Article by Jacqueline Boivin with assistance from Dr. Yue Liu and Dr. William Cheung.
Year 1-2: How can Seaweed Help Fight Ocean Acidification & Climate Change?
China’s coastline connects with the North Pacific Ocean and faces the coastline of North America. China has a coastline of approximately 18,000 km, spanning the tropics, subtropics and temperate zones, with a shallow water area within the 15-m isobath covering around 140,000 square kilometers.[1]
It’s no wonder that the extensive coastal waters holds the potential to produce large quantity of seafood. China, in particular, has a long history of mariculture (the cultivation and farming of seafood), and is currently the largest mariculture producer by weight and value. Therefore, China contributes greatly to food production and the livelihoods of the local and world’s economies.[2] However, the Chinese marine ecosystems are under great pressure (e.g. hypoxia, eutrophication etc.) due to the often competing and high intensity of human uses and impacts, Wang et al., 2016; Xiao et al. 2017.[3] These risks include pollution, species decline, and climate change (including ocean acidification) among others.[4]
Despite remarkable achievements and potential for mariculture in China, its current and future development is facing large challenges arising from the decline in coastal biodiversity. This includes environmental qualities, as well as the need for sustainable marine spatial planning.[5]
The Solving FCB China case study[6] examines the challenges and opportunities of sustainable mariculture in China. This study is being conducted by Dr. Ling Cao, Professor at Xiamen University in China[7], and PhD student researcher Yue Liu at Shanghai Jiao Tong University.
The China case study can be summarized by the below model. This model describes how provision of food is being linked with climate change and biodiversity. It describes the spatial and production potential of SSC (seaweed and shellfish cultivation), their carbon sequestration potential and projected potential, and also validation via field sampling and habitat monitoring.
The China case study strives to achieve these four main targets:
Target 1 – explore species distribution modeling and create environment suitability maps. For example, the creation of species distribution maps.
Target 2 – account for the maximum potential of carbon naturalization by seaweed and bivalve cultivation, although currently the focus is on seaweed.
This part of the study aims to determine the quantity of seaweed that can be buried and cultured. And it also considers carbon reservation maps for seaweed and bivalves cultivation, which is related to the species distribution maps of Target 1.
Target 3 – validate the habitat provision services provided by seaweed and bivalve cultivation (including their infrastructures). At present, the focus is on seaweed cultivation and the biodiversity consequences of its cultivation. An environmental DNA “eDNA” approach will be taken in North Jiangsu Province and Xiapu, Fujian Province, China.
Target 4 – quantify the impact of climate change on seaweed cultivation production and ecosystem service potential.
This target looks at the ability of seaweed to oxygenate acidic ocean waters and thereby increase water clarity and shellfish aquaculture (see Figure 3). This is because algae and seagrasses may benefit from higher CO2 conditions in the ocean, as they require CO2 for photosynthesis[8].
This may promote the growth of seaweed beds which can act as a carbon sink if such production can be buried or stored for thousands of years. Determining how best to store and bury this seaweed over a long period of time, as many as thousands of years, is one future goal that the China case study will be researching.
Conclusion:
Sustainable mariculture has the potential to become an important component of the pathways towards desirable ocean futures in China and elsewhere. The China Case Study aims to understand the potential capacity and limits for development of seaweed mariculture to support food, climate and biodiversity goals through the collection of field data and simulation modeling.
Sources
- https://www.sciencedirect.com/science/article/abs/pii/S0308597X1930675X
- Xiao, X., Agusti, S., Lin, F., Li, K., Pan, Y., Yu, Y., Zheng, Y., Wu, J., & Duarte, C. M. (2017). Nutrient removal from Chinese coastal waters by large-scale seaweed aquaculture. Scientific Reports, 7(1), 46613. https://doi.org/10.1038/srep46613
- FAO. (2022). The State of World Fisheries and Aquaculture 2022: Towards Blue Transformation. FAO. https://www.fao.org/documents/card/en/c/cc0461en
- Wang, H., Dai, M., Liu, J., Kao, S.-J., Zhang, C., Cai, W.-J., Wang, G., Qian, W., Zhao, M., & Sun, Z. (2016). Eutrophication-Driven Hypoxia in the East China Sea off the Changjiang Estuary. Environmental Science & Technology, 50(5), 2255–2263. https://doi.org/10.1021/acs.est.5b06211
- https://solvingfcb.org/case-studies/china/
- https://www.sciencedirect.com/science/article/abs/pii/S0308597X19303987
- https://solvingfcb.org/case-studies/china/
- https://mel2.xmu.edu.cn/faculty/lingcao/
- https://www.noaa.gov/education/resource-collections/ocean-coasts/ocean-acidification
Other Links
Development ideas and implementation approaches of blue granary scientific and technological innovation in China: https://www.cabdirect.org/cabdirect/abstract/20193434187
Habitat provision: https://www.mdpi.com/1424-2818/15/2/125
