1. 하구및 연안생태Coastal management
2016 년 가을학기

2. Microbial Ecology nutrient recycling by microorganisms is important
Estuary have high level of organic materials
High primary productions
Production exceeds consumption accumulation
Input of O2 is less  can not convert CO2
Oxic surface less than a few mm
Oxygen demand of 1 ml of sediment is same as O2 in 900 ml of water
Oxygen limitation result in a large anaerobic subsystem
In land: OM oxidized rapidly
Deep sea: little OM

3. 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

4. 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

5. 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/cm3 sediments
Candida spp: 104 cells/g dry weight of macroalgae

6. 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 : 250g C: 1g 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

7. 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

8. 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

9. 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

10. Bacterial metabolism:
photoautotrophy; plant
Photoheterotrophy
Chemoautotrophy
Chemoheterotrophy; animal

11. Anaerobic 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
Electron donor for methanogenesis : H2

12. Microbial secondary production
uptake of radioactive nucleic acid precursors
Density increase measurements in the absence of predators
Measurements of the frequency of dividing cells
0.01~ 10 mg C /m3/h : the rates in estuaries tend to exceed adjacent waters

13. 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)
NO2-
N2O; DNF
N2;DNF
NH3
Nitrogen fixation; nitrogenase: anaerobic environments: micro-environments in the cell
Assimilatory nitrogenous oxide reduction
Ammonification
Ammonium immobilation