The roles of macroalgae in climate change mitigation: opportunities and challenges for marine-based carbon donor

Anthropogenic activities will lead to an exponential increase in CO2 emissions in the future. Increased CO2 emissions have an impact on global climate patterns, ocean acidification, and ecosystem function. Marine vegetation has the potential to absorb CO2 through photosynthesis and store carbon in its biomass and sediments. This is known as blue carbon. Research on blue carbon in the world, including Indonesia, is more focused on seagrass and mangroves because including macroalgae carbon in the blue carbon strategy is still controversial. Currently, there are many considerations for including macroalgal carbon in the blue carbon strategy. Macroalgae have a shorter life cycle than seagrass and mangroves. In addition, macroalgae generally grow on hard substrates, resulting in lower levels of carbon storage than seagrass and mangroves. However, macroalgae can serve as carbon donors and contribute to the effort to mitigate climate change. In this review, we present the potential and challenges of macroalgae as carbon donors. Macroalgae will be significant as carbon donors if they have the following three criteria: high production of biomass; effective biomass moved to recipient habitat; and carbon donors that can be buried in recipient habitat. The fate of macroalgae carbon in recipient habitats still needs to be studied.