Environmental Microbiology - BIOL2010 Week 8 - F24

www.udst.edu.qa AHHG2010 Environmental Microbiology The Ecosystem A community of living things in a non-living environment that occurs in a specific location where a series of biogeochemical cycles and energy transformations take place. Ecosystems have boundaries that overlap w...

www.udst.edu.qa AHHG2010 Environmental Microbiology The Ecosystem A community of living things in a non-living environment that occurs in a specific location where a series of biogeochemical cycles and energy transformations take place. Ecosystems have boundaries that overlap with other ecosystems. Ecosystems are divided into living (biotic) and non-living (abiotic) components. Abiotic – sunlight, temperature, precipitation, soil, air, and chemicals. Biotic – living producers and consumers  The Ecosystem Grazing Niche – the role that an organism plays in the ecosystem We are interested in the niches that microorganisms occupy We are also interested in how those organisms interact with the abiotic components Their value to us as organisms How they contribute to our existence Microbes can be either of producers, consumers or detritivores The Ecosystem Biogeochemical cycling – the movement of elements and compounds through living (biotic) organisms and the non-living (abiotic) environment. There are several biogeochemical cycles of interest Carbon Cycle Nitrogen Cycle Oxygen Cycle Phosphorus Cycle Sulfur Cycle Water Cycle Microorganisms play a critical role in ALL of these cycles As example, phytoplankton in the ocean produce the bulk of Earth’s oxygen!! Bacteria in Soil Soil is FULL of life! It is the primary interaction between living (biotic) and non-living (abiotic) that makes soil a living system Microbes and other biotic entities extract abiotic factors from the soil Water Filtration: Soil also acts as a filter to clean ground water Soil particles act like a filter to remove contaminants Bacteria in Soil Five major groups of organisms in soil: Bacteria – most numerous (~95%) Nitrogen fixing, sulfur fixing, carbon fixing Aerobic bacteria (74%) Anaerobic bacteria (14%) Actinomycetes – denitrifiers – (13%) Protozoans – feed on bacteria Fungi – decomposers (3%) Feed on dead material Other (0.2%) Algae - Found on the soil surface Worms – nematodes, earthworms Microbes in Air Don’t generally grow in air Contained on dust and water droplets Air in buildings contains microorganisms Higher dust and moisture contents Lots of people sweating and breathing Poor circulation Mold is the most common microorganism found in air Wastewater Treatment Large scale treatment can be accomplished through Cl injection Small scale treatment can be through the addition of bleach Coliform bacteria - Rod-shaped, Gram-negative, Non-spore forming, Motile or non- motile bacteria which can ferment lactose with the production of acid and gas when incubated at 35–37°C. Sewage treatment plants require more complex methods Contains 99% contaminated water 1% solids Household wastes (faeces, detergents, grease, hair) Industrial wastes (acids, oil, chemicals, organic matter) Two levels of treatment of sewage: primary and secondary Wastewater Treatment Wastewater Treatment Primary Treatment of Raw Sewage Screens and course filters Remove solids and large debris Place in sedimentation tanks Secondary Treatment of Raw Sewage (Effluent from 1 Treatment) Trickle filters – spray over rocks/sand covered in bacteria Activated Sludge – agitate and aerate sludge Aerobic breakdown of organic matter Check BOD and release to rivers/streams/Oceans Wastewater Treatment Tertiary Treatment (If Required) Effluent from 2 treatment processed for removal of PO4 & NO3 Involve: Physical and chemical treatment Sand and charcoal filtration Denitrifying bacteria to remove nitrogenous compounds Chlorination to kill bacteria UV light to kill Cl resistant organisms Bioremediation is an alternative to Sewage Plant Bacteria introduced to raw contaminants Organisms treat effluent and contents Symbiosis Symbiosis - When two organisms develop a relationship it is symbiotic. The larger organism is the host, the smaller, the symbiont Symbiosis Commensal – beneficial to the MO but does not harm the host Bacteria on the skin Bacteria in the respiratory and gastrointestinal tract Mutualistic – bacteria and host benefit from the relationship Assist the immune system Assist in nutrient metabolism, vitamin production, and waste processing. Parasitic - the bacteria benefit while the host is harmed Blood flukes (shistosomiasis) a.k.a. bilharizia Tape worms Competition – One species outcompetes another