1. Seaweed Buffering Effects on Ocean Water
Joseph Rees
Grade 9
Pittsburgh Central Catholic High School

2. Overview of Ocean Acidification
Ongoing problem
Affects many marine life, especially shellfish
Many shellfish cannot adapt to the change
Thought to be primarily caused by human activity
Factories and power plants emit 22 million tons of carbon dioxide a day.
Scientists estimate 525 billion tons of carbon dioxide has been absorbed in the oceans since the Industrial Era began. (Late 1700s)

3. Chemistry of Ocean Acidification
Carbon dioxide forms carbonic acid when combined with water
The compound formed then breaks into a positive hydrogen atom and a negative bicarbonate atom.
The hydrogen atoms lead to the oceans becoming more acidic, while the bicarbonate is what damages marine life

4. Seaweed’s Natural Ability to Buffer Ocean Acidification
Recent studies have been conducted, showing that seaweed and algae have been able to buffer ocean acidification
Photosynthetic activity absorbs carbon dioxide
Seaweed is able to absorb carbon dioxide and turn it into food, and increased photosynthesis results in more oxygen emission

5. Laminaria Seaweed Large, brown algae
Found on the East and West coasts of the United States
On the Pacific Coast, it is present where ocean acidification has been observed
Found in depths from 8-30 meters
Habitat for many marine life
Found in cold and rocky waters

6. Purpose
The purpose was to determine if Laminaria seaweed is able to buffer acidified ocean water

7. Hypothesis
The null hypothesis is that the seaweed will not be able to produce a significant buffering effect on acidified ocean water
The alternative hypothesis is that Laminaria will be able to significantly buffer acidified ocean water

8. Materials Laminaria seaweed Instant Ocean Distilled Water
Snap Cap Tubes
Spoon
LabQuest 2 pH meter
Dry ice

9. Procedure Poured 80mL of distilled water into a Snap Cap Tube
Added 16 grams of Instant Ocean into a tube
Stirred seawater slowly
Added appropriate amount of dry ice to create selected acidification ex grams yields pH of 8.1
Added 0.63 grams of seaweed to the tube
Recorded pH value of solution every 8 hours for one day
Four tubes had seaweed added, but no dry ice, and the pH stayed the same through a 24 hour day (8.28)

10. P<0.05
P>0.05
P<0.05
P<0.05

11. P<0.05
P<0.05
P<0.05
P<0.05

12. P<0.05
P<0.05
P<0.05
P<0.05

13. Conclusion The null hypothesis can be rejected
Laminaria seaweed appeared to have a significant effect on buffering acidified ocean water
The test with the pH value of 8.1 all significantly varied, except after at hour 8
The tests with the pH values of 8.0, 7.9, 7.8 significantly varied after 8, 16, and 24 hours

14. Limitations pH levels very close to each other Used non-intact seaweed
Used small amount of water
Used Instant Ocean
Optimal lighting?
Optimal temperature?

15. Future Studies Use same seaweed in real ocean water
Try different pH levels more spread apart
Try different species of seaweed
Add organisms native to ocean water

16. Works Cited
“Climate Interpreter.” Ocean Acidification - Effects on Humans | Climate Interpreter, climateinterpreter.org/content/chemistry-ocean-acidification.
Flannery, Tim. “Seaweed Could Save the World's Oceans from Becoming Too Acidic.” Quartz, Quartz, 4 Nov. 2015, qz.com/534553/seaweed-could-save-the-worlds-oceans-from-becoming-too-acidic/.
Hakai Magazine. “Seaweed and Seagrass Buffer the Acidity of the Nearby Ocean.” Hakai Magazine, 15 Feb. 2018,
Jones, Nicola. “How Growing Sea Plants Can Help Slow Ocean Acidification.” Yale E360, 12 July 2016, e360.yale.edu/features/kelp_seagrass_slow_ocean_acidification_netarts.
Koweek, David A., et al. “Expected Limits on the Ocean Acidification Buffering Potential of a Temperate Seagrass Meadow.” Ecology, Wiley-Blackwell, 31 July 2018, esajournals.onlinelibrary.wiley.com/doi/full/ /eap.1771.
“Ocean Acidification.” Ocean Portal | Smithsonian, Smithsonian's National Museum of Natural History, 18 Dec , ocean.si.edu/ocean-life/invertebrates/ocean-acidification.
“Seaweed- a Solution to Ocean Acidification.” ESL and Cultures Resource, 8 May 2018, sites.sandiego.edu/sdpollutiontrackers/2018/05/08/seaweed-a-solution-to-ocean-acidification/.