Week 4a- Water

1. Water

1.10. MCI

stoneflies The MCI test requires the identification of a number of different species which may be biological quality markers. Species may be deemed "sensitive" (their presence indicating a high level of water quality), moderately sensitive or tolerant (whose presence would be expected in most streams).

Sensitive species include:

Caddisflies - freeliving
Caddisflies - cased
stoneflies (see image)
Freshwater mussels
Freshwater crayfish

Dragonflies These species are only found in highly oxygenated water, mainly due to their poorly developed gills.

Moderately sensitive species include:

Damselflies
Dragonflies (see image)
Beetles
Crustaceans

Species which are tolerant to most conditions include:

Snails
Maggotflies
Mosquito larvae
Leeches

Most of these species take their oxygen from the air rather than from the water which means that they are more tolerant to poorly oxygenated waters.