How Does Daphnia Affect Small Fish

This experiment is being performed to show the effect of pH levels on daphnia by changing pH levels and measuring the heart rate.

Daphnia are minute crustaceans and they live in fresh and salt water all around the world (these daphnia’s will be sourced from fresh-water). Daphnia’s are arthropods, which means they belong to the family, which includes crustaceans and insects. They usually reach a maximum of 0.5 millimeters. Although daphnia’s are very small, they are vital to the cleanliness of their environment, as they filter the water by consuming bacteria. Scientists often use daphnia’s in experiments to gain more information of the human circulatory and nervous system. As daphnia are located in fresh water, there is a real risk of fertiliser leaking from households into creeks and rivers. This task will prove the danger of this for wildlife and the effect it has

Daphnia, also known as water fleas, are small crustaceans about 1mm-5mm long and are part of the freshwater zooplankton (Ebert 2005, Hutchinson 2005 & Clifford 1991). Daphnia can be found in most fresh water habitats such as freshwater springs, ponds and reservoirs and are the predominant food for planktivorous fish. Dapnia are ‘filter feeders’ meaning they feed on small particles suspended in the water which can include algae. It has been found that daphnia tend to migrate to the upper parts of the water at night and return to the lower parts of the water in the day to hide from predators (Ebert 2005) (Hutchinson 2005). Daphnia can reproduce through sexual reproduction and also asexual

Daphnia is an order of cladoceran that are a part of the genus of small crustaceans ranging from one to five millimeters in length (Campbell, 2004; Corroto 2010). Daphnia are also naturally transparent, allowing for a variety of research opportunities that are observable with current day technology. Water fleas are another name for Daphnia due to their distinct, jerky swimming patterns (Chin, 2011; Campbell, 2004). Additionally, Daphnia seem to have tufts of hair, relatively large eyes, and red “lips”. Daphnia also feature an ocellus, a light-sensing organ under the compound eye (Chin, 2011; Corotto, 2010).

Competition determines survival of the fittest. The larger plankton eat larger particles, therefore making themselves thrive, and the smaller planktonic herbivores were extinguished from the specific lake ecosystem. When the plankton are being heavily hunted, the smaller thrive. The small plankton tend to succeed in the general plankton population because they are effective when collecting their food, and they have lower metabolic rates, requiring them to eat less. An equation was devised to represent this scenario. “The food collecting surfaces are proportional to the square of some characteristic linear dimension, such as body length, in Crystal Lake, for example, the body length of Daphnia catawba is about four times that of Bosmina longirostris, so that the filtering area of the Daphnia is about 16 times larger than that of the

Table 2: Mann-Whitney U statistical testing for the difference in average heart rate of Daphnia before and after the addition of aged water:

Title: Physiological Changes in the Heart Rate of Daphnia magna When Exposed to Stimulants (Caffeine and Alcohol).

Ectothermic animals are animals whose body temperature is affected by their surroundings. This means that if the environment is cold the animal will be cold. If the environment is warm the animal will be warm. This is because the animal doesn’t have the capability of regulating its body systems to keep a constant body temperature. When an ectothermic animal is cold, its heart rate will lower. When the animal is warmer, the heart rate will raise – as long as the temperature isn’t sufficiently high to harm the animal. (Campbell, 2005)

The additional species, Daphnia Pulex are a derivative from Daphnia Magna, which can be in located rain filled tire ruts and any stable body of water. These daphnia are established in fresh water and maintain the highest concentrations of daphnia compared to other species can be found in lakes and ponds. Daphnia magna is a water flea dependent on environmental conditions to breed and survive. Conditions such as temperature, salinity and oxygen levels can be detrimental to the lifespan of these organisms (Elenbaas, 2013. Within their existing environment daphnia consume algae, bacteria and detritus; it is this continual uptake of these organisms, which maintains the food chains integrity. Daphnia also host a number of bacteria, fungi, nematodes,

Daphnia usually eat algae and other small bacteria. They are filter feeders which allow them to eat because they are eating the bacteria that is found in the water as they filter it.

In the mid 70’s, my family bought a cabin on the Illinois River. We spent all our free time there, weekends and most of the summer. For years my family enjoyed their time at the “clubhouse” as we called it. It was our home away from home. There were about 20 cabins there, so it was like our own little community. Just about everyone there was like extended family. Any time someone needed help, the neighbors showed up. Everyone there had similar interests, hunting, fishing, boating and water skiing. I spent most of my days enjoying these activities.

The experiment took place in a laboratory setting, and the first step was obtaining sixty individual Daphnia magna (that were neither adults nor tiny offspring) from a large tank in the lab. These individuals were equally divided into three groups; low density, medium density, and high density. The twenty Daphnia assigned to the low density group were split into four groups of five and pipetted into one of four tubes filled with 10mL of Chlamydomonas algae. The twenty Daphnia assigned to the medium density group were split into two groups of ten and placed into one of two tubes also filled up to 10mL with Chlamydomonas. The final twenty Daphnia were all placed into a single tube filled with 10mL of the algae. In order to avoid suffocation-related

The effects of caffeine and alcohol on daphnia are expressive of whether these substances are harmful or beneficial to the organism. By understanding the results of this experiment, it may also be understood how these substances effect humans. In this study, one daphnia was exposed to increasing levels of alcohol, while the other was exposed to increasing levels of caffeine, each in order to test the hypothesis that when given amounts of caffeine and alcohol, the daphnia will be affected the same way a human would. The effect of each substance was measured by the daphnia’s heart rate one minute after the substance was added. Results reveal that alcohol slows the heart rate, while caffeine increases heart rate. Furthermore, caffeine shows a

In this experiment we find how caffeine can affect the heart rate of a culture Daphnia. Heart rate of a living organism’s can vary depending on the individual, age, body size, heart conditions, medication use and even temperature. This report will examine if the caffeine is good or bad for the living organism’s health and body. And discuss about where the caffeine is produced and used in daily life of human beings and on the environment. Daphnia is a water flea used in this experiment because of its genomic infrastructure with wide range of phenotypic diversity. This quality of Daphnia makes them a versatile model for the experiment. Also their transparent body allows the experimenter to visually see how the heart beats and count them under the light microscope during the experiment as required. The heart rate of Daphnia is monitored under different concentration of caffeine solution and the results are shown in a table and a graph. Experiment carried out to locate the effects of caffeine on a heart rate of Daphnia may or may not be a predictor of change in human heart rate under caffeine. The effects of caffeine can also be tested on humans but those experiment involving humans contains high risk, as Daphnia can only live for a short period of time and in nature most of them get eaten within their first few days or weeks of life.

Throughout my experiment my control acted normally, the daphnia had average movement and calm manner. On a scale from 1 to 5 I ranked the control group as a 3 for normal movement and health. When I introduced car antifreeze to my pure water daphnia there was an immediate change in the color of the daphnia, their bodies turned from a white opaque color to a light pink (the same color as the antifreeze). Not only did the physical appearance change but their behavior became more aggressive and panicked. As time passed the daphnia moved in a circular motion and the chemical caused one of their antennas to cripple. The antifreeze surprisingly resulted in no deaths so I gave the effect of antifreeze to daphnia a 2 (table 2 and 2B). When exposed