Daphnia Survival Rates

Seeing as Daphnia are living organisms, it provided equal opportunity to act on these criteria. There were many actions I performed in order to this. I made sure I did not leave the Daphnia underneath the light for too long as it would kill them. I also reintroduced them into their existing environment. This not only took into consideration the wellbeing of the Daphnia but also their environment as well. Also I did not expose to too much caffeine as I did not want their hearts to stop nor did I want to drown them. Also while transporting them to various environments I took a good amount of care and used a pipette to contain them within their own natural

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

Studies of Daphnia presented information which elluded to the idea that Daphnia would react to environmental pollutants within a relatively short timeframe; therefore, a lab was constructed to find the effects of copper sulfate in a Daphnia’s system. Before beginning, the hypothesis was gathered: if the concentrations of copper sulfate in the water are high, then the Daphnia would be afflicted with symptoms associated with physical decline. Daphnia, known as water fleas, are small crustaceans who get their common name from their jerky movements. The organisms reside within lakes and ponds often in limestone-based areas found all over the world. Daphnia consume algae, specifically the free-living green type, yeasts, and bacteria; therefore,

These findings were consistent with Gerristen’s findings. In another experiment though, he placed a hormone that is created by the Daphnia’s natural predator to simulate that there was a predator in the mesocosm. Glaholt determined that Daphnia would swim deeper into the cold water to avoid the hormone of their predator (Glaholt et al. 2016). A future study can be conducted to allow a better understanding of Daphnia, and how far they are willing to go to avoid

For both treatments, the number of Daphnia consumed during the 0-5minute interval is more than the amount of Daphnia consumed in the last 25-30 minute interval (Figure 1). The null hypothesis expects Guppy (Poecilia reticulate) to feed equally in the absence and in the presence of the plastic aquatic plant, therefore any deviance between the means of the two treatments is due to chance; the null hypothesis is rejected, the mean total number of Daphnia consumed in the presence of the plant (4.2) is significantly different from the mean total number of Daphnia consumed in the absence of the plant (14.2) (Two-sample t-test, t=3.28, df=8,

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.

Daphnia are normally used to test potentially harmful substances in water supplies, and are easy to handle and monitor. This experiment was designed around this fact,

I analyzed my Daphnia Magna everyday by observing if the Daphnia were alive or not at the end of each day. I did this by observing if the Daphnia had sunk to the bottom of the container and not moving at all for a long time. For Trial 1, SIXDAYSOX had 2 Daphnia alive while Gmark and Vitalsox only had one alive. For Trial 2, on Day 1 all the sock brands started out well and all four Daphnia survived. On Day 7 of Trial 2, Vitalsox had two Daphnia left while Gmark and SIXDAYSOX had only one alive.Also for Trial 2 one of the 4 control Daphia had died. For Trial 3, Gmark and SIXDAYSOX both had 4 Daphnia left while Vitalsox had three remaining. On Day 7 of Trial 3, Gmark had no Daphnia alive while SIXDAYSOX and Vitalsox both had one remaining.

diabolis and a close relative (Reed & Stockwell, 2014). The count data used was from censuses conducted twice each year to capture pre- and post-breeding population sizes (125 to 310 individuals per year). This census has been done annually since the species was listed as endangered due to a population decline coinciding with declining water levels from ground water removal in the late 60’s and early 70’s. The population has seen a sharper decline more recently. Efforts to establish refuges have been impeded partially due to the fact that the Devil’s Hole pupfish exhibit incredible phenotypic plasticity, meaning that when exposed to different environments or the accidental introduction of a related species will result in drastic physical changes to the individuals (Martin, Echelle, Zegers, Baker, & Keeler-Foster, 2012). In the determination of MTE, the authors used only spring population counts to ensure there was not overlap of older individuals and

This experiment investigated the effects of changing temperate and salinity on the heart rate of Daphnia sp.. The hypothesis states that the heart rate of Daphnia sp. will be significantly higher at 20oC compared to 10oC. Results showed that the heart rate of Daphnia sp. at a higher temperature correlates with an increased heart rate.

The limiting nutrient in a water source is what controls algal growth, no mater how much other nutrients is present, without that nutrient there will be no growth. In this regard it is imperative to know what the limiting resource is in a drinking water system in order to maintain the health of the system. Since phosphorous is naturally found in small quantities in water, if too much phosphorous is present then algal growth will increase. Having such high levels of algal growth can dramatically affect the lake’s health, and can effect how a municipal government must treat its water. The

Regarding pH, they can tolerate a gamut of 6.5 to 9.5 but their best condition is 7.2 to 8.5, slightly basic (2). Recall that daphnia are freshwater animals; daphnia live are able to live in a salinity level of about 1.5 to 3.0 ppt, with their ideal being 2.0 ppt (2). The range of light and temperature are very moderate, temperature being ideal at (18 to 22 °C) and a medium light intensity. This is crucial as daphnia provide vitamin D and A to its predators; as a result, it needs sunlight to produce a lot of Vitamin

fish with higher levels were found to change sex more rapidly. It was also found that the GnRH levels were significantly higher in the male brains, but there was not a significant level of the hormone in the gonads. Also, there was no significant change in the females who were given the injections. The findings support the researchers hypothesis that the GnRH hormone plays an important role in the development of cinnamon clownfish, specifically in males. Another interesting thing that the researchers found was that the chromosomes of the fish do not change, even if they do undergo a sex change. Fi the fish was originally made and changes to female then it will still have the genetic makeup of XY

Figure.1: The graphed data represents the growth rate of algae cells (population sizes million cells/mL) in each treatment over 21 day time period. We graphed the population sizes of the control, no-phosphorus, and high-phosphorus treatment. The control group contained 1 ml of Chlamydomonas and 4 ml of phosphate. The no-phosphorus group contained 0.5 ml of Chlamydomonas and 4.5 ml of phosphate . The high-phosphorus treatment contained 3 ml of Chlamydomonas and 2 ml of phosphate.

Fry and Toone (1986) found when they inject fertilised seabird eggs with DDT and its metabolites. The male chicks produced have varying degrees of intersexuality depending on dosage, reproductive system with both male and female structures. The female chicks had a partial to full developed right oviducts, instead of just left functional structures. In the area where the eggs were collected, there was multiple female-female pairing and low hatchability of eggs. Males exposed as embryos to estrogenic pesticides showed decreased to no sexual behaviour. (Fry and Toone, 1981) Louis Guillette noticed that male alligators from Lake Apopka in Florida have vestigial penis, follicle-like testis and elevated estrogens/testosterone ratios and the female hatching’s ovaries were producing multiple egg follicles and eggs with several nuclei (Luoma, 1995, Guillette et al., 1995) The females also had above normal estrogens levels. When he and his colleagues did a similar injection study with DDT and DDE, they produced results similar to those found in the field. The reduction in penis length and the abnormal gonads made the hatchlings reproductively incapable. Both the bird and alligator studies were prompted by the contamination of large water bodies by organochlorins and the low breeding success of the animals living and feeding in these areas.