One Ocean, Many Worlds of Life - Convention on Biological Diversity

Perhaps most unique and remarkable <strong>of</strong> all are the ecosystems that surround
hydrothermal vents and cold-water seeps, the discovery <strong>of</strong> which turned
preconceived notions <strong>of</strong> life on Earth on their head. First seen in 1977,
hydrothermal vents occur in volcanically active areas <strong>of</strong> the seafloor like
mid-ocean ridges, where tectonic plates are pushing and pulling above
magma hotspots in Earth’s crust and where super-heated gases and chemically
rich water erupt from the ground at temperatures <strong>of</strong> up to 400°C.
Microbial organisms are able to withstand these extreme temperatures to
create energy from the chemical compounds being forced up through the
vents—particularly hydrogen sulfide, which is highly toxic to most known
organisms—via a process called chemosynthesis. Some <strong>of</strong> these microbes
live symbiotically inside tubeworms, while others form large mats, which
attract progressively larger organisms that graze on them. So far, over 500
species that live only at hydrothermal vents have been discovered; it is
possible that these communities are the oldest ecosystems on Earth and the
place where life began.
Seven years after scientists discovered hydrothermal vents, they began to
come across cold seeps, areas on the ocean floor where water, minerals, gases
such as methane and compounds such as hydrogen sulfide are expelled from
beneath the crust. Unlike vents, those liquids aren’t superheated, but like
vents, cold seeps support an array <strong>of</strong> unique, and previously unknown, life.
Gavin Newman/Greenpeace NOAA/OEP
Unique and fantastic life forms populate the deep seas
30 Marine BiOdiversity
NOAA/OEP
NOAA/Steve Ross