Sandy Hook Bacteria Dave Grant Bacteria are present everywhere and are an important component of the bay bottom. These decomposers are the great recyclers in the estuary and break down detritus into its basic chemicals to be re-used by plants and animals. Some use oxygen like higher life forms (Aerobic) and others can live in oxygen-poor (Anaerobic) environments. (For more on microbes, click here)   The dog print of Rusty the "fishing dog " was made on a tidal flat. The lighter-colored surface sediments are stirred four times a day by the tidal currents and are oxygenated. Animals that live here (like clams) must have siphons to pump seawater to their bodies and obtain oxygen. The deeper sediments are sealed off from the water column and bacteria quickly use up the available oxygen. Anaerobic bacteria predominate and one of the characteristic smells when a marsh is disturbed is Hydrogen Sulfide (Rotten egg gas).       A cluster of mud snails plows through aerobic sediments (Light color) searching for food. (For more on microbes, click here)   Horseshoe crabs eggs ready to hatch. The reaction of horseshoe crab blood to the endotoxins of gram negative bacteria is an important diagnostic test in medicine.