Introduction

The Polish interest in the study area is reflected by the contract for polymetallic sulphide exploration between the International Seabed Authority (ISA) and the Ministry of Environment of the Republic of Poland, signed in 2018. The Polish exploration contract area is located in the central part of the Atlantic Ocean (Fig. 1) between 26°09′N–32°50′N and 39°38′W–44°43′W near the central part of the Mid-Atlantic Ridge (MAR), one of the major geological formations on Earth (Fig. 2), featuring—like other mid-oceanic ridges—active and inactive hydrothermal vent fields with their unusual and unique ecosystems. The water depth varies from about 740 m above the MAR to more than 4900 m in fracture zones and basins. The Polish exploration blocks are located to the south-west of the Portuguese submission to the Commission on the Limits of the Continental Shelf and to the north-east of the French exploration contract area. The contract area covers 10,000 km2 and consists of 100 exploration blocks, 10 × 10 km each. The blocks are grouped in 5 clusters.