An example of a photoheterotroph This photoheterotroph is called “purple, non-sulfur bacteria”.

Another example of a photoheterotroph This one is called “green, non-sulfur bacteria”.

Importance of Bacteria ON LAND & IN THE WATER

Ewww!.....Or is it?? We eat bacteria with every mouthful of food we eat. We are covered in bacteria. Bacteria line our mouths, our guts, cover our hair, our clothes. The bacterium, Escherichia coli, is a species that has allowed for tremendous advances in all fields of biological sciences as a model system and is partly responsible for allowing us to digest and absorb food as the primary commensal component of our intestinal flora. Yet, most people probably associate E. coli with the rarer pathogenic strains that cause disease and have been in countless newspapers headlines. Clearly, we live surrounded by and enveloped with bacteria all the time, and they do not cause us disease. In the majority of cases, diseases occur when conditions in the environment or with the host allow for disease to occur. The same will be seen for the marine environment.

You Don’t Say!! To date, no environment on the Earth has been found to be free of bacteria. They are tiny, and only a very few species are visible to the unaided eye. Because of their diversity, relatively few bacteria are well known. Most of those that are well known either have some relation to human health (acting as pathogens, or agents of disease) Probably the most common, and often one-sided, way people are exposed to bacteria is from the public press or lay media. Stories of “killer” bacteria, flesh-eating bacteria, infection-causing bacteria, and others prompt the production of antibiotic drugs, antibiotic soaps, lotions, and all manner of weaponry to “eliminate” bacteria. Do these soaps, lotions eliminate bacteria? We’ll find out later.

Importance of Bacteria: 1. Nitrogen Fixation Nitrogen is essential to make proteins and nucleic acids Nitrogen in Earth’s atmosphere must be converted or ‘fixed’ to a useful form Nitrogen fixing bacteria live freely in soil or in the roots of legumes These bacteria remove free nitrogen from air and convert it to nitrates which can be used by plants to form amino acids and proteins

Nitrogen Fixation

Importance of Bacteria: 2. Waste Management Some bacteria can eliminate or neutralize some toxic compounds in environment that come from oil, battery acid, PCBs, detergents, pesticides, plastics

Importance of Bacteria: 3. Sewage Treatment 5 billion kg of solid organic waste DAILY!! Some bacteria decompose the waste and recycle dead matter Technology developed to improve efficiency of bacteria digesting wastes: aerobic waste treatment facilities break down sewage more rapidly because they rely on aerobic bacteria

Importance of Bacteria: 4. Dairy Foods Lactic acid bacteria provides resistance to intestinal pathogens, stimulate the immune system and help maintain a healthy balance of microorganisms in the digestive system Now we genetically engineer lactic acid bacteria!!

What’s With Yogurt??? The Probiotic Effects of Lactic Acid Bacteria http://www.bcdairyfoundation.ca/about_milk/docs/probiotics.pdf

Importance of Bacteria: 5. Bacteria & Disease Only small percentage are pathogenic (disease causing) Pathogenic bacteria produce deadly substances called toxins in the human body that cause disease symptoms Example: toxins released by bacterium Streptococcus pneumoniae may result in the symptoms of pneumonia – cough, high fever, headache, delirium, chills, shortness of breath, etc.

Importance of Bacteria: 5. Bacteria & Disease 2 types of toxins: Endotoxins & Exotoxins Endotoxins are released when certain Gram- negative bacteria are split; are generally not fatal and cause fever, vomitting and diarrhea Endotoxin species: Salmonella and Echerichia

Importance of Bacteria: 5. Bacteria & Disease Exotoxins are released by living multiplying bacteria that travel through the host’s body Exotoxins are highly toxic and often fatal and do not produce a fever Exotoxin species: Clostridium botulinum

In Coral Reefs.... Marine bacteria are virtually unknown Just as numerous in the water as on land Bacteria are water purifiers, decomposers of organic material, and a primary source of protein for both those animals that directly graze on them and those that acquire them indirectly through secondary consumption (e.g – bacteria that live on plankton).

Bacteria & Coral Reefs Bacteria are a primary food source for corals All corals studied to date consume dissolved organic material, bacteria, and detrital material. Bacteria not only provide carbon and nitrogen for the polyp, but also provide an important source of phosphorous for the zooxanthellae, in addition to other elements such as vitamins and iron

Bacteria & Coral Reefs Bacteria exist in very high diversity and biomass in the marine environment, and especially on coral reefs and on coral surfaces. They play critical roles in virtually all ecological processes that control reefs and are a major component of food webs. Corals feed on bacteria at levels and efficiencies that rival all other bacterial consumers

Not all Bacteria are Good... White pox is characterized by coral tissue degradation that occurs in association with circular lesions on the Caribbean coral Acropora palmata It is caused by the bacterium Serratia marcescens, a well- known species that is widespread in both terrestrial and aquatic environments as well as in mammalian and arthropod hosts

Not all Bacteria are Good.... Bacterial bleaching is caused by a specific bacterial/coral interaction. Specificity includes recognition by the pathogen of host (coral) surface receptors; invasion of coral tissue; multiplication of bacteria in coral tissue; and release of bacterial toxins that cause bleaching

References Article: Coral Death Results From Bacteria Fed by Algae http://www.sciencedaily.com/releases/2006/06/060612221839.htm http://reefkeeping.com/issues/2003-01/eb/index.php