http://oceanservice.noaa.gov/facts/seamounts.html http://oceanservice.noaa.gov/facts/seamounts.html Image 4. http://oceanservice.noaa.gov/facts/seamounts.html seamounts seamounts www.oceanservice.noaa.gov seamounts underwater sea mountain seamounts seamounts NOAA http://oceanservice.noaa.gov/facts/seamounts.html 28.8 million square kilometres http://oceanservice.noaa.gov/facts/seamounts.html http://oceanservice.noaa.gov/facts/seamounts.html NOAA seamounts seamounts seamounts http://oceanservice.noaa.gov/facts/seamounts.html seamounts seamounts http://oceanservice.noaa.gov/facts/seamounts.html http://oceanservice.noaa.gov/facts/seamounts.html biological hotspots seamounts Seamounts