Healthy Atmosphere, Healthy Ocean: Exploring the Impacts of Ocean Acidification

By: Amy Asmussen

“Why is it so important to keep our oceans healthy?” asked KIDS for the BAY Educator Neda Ibrahim. This question prompted our Oakland Environmentalists to launch into important discussions about what our ocean and marine food webs provide for us, and the many ways humans and wildlife depend on the ocean for survival. “We won’t have sushi or good seafood to eat if we don’t take action to keep our oceans healthy,” said Mackenzie. “Salmon migrate to freshwaters to breed, and then return to the ocean. Our impact on the ocean would affect the salmon population, which would affect woodland creatures, like bears. If we keep our oceans healthy, we also keep other ecosystems healthy,” said Amiyah.

Students at Piedmont Elementary School in Oakland completed an Ocean Acidification Action Project to learn about the impacts of acidification on marine organisms, and how to prevent ocean acidification by conserving energy and reducing carbon dioxide pollution. Through applied, hands-on science, the young Environmentalists discovered firsthand the importance of keeping our oceans healthy, and the consequences of our reliance on energy from fossil fuels. This Action Project empowered our young scientists to take action to protect the delicate balance of the marine food web and make behavior changes to reduce their carbon footprints. 

“What is CO₂?” asked Ms. Neda. “CO₂ is carbon dioxide!” shouted the class. “CO₂ is what cars and factories release into the air!” added Kendrick. “Too much CO₂ can change our Earth,” explained Ms. Neda, “but where does all of this extra CO₂ come from?” Karl suggested, “I think different types of transportation, like traffic, can create CO₂ pollution.” Mackenzie added, “When we make electricity, we make extra CO₂!” “We make extra CO2 when we cut down trees,” shared Diwon. “We use a lot of gases and energy to make products like toys and plastic packaging,” said Clover. “Too much CO₂ can cause the greenhouse effect, which makes the world hotter,” said Otis. “That’s right! CO₂ in our atmosphere is like a blanket. It traps heat from the sun and makes Earth hotter!” said Ms. Neda. “It’s like the Earth is wearing a jacket, but the jacket is making the Earth too hot!” summarized Youcef. 

Students learned that CO₂ can be absorbed into the ocean, making it more acidic. “Imagine you are trying to build a house, but halfway through, you realize you don’t have enough materials to build it,” said KftB Educator Neda Ibrahim. “When the ocean is more acidic, it dissolves calcium carbonate (CaCO₃), the special material that organisms need to build their shells,” explained Ms. Neda. “Can you think of any marine animals that have a hard shell?” Abigail replied, “The Dungeness crabs that we investigated had a hard shell, called a carapace.” “Yes, Marine organisms like crabs, limpets and coral rely on calcium carbonate to build their shells,” confirmed Ms. Neda. “If CO₂  pollution changes what the ocean is like, animals can’t build their shells, and this makes it harder for them to survive,” concluded Cristiyonna. “Crabs and other animals need shells for shelter and protection!” added Tia, remembering what she had learned about animal adaptations in her previous KftB lesson. 

Students investigated shells and studied a diagram showing an array of pteropod shells from the healthiest, most opaque shells to the most translucent and deformed shells. “That shell looks super transparent and it’s a weird shape,” said Lily. “Those shells do not look healthy!” observed Sophia.

Students also examined a diagram depicting food chain relationships between bay and ocean organisms, including plankton, oysters, red rock crabs and pacific halibut. “Which animals in this food chain will be affected by ocean acidification?” asked Ms. Neda. “The red rock crab, the Dungeness crab, the limpet and the oysters,” Liya shared.

“What would happen if these organisms disappeared from our food chain?” asked Ms. Neda. “The Pacific halibut wouldn’t be able to find enough food!” said Amari. “What do you think would happen to humans, if all the shelled organisms disappeared?” continued Ms. Neda. “We wouldn’t be able to eat oysters or shellfish,” predicted Youcef. “It’s a chain reaction. If something is wrong with the crabs and snails, it will affect the whole food chain,” shared Brielle. “How many people rely on the ocean for food?” asked Ms. Neda. “70% percent of the population!” guessed Liya. “Three billion people rely on the ocean for food! That’s almost half of the human population!” exclaimed Ms. Neda. 

Students were thrilled to learn that they would be building a Tiny Ocean to observe the process of ocean acidification with their own eyes! First, students observed a diagram depicting the pH scale and discussed the difference between an acid and a base. Next, students took turns adding drops of Bromothymol blue to a plastic cup with a pipette. “I think bromothymol blue is similar to a litmus indicator! It will tell us if a liquid is acidic or basic,” predicted Otis. “If we added bromothymol blue to lemon water, what would happen?” asked Ms. Neda. “It would turn yellow! If it turns yellow, it’s acidic, and if it turns blue, it’s basic,” said Orlando. Students added baking soda to a small paper cup taped to the rim of the larger, plastic cup containing the bromothymol solution. Before proceeding to the next step of the experiment, students engaged in the scientific process by predicting what would happen. “I think mixing vinegar and baking soda will make carbon dioxide,” predicted De’Niyah. “If the water turns yellow, it means there is too much acid in our Tiny Ocean!” suggested Lily.

In this exciting, hands-on experiment, our young Environmentalists learned about the importance of reducing carbon dioxide pollution to keep our oceans healthy and observed the rippling impacts that ocean acidification can have on entire marine food webs and the communities and ecosystems that depend on them.