Abstract:
The cold-water corals (CWCs, including Hexacorallia and Octocorallia) are widely accepted as indicators of the presence of Vulnerable Marine Ecosystems (VMEs). As species widely distributed on the seabed, CWCs play an important ecological role in deep-sea ecosystems by maintaining the stability of deep-sea ecosystems and preserving biodiversity. This study compiled and analyzed the spatial distribution data of CWCs species in the North Pacific (NP), aiming to construct the distribution pattern of cold-water coral diversity in the NP and analyze the relationship between the formation of this pattern and habitat types and environmental factors. Research indicated that, at the horizontal scale, the hotspots of the CWCs species diversity in the NP were found in the waters around the Hawaiian Islands, while the vertical scale, they were located within the at depths less than 500 meters. The overall distribution latitude of the octocorallians (Octocorallia) was higher than that of the hexacorallians (Hexacorallia). Hexacorallians were concentrated south of 35°N, while the octocorallians were mainly concentrated north of 30°N. Habitat type analysis at the order level revealed that the high-relief shelf and slope were the most suitable habitat for various orders. The strongest correlations with the species richness of the Hexacorallia was pH (0.47) and silicate concentration (−0.39), while species richness formation of the Octocorallia was more strongly correlated with slope (0.44) and aragonite saturation (−0.44). The nitrate (positive impact) and phosphate (negative impact) had the greatest influence on their richness changes. This study is the first to analyze the diversity distribution patterns of cold-water corals in the NP, and found differences in diversity, habitat, and environmental suitability preferences of two classes cold-water corals. These results are important for understanding the diversity suitability patterns of related species, ecosystem restoration, and delineating more efficient marine protected areas.