Course work Essay Example

Course work Essay Example Course work Essay Course work Essay After considering other ponds to org at I choose Lily pond as there was little leaf litter compared to the natural ponds which made it easier to identify invertebrates in pond samples. Mayfly Nymphs are the invertebrates I choose to study as there is a generally high abundance in Lily pond therefore the changes in abundance in microcircuit can be seen more easily. Ephemerals nymph has very short life span as an adult that can last for a day or less than 30 minutes Figure 1 show the life cycle of Mayfly Nymphs. The adult Mayfly lays its eggs in the pond; the offspring enter the first stage when they hatch as Nymphs. The sub-imago stage shown in Figure 1 is the first flying stage [2] and the final stage is the adult stage in which Mayflies mate and then die. The Nymph stage last longer than the adult stage from months up to years [3]. This is because the adults do not eat and use the energy absorbed at the Nymph stage. The Mayfly Nymph shape varies according to the type of sub- species. Mayfly Nymphs have gills along their abdominal area which can be seen in Figure 2. They have three tails which can create a wave like movement allowing the Nymph to swim These are structural adaptations that enable he Mayfly Nymph to survive in a pond ecosystem. Mayfly nymph are usually vegetable feeders and many feed on algae [1]. Vegetation and algae are authors that are able to make complex molecules such as glucose through the process of photosynthesis. After loss of energy through respiration the total energy remaining is called net primary productivity. This energy is the available to herbivores such as the Mayfly Nymph. However not all of the energy will be transferred to the Mayfly as some of the plant material may not be digested Mayfly nymph have important role in the food chain which can be seen in Figure 3, as it provides a pathway for energy to be transferred across tropic levels. Figure 3 also shows some of the predators are carnivorous water beetles, Dragonfly Nymph, Water Boatman and Newts. Mayfly Nymphs in the pond live in different microcircuits. Microcircuits are smaller habitats with a larger one [5]. Figure 4 shows the different microcircuits found in a pond. The detritus is a microcircuit at the bottom c the pond where dead plants and animals are found.. Vegetation is a microcircuit that contains both Submergence and Emergent plants. Submergence vegetation is found below the surface of the water and the emergent vegetation is above the surface. Open water microcircuit can be described as an area which does not contain vegetation. The independent variable in my study was the type of microcircuit. My dependent variable was the abundance and size Of Mayfly Nymph. In my investigation will not be observing Mayfly Nymphs in the detritus microcircuit as the dependent variable was easier to compare as there is not as much dead plant material in the other microcircuit. Figure 4 shows areas I looked at during my investigation at Lily pond. Abundance of an organism is affected by both biotic and biotic factors in the ecosystem. Biotic factors are non-living part of an organisms habitat and the biotic factors are the living part [5]. Shelter is an biotic factor that can affect abundance as it may provide safety for an organism from predators; therefore they are more likely to survive and reproduce leading to a higher abundance of the organism. There is more shelter in the vegetation in the leaves of the plants so I may find a higher abundance of Mayfly Nymph there. Another reason the abundance of Mayfly Nymph may be higher in vegetation s because the vegetation provides food for the Mayfly Nymph. However there may not be any difference in abundance in open water and vegetation as Mayfly Nymphs are opportunistic generalists [2] and may eat the plant particles and leaf litter in the open water. Temperature off microcircuit also affects the abundance of Mayfly Nymphs In each microcircuit. This is because the enzyme activities of the body increases as temperature increases resulting in faster metabolic reactions and growth of an organism. The life cycle of the Nymph will be shorter at a higher temperature and they will produce faster therefore the abundance will increase. I will measure the temperature of each microcircuit in order to see if it may have significant effect on the dependent variable. However it may not have a significant effect as water has a high specific heat capacity so increase in heat may not affect the overall temperature of the pond [6]. Mayfly Nymph are sensitive to the amount of oxygen dissolved in water, this is a reason why it is sometimes used as an indicator species to see the amount of pollution of a pond will measure the amount of oxygen dissolved in each microcircuit. Again the abundance of Mayfly Nymph may be greater in the vegetation as plants photosynthesis and release oxygen as a by product therefore the concentration will be higher than in open water. Open water also has leaf litter which may have decomposing bacteria breaking it down however that use of oxygen when they respire. Planning Null hypothesis: There will be no difference In abundance of Mayfly Nymphs in Vegetation than the Open water microcircuit. Working hypothesis: The abundance of Mayfly Nymph will be greater in the Vegetation microcircuit. Risk assessment Key Likelihood score (L) unlikely to occur very rarely but only rarely sometimes Likely to occur often Severity scores (S) 1. Highly 1 . Slight inconvenience 2. May occur but 2. Minor injury requiring first aid 3. Does occur 3. Medicaid attention needed 4. Occurs 4. Major injury leading to hospitalizing 5. 5. Fatal or serious injury leading to disability Hazard and outcome Likelihood (L) severity (S) Risk (LOS) Wet soil- could slip and fall which lead to injury 3 9 Being too close to pond edge- could fall into pond. The water is deep so danger Of drowning 2 6 Water borne diseases- such as wells disease 5 The first hazard on the table can be minimized by being more careful not to spill water on the soil. There are signs around the pond such as the one shown in figure 5, which are reminder to not to be too near to the edge of the pond at all time. This will help reduce the likelihood of falling into the pond. The last hazard has a severity of 5 therefore there should be good measures taken to reduce the chance of getting Water borne disease. I have covered any cuts I had on my hands with plasters. I have also used gloves when handling pond water so that my hands are not in contact with contaminated eater. Method collected data about the abundance using the equipment in Figure 6. Method for measuring abundance of Mayfly Nymphs: I will use a stratified sample in which I will choose the locations in the pond that IS representative of my independent variable. One location will be an open water microcircuit and the other that will be a vegetation microcircuit. For each microcircuit will use the following method: will half fill a tray with pond water; this is for the invertebrates to be placed in. I will also fill two pots with pond water. After I will use a net to sweep the area of the pond to collect he invertebrates. I will ensure that I use a figure 8 movement when am sweeping to ensure that less invertebrates are lost than compared to if I sweep only in one direction. The net will then be upturned onto the tray and I will pour the content of one of the pots on to the net. This is to stop invertebrates remaining on the net. If there is any trapped inside the net will use the plastic spoon to carefully to remove them and put them in the tray. Then will use the plastic spoon to remove the Mayfly Nymphs from the tray into the other filled pot. I will count the Nymphs in the sun in order to see hem more clearly and record the results. Method for measuring control variables: To measure the pH will collect pond water from each microcircuit inside sample containers. Will dip pH strips inside each container and remove it after 5 seconds. I will then leave it for 2 minutes and Compare the results against a reference sheet such as the one shown in figure 7. Oxygen concentration of pond water will be measured using oxygen meter. However the oxygen meter was unavailable therefore resorted to using secondary data for oxygen concentration in open water and vegetation (reference tutor). The temperature of each microcircuit will be measure using a thermometer which will be dipped into the pond and waiting for around 40 seconds to be more certain Of the reading. Record the reading on the thermometer. The magnifying pot and CACM ruler shown in figure 10 will be used to measure to the size of the Mayfly Nymph. I will put some water from the pond into the pot and place one Mayfly Nymph inside. The magnifying pot has a grid on the bottom with MIM squares. The ruler will be used to measure the length of the Mayfly Nymph with aid of the squares on the magnifying pot.