The article, titled The Role of Seaweed in Carbon Sequestration and Climate Change Mitigation: A Review of Blue Carbon Potential, positions seaweed as an underutilized but powerful component of blue carbon strategies—nature-based climate solutions that rely on oceans and coastal ecosystems to reduce greenhouse gas concentrations. At a time when governments and industries are searching for scalable and affordable climate mitigation options, the findings highlight seaweed farming as both environmentally effective and socially relevant.
Why Seaweed Matters in the Climate Debate
Climate change continues to intensify due to rising atmospheric CO₂ levels, driving extreme weather events, sea-level rise, and ecosystem degradation. While land-based solutions such as reforestation have dominated climate discussions, marine-based solutions are increasingly seen as essential complements.
Blue carbon ecosystems—including mangroves, seagrasses, and macroalgae—capture carbon more efficiently per unit area than many terrestrial systems. However, seaweed has long been overlooked in climate policy because it does not grow rooted in sediment like mangroves or seagrasses.
Sri Mulyani’s review challenges this assumption by showing that seaweed’s rapid growth rate and high photosynthetic capacity allow it to remove CO₂ from seawater at remarkable speed. This makes seaweed farming especially attractive in regions with limited land availability but extensive coastlines, such as Indonesia.
How the Review Was Conducted
Rather than conducting new experiments, the study synthesizes findings from peer-reviewed international research published over the last decade. The review follows a structured literature assessment framework, drawing data from major academic databases including Google Scholar, Scopus, and Web of Science.
The analysis compares:
- Different seaweed species used in farming
- Various cultivation systems, including offshore farms and integrated aquaculture
- Key environmental factors that influence growth and carbon uptake
By consolidating results across multiple studies, the review provides a broad and balanced picture of what is currently known—and what remains uncertain—about seaweed-based carbon sequestration.
Key Findings: Not All Seaweed Is the Same
One of the most important conclusions is that carbon sequestration capacity varies widely between seaweed species and farming conditions.
Several species stand out:
- Ulva lactuca shows exceptionally fast growth, exceeding 35 percent per day under high CO₂ and optimal temperature conditions, making it effective for rapid carbon uptake.
- Kappaphycus alvarezii, widely cultivated in Southeast Asia, grows more slowly but demonstrates stable nutrient absorption and consistent biomass production.
- Gracilaria species perform well in nutrient-rich waters and are suitable for integrated farming systems.
These differences underline the importance of species selection when designing seaweed farms for climate purposes.
Farming Systems Shape Carbon Outcomes
The review identifies Integrated Multi-Trophic Aquaculture (IMTA) as one of the most effective farming approaches. In IMTA systems, seaweed is cultivated alongside fish or shellfish, allowing waste nutrients from animals to be absorbed by seaweed.
This approach delivers multiple benefits:
- Increased seaweed growth and carbon uptake
- Improved water quality
- Reduced environmental impacts from aquaculture waste
“Integrated systems improve nutrient recycling while strengthening the carbon sequestration function of seaweed farms,” Sri Mulyani notes in the review, emphasizing their potential for sustainable expansion.
Other systems, such as tank-based cultivation and vertical farming structures, also show strong results when environmental conditions are carefully managed.
Environmental Conditions Are Critical
Seaweed does not absorb carbon effectively under all conditions. The review highlights several environmental drivers that strongly influence outcomes:
- Temperature: Optimal growth typically occurs between 20–24°C
- Salinity: Best productivity is observed around 31–33 PSU
- Nutrients: Nitrogen and phosphorus availability directly affect photosynthesis
- Light: Adequate light exposure is essential, particularly in controlled systems
Negative factors such as poor water quality, excessive epiphyte growth, and climate-induced stress can significantly reduce carbon capture efficiency.
Economic Opportunities and Policy Challenges
Beyond environmental benefits, seaweed farming offers economic opportunities, especially for coastal regions. The review points to growing interest in linking seaweed cultivation to carbon credit markets, which could provide new income streams for farmers.
Seaweed farming also supports:
- Job creation
- Coastal livelihood diversification
- Development of sustainable marine industries
However, large-scale adoption faces obstacles. These include limited infrastructure, unclear regulatory frameworks, competition for marine space, and ongoing scientific debates about how long seaweed-derived carbon remains stored.
Sri Mulyani stresses that without clear governance and standardized measurement methods, seaweed’s role in climate mitigation may remain underutilized.
Implications for Indonesia and Global Climate Policy
For Indonesia, one of the world’s largest seaweed producers, the findings are particularly relevant. The review suggests that seaweed farming could be formally integrated into national climate strategies, blue economy planning, and coastal development policies.
Internationally, the study contributes to growing evidence that marine-based solutions should be included alongside terrestrial approaches in climate action plans.
“Seaweed farming combines carbon mitigation, ecosystem services, and economic value,” Sri Mulyani writes, highlighting its relevance for both environmental and development goals.
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