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An Introduction
Understanding Biodiversity Using Biofilms
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The Chesapeake Bay is the largest most productive estuary in the United States providing habitat for some 2,700 species of plants and animals. The health of the Bay is important in maintaining this high level of biodiversity - the variety of species located within an ecosystem.
Many of us have heard about or participated in water quality monitoring throughout the Chesapeake Bay region and the importance of these measurements for understanding the health of Chesapeake Bay. Water quality can be directly related to the biodiversity within the Bay ecosystem. The connection of water quality and biodiversity can help us understand how the abiotic (nonliving) factors have an impact on the biotic (living) factors in an aquatic environment. One way to measure biodiversity is to examine biofilm communities. In this unit, you will evaluate 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 biofilm discs were checked by groups of teachers and students twice per week for colonization and species diversity. The project demonstrates how water quality, depth, and biodiversity are linked by finding answers to these questions:
As you progress through the unit, you will learn how to make your own biofilm rack and conduct your own biofilm experiment. Return to top What Are Biofilm Communities?Biofilms are a hot topic in microbiology today. Scientists are studying the ways bacterial colonies form these slimey layers, which can be resistant to antiobiotics and the immune system, in hopes that new information will help us understand how the layers form, adhere to surfaces, and how they can be prevented. Biofilms moved to the forefront of microbiology after a 1994 case that involved the infection of hundreds of asthmatics. It was found that all the asthmatics used the same inhalant contaminated with a bacterium known as Pseudomonas aeruginosa. This bacterium was able to survive the routine disinfection of the inhalant during manufacturing by forming a biofilm comprised of many colonies. The contaminated inhalers contained pieces of the biofilm which were transported directly to the lung tissue by the asthmatics. In the lung tissue the Pseudomonas biofilm was able to flourish. One hundred people died from the biofilm infection, a dramatic example of the danger posed by some bacterial biofilms.Biofilms can be found in many areas of the human body and the environment. Teeth, intestines, medical devices, contact lenses, drainage pipes, and the bottoms of ships. The common demoniator is all the biofilms are comprised of a primary layer of bacteria that provide an attractive environment for other bacteria and larger organisms. Biofilms found on the hull of a ship consist of large organisms like barnacles, mussels, and host of other zooplankton and phytoplankton. These biofilms slow a ship and are expensive to remove and prevent. Current methods to prevent biofilm formation on ships include a wide variety of toxic marine paints. However, these paints tend to wear off and biofilms which are resistant form on them without regard to the toxins. How do biofilms form? Read The Sequence of Fouling of Engineering Materials In the Sea written by Dr. Robert E. Baier, Professor and Executive Director, Industry/University Cooperative Research Center for Biosurfaces. Return to top |