Rain forests are known as the lungs of the earth, absorbing carbon dioxide and releasing oxygen. Like the forest on the land, the ocean and its inhabitants are part of the carbon cycle, storing carbon and producing oxygen.
Carbon is the basic building block of all life – it is present in all living things on Earth and is stored in plants, land and in the ocean. Carbon passes through the Earth and all its inhabitants in a process called the Carbon Cycle. Through this cycle, carbon is reused in a continuous cycle forever.
Carbon is found in our atmosphere as carbon dioxide, and carbon dioxide is a greenhouse gas that traps heat in the Earth. While carbon dioxide is produced naturally, human activities such as the burning of fossil fuels for energy is releasing carbon dioxide into the environment. Why does the burning of fuels release carbon dioxide? When animals die, the carbon in them is locked away and buried under the earth. Over time with heat and pressure, their remains may turn into sources of fuel, such as natural gas, crude oil and coal. When these fuels are used for energy, the carbon that was once stored in them is released into the environment, where it becomes carbon dioxide. Current human activities are releasing carbon at such high levels and in such short periods that it is becoming too much for the Earth to handle. This has led to global warming.
Luckily for us, carbon sinks, which are plants, land and ocean, absorb carbon dioxide through the carbon cycle and store them away for periods of time, be it a day or a millennium. Thanks to these carbon sinks, about 50% of carbon dioxide produced are removed from the atmosphere, effectively slowing down the warming of the planet.
Photo by Wiltven Lim
The ocean is the second largest carbon sink on earth, and research has found that the ocean absorbed 31% of carbon dioxide produced by humans between 1994 and 2007. The ocean absorbs carbon dioxide through 2 ways. The first is the natural exchange of gas between the ocean surface and the atmosphere, which accounts for 90% of the CO2 absorbed. Diffusion occurs when the CO2 in the ocean surface is less concentrated than the CO2 in the atmosphere, diffusion will occur, and CO2 will enter the ocean. The movement of the ocean surface encourages gas exchange, and it is proven that colder waters can take up more CO2, so the amount of CO2 in the water differs by regions.
The second way CO2 is absorbed is through the organisms that live in the ocean, mainly phytoplankton. Phytoplankton are a mix of many species of microorganisms, and they live in the surface waters. Using sunlight for photosynthesis, these phytoplankton absorb carbon dioxide and release oxygen into the water. When they die, these phytoplankton sink to the bottom of the ocean, locking the carbon inside them there. Through this process, they account for 10% of the carbon dioxide taken in by the ocean.
Other organisms in the ocean also contribute to absorbing the carbon dioxide, including seagrass and seaweed. The forests of seaweed and seagrass also use the process of photosynthesis to create food. There are people who are researching the potential of using seaweed for carbon sequestration in the ocean. Seaweed is fast growing, and they absorb a lot of carbon dioxide during their lifetimes. Carbon sequestration works by letting dead seaweed sink into the ocean bed, taking the carbon with them and storing it there for years. While this method of storing carbon is still being researched and debated, seaweed does benefit the ocean, mainly providing a habitat for marine creatures, and producing oxygen for them. Seaweed is also a good source of nutrients for humans, and as a material is also very useful.
A Social Enterprise in Indonesia has turned to seaweed to produce packaging for food products that can replace single use plastics. This enterprise is Evo & Co. with their brand Evoware, which has successfully created seaweed packaging. Ocean Purpose Project has worked with David Christian, the co-founder of Evoware, for our #StartTodaySaveTomorrow Global Livestream, and we learnt how by using seaweed, Evoware is positively impacting the oceans, the environment and the seaweed farmers in Indonesia. The team at Ocean Purpose Project is working to bring the sustainable packaging to Singapore, and implement it in Singapore. (not sure about this, please advise. Thank you!)
The ocean and its inhabitants are definitely a great carbon sink, and we have them to thank for slowing down global warming. While this natural sink is great, there is a limit to how much it can absorb before it negatively affects the ocean. When CO2 enters the ocean, it dissolves into the water and is acidic. When there is too much carbon, the water becomes too acidic and pH level is lowered, causing ocean acidification. This change in pH level could affect marine creatures who are unable to adjust to the new pH, and push them towards extinction.
Carbon sinks have helped us slow global warming, but there is still work to be done to reduce our carbon emissions. There is a limit to how much the carbon can be stored naturally. Hello, please advise if there are any projects/research that OPP is working on regarding carbon sequestration/emissions etc? Thank you!!