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66th Hawaii State Science and Engineering Fair

On Friday, April 14, 2023, the Friends of Hanauma Bay awarded 2 special awards in the area of Earth and Environmental Sciences. Senior and junior division student winners and their respective teachers were honored for their projects dealing with ocean acidification. All winners receive a monetary award, letter, certificate, and a one-year subscription to our FOHB newsletter. In addition, the two students will each receive a copy of David Gulko’s book, Hawaiian Coral Reef Ecology.

Ocean acidification is a serious issue. Due to global climate change immense amounts of carbon dioxide is being absorbed into our oceans. During the past 200 years, carbon dioxide levels have affected the acidity of water by over 30 percent. Ocean acidification has become a big problem for marine life and coral reefs.

Senior Winner: Sydney Yamamoto, Mililani High School “The Effect Ocean Acidification Has on Shellfish”

Hypothesis: If the shell mass is exposed to the acid then the shell mass will be reduced. Shell organisms create their shells by extracting dissolved calcium and bicarbonate from the ocean but as the ocean becomes more acidic there will be fewer carbonate ions thus making the shells weaker.

Methodology: Plastic liter soda bottles were filled with a mixture of distilled white vinegar and baking soda powder. Each shellfish of clams, oysters and mussels were placed into the bottles. Over 4 week period, different concentrations of the mixture were added. Each shellfish was weigh and its weight recorded each time.

Results: The mass of each shell was reduced when the acid content was higher. Degradation of the shells was also observed.

Conclusions: The higher the acidity is the more mass of the shellfish was lost. Slightly acidic water also had high amount of shell mass loss. Oysters lost the most mass indicating they may not be as adaptable to rising levels of acid in the ocean. Even though the shell was intact, data showed that the shell was not strong enough to maintain the structure. Shellfish need the carbonate ions that acidification is taking from them to build their shells. We need to improve our carbon footprint and take measures to reduce CO2 being emitted into the air so shellfish and plants can thrive in the ocean.

His teacher, Mr. Nampthip Sitachitta mentored Sydney on his project.

Junior Winner: Lilikoi DeMartini, Kahuku High and Intermediate School “Dissolving Sea Shells”

Hypothesis: If 5 types of seashells (cowry shells, chunks of coral, sea urchin shells, white clam shells and black purse shells) sit in vinegar and saltwater, then the clam shells will dissolve the most in 10 days. Which species would prove to be the most susceptible to ocean acidification?

Methodology: The five types of seashells were placed into small cups of vinegar and saltwater. Acidified seawater was made by adding 4 parts seawater to 1 part distilled white vinegar. After 10 days the shells were rinsed, dried and weighed to the nearest 0.0001 g.

Results: The chunks of coral dissolved the most as measured by grams. This means that chunks of coral will dissolve the fastest as the ocean acidifies.

Conclusions: The results were chunks of coral dissolved fastest, followed by sea urchins, cowries, black purse shells, and clam shells. It may be possible that coral is not as dense as the shells used. The coral chunks have less aragonite than shells and also other forms of calcium carbonate, which are easier to dissolve. Chunks of coral are less dense so the vinegar dissolves them easier.

Her teacher, Ms. Amber O’Reilly mentored Lilikoi on her project.