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Seaweed or sea vegetables are forms of algae that grow in the sea. Acting as a food source for ocean life, they grow along rocky shorelines around the world. Containing a myriad of species, each type of seaweed has its unique characteristics and colour - ranging from red to green to brown to black. It's most commonly eaten in Asian countries such as Japan, Korea and China, in forms such as Wakame, Kombu, Nori, Dulse etc.

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ABOVE: Seaweed can be found in abundance in our oceans

Acting as an invaluable resource of our ocean ecosystem, seaweed plays a pivotal role in many ways. Contrary to other types of snacks, they contain many hidden benefits to human health if an appropriate amount is consumed, including minerals and antioxidants and vitamins A, C, E, and B12.


Apart from benefiting human health, seaweed also helps our ocean ecosystem, as they are incredibly efficient at sucking up carbon dioxide and using it to grow. Eelgrass, mangroves, and salt marshes are already known for their ability to store carbon. But seaweeds pull more of the greenhouse gas from the water than all three combined based on biomass. This is because seaweed sucks up carbon dioxide at a rapid rate as it proliferates under the process of carbon sequestration. Once it is locked up in seaweed biomass, it can be harvested for use or returned to its source - the seafloor. That means seaweed farms can help to combat the local impacts of ocean acidification. 


Seaweeds also gobble up nitrogen and phosphorus. In large quantities, these nutrients cause algal blooms that deplete the ocean of oxygen when they decompose. Excess nitrogen and phosphorus from stormwater runoff and point sources are behind the dead zones that form in specific regions. Seaweed farms can help lower nutrient levels in nearby waters.

Ongoing Seaweed Projects

As climate change continues to ravage the world, many communities have been devastated by unprecedented natural disasters, ranging from more violent earthquakes, tsunamis, flooding, and other types of extreme weather.


Therefore, many groups have been taking a proactive approach to solving or alleviating this issue through generating innovative solutions.


A group named Oceans 2050 are one of the changemakers. The non-profit aims to restore the health of the oceans. One of its key projects relates to a study that seeks to “deliver evidence and the methodology to validate and monetise the carbon sequestration impact of ocean farming”.


Co-founded by Alexandra Cousteau and Fritz Neumeyer, the prize-winning project consisted of quantifying carbon sequestration by seaweed in sediment across 19 seaweed farms, in 12 countries, in a bid to provide empirical evidence of their carbon sequestration rates.

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ABOVE: The 15-month project aims to quantify the amount of carbon sequestered by seaweed farms to pave the way for a new blue carbon market.

The group aims to develop a means by which seaweed farms can issue carbon credits to global buyers, enabling them to benefit financially from the carbon dioxide their farms sequester. This also creates a new, scalable blue carbon market, and catalyses global expansion of the seaweed farming sector.


This project eventually won The Keeling Curve prize for developing ways of increasing carbon uptake and drawing down atmospheric carbon levels.


From this successful example, Carbon Neutral believes that it is feasible to implement this project, as it is cost-effective and beneficial to the environment. The seaweed grown can be harvested for consumption while the carbon captured can successfully be dissolved.

Carbon Neutrals Proposal

As a group founded with a core focus on the UN SDGs, Carbon Neutral endeavours to focus on the objectives of SDG 12 - Responsible Consumption and Production, SDG 13 - Climate Action, and SDG 14 - Life Below Water. These SDGs are intertwined within this project, as it aims to foster a responsible consumption of natural resources to ensure our habits are creating a positive and profound impact on our environment, whilst trying to limit the effects of climate change and protect life below water to suffer from ocean acidification and pollution.

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ABOVE: The United Nations Sustainable Development Goals

As this is a large-scale project involving many stakeholders, we will contact the relevant government departments to ensure we are strictly adhering to any rules and regulations. Once our project is approved, we will contact relevant NGOs such as Plastic Free Seas to learn more about their viewpoints as trained professionals working in the industry for years. We will also partner up with the organisations to locate, identify, and examine areas that are most optimal for this project to be conducted in.


Furthermore, we will utilize the latest technology - satellite imaging and artificial intelligence to investigate further other regions around the city that are appropriate and effective. This will create a more efficient and autonomous process, where weather conditions are also taken into close consideration. This process enhances our project as artificial intelligence can consider aspects that humans might be more negligent towards.


Once the location is confirmed, we will recruit volunteers through Island School and the NGOs we are partnering up with and go on weekends to undertake a trial run of our project before going full-on and making an impact.


This is an unprecedented project we are incredibly excited about as it involves the usage of unparalleled technology and impressive intricacy. We genuinely believe this will be able to impact our community.

Investigating Preliminary Data On Carbon Dioxide Reduction from Seaweed


Groups Involved


  • Carbon Neutral - Carbon Neutral (CN) is a high-school student-led initiative that aims to survey existing frontier technologies and nature-based solutions in carbon capture so that they can be implemented by youth in Hong Kong/China and subsequently across Southeast Asia. We aim to work with NGOs that specialise in carbon related solutions to improve our understanding of the processes and to help with implementing our strategies. Additionally, we intend to create a community of passionate like-minded youth through offering opportunities of involvement to schools for our projects, advocating the importance of the SDGs and collaborating with other student-led initiatives.

  • Drop In The Ocean - In modern society, environmental stewardship is increasingly important. Our goal should be to not further exacerbate our limited resources but instead work towards conservation. Drop in The Ocean (DITO) is a student-driven and led environmental group that strives to establish sustainability as a CIS school value through systemic change, community dialogue and education. As quoted from our school’s objectives to “serve as environmental advocates through the school’s practice and curriculum”, we aspire to be leaders and agents of change. DITO is the umbrella term for its sub-strands of CIS Footprint, Urban Farming, and Beach Cleanup. Beyond acts of service, Drop in the Ocean (DITO) aims to bolster commitment and implement sustainable strategy across campus. The DITO student group actively connects and collaborates with student groups to provide student voice and agency towards environmental stewardship at CIS.


Summary of Experiment


There was a 24% of CO2 concentration over 2 hours and 30 minutes. With 9 pot kelps in a sealed container, the experiment showed that at the start of our experiment there was 484 ppm of CO2 and by the 8760th second there was only 368ppm of CO2.



Experiment Setup



ABOVE: An image of the seaweed investigation and a corresponding graph.



Data Analysis





















The above experiment started in a tank with a CO₂ Concentration (ppm) of 518. A measurement of the CO₂ in the tank was conducted every second. However, just after 7 minutes, this has been reduced to 419. This 20% decrease effectively demonstrates the power of seaweed in absorbing carbon dioxide. However, the data here is considered inconsistent with an R2 value of 0.64, meaning that the data doesn’t really fit in with the line of best fit. This might be because there were anomalies in the experiment or that the time simply wasn’t long enough. Another experiment was conducted below with these improvements.






The above experiment started in a tank with a CO₂ Concentration (ppm) of 484. A measurement of the CO₂ level was conducted every 30 seconds. After around 2.5 hours, a CO₂ Concentration level of 368 was observed. This may be inconsistent with the above experiment due to a different setup, or because a different amount of seaweed was used. The R2 here is much more apparent at 0.998 which is a very pleasing result as it is consistent with the polynomial data trend line.



These two experiments concluded that seaweed indeed effectively reduces the CO₂ levels in the water, through absorption processes. Although these experiments provided rough and preliminary data, there are further comprehensive data on the internet that seems to support this trend as well.


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Report Published In Collaboration with Assistance from Drop In The Ocean & Chinese International School Science Department & Stakeholders


Credits to:

Alexander Zhang

CIS Science Department

Drop In the Ocean

Students for Science

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