Seagrass beds are important blue carbon deposits and play a key role in natural carbon sinks. However, Taiwan's seagrass ecosystem has faced a severe decline in recent years due to threats from climate change and human development. Professor Liu Biren of the Institute of Marine Biology at National Tung Hwa University noted that the world has already lost 29% of its seagrass, and estimates indicate that another 30-40% of this blue carbon ecosystem will be lost over the next 100 years.
At the end of last month, at an online lecture co-organized by the Taiwan Environmental Planning Association and Chengyang Environmental Consultants, "Taiwan Seagrass Carbon Sink and Restoration Path," Liu Biren discussed in depth the role of Taiwan's seagrass beds in the blue carbon issue and the current status of restoration.
Can't tell the difference between seaweed and seaweed? The biggest difference lies in the vascular bundle
Many people often confuse seagrass with algae, but unlike algae, which lack a vascular system, seagrass possesses true roots, stems, and leaves, absorbing water and nutrients and performing photosynthesis through its vascular bundles. Seagrass is a flowering plant that lives in shallow ocean waters. It submerges, attaching its roots to the sandy bottom, and grows in shallow coastal waters with ample sunlight and clear water. Liu Biren emphasized that seagrass can flower, bear fruit, and produce seeds, making it significantly different from algae in both appearance and classification. Taiwan boasts a high degree of biodiversity, and the seagrass beds on the main islands and outlying islands are no exception. Seagrass primarily grows in waters less than 10 meters deep in diverse habitats, ranging from sandy beaches and coral reef platforms to intertidal zones. Its distribution ranges from Hsinchu and Taichung to Chiayi, Tainan, Pingtung, Taitung, and outlying islands. There are currently 12 species of seagrass in Taiwan, including Glycyrrhiza uralensis (Glycyrrhizae family), Baker's saltweed (IUCN Red List), and Dipterocarpus monovenus (Hydrocarpus monovenus) (Hydrocarpus family). Although seagrass beds are found in many locations throughout Taiwan, the estimated area of seagrass beds on the main island is only approximately 50 hectares. The highest density and largest area of seagrass beds in Taiwan is in Dongsha Atoll, 1,600 kilometers away from Taiwan. Dongsha Island and the surrounding atoll cover 5,420 hectares of seagrass beds, with nine species, making it a global seagrass hotspot and a significant carbon sink.
Taiwan's Seagrass Restoration: Designating Protected Areas and Establishing Artificial Seagrass Nurseries
In recent years, extreme climate events, coastal development, high-decibel noise, and human pollution have put seagrass beds under severe threat of decline. Liu Biren's research indicates that approximately 340,000 to 980,000 hectares of blue carbon ecosystems are destroyed annually. Globally, 29% of seagrass has been lost, and a further 30-40% is projected to be lost over the next 100 years. Restoration efforts are crucial. Current strategies for protecting and restoring seagrass beds in Taiwan include actively designating protected areas, promoting long-term monitoring and quantitative scientific research on seagrass beds, and increasing public awareness through science outreach. Asexual reproduction and restoration of seagrasses is a key focus of Liu Biren's research. In addition to advocating for the establishment of protected areas and passive restoration of seagrass beds, his research team is also focusing on active restoration methods, both sexual and asexual. They are converting abandoned or unused salt pans, fish ponds, and fishing ports into restoration pilot sites, hoping to establish underwater seagrass nurseries, similar to those used for planting seedlings. The team has currently selected Houwan, near the Pingtung National Museum of Marine Biology and Aquarium, as the restoration site. Liu Biren admitted that China's understanding of seagrass phenological ecology is still quite limited. Although it can reproduce asexually, how to make the planted seagrass bloom, bear fruit and produce seeds is a huge challenge.
Ecosystem Services and Carbon Storage: The Vital Mission of Blue Carbon Seagrass Beds
Improving carbon sinks is a key measure for Taiwan to achieve its net-zero carbon goal. While there are green carbon sources on land, such as forests and farmland, landmass is limited, making it difficult to increase further terrestrial carbon sinks. Therefore, "blue carbon," stored in marine and coastal ecosystems, is a highly sought-after target for sink enhancement. Seagrass beds not only provide an excellent habitat for marine life, but also protect and stabilize the coastline and purify water quality, providing diverse ecosystem services. Liu Bi-ren explained that the roots and rhizomes of seagrass beds, buried in the sand, expand horizontally and vertically, forming a rhizome network within the substrate. This dense underground part, along with sediments preserved in anoxic conditions for long periods, is the primary source of blue carbon. In addition to increasing carbon sinks, Liu Bi-ren emphasized the need to balance carbon reduction with economic development. He reminded, "The global carbon cycle is like a rubber band: gently flexed, it oscillates and then returns to normal. But currently, the rubber band is stretched tightly. If the tension becomes too great, the band will break, and ecological balance will be lost."
Sources:
Environmental Information Center
