Research- Intro The Effect of pH Changes on Heart Rate, Mortality Rate, and Evolutionary Adaptation of Daphnia magna
The Effect of pH Changes on Heart Rate, Mortality Rate, and Evolutionary Adaptation of Daphnia magna
Amina Nur, Caleb Smith, Katherine L Rupp , Mark Malabuen, Timothea Muljadi
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| Figure 1. Water flea Daphnia magna. |
In this experiment, we will explore the effect that the pH of an environment has on the heart rate D. magna. Using this data, we will be able to determine an optimum pH for D. magna survival, and whether this means they prefer an acidic or basic environment. We will be collecting data four times over the course of ten days to observe D. magna’s heart rate in 4 different pH environments. We will also collect data from a control environment (normal pond water), and it will be the expected results. We will use a microscope to observe and count the heart rate with a manual tally counter. Because D. magna’s hearts are located on their backs, their heart rate can clearly be monitored through a microscope under a total magnification of 40x. The pH will be measured every experiment day using a Vernier LabQuest and pH probe system to make sure that it stays relatively constant. Using this system, we will be able to document any changes in the pH of each environment. Additionally, we will also document any unusual behavior exhibited by the D. magna, as this resulting behavior could be an effect of the environment’s pH.
Hypothesis: The pH of an environment will affect the heart rate of D. magna.
Prediction: Environment with lower pH level will slow down the heart rate of D. magna. Neutral pH environment (around 7) will be the optimum pH for the daphnia and they will not show a significant change in their heart rate.
Aquatic acidification in freshwater environments has the potential to drastically impact the ecology of these locations throughout the world. While the implications and effects of ocean acidification via increased atmospheric CO2 levels have been the subject of intense study in recent years, the consequences of this same process in freshwater environments have been far less explored (Phillips et al. 2015). Determining the resilience of organisms in response to changes in environmental pH is essential to understanding the long-term effects of acidification.
One of the challenges we faced so far was that some of the equipments we decided to use in this experiment may not be available in the Biology department like the pH meter and Vernier LabQuest. However, they are available in the Chemistry department, and we were able to coordinate with them to borrow the listed equipment.
References:
Ebert D. 2005. Ecology, Epidemiology, and Evolution of Parasitism in Daphnia. Bethesda (MD): National Center for Biotechnology Information (US). Chapter 2, Introduction to Daphnia Biology.[Internet]. [Accessed 9 Feb 2018 ]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK2042
M Mahassen, E Ghazy, M Habashy, E Mohammady. 2011. Effects of pH on Survival, Growth and Reproduction Rates of the Crustacean, Daphnia Magna. Australian Journal of Basic and Applied Sciences. [Internet].[ Accessed 9 Feb 2018]; 5(11): 1-10. Available from: http://ajbasweb.com/old/ajbas/2011/November-2011/1-10.pdf.
M. R. Alibone, P. Fair. 09 February 1981. The effects of low pH on the Respiration of Daphnia Magna Straus. Sprinker Link. [Internet]. [accessed 9 Feb 2018 ]. Available from: https://link.springer.com/article/10.1007/BF00006629
Phillips, J.C., G.A. McKinley, V. Bennington, H.A. Bootsma, D.J. Pilcher, R.W. Sterner, and N.R. Urban. 2015. The potential for CO2-induced acidification in freshwater: A Great Lakes case study. Oceanography. [Internet]. [Accessed 9 Feb 2018]; 28(2): 136-145. Available from: http://dx.doi.org/10.5670/oceanog.2015.37.
W. E. Walton, S. M. Compton, J. D. Allan, and R. E. Daniels. 1982. The effect of acid stress on survivorship and reproduction of Daphnia pulex (Crustacea: Cladocera) . 60 ed. University of Maryland: Canadian Journal of Zoology. [Internet]. [Accessed 9 Feb 2018]; p 573-579. Available from: https://www.researchgate.net/profile/William_Walton2/publication/237990821
Hi group,
ReplyDeleteFirst off, I feel sad to see "mortality rate" on the title, as that means daphnias will die in this experiment! Just kidding though. I think your topic could bring some very interesting findings, and I would love to know how pH values affect daphnias' heart rate! One question arise as I read the post, how will you guys determine whats the best (optimum) heart rate for daphnias? Since you guys are considering pH 7 is their optimum pH, while a pH 5 might gives daphnia their best heart rate. Well, these are just some of my thoughts and I am not challenging you guys, as I have mentioned, I think this is a very interesting topic! Overall great post!
Hey, this is a pretty interesting experiment! While our group was researching on what type of organisms to experiment on, we ran across specific worms that were introduced to different pH levels too and actually died when they came into contact with a pH of 2! It's interesting to research this topic too because you guys can relate it back to how humans heart rate can relate to pH levels as well and I'm glad you guys are relating it also to how pH levels can affect the oceans organisms as well, because that's where we're polluting a lot & how we can change those polluting to not polluting at all.
ReplyDeleteHey hey everyone. I like the idea of changing the Ph and testing the heart rate/surivability. The only problem I can see is keeping a consistent Ph as that might get harder as the days go on. But still you guys look like you've prepared and are ready to get going. Good luck on your project
ReplyDeleteHi guys, daphnia is one of the organism that I really liked working on its lab. Your experiment is very interesting, as you can relate your results to chemistry. I mean why change in the pH level cause change in the heart rate. I was thinking why the change in the concentration of hydrogen cause change in the heart rate is it only about preferred medium, our does it relate to molecules interactions. I am expecting very interesting results from your research. Good job proposing your project!!
ReplyDeleteHi guys,
ReplyDeleteI like how you connect the animal project to the environment. This experiment can show how the pH of the water affect the organisms such as the tiny daphnia. When I was doing the daphnia lab, I found it interesting how the change of the chemicals in water can influence the heart rate of daphnia in a short period of time. Therefore, I am looking forward to see the results of your project! Great job guys!
pH is becoming a pretty big factor in our waters when it comes to climate change and its effects. It is definitely a great research project to see what these effects could have on some of its inhabitants.
ReplyDeleteHi Amina's group,
ReplyDeleteMy group also observed daphnia, however; we measured reproduction rate. You mentioned mortality rate, I am curious to know if you counted how many died or how you managed this. Our group wanted to do mortality rate but found they disinegrated too fast to see, hence we ditched that idea. It was interesting to see a ph comparison to the effects on daphnia, our group for future would have measured toxicity in the water. Thank you for your post.