Biotic index - Introduction
The Biotic Index is a scientific research method based on objectively judging the quality of running water. We base our method on the fact that not all organisms are equally susceptible to pollution. In pure clear water, not only more, but also different organisms are found. The method we are about to present here is based on BISEL (Biotic Index at Secondary Education Level).
The determination of the BI is an indispensable supplement to further research. Analysing chemical and physical elements of water give you information about its present conditions but this can change over hours and days. The BI however, since it studies the organisms found in water, also provides you a historical view of the water’s health because it shows the long-term condition of the water. A good BI proves that water quality is good because it already had been good the days, weeks or even months before. These little creatures need a long period of positive or poor conditions to be in a specific state of good or bad health.
Macro-invertebrates (small invertebrate animals, still perceptible to the naked eye) are identified using an classification card. When this is done correctly, the BI can be calculated quite easily.
For the students in the ‘lower level’, the analysis of animals is less complex and the calculation of the BI is simplified.
In contrast to other checklists, the BI cannot be just partially executed. When your work is finished a score will be shown from 0 (very polluted) to 10 ( very clean). Comparing your score to others can be very useful. You can look for a partner using the ‘school list’ or ‘notice board’.
Please note that you have to register, if you want use the checklist and that you have to fill in the data in the Book of the River!