Organic Matter Dentrivory Flashcards
what are biofilms and where are they found in streams?
They are complexes of sugars, enzymes, bacteria and other microorganisms. Find primarily on substrate
What do biofilms consume?
Absorb DOM (dissolved organic matter) and collect FPOM (fine). They are a site of nutrient cycling
Leaf packs are generally colonized by what first?
Conidia, asexual spores, of aquatic hypohomycetes.
“Hot spots” of fungal production
leaf packs
How are leaf packs formed?
Form numerous ways, accumulate in slow or dammed areas
What happens when a leaf first enters a stream?
Leaves are generally nutrient deficient, soluble compounds leech out and enter the water column
How do fungi break down leaves?
They produce external enzymes that break down more durable leaf structures. “Conditioning” the leaf.
What does conditioning do, in regards to leaf decomposition? What happens after?
Improves nutrient value and availability. Leaves begins to fragment and move downstream
What time scale does this occur?
Depends on the stream and various environmental factors such as stream flow. Can occur constantly and over a long time period.
What is DOM?
Dissolved organic matter. Brown color indicates high concentration.
What determines amount of DOM?
Soil constituents are very important, storm runoff has large affect as well.
How does the microbial loop relate to DOM?
Alternive to traditional trophic structure. Occurs outside of PP. Bacteria act upon organic carbon, make available to other organisms.
What is refractory carbon?
Difficult to biologically access, decomposes very slowly and is inert for long periods of time
What is labile carbon?
Carbon can be biologically utilized in a much shorter time frame.
FPOM?
Fine Particulate organic matter
FPOM and seston?
Seston referes to suspended, FPOM can vary in size substantially from .45 to 1000 microns.
Can is FPOM made up of?
Living organisms, detritus, sediments, leaf particles
Where does FPOM originate?
Physical forces breaking down leaves, twigs, rocks, etc. Very important food source for filter feeders.
Where does benthic FPOM occur and why?
Benthic FPOM is determined by flow, fast will remove, slow deposit. Benthic FPOM occurs more in pools and floodplains.
CPOM
Coarse particulate organic matter, wood, debris, allochthonous.
CPOM often times causes?
deposition because of debris dams, slowing of water allows for more biological functions
Retention of organic matter is influenced by what?
Hydrology, sediment, riparian, wood/organic debris dams.
Wood in streams?
Determining factor for channel morphology, water velocity, and sediment storage.
wood is a function of?
lateral input from riparian and tributary sources.
