Coastal management 2014 Microbial Ecology nutrient recycling by

하구및 연안생태 Coastal management 2014 년 가을학기

Microbial Ecology - nutrient recycling by microorganisms is important -Estuary have high level of organic materials -High primary productions -Production exceeds consumption accumulation -Input of O 2 is less can not convert CO 2 -Oxic surface less than a few mm -Oxygen demand of 1 ml of sediment is same as O 2 in 900 ml of water -Oxygen limitation result in a large anaerobic subsystem -In land: OM oxidized rapidly -Deep sea: little OM

Ecology of estuarine microorganisms - viruses, bacteria, fungi, protozoans, algae -Blue-green algae : cyano bacteria : procatyotic; monera -Virus: obscure position -Small metazoans : nematods and harpacticoid: meiofauna -Direct identification is almost impossible -Very diverse -Small size -Easy to contaminate -Morphology changes continuously - often classfied by functional groups rather than individual species

Identification and enumeration - morphology, cultural, staining, physiological, biochemical and genetic characteristics -Isolation pure culture tests -Unique morphology is rare -Often “function” is more important -Enumeration: -viable count : dilution and colony count ; depends on medium -Microscopic: stain and count: acridine orange : epifluorescence microscope -Total : viable=10: 1~10000: 1 -Sediment has more bacteria

Identification and enumeration of fungi -Morphology, physiological characteristics -Difficult to identify and enumeration: -Contamination -Differential growth -Difficult separate in filamentous mycelia -Over 100 species filamentous fungi occur in spartina -Fungi can occur large densities in various estuarine habitats -Much of the microbial biomass in decaying material may be fungi hyphae - 9 x 104 yeasts/cm 3 sediments -Candida spp: 104 cells/g dry weight of macroalgae

Biochemical technique - ATP : gives an index of the microbial biomass -Sediment: 640~6400 ng/g -Decreased with depth -Larger in estuary -Estuarine water: 100~1200 ng/L -Conversion : 250 g C: 1 g ATP -ATP + total adenylate nucleotide pool concentration: living biomass -Muramic acid(ceel wall): biomass index -Lipid posphate: biomass -Poly(beta-hydroxybutyrate): nutritional history -Lipid composition: community structure -Relative importance of bacteria, protozoan algal biomass

Habitate composition - water column - sediments - sea grasses -“everything is everywhere !!”: difficult ot assign species lists to the habitate -Bacterial specialist can only deal with small portions : “ aerobic, heterotrophic “ -It’s difficult to identify species level

Processes - What do they do? Almost everything!!; depends on the methods that may be used. -Much of the processing of energy and matter in many, if not most estuaries is done by microbes. -Half of aerobic respiration + almost all anaerobic transformation

Energy flow and carbon cycling - Estuarine food chain : staring grasses and ending with large carnivores ? Microbes represents major portion -Producers : Nanoplankton is responsible for primary production -Macrophyte; lost by respiration of the microbes, leached as DOM, incorporated into bacterial biomass, transformed to other OM - decomposers : dead plant tissue: Structural lignocellulose: need gastrointestinal enzyme ; if this is transformed into bacterial biomass, it will be available to animal consumers -DOM consumer; amino acid can be consumed only by bacteria -Bacteria as a grazers and pathogens

Bacterial metabolism: - photoautotrophy -Photoheterotrophy -Chemoautotrophy -chemoheterotrophy

Catabolic processes - fermentation -Dissimilatory nitrogenous oxide recuction -Dissimilatory sulfate reduction -Methanogenesis -Complex OM : Nox reducers and fermenters -Simple OM: sulfate reducers and methanogens -Limiting factors : electron acceptors

Microbial secondary production - uptake of radioactive nucleic acid precursors -Density uincrease measurments in the absence of predators -Measurements of the frequency of dividing cells -0. 01~ 10 mg C /3/h

Nitrogen cycling - major limiting nutrient - N transformation by microorganisms -To get the N for their body -To get energy: -Nitrification; Nitrosomonas nitrobacter -Dissimilatory nitrogenous oxide reduction (4 final products) -NO 2 -N 2 O; DNF -N 2; DNF -NH 3 -Nitrogen fixation; nitrogenase: anaerobic environments: micro -environments in the cell -Assimilatory nitrogenous oxide reduction -Ammonification -Ammonium immobilation