Laboratory Exercise 2 Winogradsky Column PDF

Soil 113 – Soil Microbiology Laboratory Exercise No. 2 Winogradsky Column: Understanding the Microbial Community Structure Objectives a) To create a microcosm (a model microbial ecosystem) in which complex microbial communities are cultivated b) To gain an appreciation on the div...

Soil 113 – Soil Microbiology Laboratory Exercise No. 2 Winogradsky Column: Understanding the Microbial Community Structure Objectives a) To create a microcosm (a model microbial ecosystem) in which complex microbial communities are cultivated b) To gain an appreciation on the diversity of methods microorganisms use to gain energy and how these metabolic processes affect the surrounding environment c) To determine the microbial community composition and succession Soil 113 – Soil Microbiology Soil: A Microhabitat One of the most abundant, complex and valuable natural products of the Earth Habitat for bacteria, fungi, plants and animals Display a large diversity of soil types Soil 113 – Soil Microbiology Soil: A Microhabitat Covers 30% of the Earth’s surface healthy and fertile soil can be regarded as a ‘threatened species’ (Kaiser 2004,Drohan & Farnham 2006, Lehman et al. 2015). Soil 113 – Soil Microbiology  Soil: A Microhabitat Degrade more rapidly than it is replenished (Quinton et al. 2010, Stockmann et al. 2014) Soil 113 – Soil Microbiology Soil: A Microhabitat on a microscale (< 1 mm3) is highly heterogeneous numerous microhabitats per gram of soil strong driver of community assembly and function of soil micro-organisms such as prokaryotes (‘Bacteria’ and ‘Archaea’) and fungi. Soil 113 – Soil Microbiology Prokaryotes (Bacteria and Archaea) Unseen majority (Whitman et al., 1998) The most dominant and diverse form of life in the soil gram of soil may harbour from 108 (bulk soil) up to 1011 (rhizosphere) prokaryotic cells (Torsvik et al. 1990) Soil 113 – Soil Microbiology Prokaryotes (Bacteria and Archaea) Unicellular Lack nucleus Binary Fission independent entities that carry out their life processes typically independently of other cells (Madigan et al. 2010) Soil 113 – Soil Microbiology Prokaryotes (Bacteria and Archaea) Species diversity - 4x103 Species – 8x106 Central to the important ecological functions in soil Soil 113 – Soil Microbiology Prokaryotes (Bacteria and Archaea) collectively encompass a taxonomic and a metabolic diversity that far exceeds that of plants and animals. so called ‘Higher Animals’ Soil 113 – Soil Microbiology  Sergei Winogradsky Martinus Beijerinck (1856-1953) (1851-1931) Russian Microbiologist Russian Microbiologist Soil 113 – Soil Microbiology  One of the founding founders of microbial ecology focused on environmental microbiology and developed techniques for cultivating and studying complex microbial communities (such as the Sergei Winogradsky Winogradsky column) (1856-1953) Russian Microbiologist Soil 113 – Soil Microbiology  Environmental microbiology Microbial diversity Microbial physiology Microbial autotrophy Environment nutrient cycling (sulfur and nitrogen cycling) Sergei Winogradsky (1856-1953) Russian Microbiologist Soil 113 – Soil Microbiology Winogradsky Column A miniature, self contained ecosystem models ecological conditions found in a typical Michigan lake in late summer Spring thaw results in a mixing of lake water so that the water is more or less uniform at different depths. Soil 113 – Soil Microbiology  Winogradsky Column As summer progresses gradients begin to form in the water column Light gradient Temperature Nutrient O2 H2 S Soil 113 – Soil Microbiology Winogradsky Column These gradients result in a complex interaction of microbes with their environment and with one another. Soil 113 – Soil Microbiology Winogradsky Column Results in a series of community successions Ultimately, stratification of microbial populations in a water column. Soil 113 – Soil Microbiology Prepared by: Mr. Kenneth Oraiz, MSc Winogradsky Column Begins as a uniform slurry soil, mud or lake sediment and water Supplemented with nutrients (carbon and sulfur) The ingredients are mixed into a uniform slurry, poured into a tall, transparent vesicle (soda bottle) Soil 113 – Soil Microbiology Winogradsky Column Series of gradients (e.g. oxygen, H2S) soon develop in the column as a result of bacterial metabolic processes. Soil 113 – Soil Microbiology Winogradsky Column Aerobic photosynthetic organisms and exposure to the air will produce O2 near the top of the column which can then be used by other microbes for aerobic respiration. Soil 113 – Soil Microbiology Winogradsky Column Similarly, sulfate reducers in the anoxic region near the bottom of the column will produce H2S, which can be used by H2S utilizers and anoxic phototrophs. Soil 113 – Soil Microbiology Winogradsky Column Different organisms soon gain a competitive advantage in different regions of the column causing a stratification and continual regional succession of organisms. Soil 113 – Soil Microbiology Winogradsky Column Clostridium – (gray) cellulose degrading bacteria which grows when oxygen is depleted Desulfovibrio - uses fermentation products in anaerobic respiration uses sulfate as the electron accepter makes hydrogen sulfide (H2S) Makes the mud black H2S helps the anaerobic photosynthetic bacteria to grow Soil 113 – Soil Microbiology Winogradsky Column Chlorobium – green sulfur bacteria Chromatium – purple sulfur bacteria Most of the column red/rust due purple nonsulfur bacteria, Rhodospirillum Soil 113 – Soil Microbiology T1 – Mud soil T2 – Mud soil + T3 – Mud soil + T4 – Mud soil + T5 – Mud soil + shredded paper CaCO3/chalk CaSO4/egg iron nails (Fe) (P) powder (C) yolk(S) T6 – Mud soil + T7 – Mud soil + T8 – Mud soil + T9 – Mud soil + T10 – Mud soil + rice hull char C + S + Fe C + S + Fe + P mannitol + C + RHC + C + S + (RHC) S + Fe + P Fe + P