Deep sea reefs are sometimes referred to as "mounds," which more accurately describes the large calcium carbonate skeleton that is left behind as a reef grows and corals below die off, rather than the living habitat and refuge that deep sea corals provide for fish and invertebrates. read more
For me, the most interesting fact about the North Sea is that the average depth is only about 300 feet. In fact, the Dogger Bank, which sits about 60 miles off the English coast, is a large sandbar with an average depth of only 50 - 100 feet. read more