Macroinvertebrates Science Project

Abstract:

The project was conducted to see if the imperviousness of the area had a correlation with the water pollution. The hypothesis stated that there would be more pollution with the higher percent of imperviousness. The first, and probably the hardest step to this project, was finding streams that were all similar with a shallow riffle. Then the conductor will place a net in the water, start the timer and turn over as many rocks as possible, upstream from the net (macroinvertebrates should be trapped in the net). When the timer reaches 2 minutes the net should immediately be taken out of the water and everything on the net should be transferred to plastic bags. The last step is identifying and counting all the macroinvertebrates.

The results showed no direct correlation between the data. There could have been many reasons for this; not only was the environment of the stream a huge factor (current, amount of rocks...) but the temperature and the way I estimated the imperviousness.

Introduction

The purpose of this experiment was to see if the imperviousness of the surroundings was related to the amount of pollution in a stream. The hypothesis was that there would be more pollution in areas with a higher imperviousness percent. . It is already known that imperviousness has a big impact on macroinvertebrates species.

Impervious areas are usually constructed areas such as rooftops, sidewalks, roads, and parking lots. All of these areas are covered with impenetrable materials, which seal surfaces, and repel water that prevent precipitation and melt water from getting into the soil beneath it. When the rainwater, melt water and even chemicals cant soak into the soil they usually run onto the impenetrable area and usually end up going straight into a water source, sometimes causing pollution.

Macroinvertebrates are found in almost any water source, streams, ponds, marshes and puddles. They help maintain the health of the water by eating bacteria, dead plants and dead animals. Macroinvertebrates, are considered the most accurate way to chart the health of a stream by most experts for many different reasons. They are extremely sensitive to changes in the ecosystem and most of them live longer than one year. Another big factor is that no particular organism will dominate the macroinvertebrate population in a river or stream. They are easily caught and identified without a microscope. Unlike the types of macroinvertebrates, the Ph and amount of dissolved oxygen is able to change frequently and may not be exact. Fish cannot be used because they can leave a polluted area and return when it is has become less threatening. Macroinvertebrates are divided into 4 groups, which are directly connected to how tolerant to pollution they are. The first group is sensitive to pollution, group 2 is semi-sensitive to pollution, group 3 is semi-tolerant to pollution and group 4 in tolerant to pollution. Basically, if a river is very polluted you would only find group 4 macroinvertebrates, whereas if the stream was healthy, you would expect all the groups to be present. Group 1 macroinvertebrates consisted of: dobsonflies, alderflies, water snipeflies, and stoneflies. Group two includes: caddisflies, damselflies, craneflies, water penny larvae, freshwater mussels, riffle beetles, dragonflies, mayflies and crayfish. Group three includes the following: blackfles, non-red midge, orb snails, gilled snails and amphipods. Isopods, pouch snails, bloodworm midge larvae, tubifexes and leeches are all members to the last group, group four.

If someone were to conduct this study, one very important control is to gather data at a riffle within the stream. A riffle is the part in a river where the current is faster, usually shallower, and pebbles, rocks, or boulders are present on the bottom.

Materials

*Magnifying glass

*Bucket

*Plastic bags

*Spatula

*GPS unit

*Net

*Timer

*Helper

*Permanent marker

Methods and procedures

The first step to this experiment is to gather all the materials and have them ready. This is important because its not good if the person gets to the stream and forgets a timer. After the conductor has all the supplies, they need to find about 10 similar streams or rivers (all having a riffle and not just sandy ground.). Once at the site, a GPS reading will be taken by pressing POWER, the right over button (>), and then SAVE. The second step is to label a plastic bag with the number that is assigned to the stream or river. One person should stand in a spot that has many rocks upstream from it. Once the spot has been determined, the person will place the net into the river so that all the water flows through the net catching everything. You may need to place rocks on the edge of the net to prevent it from curling up. At the moment the net is placed into the water the timer should be started. Once the timer is started the helper should begin turning up rocks and rubble with their feet or hands. This should occur a couple feet upstream from the net so that all the leaves and macroinvertebrates are caught in the net. When two minutes pass, gently pull up the net and start transferring everything caught in the net into the labeled plastic bag. Once the conductor is in a comfortable position, a

magnifying glass should be used for counting and identifying all the macroinvertebrates in the plastic bag. The person going through