Exploring Global Estimates of Suitable Areas for Marine Algae Farming

Article by Jacqueline Boivin with assistance from Yue Liu

Solving FCB researchers Ling Cao, Yue Liu, William Cheung and Rashid Sumaila have been studying the potential for marine algae farming, by looking at global suitable areas. In this study, they considered species distribution models and suitability of 21 different seaweed species to be cultivated globally. The economic viability of seaweed mariculture and other economic pathways were also considered.

Some examples of economic pathways, include using seaweed as food. Or, in the case of red seaweed, for production of paper products.^[1,2] Seaweed can also be used as biofuel and as animal feed in some cases.^[3]

It was noted in the article that, “Australia has the greatest area suitable for seaweed farming, followed by Indonesia, Russia, Canada, and the United States. However, for the seaweed species we studied, China had the most outstanding production, followed by the Philippines, Korea, Malaysia, and Japan” (see fig. 5, below).

The researchers pointed out that, “It is a paradox that countries with the largest area suitable for seaweed farming are not currently producing much seaweed”. This could be for reasons due to lack of production knowledge or consumer demands for seaweed as a food. If countries with these larger suitable areas are able to leverage this for seaweed production, this could contribute to the local economies and help reduce climate change globally.

Researcher Yue Liu, who is a PhD student working on the China Case Study, will subsequently focus on S. japonica (kelp) as a model species. He is currently examining the cultivation of S. japonica and its influence on the species distribution of neighboring organisms. Additionally, he is delving into the environmental impacts of seaweed farming, especially its interaction with carbon neutralization and ocean eutrophication (the death of ocean life due to a lack of oxygen caused by an over-excess of nutrients from land runoff). The eutrophication issue has been similarly highlighted in the Costa Rica case study, emphasizing its effect on biodiversity.^[4]

Another dimension Liu intends to investigate, concerns the ideal latitudes for kelp farming, especially considering the ramifications of ocean warming. Preliminary analyses suggest that the potential for kelp farming diminishes at middle or lower latitudes but sees an uptick at higher latitudes. Liu is currently conducting tests on habitat services using environmental DNA. Based on his current findings, Liu observes no significant impact on biodiversity. He adds, “While further examination is warranted, current data doesn’t indicate significant variances in biodiversity indicators. This observation is further corroborated by findings from other researchers”.^[5]

In summary, seaweed offsetting impacts are still in the early stages of research. As quoted from a 2019 paper by Froehlich et al. on this subject:

“Ultimately, seaweed offsetting can likely play only a relatively small role in reversing GHG emissions to mitigate climate change, but its potential is on par with those of many other options being considered or pursued, yet it has essentially been ignored to date. Our work highlights the potential for an industry that has yet to be realized but could be part of the climate mitigation portfolio, especially when it comes to making aquaculture more sustainable more quickly. The urgency of climate mitigation demands use of every possible tool available.”^[6] 

In light of this, seaweed farming holds promising potential as a tool. However, various factors should be further investigated to achieve our overarching goal of “Solving the Sustainability Challenges at the Food-Climate-Biodiversity Nexus.”