Scientists have produced the first high-resolution map of seagrass ecosystems around the world, revealing that nearly 70% of global seagrass cover is concentrated off the coasts of just five countries. The study, led by researchers at Arizona State University and published in the journal Nature<\/em>, used satellite imagery and artificial intelligence to map seagrass meadows across two periods: 2019-2020 and 2023-2024.<\/p>\n The team identified a total of 148,506 km\u00b2 (about 57,340 square miles) of seagrass globally\u2014an area larger than England\u2014with the majority lying in subtidal areas. Only 21% of this seagrass falls within marine protected areas (MPAs), highlighting a critical gap in conservation coverage.<\/p>\n Jiwei Li, assistant professor at ASU\u2019s School of Ocean Futures and lead author, explained that seagrasses\u2014the only flowering plants in the ocean\u2014have been understudied compared to coral reefs. \u201cSeagrass is an underwater rainforest, but it\u2019s not as shiny and colorful as coral reefs,\u201d Li said, noting that this lack of attention motivated the large-scale mapping effort.<\/p>\n The team trained a deep-learning AI model to identify seagrass from satellite images. Partners around the world corroborated the data using research dives and underwater cameras. The model then analyzed four years of satellite data to generate the high-resolution map.<\/p>\n The map reveals that the Bahamas, the United States, Australia, Indonesia, and Cuba host the majority of the world\u2019s seagrass. Over the four-year study period, nearly 4% of seagrass cover (5,969 km\u00b2) was lost, and an additional 6,220 km\u00b2 in tropical regions was degraded. Importantly, nearly 80% of seagrass loss occurred outside marine protected areas.<\/p>\n Seagrass meadows face threats from marine heat waves, hurricanes, disease, coastal development, and sediment runoff. However, the map also highlights restoration successes: improved water quality in South Bay, Los Angeles, and in Cuba led to natural seagrass recovery. \u201cIf the water conditions are good, and there is no disturbance from human activities, it comes back really fast,\u201d Li said. \u201cThat gives us hope for seagrass conservation.\u201d<\/p>\nMethodology: AI and Satellite Imagery Power the Map<\/h2>\n
Key Findings: Concentrations and Losses<\/h3>\n
Threats and Restoration Success<\/h3>\n