Lecture 2; River Continuum Concept (RCC) and Nutrient Spiralling Flashcards
name order of hierarchical scale
stream, segment, reach, pool/riffle, microhabitat
different flow types
pools, riffles, gliddes
how have we made it a one way flow?
urbanising and channelling rivers
instars are…
different growth stages when the insect sheds its exoskeleton and grows a new one
name for insects which undergo incomplete metamorphisis stage, series of instars to become an adult?
Hemimetabolous
name for insects which undergo complete metamorphisis and become larvae/pupae
Holometabolous
4 functional feeding groups
shredders
collectors (gatherers and filterers)
sracpers
predators
role of shredders?
utilize CPOM and produce FPOM in this process
role of collectors gatherers?
collect organic matter form the bed of river
Role of collector flterers?
filter FPOM from water column, spin silk and build nets between rocks to filter FPOM
Role of scrapers?
scrape diatoms and attached algae form the surface of stones and rocks
Role of predators?
eat other 3 types of invertebrates
4 stages of decay of leaves in streams?
- leaching
- conidiotniing
- Invertebrate shredding
- Physical abrasion
which decay phase takes 30 days?
conditoning
what attracts shredders to leaves?
bacteria and funghi
when was RCC introduced?
1980
what does RCC explain?
communities and different reaches of the rier develop different strategies wot use carbon/energy inputs and minimise carbon loss
what is stream order?
a way to classify streams by size in relation to whats going on
what is a first order stream?
a stream which flows directly from any source
How is a second order stream made?
when 2 first order streams meet,
how is third order stream made?
by 2 second order streams meeting
3 different sectiosn of the RCC
- headwaters
- middle reaches
- lower reaches
name the functional groups which dominate headwaters?
shredders and collectors
functional groups which dominate middle reaches?
collectors and scrapers
functional groups which dominate lower reaches/larger rivers?
collectors and predators
where is P/R LOWER than 1?
headwaters and lower reaches
where is P/R GREATER than 1?
middle reaches
what conditions do collectors favour?
- available FPOM for them to feed on
what conditions do shredders favour?
- high amount of leaf retention
what conditions do predators favour?
- higher order streams, larger
when is a stream considered heterotrophic?
- where p/R < 1
- limited light penetration
What is DIC?
- dissolved inorganic carbon
- consists of co2, bicarbonate and carbonate
What is DOC?
Dissolved organic carbon
- organic material that can pass thorugh a filter (<0.7um)
what is PIC/POC?
Particulate organic/inorganic carbon
- cant pass through a filter
how is FPOM produced in the stream?
- DOM gets shredded and becomes FPOM used by collectors
- autotrophs used by scrapers produce FPOM
name 3 nutrients which are limiting to productivity
- C, P, N
What are the different relative %s of inorganic and organic carbon in the stream?
- 90% travel downstream inorganic
- 10% as organic
uptake length?
average distance travelled by a nutrient molecule in inorganic form before removal from the water column
spiral length =
uptake length (inorganic) + turnover length (organic)
geomorphic factors influencing nutrient uptake?
- physical properties of channel
- dictates residence time of water within reach
geomorphic retention of nutrients depends on…
-hydrology
- size of particle
- heterogeneity of stream bed
LWD
