MBIO 3280 Lecture Notes - Lecture 22: Sodium Chloride, Sodium Bicarbonate, Rhizobium

• School: University of Manitoba
• Department: Microbiology
• Course: MBIO 3280
• Professor: Vladimir Yurkov

Document Summary

Hydrosphere: freshwater limnology, marine oceanography. Many ways to characterize: light penetration, depth, temperature, microbial populations, activities of microbes. Unusual lakes: meromictic lakes, salt lakes, soda lakes. Light with low wavelength (high energy) penetrates the deepest. Euphotic zone at top has light: phototrophs, primary producers (in top region) Profundal zone is area of deeper water beyond the depth of effective light penetration (<1%: secondary producers (recyclers) Thermal stratification in summer: warm water less dense than cold. Lake turnover in the fall: thermocline breaks down -> mixing of water (and microbes, only happens on lakes that are deep. Epilimnion: warm, light, o2, phototrophs release organic compounds, deplete minerals. Thermocline: steep temperature gradient, little mixing across this boundary. Hypolimnion: cold, little light, lower o2 because heterotrophs consume it, has mineral and potential anaerobic growth. Culturable: 10^2 to 10^5 cfu/ml in water (10^6/g sediment: cfu = colony forming units. Heterotrophs found throughout: most at thermocline, neuston and benthos, often found on detritus particles.