Presentation on theme: "Benthic Macroinvertebrates. Benthic – bottom-dwelling Macro – can be seen with the unaided eye Invertebrates – without a backbone or spinal column Examples:"— Presentation transcript:
Benthic – bottom-dwelling Macro – can be seen with the unaided eye Invertebrates – without a backbone or spinal column Examples: clams, snails, worms, crustaceans, insects
Question How do we know whether a stream is “healthy” or polluted?
Qualitative Sampling (finding as many as you can) D net Kick the stream bed vigorously upstream Collect in different habitats – Sand, silt, gravel, mud, rub large stones, overhanging banks, under overhanging brush, etc.
Benthic Macroinvertebrates as Indicators of Water Quality Every species has a range of conditions in which it can survive “Tolerant” species - can survive in a wide range of conditions “Intolerant” species - are sensitive to pollution A large number of intolerant species indicates unpolluted water