Comparison of two ponds at the end of the stream, and how different factors may affect the inhabitancy of the ponds

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Mohammed Mubashar Ishfaq                Biology coursework

Comparison of two ponds at the end of the stream, and how different factors may affect the inhabitancy of the ponds.

AIM

In my investigations I will study two of the four ponds at the end of a stream (the first and last). I will use a wide range of equipment to find out how the two ponds vary and how this could affect its inhabitancy. I will look at various factors such as light intensity, depth; pH, temperature and take into account how these factors might affect the difference between the two ponds including differences in wildlife.  

Background information 

The ponds that I will study are at the end of a stream. There are four ponds in total each after the other. The ponds that I will study will be the first and last ponds. The first pond, which comes directly from the stream, contains more mud and is more turbid. As you go along the ponds, they come less muddy and turbid as dirt gets filtered out. This is one factor that is of significance in my investigations.

What is a pond?

A pond is a small area of still, fresh water. It is different from a river or a stream because it does not have fast moving water and it differs from a lake because it has a small area and is no more than around 1.8m deep. Some ponds are formed naturally, filled either by an underwater spring, or by rainwater – sometimes known as ‘dewponds’; other ponds are man-made. The ponds that I will study are man made ponds.

If a pond is to be a successful habitat it must have plants growing in it. They provide food, oxygen and shelter for most animals. Green plants need sunlight to make their food via photosynthesis. Therefore a plant in the open with lots of sunlight will be more successful than one that’s in the shade e.g. covered by a tree.  

Pond wildlife

Macro-invertebrates refer to a whole range of different species of ‘bugs’ that live or spend part of their life cycle in water. They are an ideal way to measure the ‘health’ of rivers and streams. Different species of invertebrates show various levels of sensitivity to deterioration in water and habitat quality. These types of species are called indicator species. Indicator species are species whose presence, absence, or relative well-being in a given environment is indicative of the health of its ecosystem. Generally, the poorer the quality of the water, the less diversity of invertebrates that will be found. Some of the more sensitive include mayflies, stoneflies, caddisflies, dragon and damsel flies. Beetles, water boatmen and shrimp tend to have moderate tolerance, and the more tolerant (can survive poorer water quality) include snails, worms, chironomids, blackfly and mosquito larvae.

Different forms of pond invertebrates

Water boatman- Water boatmen occur most commonly in ponds and along the edges of lakes. Most water boatmen eat algae, tadpoles and minute aquatic organisms. Some are predaceous and feed on mosquito larvae and other small aquatic animals.

Dragonflies- dragonflies can fly at up to 50 kph and capture other insects in the air, while flying. Dragonflies are preyed upon by fish, reptile’s frogs and birds. Female dragonflies lay they eggs in or near water. Eggs hatch into nymphs, commonly known as mudeyes. Dragonflies eat many insects such as fish, frogs, birds, reptiles, mosquitoes, bees, flies and butterflies.

Midge lava- midge larvae have a worm-like body and small antennae. They are often red in colour, and are hence referred to as bloodworms. They may also be white, green or yellow in colour. Larvae develop into pupae, which attach to materials below the water surface. Adult midges are commonly seen in swarms around the edges of wetlands. Midges are also pollution tolerant.

Fly larvae - Fly Larva can tolerate organic pollution as they feed on organic particles. They can live in water with low levels of dissolved oxygen as they often come to the surface to breathe. Some Fly Larvae feed on decaying matter and play a key role in recycling nutrients.

Tadpoles- Tadpoles first develop in the egg, and then they eat the egg case. After this they often seem to disappear, this is because they are so small. Often they will be seen in the warm areas around the edge. They at first eat algae, then they progress on to other plants and then sometimes on to meat - such as worms and daphnia. They will even eat each other. Tadpoles absolutely depend on having fresh, clean water and like warm conditions. They then later metamorphose into frogs.

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Pond skaters- Pond skaters are Usually seen skating over the surface of ponds. They have tiny hairs on its feet which repel water and allow it to walk on the surface film. Pond skaters feed on small insects.

Pond plants

Duck weed Duckweed contains very small freshwater plants, which float on the surface or underneath water. When there are many Duckweed plants growing together, they create the effect of a green blanket floating on top of the water. duckweed absorbs lots of sunlight from the sun.

Filamentous algae- Filamentous Algae are primitive aquatic plants which are different from other plants ...

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