eutrophicacion Flashcards
trophic state definition
level of ecosystem productivity
trophic state 3 levels
oligotrophic (few food)
mesotrophic
eutrophic (many foods)
what are some measures used to define trophic level in lakes?
water clarity
phytoplankton biomass
nutrient concentration
natural eutrophication:
- associated will filling of a lake with _____ over time
- _____ of plants and _____ of nutrients from basin increases _______ and _____ of filling over time
sediments
decay of plants and addition of nutrients increases productivity and rate of filling over time
what is cultural eutrophication
accelerated rate of eutrophication due to nutrients added from human activities
chlorophyll a is a marker of
algal growth
lots of primary producers in a lake = ______ secchi depth
low
secchi depth tells us how far light can penetrate water (clarity)
high secchi depth in ______ lakes
oligotrophic
(you can see far down in low producivity lakes)
lakes with high shoreline development = ______ eutrophication of lakes
high
(lots of nutrients can flow from shore to water)
T/F: lakes have constant/persistant trophic level throughout time
false, trophic level can change over time (ex. nutrients/soil gets dumped into lake = changes from oligotrophic to eutrophic)
natural vs cultural eutrophication
natural = normally occurs slowly in environment
cultural = humans speed up this natural process
causes and effects of eutrophication of lake winnipeg
eutrophication (hydro dam blocks outflow of water)
- nutrients (P) retained behind dam = algae bloom
- low water quality
- x2-3 more species in lake (more fish)
- lots more lethal algae growth (cyanobacteria)
- dead algae gets eaten up by microbes using O2 = decline O2 = dead zones
- marshes (which normally eat up a lot of P) are slowly disappearing
how they’re trying to fix eutrophication problem of lake winnipeg
- restoring marshes to slow runoff from farms (removing P) before hitting lake
- filter basins
