Mountains in the Sea:
Although mountains and the oceans appear to have only little in common, there are also some similarities: Like the terrestrial landscape, the ocean floor comprises not only vast plains, but also mountains such as islands and seamounts, and huge mountain ranges, the oceanic ridges. These topographic features are prominent in all oceans; and in fact the highest mountains and the longest mountain ranges on earth are located in the oceans. Like their terrestrial counterparts, underwater mountain ecosystems are subject to a distinct vertical zonation, affected mainly by light availability, temperature gradients, flow field and sometimes oxygen concentration. Seamounts are regarded as biodiversity hotspots, often featuring rich communities of corals and sponges, but also accumulations of pelagic predators, which make them attractive for the fishing industry. Climate change can affect seamount communities particularly through temperature rise, ocean acidification and changes in hydrographical conditions.