I will be working in a freshwater environment measuring certain variables in order to investigate my hypothesis, which is as follows - My hypothesis is that there will be wider species diversity with increasing oxygen saturation.

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I will be working in a freshwater environment measuring certain variables in order to investigate my hypothesis, which is as follows:


My hypothesis is that there will be wider species diversity with increasing oxygen saturation. 

Mayfly nymphs Ephemeroptera: Biological Indicators

Mayflies are insects that spend most of their lives as nymphs in streams, emerging briefly as adults (“ephemerally”) to mate and lay eggs. Gills are often visible along the abdomen. If an animal has three hairy tails it’s a mayfly; but some mayflies have two tails. Mayfly nymphs are strong swimmers and move like dolphins. As nymphs many mayflies feed on freshwater algae; as adults they do not eat, because they live only a few hours or days. Mayfly diversity declines as streams are degraded. Mayflies are particularly sensitive to waste from mines. Are rarely found in areas of high pollution due to them being high oxygen demanders. Also not found in areas of high sediment due to fact that sediment particles may clog up gills, making it harder for mayfly to respire. This specie has a biological indicator number of 1.

                            Caddis fly larvae  (Trichoptera)

Caddis fly larvae, in freshwater, use silk to build protective cases from gravel, twigs, needles, or sand. Different species build distinct cases, but they often lose them when removed from a stream. Caddis flies are invertebrates that emerge to mate as winged adults. Caddis fly larvae make a living in a variety of ways: some capture food in nets, others scrape algae or shred leaf litter. Free-living caddis fly larvae do not build cases; many are predators and need to move quickly to capture other animals for food. Some caddis flies are very sensitive to human disturbance, whilst others are more tolerant.

Rat-Tailed Maggot

Rat-tailed Maggots

The rat-tailed maggot is the immature or larval stage of a fly that resembles a honeybee. These 3/4 inch long whitish larvae are different from other fly maggots in having a 1/2-inch long "tail" that is used as a breathing tube when they are in the water.

Large numbers can be present in most any accumulation of stagnant water, such as manure pits or lagoons, where they feed on decaying organic matter. The maggots become a nuisance when they crawl away from their breeding site to find a dry place where they can transform to the adult stage. In the wandering stage, hundreds of maggots may enter milking parlors, milk rooms, feed rooms, or other areas. They are harmless; small numbers can be swept up and thrown away.

These tough-bodied larvae are usually not affected by even insecticides sprayed directly on them as they crawl along the ground. Insecticides are not easily absorbed through their thick covering. Placing a 4" to 6" wide, 3" deep barrier of dry, loose soil or sand in the path of the wandering maggots generally will stop them. They will burrow into loose, dry material and remain there. The soil and maggots can be shoveled up and discarded outdoors away from buildings.  

Agitation of the pit contents or routine clean out, if practical, also can kill developing maggots. They can live in most any accumulation of shallow, stagnant water so keeping water from pooling around barns will reduce the number of breeding sites. These have a biological indicator number of 5 as they live well in areas of low oxygen.

Adults, called bee flies because of their resemblance to honey bees, are rarely seen. They do not remain around breeding sites like houseflies do. Bee flies visit flowers for nectar but also will go to decaying odors where they may lay eggs. These flies neither bite nor sting and apparently do not carry diseases.

Freshwater Shrimps

Freshwater Shrimps belong to the group of Crustacea, which is to be found in many rivers and streams of this country. They seem to prefer running water which is shallow and therefore probably containing more oxygen. The first three limbs on the abdomen vibrate continually and they poduce a current of water over the gills at the base of the thoracic legs. The following three pairs of abdominal legs are curved backwards and are used for jumping. The bodys colour changes from a pale reddish-brown to a grey-brown and size goes  up to about 2 or 3cm.

Tubifex Worms

Members of this family have usuaally red blood which makes the blood-vessels stand out very clearly in the transparent white body. The bundles of bristles have more than two short bristle each and the ventral ones are always hooked with the tips left. They are usually found in dirty mud waters, where oxygen levels maybe quite low. They construct tubes out of which their tails  project  and wave about.

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Mud passes through their bodies along with digestible material, which is removed on the way. The tail is used as a gill to obtain oxygen, as there is very little oxygen in muddy water. In  waters, which is poorly oxygenated, a greater length of tail is extended. This allows the tubifex worn to live in area’s of poor water quality and low oxyegen saturations.

Key Variables

In order to obatin fair results a number of factors must remain the same. I must maintan a 20m distance, minimum, between each sites. Abiotic readings will always be taken before ...

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