EESA11H3 Lecture Notes - Eutrophication, Water Cycle, St. Clair River

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Published on 16 Apr 2013
School
UTSC
Department
Environmental Science
Course
EESA11H3
EESA11 Lec 9 KNOW + possible questions
Know:
Main issue of Lake Erie area of eutrophication, hotspot for enviro Canada
o West shallow and small, always mixes. NO oxygen problems
o East very deep, no oxygen depletion
o Central basin (PROBLEM AREA!!)
Eutrophication most happens here; deep enough to get stratified, not deep
enough to get oxygen. Once oxygen depletes, have problems with the
sediment. Only the top area of this part gets oxygen
Bottom layer of water does not mix with warmer surface water no
opportunity for oxygen replenishment from the atmosphere
Human impact on freshwater ecosystems: demotechnic concept:
o Combined effect of the population as well as of production-consumption in a
technological sense
Phytoplankton
o Producers take energy from the sun and nutrients from the water and convert them
into food
Largest number of producers in the Great Lakes = phytoplankton
o Survive as long as they are near water surface and have proper nutrients. Bloom
in the spring when the water is warming up and the most nutrients are available.
o E.g. Anabena form chains hundreds of cells long
Pediastrum collection of small phytoplankton cells that join together in a
circle
Cladophora branching, green filamentous algae. Grows attached to
solide substrate
Zooplankton free-floating animals. Types:
o Copepod all have antennae and a fan tail
o Mysis one of the largest and can move very fast through the water when
threatened. Good food for young fish
o Rotifer using small, hair-life fibers, they swirl water by their mouths to gather
food for themselves. Once the food is caught, they close their mouths and digest it
o Holopedium for a clear, gooey envelope around themselves where the females
carry eggs
Managing Methods what is TFM and how it deals with invasive species
o Barriers + male-stereilization + TFM (currently used by GLFC)
TFM (3-trifuluoromethyl-4-nitrophenol) was effective in controlling sea
lampreys without affecting other species is most effective when it is
used to target larval sea lampreys in streams. Is applied to streams NOT
open waters
o Emerging alternative method: pheromones and repellants
Alternative managing methods:
o Pheromones secreted or excreted chemical factor that triggers a social response
in members of the same species. Impacts the behaviour of the receiving individual
o Larval pheromones (migratory odors) 90% of the time, lampreys head to
streams with presence of larval odour
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Document Summary

Main issue of lake erie area of eutrophication, hotspot for enviro canada: west shallow and small, always mixes. No oxygen problems: east very deep, no oxygen depletion, central basin (problem area!!) Eutrophication most happens here; deep enough to get stratified, not deep enough to get oxygen. Once oxygen depletes, have problems with the sediment. Only the top area of this part gets oxygen. Bottom layer of water does not mix with warmer surface water no opportunity for oxygen replenishment from the atmosphere. Human impact on freshwater ecosystems: demotechnic concept: combined effect of the population as well as of production-consumption in a technological sense. Phytoplankton: producers take energy from the sun and nutrients from the water and convert them into food. Largest number of producers in the great lakes = phytoplankton: survive as long as they are near water surface and have proper nutrients. Bloom in the spring when the water is warming up and the most nutrients are available: e. g.

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