1. CHEMOSYNTHESIS Who’d a thunk it?

2. Chemosynthetic bacteria  The basis for all life at hydrothermal vents.  Archaea – very primitive, different from other bacteria. Given their own KINGDOM.  Extremophiles.

3. Three types of bacteria at the vents:  Symbiotic bacteria – live inside worms, clams, mussels.  Plume bacteria – live in the cloudy water around the vents.  Mat-forming bacteria – cover the surfaces everywhere with a slimy layer of them.

4. Symbiotic bacteria live inside tubeworms, clams, and mussels, in a relationship that is mutually beneficial to each. “You scratch my back and I’ll scratch yours.”

5. Chemosynthesis  Energy source is H 2 S (hydrogen sulfide), an energy-rich compound that releases energy when it oxidizes.  No sunlight required!  Uses hydrogen from H 2 S, carbon dioxide and oxygen to make simple sugar.

6. Photosynthesis vs. Chemosynthesis Photosynthesis  Light energy (sun)  Chlorophyll needed  CO 2 + H 2 O -> C 6 H 12 O 6 + O 2  (Oxygen is a product / Water is a reactant.)  Any cells with chlorophyll (plants, phytoplankton, algae, and some bacteria) can photosynthesize.  Basis of most energy webs on Earth. Chemosynthesis  Chemical energy (H 2 S)  Chlorophyll not required  CO 2 + H 2 S + O 2 -> CH 2 0 + S + H 2 O  (Water is a product / Oxygen is a reactant.)  Only a few types of bacteria able to chemosynthesize.  Basis of energy webs at hydrothermal vents.

7. What do photosynthesis and chemosynthesis have in common?  Both produce simple carbohydrates (food).  Both require CO 2 as the carbon source.  Both supply the energy to sustain many other forms of life through food webs.

8. Hard to imagine, but the sun could die out tomorrow, and chemosynthetic bacteria and all the other animals in their ecosystems wouldn’t even know the difference.

9. Interestingly, chemosynthetic bacteria using hydrogen sulfide as “fuel” have been found other places besides hydrothermal vents.  Hot springs on land.  Cold seeps.  Whale carcasses deep on the ocean floor.  Sunken ships.  Even in caves. Click for video 5:24 Click for video 5:24  And other types of chemosynthetic bacteria (using compounds besides hydrogen sulfide) are also found in wetlands, intestines of some animals, and in the soil.