How Can We Restore the pH of the Ocean?


I chose the topic of Ocean Acidification because of the critical state that our oceans are in and are going to be in in the near future. I researched ocean acidification and found that the most environmentally sound solution would be to plant eelgrasses and kelp in areas with lowest pH. I hypothesized that through photosynthesis, the marine plants would lower the pH of the water by removing excess CO2. I created an experiment that would allow me to monitor the plants and pH  in an easier way. I decided that I would plant freshwater plants in plastic tubs and alter the pH by using carbonic acid, which is much more commonly know as club soda. I would then monitor the tubs and their pHs by testing them every evening and recording the results. 

When I had concluded my experiment, my results supported my hypothesis because the aquatic plants' photosynthesis lowered the amount of acid in the water.

My experiment will be useful for scientists, like myself, to have an idea of how this solution may affect the ocean on a larger scale. My suggestion for scientists moving forward is that it would be best to begin testing solutions for ocean acidification now, so that later on the damage to our oceans is not irreparable. My next move, now that I have this information, is to invent a new system that would allow us to reduce the amount of acid in the ocean without effecting its ecosystems in the ocean.

Question / Proposal

What would be a cheap and easy solution for ocean acidification? 

To solve this issue in an environmentally sound way, scientists should slowly start planting controlled seagrass beds in coastal oceanic areas with a pH of 8 or lower to prepare the area in advance to fight ocean acidification and to emit more dissolved oxygen into the water.

Formal Hypothesis: If we would be able to increase the intake of carbon dioxide by aquatic plants by planting more aquatic plants, then there wouldn't be as much free carbonic acid in the water, because the plants would absorb the excess CO2 and use it to create oxygen and glucose during photosynthesis reactions (6CO2 + 6H2O -> C6H12O6 + 6O2), which will increase the pH of the water due to there being less CO2 and carbonic acid in the water.
I am expecting the pH of my tubs with aquatic plants to increase slowly and then plateau out. I believe that the pH of the tubs that I have added carbonic acid to will increase faster that the pH of the tubs that I have not added carbonic acid to. I also believe that the dissolved oxygen of the tubs will increase because the plants are photosynthesizing and releasing oxygen as a byproduct.


I searched for previously explored ideas by scientists in the oceanic ecology area of study that seem to have a positive outcome with minimized negative effects. I have found that Francesc Montserrat of the Royal Netherlands Institute for Sea Research is looking into putting olivine into the ocean. Olivine has been suggested to soak up atmospheric carbon but it could also be used to absorb protons are making the ocean more acidic. Adding olivine to the ocean would only be plausible in local areas with lower pH than normal, because adding too much olivine can cause magnesium poisoning in marine life. Another solution to ocean acidification that has been suggested is to plant seagrass fields in areas with higher acidity, because the seagrasses would take in carbonic acid during photosynthesis and produce oxygen as a waste product. This solution would also be contained to local areas with a low pH and would also be affected by the fact that most of the ocean floor is below the 200 meter limit where light is strong enough to support photosynthesis. 

After first finding the ideas to put olivine or other foreign materials into the ocean and believing that this may be an easy solution to test and implement, I discovered that the public was worried about these methods because the ocean's reaction is difficult to predict due to the large amount of variables involved. I also found that the production of the materials needed to implement these solutions also creates carbon dioxide which makes this idea practically useless because the effects of the carbon dioxide going into the atmosphere cancels out the materials going into the ocean. This discovery deterred me from concluding that this idea would be the best solution and steered me to look for a more simplistic and natural solution. 

Next, I went back to researching and found a solution proposed by Oregon State University marine ecologist, George Waldbusser, suggesting that we should replenish seagrass beds to protect the ocean from increasing amounts of carbonic acid. He has found that the native seagrasses lower oceanic pH by photosynthesizing and they help to improve the conditions of another problem facing the Northwest, hypoxia which is also plaguing the ocean. He also noted the importance of using seagrasses that wont negitively effect the enviroment, whether the shed their leaves or if they are posionous to native species.

In the Northwest and around the globe, ocean acidification is affecting calcifying organisms by making calcium carbonate, a vital ingrediant in building their shells, more difficult to aquire. This causes them to waste more energy building their shells instead of allowing them to use that energy to reproduce and find food, which is causing the population of these organisms to decrease. The limited amount of these organisms will cause  the millions of people who rely on them, whether for their job or as a food source, to starve. Ocean acidification is also slowly dissolving biodiversitiy hotspots around the world, coral reefs.

Method / Testing and Redesign


x4 - 59.7 x 42.9 x 31.1 cm Plastic Tubs

2-4 Old Cloth Towels

2 1/2 Liters of Carbonated Water

~1593.023 kL of Fresh Water per tub

110 grams of Calcium Carbonate Powder

16 Aquatic Plants

Aquarium Gravel

Plastic Wrap

2 Suspended Grow Lights

Measuring Cup(s)

pH Testing Kit

Vernier pH Meter

Vernier Dissolved Oxygen Meter

Vernier LabQuest Mini

Fish Tank Thermometer


Day 0

  1. Obtain all of the materials
  2. Lay down old towels where tubs are going to rest
  3. Fill plastic tubs with fresh water and set on old towels
  4. Add aquarium gravel
  5. Hang/place grow lights above tubs
  6. Plant aquatic plants in gravel
  7. Measure out and add 1 liter of Carbonic acid (carbonated water) to tub 1 + tub 2
  8. Measure and record pH
  9. Cover tightly in Plastic wrap

Days 1-2

  1. Measure and record pH

Day 3

  1. Add 55g of Calcium carbonate to both Tubs 1 + 3
  2. Add 250 mL of Carbonic acid to both Tubs 1 + 2
  3. Measure and record pH and Dissolved Oxygen

Days 4-6

  1. Measure and record pH and Dissolved Oxygen

Day 7

  1. Measure and record pH and Dissolved Oxygen


Independent Variables: time allotted for experiment,  Amount of Carbonic acid to added to tubs 1 + 2, amount of calcium carbonate added to tubs 1 + 3, 

Dependent Variables: pH of water, dissolved oxygen in water

Controlled Variables: amount of time allotted for grow lights to be on during the day, temperature the water was kept at, brand of carbonated water, species of aquatic plants, amount of water in all of the tubs.


