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
