File:BlueMarble-2001-2002.jpg|Marine biology studies species that live in [[marine habitat]]s. Most of the Earth's surface is covered by [[ocean]], which is the home to [[marine life]]. Oceans average nearly four kilometers in-depth and are fringed with coastlines that run for about [[Coastline paradox|360,000 kilometres]]. | File:BlueMarble-2001-2002.jpg|Marine biology studies species that live in [[marine habitat]]s. Most of the Earth's surface is covered by [[ocean]], which is the home to [[marine life]]. Oceans average nearly four kilometers in-depth and are fringed with coastlines that run for about [[Coastline paradox|360,000 kilometres]]. |