Microbial Ecology • • • • • Microbes in their Environment Microbe-Microbe Interactions Biogeochemistry (Cycling of Elements) Microbe-Higher Organism Interactions Environmental Pollution Control Positive Population Interactions Protocooperation Protocooperative Consortium Negative Population Interactions Predators Ant-Fungi Mutualism Actinomycete amensalism of parasitic fungi Fungal-Fungal Parasitism Carbon Biogeochemistry Aerobic Carbon Use Anaerobic Carbon Use (No Oxygen) Carbon Biogeochemistry SOIL • Oxygen supply limited by mineral particle size, organic matter content and water content. • Plant roots may also add oxygen to deeper soils or anaerobic soils. • Water saturation leads to anaerobic conditions and increased denitrification. • Distribution of microbes depends on organic matter supply and source (humus and root exudates) Soil Close-Up Geosmin = “earthy smell” = Cyanobacteria = Actinomycetes Mycorrhizae Fungi Ectomycorrhizal association between Douglas Fir (Pseuditsuga menziesii) and a boletus-like mushroom (Suillus caerulescens). Legume Root Nodule formed by Rhizobium spp. Bovine Rumen It’s a 100+ liter cellulose-degrading methane-producing microbial incubation. There are only a few manned submersibles in the world that can explore hydrothermal vent communities (e.g. Alvin) Control Point Sources Wastewater Treatment • Raw Sewage (99.9% water to 0.1% waste) • Pollutants in sewage are: – – – – – – – Debris and grit Particulate organic material Colloidal and dissolved organic material Dissolved inorganic material Human Pathogens Toxic Chemicals Pharmaceuticals Wastewater Treatment • Preliminary (physical screening) • Primary (physically settle solids) • Secondary (biological) – Remove organics aerobicaly (lower BOD) – Solids production (separate water and “sludge”) – Sludge Treatment (solids reduced) • Tertiary (biological or chemical “polishing”) – Biological nutrient removal systems – Pathogen removal by chlorine or ozone – Chemical nutrient removal (costly) Wastewater Treatment Secondary Treatment: Activated Sludge (aerobic) Trickle Filters (aerobic) Anaerobic Sludge Digesters Trickle Filter Biofilms What da Floc? • Bacterial growth in activated sludge digested (aerobic) will aggregate (floc). • Dissolved organics aggregate with bacterial growth and removed from the water. • Imbalances may cause growth of filamentous bacteria or fungi; prevents settling; called “bulking”. Anaerobic Sludge Digester (Methane Production) What’s a coliform? Why test them? How can we test for them?