 Later on, due to increasing demand for the installment of submarine cables, accurate measurements of the sea floor depth were required and the first investigations of the sea bottom were undertaken.The first deep-sea life forms were discovered in 1864 when Norwegian researchers obtained a sample of a stalked crinoid at a depth of .From 1872 to 1876, a landmark ocean study was carried out by British scientists aboard the HMS "Challenger", a sailing vessel that was redesigned into a laboratory ship.