You will investigate chemosynthesis and the symbiotic relationship between certain species of bacteria and tubeworms that exist near hydrothermal vents.
After completing this tutorial, you will be able to complete the following:
Chemosynthesis is a process of converting chemicals into the carbohydrates and energy that all organisms need to function. Chemosynthesis and photosynthesis are similar in that they both convert chemicals into energy, however, photosynthesis cannot take place without sunlight, while chemosynthesis does not rely on sunlight. It only requires heat and certain chemicals.
In 1974, hydrothermal vents known as black smokers were discovered in deep ocean waters where there is no available sunlight. Scientists were surprised to find that there were many different types of organisms dwelling near these vents in complex ecosystems. These organisms survive in harsh conditions with temperatures close to the boiling point due to the hydrothermal vents and extremely high pressure, due to the depth of the ocean environment. Many, including certain bacteria and tubeworms, have developed symbiotic relationships based on the mutually beneficial process of chemosynthesis.
Close to these hydrothermal vents, certain bacteria use water, dissolved carbon dioxide, and hydrogen sulfide to create sugar and sulfur compounds. This is represented in the equation: H2S + O2 + H2O + CO2 Ť H2SO4 + glucose.
The carbon dioxide comes from carbon dioxide dissolved in the ocean water, along with the water. The hydrogen sulfides are emitted from the hydrothermal vents and are absorbed by the bacteria. The chemoautotrophic bacteria oxidize the chemicals to produce sugar and sulfur compounds. They use the sugar for energy, and release the sulfur compounds into the ocean water.
The tubeworms need food, and the bacteria need certain chemicals in order to carry out chemosynthesis. Tubeworms provide all the necessary chemicals, including hydrogen sulfide, oxygen, and carbon dioxide. The bacteria use these chemicals to manufacture the glucose that nourish the tubeworms. This all takes place within an organ inside the tubeworm called a trophosome, which is packed with blood vessels and chemosynthetic bacteria. Scientists think the blood-red hemoglobin that fills the tubeworm's cardiovascular system, and which gives its plumes their spectacular color, is important in the transport of sulfur and oxygen.
|Approximate Time||30 Minutes|
|Pre-requisite Concepts||Students should be familiar with photosynthesis.|
|Type of Tutorial||Concept Development|
|Key Vocabulary||amino acids, bacteria, Benedict solution|