Microorganism in terrestrial ecosystem

Physicochemical condition which affect the microbial populations

A)Surface

Smooth

enough nutrient & moisture

Clay particle

B)Water

Thin water film = Oxygen higher

Dependant on rainfall, particle size, drainage.

Affects movement of microorganism between pores and particles.

C)Temperature

Determine the composition of soil microflora (sandy beach)

D)Acidity & Alkalinity

Usually pH 4 - 8.5

Influenced by microbial activity

E)Soil

Well drained soil well

Category of soil

Mineral soil = less than 20 % organic carbon ( most of Earth's soils.)

Organic soil possesses at least 20% of organic carbon

Microorganism

Soil Metagenomics

Community genome size

Microbial loop

Differs fron that opearting in photic zone of the open ocean

4 functional group of soil

3 genera function of soil fungi

Decomposer

Mutualistic

Pathogens

Litotrophs or Chemoautotroph

Microbe plant interaction

Epiphytes

Microbes that live on the surface of plants

Endophytes

Microbes that colonize internal plant tissues

Rhizosphere and Rhizoplane Microorganism

Rhizosphere

Volume os soil around the root influenced by materials releases from root

Rhizoplane

surface

Roles of microbes in Rhizopshere and Rhizoplane

Labile source of nutrient, creating microbial loop

Synthesis and degradation of organic matter

Promotion of plant growth

Other plant pathogen

Viruses

The subsurface Biosphere

Deep Hot Biosphere

Deep Subsurface

Soil as microbial habitat

Is very complex and contain a large variety of habitat

Level of microbial diversity in soil habitat on earth

Soil organic matter

Retain nutrient

Maintain soil structure

Hold water for plant use

Production of SOM

Release of carbon dioxide and biomass production

Small fraction become SOM

Nitrogen in the soil Ecosystem

Fertilizer often added to agricultural soils to increase nitrogen level

C/N of 20 or less results in loss of soluble nitrogen from the system.

Nitrogen

Level in soil impacted by nitrogen release

Nitrogen saturation

Phosphorus

Also present in fertilizers

Is the limiting element in most freshwater system

Phyllosphere microorganism

Phyllosphere

Aerial surfaces of plant

SSU rRNA analysisi shows millions of new bacteria yet discovered

Mycorrhizae

Mutualistic fungi associatons

Micorrhizal Associations

Endomycorrhizae

Fungi that enter the root hair

Ectomycorrhizae

Fungi that remain extracellular, forming a sheath of interconnecting filaments around the root.

Type

Ectomycorrhizae

Arbuscular Mycorrhizae

Agrobacterium tumefaciens