Deep Ocean

 <1% of deep sea has been explored  Most exploration in the past 35 years Deep Ocean depth 700 m

Deep Ocean It’s weird down here:

Deep Ocean Then it gets even weirder when things seep out of the ocean floor...

Hydrothermal Vents

 Extreme conditions near vents:  High temperature  High chemical concentrations  High acidity  Bacteria, archaea live closest to vents (up to 121°C!) Hydrothermal Vents

 Chemosynthesis – energy from chemicals, not the sun  Chemosynthetic bacteria, archaea:  Outside on rocks  Inside some animals (tube worms, mussels, clams) Hydrothermal Vents

Hydrothermal Vents  An oasis of warmth and food

 Hydrogen sulfide  Methane, oil, mud volcanos  Brine Cold Seeps

NOAA Oil droplets on orange methane hydrate Cold Seeps Methane bubbles Methane gas plume from mud volcano NOAA

 Methane seep communities  Chemosynthetic bacteria, archaea  Outside on rocks  Inside some animals (worms, clams) Frozen methane hydrate with polychaete “ice worms” Cold Seeps

 Methane seep communities Cold Seeps

 Brine pools:  Gulf of Mexico was shallow sea that dried up in Jurassic period  Thick layer of salts covered with sediment when seawater returned  Salt seeps up through cracks in sediment NOAA Cold Seeps

 Brine pools:  Underwater lakes of super salty water  Methane gases also seep out NOAA depth 700 m Cold Seeps

NOAA  Chemosynthetic bacteria in mussels  An oasis of food