Using multibeam backscatter strength to analyze the distribution of manganese nodules: A case study of seamounts in the Western Pacific Ocean

Abstract Multibeam backscatter strength can be used to characterize seafloor acoustic characteristics, and classify seabed substrate types. Herein, we use acoustic reflectance data to examine the distribution of manganese nodules in deep-sea substrates in a seamount region of the Western Pacific Ocean. Based on the multibeam backscatter strength, the backscatter mosaic image is firstly corrected by a series of error corrections, and then a size-insensitive integrity-based Fuzzy C-Means (siib-FCM) technique is used to analyze the distribution of manganese nodules. The results show that the method can reveal the distribution of deep-sea manganese nodules and is suitable for the classification of seabed substrates with few sampling points. The distribution of manganese nodules has two characteristics: (1) In basin and plain areas with relatively flat terrain, manganese nodules are associated with sediment, occur in patches and their distribution is relatively sparse. (2) In seamount areas with complex terrain, manganese crusts are distributed mainly at mid-slope elevations displaying a circular distribution around the seamount. The processing technique and results of the present study form a basis for future investigations into the occurrence and distribution of manganese nodule resources in the deep oceans.