Submarine canyons can also develop when powerful ocean currents sweep away sediments. Just as rivers erode land, these currents carve deep canyons in the ocean floor. Strong currents of the Atlantic Ocean prevent Whittard Canyon, about 400 kilometers (248 miles) south of the coast of Ireland, from filling with sediment. Scientists studying Whittard Canyon believe glacial water mixed with seawater to rush into the submarine canyon thousands of years ago.