Monday, May 27, 2019
Daphnia Ecotoxicology Lab Report Essay
IntroductionEcosystems have a way of maintaining themselves under ordinary conditions but when a new compute is added that will most likely threaten the environment action needs to be put forth. Our environment is affected by m any(prenominal) pollutants on a daily bases forming a threat to natural stability. For example some of the most polluted parts of the environment be bodies of water like that explained in our lab. in one case pollution occurs animals lav be affected in many ways even to the brink of death. In the lab the stream is getting pumped with savoury potassium filled water that can kill daphnia, habitants of the stream, if the parsimony gets excessively high. To prevent this a real-time curb can be performed. This is a victimize timed test that we use to taproom the effect of pollutant on organism by finding the smallest c erstntration possible that could still be a bother. This is a valuable tool because we can get direct results from a living organism by det ecting stress signals all in a soon period of time allowing us o fix the problem quicker. Using an organism for the assay is the best choice because there ar many variables that can be used to identify stress on the subject because of a specific input.Materials and MethodsE genuinelything is kept the same in every experiment except when concentration differences need to be changed. Meaning all lighting, heating, vibration daphnia numbers will not change to make sure there ar borderline changes and differences in the experiments. The sizes of the daphnia are as well as better to be kept around the same. Daphnia are really quick so picking something to measure in a two-hour interval made it easier to narrow it down to heart rate. Since we can control their space, mean less area of movement we can peck their heart better. This also meant it wouldnt allow us to measure other things that require a larger area of movement which were the majority of the variables. Chasing down the critters is very hard.Week one was the period of observation where all materials were used while looking at the daphnia so that the variables to be measured are elect and the methods in how they will be measured are ruled out. Before the lab a handout with information on daphnia should be lease to familiarize oneself with the little organisms. For observation we are given a stock microscope, to use with it regular shallow white well plates and a dissecting scope, to use with it a gibe through 24-well plate. A small amount of water should be added to the both the white wells and closely three or four of the do wells. Now that everything is ready for the daphnia they are to be transferred to the wells be using a pipet that has had its tip cut of to a diameter of about 2-3 mm so the critters arent damaged. Write down any observations you see such as variables and movements and any ideas for a possible assay.Week two an assay system will be created using the variable that is chosen versus the concentration of KCl. The concentration we started with, was given, a 11 ratio of KCl to pond water meaning that half of the mixture is KCl and half is pond water. To perform this experiment we also need a control that would be 100% pond water. Two regular microscopes are used with the three well white trays. In one tray pond water is added to the three wells, half of the group will look at these and in the other the mixture of 11 KCl pond water is added, the other half of the group will look at these. Daphnia are then transferred using a transfer pipet that has the tip cut to a diameter of 2-3 mm. The experiment needs to start after a 15-minute exposure period maybe shorter because they may start reacting to the different concentrations.Once the slides are in focus view the daphnia to see if there are any changes in the variable if so one partner should start counting while the other is keeping time and writing down results. Every once in a while to keep thing consist ent switch who counts and switch around the wells. After the observation period make sure the lights are off so the daphnia arent heated and they have enough water, and make sure they dont get moved around too much. Once the experiment is compare results of KCl concentration versus the control. If something did occur to the daphnia do the KCl concentration experiment but half it, If nothing happened double the concentration. Once you are done take our results and plot them using a T-Test in excel.Week three the daphnia are tested under different concentrations of an herb to see if the herb causes any types of stress on the variable. All of the same methods are done as in week one and two except in preparing the herbal solutions. To prepare the herbal solution the herb needs to be grinded mixed with wood alcohol and left to sit for a few minutes so it can react and separate the important contents of the herb out. In large clear wells the mixture is measured in microliters of 500, 50 and 5, we also measure out 500 of methanol and all of these are left to dry out. Then 5ml of water is added to 5 wells the four including the substances and one without. The methanol only and water only wells are our controls once this is finished the variables are measured like in the previous experiments.Results(on graphs and tables)DiscussionDaphnia are very easily affected by even the smallest amount of KCl slowing down their heart rate compared to our controls. Our 14 ratio of KCl still slightly affected the heart rate of our daphnia. The daphnia give a clear and quick report on the environmental condition this is why they are straightforward to experiment on.