- Scientists have produced the first high-resolution map of seagrass ecosystems around the world.
- Data from the map reveal that 70% of global seagrass cover is concentrated off the coasts of just five countries.
- The map also found that nearly 80% of seagrass loss happened outside marine protected areas, emphasizing the importance of targeted conservation action.
- Seagrass ecosystems play an important role in protecting coastlines and carbon sequestration; however, they face threats from hurricanes, coastal development, and marine heat waves.
Almost 70% of the global extent of seagrass meadows is found off the coasts of just five countries. However, only 21% of this fall within marine protected areas.
These are some of the key findings from the first high-resolution map of seagrasses around the world.
Scientists at Arizona State University in the U.S. used satellite imagery and artificial intelligence to map seagrass cover over two periods, 2019-2020 and 2023-2024. According to a study, recently published in the journal Nature, the team identified “148,506 km2 of seagrass globally,” or about 57,340 square miles, a combined area larger than England, with the majority lying in subtidal areas.
“We wanted to map seagrass in a very accurate manner,” Jiwei Li, an assistant professor at ASU’s School of Ocean Futures, who led the study, told Mongabay in a video interview. “And tell people where the seagrass is and where there is potential to protect it.”
Seagrasses are the only flowering plant species in the ocean, and form vast meadows in shallow waters. Apart from being habitats for many marine species, these meadows are also crucial carbon sinks that can absorb CO2 35 times faster than terrestrial forests. They also protect coastlines and filter pollutants in the water. However, seagrass ecosystems face threats from marine heat waves, hurricanes, disease, coastal development, and sediment runoff from agriculture and industry.
Despite their significance, seagrasses haven’t been as widely studied and mapped as coral reef ecosystems. “Seagrass is an underwater rainforest, but it’s not as shiny and colorful as coral reefs,” Li said. “That’s probably one of the reasons there has been no large-scale mapping or monitoring yet.”
While the team had previously attempted to map seagrass along with coral reefs, they quickly realized that mapping them required different techniques. That’s when Li and his team started training a deep-learning AI model to identify seagrass from satellite images. Partners and collaborators from around the world helped corroborate the data on the ground using research dives and underwater cameras. They then used the data to train the model on the satellite images from the same locations. The model was then used to analyze satellite data from across four years to create the map.
From the data, the team found that the Bahamas are a major habitat for the world’s seagrasses, along with the U.S., Australia, Indonesia and Cuba. For the four years they gathered and analyzed data, they found that close to 4% of seagrass meadow cover, amounting to 5,969 square kilometers (2,305 mi2), was lost. An additional 6,220 km2 (2,402 mi2) in tropical regions were found to have been degraded over the four years.
But it’s not all doom and gloom.
The maps also highlighted areas where restoration efforts are paying off. For instance, improved water quality in South Bay, Los Angeles, as well as in Cuba was found to have aided seagrass recovery. “That was unexpected. If the water conditions are good, and there is no disturbance from human activities, it comes back really fast,” Li said. “That gives us hope for seagrass conservation.”
The team say they hope that the data and maps will be used to inform conservation decisions. For instance, the data found that nearly 80% of seagrass loss happened outside marine protected areas. With this data in hand, Li said, conservationists and policymakers could create and establish more protected areas targeted toward protecting seagrass ecosystems.
“Our hope is that these maps enable more data-driven decisions for coastal management and climate mitigation,” he said.
Abhishyant Kidangoor is a staff writer at Mongabay. Find him on 𝕏 @AbhishyantPK.
Disclosure: One of Mongabay’s board members, Robin Martin, is married to Greg Asner, one of the author in the study. Mongabay editorial staff retain full editorial control of this and all published articles.
Banner Image: Seagrass meadows, pictured above, play a critical role in carbon sequestration and protecting coastlines. Image courtesy of Will Greene, Perry Institute of
Marine Science, ASU.
Citation:
Peng, J., Li, J., Krause, J. R., Lyons, M. B., Murray, N. J., Schill, S. R., … Asner, G. P. (2026). Global high-resolution mapping of seagrass to support conservation. Nature. doi:10.1038/s41586-026-10704-3
Cite this article
Abhishyant Kidangoor (2026). Scientists use AI to produce first high-resolution map of global seagrass extent. Mongabay Conservation news. DOI: https://doi.org/10.66709/news-323038Credits
