Rivers Flashcards
River Continuum Concept (RCC)
Stream order
1st through 12th ; 1st orders meet, for 2nd order stream; 2nd orders meet, form 3rd order streams,etc.
1st order streams can go directly into an existing 3rd order stream
Streams vs Rivers
Streams have steep gradients, rivers are wider, usually have gentler gradients
Stream order can be related to biological processes/communities
Starts as allochthonous then becomes autochthonous
Lower order streams are allochthonous
Think about it like it needs a jump start
CPOM
Coarse particulate, organic matter
From broken twigs and leaves
DOM
dissolved organic matter
From algae
Gets eaten by bacteria in a Microbial loop
FPOM
fine particulate organic matter
Made from CPOM
Newest tyep
Feeding groups
Shredders
Crayfish and insect larvae
Convert CPOM to FPOM
Benthic collectors
Consume DOM and FPOM
Scrapers and grazers
scrape periphyton (diatoms, organic microlayer)
Predators
consume insect larvae, smaller fish and fish larvae,
some also consume macrophytes (omnivorous)
Origen of Rivers
overland flow
shallow subsurface storm flow
groundwater
Current speed (- cm sec)
Current speed drops rapidly as go toward the bottom of a stream -drag resistance, sides of stream also affected by drag.
Determines sediment size