[biofilms & biodiversity]

Rack Design & Construction

Basic Rack Designs | How We Used A Rack

[2 biofilm disks]

Basic Rack Designs

Our collection of rack designs are simple and inexpensive to build. All use materials that are available at most hardware stores.

To the right are some crusty old acrylic discs after 4 weeks in the Baltimore Inner Harbor. The disc on the left has an abundant of whip mud worms and the disc on the right has a number of small barnacles (find out about this research project).

This study used the biofilm on a string rack design. We now prefer a rack design that we call the biofilm pipeline with acrylic discs.

Biofilms can also grow on compact discs (CDs). Our third design, called CD Pipeline, was developed by Roger Lindblom, one of our partners in the original Virtue Project. The Virtue Project (http://new.virtuedata.se/en) collaborators in Sweden, Mikael Olsson and Susan Gotensparre, have continued this work and are now expanding the reach of Virtue once again.

For each rack design, you will need acrylic (or CDs) discs with a hole drilled in the center. The size of the discs can vary, but a 10 cm width *disc fits perfectly in a plastic sandwich container or baggie for transport to the lab and are easily viewed under a stereoscope.

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[Biofilm Rack Design]
    Video of racks in the Inner Harbor:
Quicktime movie


How We Used A Rack

An interesting experiment evolves around the comparison of invertebrate communities and depth in the water. Discs placed at different intervals along the line make this easy to accomplish.

The student activities evaluated some biofilm cultures grown on plexiglass discs that were suspended vertically in the Baltimore Inner Harbor water. These discs were suspended so we could monitor water quality and biodiversity in three regions of the Inner Harbor - shallow water (0-1m), middle level depth (2-3m) and deep water (3-4m). The rack design used is shown on the right. The biofilm discs were checked by groups of teachers and students twice per week for colonization and species diversity.

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