rotifers in pond water

Rotifers in pond water.

Since these were the organisms that we discovered on a newly introduced “synthetic” micro-ecosystem, we call these first settlers our Pioneer Protists from the Green Sponge. Since it all began in a new habitat, uninfluenced by any pre-existing communities, we could technically call this a primary succession (whereas it would be called a secondary succession if the pre-existing communities were already disrupted by a disturbance)

We tried to keep the first settlers alive by placing the sponge in a container with pond water, aerating it and placing it inside the dark box where other cultures reside, but a few days later bacteria had started to colonize the container and a foul odor came from its flask. We clearly had to dispose of this culture.

However, we have already placed a new sponge in the fish tank in the hope that we can recreate this event, and possibly keep the First Settlers going.

So now…if you see a sponge in the fish tank…you know why.

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4 Comments leave one →
  1. goldfire407 permalink
    August 30, 2014 2:02 pm

    Thanks Deb.  

  2. September 1, 2014 8:54 pm

    cool ! What fish do you have?

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