My process was fair thanks to the plastic wrap because it didn't allow for the carbon dioxide or water vapor to escape the tubs and because I controlled of the experiment where it was possible. See Controlled Variables

This experiment took place on the second floor of my family's house.

No safety measures were taken because no dangerous equipment, chemicals, or procedures were necessary.


Tub 1 Graphs: 

Tub 2 Graphs: 

Tub 3 Graphs: 

Tub 4 Graphs: ​​​​​​

During the experiment, I noticed that the pH of the tubs slowly began to rise as the plant photosynthesized. I also noticed that the dissolved oxygen increased which also had to do with photosynthesis. The pH also decreased when the carbonate water with the carbonic acid was added.


This experiment allowed me to test the easiest and the cheapest solution to ocean acidification. In the begriming of this process, I hypothesized that planting aquatic plants in more acidic water would lower the acidity of the water. After performing the experiment, my hypothesis was proved correct, because the pH in the water increased due to the plants photosynthesizing and consuming the carbonic acid that was added to it to simulate carbon dioxide being absorbed by the ocean.

If I had the opportunity, I would like to redo my experiment on a larger scale, be able to use saltwater and marine plants, have a longer testing time-frame, and more accurate equipment. My results probably are not 100% accurate because I was unable to keep a complete seal on my tubs, use the most reliable equipment, get a very long time frame to measure me experiment on, use a larger scale model, or use saltwater life. If I were to improve my method, I would acquire better equipment, sealable fish tanks, more student scientists to help me, and less fluctuating temperature.

With the time I allotted myself, I feel that my experiment was very successful. Even if my experiment was not the most accurate, I know that I learned a lot about the environment and the scientific process while formulating and conducting my experiment.

I hope that my experiment may bring to light the struggle that the oceans are enduring now and will continue to endure in the future if we do not do something now. Personally, I now know how important our oceans are and that I need to raise questions about what we might do to to reverse all of the negative effects before the ocean is irreparable. I also now know of all of the scientists who have started working to fix this problem.

About me

I enjoy writing, learning, participating in hands-on activities, math, history, and science.

My mom introduced me to the STEM field when she signed me up for challenging summer camps all through 1st grade to 8th grade. STEM has influenced my life by giving me the tools necessary to change the world and allowed me to believe that I have the capability to succeed in school and in life afterwards. I am extremely grateful for all of my experiences because I would not be striving to be the person I am without STEM and them.

I have not been inspired by a single scientist, but by many because they have all relied on the others to seek answers to the questions they did. Without the whole field of science and the scientists in it, humans would not be as capable as we are now.

I am planning on gradating from the IB program that is offered at Lincoln High School and then continuing my education at Stanford. Once in college, I am not sure what I would like to major in because I do not want to commit to a subject the will shape the course of the rest of my life. 

I want to win this competition, not for the prize money, but for the exposure that ocean acidification will receive. Winning would change my life because it would allow me to become a recognized person and allow me to meet other student scientists that are passionate about their work.

Health & Safety

I did not follow any health and safety procedures because my experiment did not require any.

Bibliography, references, and acknowledgements

Works Cited

Jones, Nicola. "How Growing Sea Plants Can Help Slow Ocean Acidification." Yale Environment 360, 12 July 2016, Accessed 29 Oct. 2018.

Klein, Alice. "Adding Rocks to Oceans Could De-Acidify Water and save Coral." NewScientist, 10 May 2016, Accessed 24 Oct. 2018.

Marshall, Micheal. "Rock-Burning, Sea-Zapping Geoengineering Could Cut CO2." NewScientist, 12 Nov. 2010, Accessed 25 Oct. 2018.

Metzner, A.P. "Photosynthesis in Aquatic Plants." Sciencing, 13 Apr. 2018, Accessed 11 Dec. 2018.

Nowak, Racheal. "Acid Oceans No Laughing Matter for the Clown Fish." NewScientist, 2 Feb. 2009, Accessed 24 Oct. 2018.

"Ocean Acidification." NOAA, Nov. 2013, Accessed 25 Oct. 2018.

University of Southampton, Heather. "Ocean Acidification: An Experiment to Try at Home." University of Southampton, 19 Nov. 2014, Accessed 24 Oct. 2018.

"What Is Ocean Acidification?" PMEL Carbon Program, NOAA, Accessed 24 Oct. 2018.

Zukerman, Wendy. "Acidic Ocean Robs Coral of Vital Building Material." NewScientist, 13 Apr. 2011, Accessed 24 Oct. 2018.



I'd like to thank my mom for reading, editing, and subsidizing my submission.

I'd like to thank Mr. Josh Barnes for lending me the equipment needed to complete this experiment.

Other than this, I did everything on my own.