Biochemical oxygen demand is the amount of oxygen needed by aerobic organisms (need oxygen) to break down organic matter in a given water sample at a certain temperature. Organism require oxygen, and in water bodies, they get that oxygen in the form of dissolved oxygen. As the name implies, Dissolved oxygen (DO) is oxygen that has dissolved in water. Like plants and animals living on land, aquatic organisms and microorganisms also need oxygen to breathe. For aquatic organisms, they get their oxygen from dissolved oxygen. Therefore, it is important that there is enough dissolved oxygen in a water sample to ensure a healthy community. However, there are many factors that may cause DO levels to decrease. An increase in light/sun light will result …show more content…
The most common way to calculate BOD is through a method called BOD5. Firstly, the water sample you want to measure is brought into a science lab where a dissolved oxygen probe is used to measure it’s DO. The water sample must be kept in a air tight beaker filled to the the top. The sample is than kept in a dark incubator at 20. This is done to ensure that it doesn’t undergo photosynthesis and only respiration. The bottles are than kept in the incubator for a total of 5 days. At the end of the 5 days, using the same oxygen probe, measure the new DO concentration. The new levels must be less than the original as this shows that in the 5 days, bacteria/ microorganism consumed oxygen in order to break down organic matter. I speculate that an increase in the concentration of fertilizers will cause a greater BOD value as there would be more organic matter for the bacteria to consume. However, if there is so much organic matter, the bacteria may consume all the oxygen before it is able to break down all the organic matter. I currently reside in Vancouver Canada and have been living here for the past 9 years. I live near a golf course and every time I pass by it, I see the river right beside it filled with with plankton. I’ve always wondered what caused this phenomenon to occur. It was only after doing a lot of research that I learnt that golf courses use a tremendous amount of fertilizers, and when …show more content…
Because the conditions necessary to these algal blooms are sometimes temporary or because the algae exceed the threshold level of some other limiting factor, the blooms are only temporary. They often last only a few days. What happens when the bloom is over? The algal cells don't have enough nutrients and most of them die. At this point, the aerobic bacteria become important and start to decompose the algae. Because there is so much food for them, they also experience a sort of bloom, and they literally suck the oxygen out of the water. When the oxygen is gone, the bacteria and most other aerobic creatures in the aquatic system start to
Dissolved Oxygen, pH levels, Temperature Change, Fecal Coliform, BOD, Nitrate, Phosphates, Turbidity, and Total Solids were each tested in the stream at least one time. If more time and enough supplies were given, then certain tests should be done more than once. Temperature Changes should be tested every other month because it is quick and a change in temperature can affect the health of the organisms living in the stream and therefore the quality of the stream. Temperatures can also drastically change in a short amount of time and there is a large difference in water temperatures in summer and winter. Another test that should be done every other month is dissolved oxygen because it is related to the temperature of the water. Cooler waters have a greater capacity for dissolved oxygen than warmer waters. This test is important because due to human activity and industrial processes, can increase water temperature and therefore decrease the dissolved oxygen levels. Certain organisms living in the stream need a sufficient amount of dissolved oxygen to survive. Another test that should be done more often is the
Dissolved oxygen varies depending on the temperature in the water, salinity, oxygen depletion, oxygen source and other parameters (Stoddart 2014). Biochemical Oxygen Demand BOD can be defined as the amount of dissolved oxygen that microbes utilize to decompose organic matter in the water (Academic 2015). Results from BOD can be usually found after 5 days. However, some times in order to get a complete biochemical Oxygen, BOD must be measured for 20 to 25 days (Pisarevsky 2005). Chemical Oxygen Demand COD measures all organic carbon in a water sample by oxidizing organic matter with strong chemicals. COD is a chemically/thermal oxidation reaction. COD includes both biodegradable components and non-biodegradable components (Levarage
In this project, C. Elegans are hermaphrodite worms that will be used since they are easy to maintain in lab, as well as have short life cycles. The gene that the project attempted to knockdown in C. Elegans with RNAi treatment is the unc-22 gene. RNAi disrupts gene expression in the presence of double stranded RNA (dsRNA) that is complementary to target gene sequence. The unc-22 gene codes for a muscle protein called twitchin in wild-type worms. The Unc-22 is required for muscle regulation and maintenance in C.Elegans. To verify that the RNAi treatment worked, would check the unc-22 mRNA levels in the worms, in addition to phenotype observation.
