[biofilms & biodiversity]

An Introduction

Understanding Biodiversity Using Biofilms
What Are Biofilm Communities? | How Do Biofilms Form?

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 between 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 interactive website, you will learn how to set-up a field-based aquatic biodiversity experiment, use interactive tutorials to learn how to calculate measures of biodiversity, and evaluate some virtual biofilm cultures grown on acrylic discs suspended vertically in the Baltimore Inner Harbor. These discs were suspended so we could monitor water quality and biodiversity at three depths in the Inner Harbor - shallow water (0-1m), middle level depth (2-3m) and deep water (3-4m). The biofilm discs are checked by groups of teachers and students periodically for colonization and species diversity.

This project based science model demonstrates how water quality, depth, and biodiversity are linked by investigating the following questions:
  • How can we design an experiment to answer these questions?
  • How will data be collected?
  • How can the data collected be analyzed?
  • How does depth of the water effect the species diversity?
  • What tiny creatures lurk in the Baltimore Inner Harbor?
  • What relationship do these organisms have with the water quality in the Inner Harbor?
The Biofilms and Biodiversity lesson supports key components of the instructional strategy Claim, Evidence and Reasoning (CER) that is rapidly being used as a model for teaching students about the process of science. Additionally, the lesson also supports modeling and design cross cutting themes in the Next Generation Science Standards (NGSS) and the overall philosophy of the value of PBS. As you progress through the interactive lesson, you will learn how to make your own biofilm rack, conduct your own biofilm experiment, and learn how to collect, analyze and interpret data.

CER References

Dr. Katherine L. McNeill, Boston College, Lynch School of Education

McNeill, K. L. & Martin, D. M. (2013). Claims, evidence and reasoning. In Froschauer, L. (Ed.). A year of inquiry: A collection for elementary educators. (pp. 170-175). Arlington, VA: National Science Teachers Association Press.

The Teaching Channel

Edutopia (George Lucas Foundation)

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What Are Biofilm Communities?

Biofilms are a hot topic in microbiology today. Scientists are studying the ways bacterial colonies form these slimy layers, which can be resistant to antibiotics and the immune system, or critically important in the formation of the human microbiome and our health. These vast areas of study will help inform how biofilm layers form, adhere to surfaces, how they can be prevented, and how they can be encouraged. 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 that 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, intestinal gut, medical devices, contact lenses, drainage pipes, and the bottoms of ships. The human gut microbiome is the hottest of all these topics today and research has shown evidence that our health is closely tied to a healthy gut community of bacteria. It is now well known that there are far more microbial cells in and on our body than the total of our own human cells. Estimates are that there are 10 times more microbial cells making us a type of super-organism and an excellent example of symbiosis. The common denominator is that all biofilms are comprised of a primary layer of bacteria that provide an attractive environment for other bacteria and larger organisms. Biofilm communities found on the hull of a ship consist of large organisms like barnacles, mussels, and a 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.

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How Do Biofilms Form?

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.

Biofilms and Biodiversity: An Interactive Exploration of Aquatic Microbial Biotechnology and Ecology, an article in the Journal of Industrial Microbiology and Biotechnology by J. Adam Frederick, Dan Jacobs and William R. Jones (2000, 24(5):334–338).

Aquarium Culture of Freshwater Invertebrates, an article in The American Biology Teacher by Timothy S. Wood (1996, 58(1):46-50). The article demonstrates replicable techniques for aquarium culture of freshwater invertebrates and provides and an excellent hands-on method for supplementing the biofilms and biodiversity activities in the classroom.


NY Times, Some of my best friends are germs

Human Microbiome Project

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