It is well known that ~70% of the earth’s surface is covered by water. Of this, 90% lies beyond the continental shelf and is greater than 200m with 79% is greater than 1000m. However, scientist now know that the deep sea comprises a variety of habitats such as methane seeps, seamounts, hydrothermal vents, etc. (I will discuss these different habitats in more detail in a later 25 Things You Should Know About the Deep Sea). So this idea can be restated to be more precise. The largest habitat on earth by volume is deep-water pelagic systems or by surface area the soft-bottom benthos (mud, silt, or clay bottoms as opposed to rock).