1. A table of the invertebrate data for EACH GROUP in the class; present the taxonomic groups in rows and the student groups (1-10) as columns. Individual cells should show counts. Include all the taxa that were recorded; you can delete the rows for the taxa that were not found.
At the bottom of the table, add extra rows for: the number of taxa identified, BMWP score, ASPT score and river grade for each group. Compare the number of taxa and the ASPT score with the values predicted by RIVPACS for the River Uck (see handout and lecture slide). The river grade can then be obtained from the table in the handout and the lecture slide.
Add a further column on the right-hand side for the combined data across all groups (i.e. as if the samples from all ten groups had been combined) and present the scores and river grade for this combined sample.
2. A table of river chemistry data for EACH GROUP in the class; present the chemistry parameters in rows and the student groups (1-10) as columns. The table should include separate rows for each replicate of: pH, dissolved oxygen (mg/l), % oxygen saturation, temperature and conductivity of the river water. On the right-hand side of the table, add extra columns for the mean, standard deviation and coefficient of variation for each variable (remember that these should be across all replicates – i.e. one mean, standard deviation and coefficient of variation for each variable). Add further columns for the means and standard deviations for each variable (a) for your group alone (remember to state your group number), and (b) for the rest of the class (i.e. with your group’s data excluded). For each variable, indicate whether or not your group’s mean value lies between +/- 1 S.D. of the mean for the rest of the class.
This section should discuss what conclusions can be drawn from the results. There are no hard-and-fast rules for what should be included, but you might consider the following:
• Discuss the values of the water chemistry meter readings. Are they consistent with each other? Are the levels what would be expected for such a site? Think about background geology and its effect on pH. For conductivity, you may need to search the web for information on what would be expected for a typical river in lowland Britain.
• Comment on the composition of the macro-invertebrate community – was there a mixed community of invertebrates with different feeding strategies or do a few taxa predominate? How do the invertebrate data for your group compare with those for the rest of the class? Are there particular invertebrate taxa that are especially informative about water quality?
• How do the invertebrate scores compare with the RIVPACS predictions? Can you explain any discrepancy between the predictions and what was observed?
• What do the invertebrate and chemical data tell you about the water quality at this particular site? Do you think the river class is a true reflection of water quality at the site?