The unknown and the unexplored: Using recent ROV data to derive insights into the Pacific Deep-Sea

Over the past 5 years, there have been several deep-sea exploration efforts across the Pacific Ocean. NOAA and partners organized and implemented a Pacific-wide field campaign entitled CAPSTONE: Campaign to Address Pacific monument Science, Technology, and Ocean NEeds, which was the flagstone effort whereby NOAA mapped 597,230 km2 of the Pacific seafloor including 323 seamounts, conducted 187 ROV dives and documented >347,000 individual organisms. These efforts were augmented by explorations using the R/V Falkor (Schmidt Ocean Institute) and the E/V Nautilus (Ocean Exploration Trust). Together, these comprehensive efforts yielded dramatic insight into differences in biodiversity across depths, regions, and features, at multiple taxonomic scales. We primarily used CAPSTONE data to examine benthic fauna large enough to be visualized with the ROV and found that fewer than 20% of the species were able to be identified. The most abundant and highest diversity taxa across the dataset were from three phyla (Cnidaria, Porifera, and Echinodermata). We further examined these phyla for taxonomic assemblage patterns by depth, geographic region, and geologic feature. Within each taxa, there were multiple genera with specific distribution and abundance by depth, region, and feature. We found surprising patterns of habitat specificity for some deep-sea taxa (for example, differentiation between preferences for seamount slopes resulting from atolls versus islands). These patterns are unexpected in the deep-sea, given the presumed similarity between deep-sea slope features. To explore these patterns, we analyzed habitat preference across depth, region, and feature for taxa previously unknown to have such high specificity. The incredible amount of new known and unknown information about the Pacific deep-sea in the last 5 years makes it possible, for the first time, to take a big data approach to examining the distribution and abundance of deep-sea taxa on seamounts.