The velocity of the water or speed of water determines the dissolved oxygen levels in the water. The higher amount of dissolved oxygen the better the water is to the aquatic life in the creek. Because fish need dissolved oxygen to survive, low level of dissolved oxygen will be bad for aquatic life. Also the creek would not be healthy with low amounts of dissolved oxygen. The results of the test had an average of 9.8 . This is the average number a normal and healthy creek should have.
Two things I learned was from Turtle pond lab was what B.O.D means for the ponds water quality and how to calculate it. To answer question number two I chose to explain the B.O.D results. I didn´t know much about the Biochemical oxygen demand so, I had to do a little bit of research on it. I find out that a high B.O.D measurement is actually bad because it means that the water is polluted and that B.O.D is used to measure a number of dissolved oxygen that an organism needs to break down organic material in a water sample. During this lab, I also learned how to measure BOD. When we were at the pond my job was to take a sample of the water in a black bottle and then 5 days later we would measure the dissolved oxygen in the sample. To find the
- Having more dissolved oxygen increases the number of fish observed in the body of water.
The mean voltage of the battery terminals while connected to the identification resistors is presented in Figure 4 12. These samples have been pulled out from the voltage sensor of the PEB panel. The voltage decreased as expected from 12.53 to 12.5 during first 20 seconds of connection to the
The mole is a convenient unit for analyzing chemical reactions. Avogadro’s number is equal to the mole. The mass of a mole of any compound or element is the mass in grams that corresponds to the molecular formula, also known as the atomic mass. In this experiment, you will observe the reaction of iron nails with a solution of copper (II) chloride and determine the number of moles involved in the reaction. You will determine the number of moles of copper produced in the reaction of iron and copper (II) chloride, determine the number of moles of iron used up in the reaction of iron and copper (II) chloride, determine the ratio of moles of iron to moles of copper, and determine the number of atoms and formula units involved in
Eutrophication is when there is too much nutrients in the water, as stated above. Eutrophication can come from farmers fertilizing their fields and some detergents. We tested for phosphates, salts or ester of phosphatidic acid. We also tested for nitrates, salts or ester of nitric acid. The more the phosphates and nitrates, the more eutrophication is present in the stream. We tested for dissolved oxygen, the amount of oxygen in the water, as well. We found found a very low level of phosphates with an average of 0.1 parts per million (ppm). We also found a very low level of nitrates with an average of 0.9 ppm. The dissolved oxygen level was 9.8 ppm. The higher the velocity of the water, the more dissolved oxygen it will contain. All of these measurements are very good and show that there is little or no eutrophication in the
October 17, 18, and 19, samples were collected from multiple sites along the BSR. The class was split into groups, and samples were collected from seven separate locations along the river and WWTP. There was also a sample collected by the S which is located between sites four and five. For each of these sites, there were ten groups from other labs that also collected a sample from the BSR. At site two of the river, the location included multiple sources of possible contamination. A drainage site was located 200 yards upstream, along with a small PVC drainage pipe next to the collection site. Not only was there drainage running into the river, the site was under a bridge, and contained other trash scattered throughout the area. The
A comprehensive investigation on how nutrients in waterways were increasing, was undertaken by a body of individual scientists and their findings were as follows;
The CTDEP collected bottom- dwelling fish and invertebrates and compared the quantity of organisms and number of species with the levels of oxygen in the water. Both of these studies confirmed that severe effects occurred whenever levels of oxygen fell below 2.0 mg/l. Large reductions in the numbers and types of aquatic life present were noted. The lab experiments recorded reductions in both growth and increase in death.
During the summers the oxygen content atop the water normally has a salinity level consistent with “more than 8 milligrams per liter”; but when oxygen content drops down to “less than 2 milligrams per liter” the water is then known to be in hypoxic state (CENR, 2000; USGS, 2006). Hypoxia is the result of oxygen levels decreasing to the point where aquatic organisms can no longer survive in the water column. Organisms such as fish, shrimps, and crabs are capable to evacuate the area but the fauna that cannot move either become stress and/or die. Due to this, many call the hypoxia zone the “dead zone” (Overview, 2008; USGS, 2006).
Purpose: is to determine the unknown bacteria with a variety of biochemical tests. There are many reasons that contribute to why it is so important to test patients for both high and low risks diseases. The most important reason would be to know the identity of microorganism and how it can be treated .This study was performed in microbiology laboratory class by applying the microorganism to the tests that have been performed in the class prior to the identification of the unknown. First, the lab professor handed out a bacteria that was on the unknown streak plate labeled B5 that consisted of an unknown gram positive or gram negative bacteria.
The graph indicates that between 1980 and 1985 there was a rapid increase in the mean proportions of chlorophyll in phytoplankton and other algae micro organisms. 1986 brought about nutrient