Applicability of Satellite Data in the Selection of Protected Areas Within REMP

The International Seabed Authority (ISA) is considering establishing Areas of Particular Environmental Interest (APEI) as part of the Regional Environmental Management Plan (REMP) for deep-sea mining. Ideally, the number, location, and area of APEIs should be determined based on information that considers the biodiversity network, ecosystem functions of the entire region, and other factors. However, at present, there is a significant lack of data for examination based on these features. In particular, there are issues such as accuracy discrepancies, spatial heterogeneity, and lack of time-series data. Based on these facts, the authors examined the linkage between surface and bottom ecosystems through the water column and evaluated the utility of satellite data. In the present study, the Clarion-Clipperton Zone (CCZ)-REMP and its APEIs were assumed to be the completed model, and the degree of effectiveness and limitations related to satellite data for APEI establishment were considered. As a result, it was confirmed that the satellite data captured spatiotemporal variation of the surface ecosystem, that the primary production calculated from the satellite data correlated with the amount of sedimentation of particles in the deeper ecosystem, and that the amount of sedimented particles correlated with benthic biomass. For this reason, we concluded that satellite data, which has uniform accuracy, covers the entire region, and can be expected to provide year-round data, are an effective tool for examining APEI. On the other hand, it was also found that water depth and the amount of manganese nodules, which are unrelated to the surface ecosystem, also affect benthic biomass, and because APEI study also requires biodiversity and linkages between ecosystems, satellite data alone are not sufficient. Given these strengths and weaknesses, we believe that satellite data could be utilized for primary screening for APEI determination.