soil biology – a primer who is who & what do they do? elizabeth sulzman, oregon state & t....
TRANSCRIPT
Soil Biology – A PrimerWho is who
&
What do they do?
Elizabeth Sulzman, Oregon State& T. Kittel
Important Groups of Soil Organisms
• Macroflora
• Microflora
• Macrofauna
Vascular plants, mosses (autotrophs)
Vascular plants (root hairs), algae, actinomycetes, bacteria, and fungi (auto- and heterotrophs)
Vertebrates, arthropods, earthworms, snails… (herbivores, detritivores, predators)
Size, functional groups:
• Mesofauna
• Microfauna
Arthropods, worms (detritivores, predators)
Nematodes, protazoa… (detritivores, fungivores, bacterivores, predators)
Relative Sizes
http://commtechlab.msu.edu/sites/dlc-me/zoo/zdrr0101.html
Animated gif – view in slideshow mode
Note ruler for scale
• heterotrophs (bacteria, fungi) & autotrophs (algae, cyanobacteria)
• the primary decomposers• release plant available nutrients
• stabilize soil aggregates
Microflora
Soil fungiSoil bacteria
Aggregates held together by:– Fungal hyphae– Bacterial “glues”– Organic matter
sand
silt
hyphaeclay
bacteria
Microflora –
Amoebae
CiliateFlagellate
Nematode
• heterotrophs; some parasitic
• feed on bacteria and fungi
• release plant nutrients – protozoa KEY for N
Nematode
Microfauna
eeee!
Collembola (springtails)
Fungus feeding mite
• heterotrophs (detritivores, predators)• feed on fungi, protozoa, nematodes, mites• important in regulating populations of everything smaller
Nematode feeding mite
Mesofauna
Photo by Suzanne Paisley
• heterotrophs
• shred plant material
• feed on bacteria and fungi associated with organic matter
Macrofauna
Addo National Park, South Africa
Tembe Elephant ReserveKwaZulu Natal, South Africa
Dung Beetles
Amboseli National Park, Kenya
Macrofauna –
Key disposer of elephant dung and so a protected species!(you can imagine the ‘or else’…)
Soil Food WebEcosystem Function –
Influence of soil biota on soil processesNutrient cycling Soil structure
Microflora
Microfauna
Mesofauna
Macrofauna
Break up O.M., mineralize and immobilize nutrients
Bind aggregates, hyphae entangle particles
Regulate bacterial and fungal populations
Indirectly affect structure
Regulate above pops.; fragment plant tissue
Fecal pellets, pores
Fragment plant tissue Mix O.M. and mineral soil; pores; feces
Ecosystem Function –
Recall: Rate of decomposition depends on –
• Physical and chemical nature of the litter material
• Temperature and moisture of the soil environment
• Aeration (vs. anaerobic)
• The kinds and numbers of soil fauna
More bugs, and more different kinds of bugs, means more decomposition
Ecosystem Function –
– Mendenhall