Introduction to the Emperor Seamount Chain studies

Abstract

Seamounts are of interest to the scientific community as they occupy a significant part of the ocean floor area and are areas of high biodiversity and productivity. The Hawaiian-Emperor Chain, formed by the Hawaiian mantle plume, is crucial for understanding of the lithospheric plates’ movement in the past. The chain is the longest contiguous chain of islands, guyots and seamounts in the world, whose edges are located in contrasting climatic and biogeographic zones. It may provide stepping stones for dispersal of deep-sea fauna and serve as their refugia, as well as containing commercial resources. The geological features, plankton and fish stocks of this area have been studied since the 1970s, but bottom systems are poorly studied. With the development of deep-sea surveys and the use of ROVs, the bottom communities of the seamounts in the North Pacific and the Emperor Chain have been studied over the last 10 years.

Results

of three research cruises to the area performed in 2019 and 2021 are presented. Numerous new faunistic and biogeographic findings, including the biogeographic boundary between North Pacific and Central Pacific assemblages of species, are made. The feeding modes of the deep-sea corals in the Emperor Chain were surveyed. New data regarding high vertical mixing rates in the area (using Sr isotopes ratio) and possible influence of Aeolian dust input from Asia into the area were obtained. Although seamounts were not previously considered important regions for methane production, substantial methane generation at the Emperor Chain area was discovered. Given the large number of seamounts in the ocean, the global methane budget should be reconsidered.