Lecture 7: Detecting Pollutants & Their Impacts Flashcards
What is paleoecology? How is it used for long-term tracking of pollutants?
= the ecology of fossil animals and plants.
used to study the relationship b/w pollutants and previous generations of animals/ plants
the concept of uniformitarianism=
the present is the key to the past
analogy=
application of modern organismic features to ancient organisms, including:
- enviro tolerance
- abundance of organisms
- understand past enviro/ communities
how is lake history preserved?
in the lake bed (preserved in the sediment)
paleolimnology=
the study of lake sediments
the paleolimnological approach:
(6 steps)
- select study lake
- select coring site and retrieve sediment core (deepest part)
- section and date sediment core (slice it, then date using isotopic/ radioactive dating)
- sub-sample sediments and isolate indicator of interest
- collect indicator data
- analyze data
What are the following used for?
- diatoms
- chrysophytes
- chironomids
environmental indicators in aquatic systems
- we look for these organisms in sediment because they preserve well (silica skeletons)
What are 3 environmental indicators from land that we use?
- pollen
- mineral particles
- insect remains
what can environmental indicators on the land tell us?
- if/ when the forest around the lake burned
- conditions of the lake surroundings
What are 3 environmental indicators from the atmosphere that we use? Where do they end up?
- carbon particles (from C combustion like fires)
- fly ash from coal combustions (industrial)
- metals & other pollutants from industry
they end up in the lake and sediment
when taking cores from the bottom of lakes, the content of the ___ is also usually sampled
water
when analyzing sediment cores, light layers are from ___ and darker layers are from ___
summer= light
winter= dark
1 varve=
1 year of sediment deposition
organic varves are ___ b/c they contain
clastic varves are ___ b/c they contain
darker –> organic material
lighter –> sediment only (in glacial lakes/ arctic)
if a sediment core shows us a shift in organism abundance, what could that suggest?
change in acidity (acid rain)
some thrive in higher acidity, some die
T/F
Ice cores can be stored and reused as our technology improves
true!
Explain the mesocosm approach of determining ecological impacts
performed outdoors: isolate and control a natural area
- contaminant asses to the isolated area- observe rxn
- can manipulate biotic/ abiotic factors w/o impacting the whole enviro
- predicts what may happen in the future
what’s a problem with the mesocosm approach?
you lose contact with the natural environment (isolated enviro becomes too different from natural enviro)
Explain The Whole Ecosystem Experimentation Approach
do an experiement on a whole ecosystem (for example a whole lake, instead of an isolated part inside the lake)
What is the ELA?
experimental lakes area in ontario- experiments done on entire lakes
started by gov of canada
what’s an example of a famous study done at ELA?
Lake 266
eutrophication study to prove phosphorus was causing it
divided lake into 2 parts, added P to one part and not the other
What is the forest (terrestrial) equivalent of the ELA?
Hubbard Brook Experimental forest (est 1955)
what kind of experiments happen at the Hubbard Brook forest?
- long-term studies on air, plants, soil, animals, invasive species
- clear cutting
- ongoing experiment: how increased CO2 affects growth of forest
give a summary of each:
Mesocosm:
Whole-Ecosystem:
Mesocosm:
- smaller scale
- short-term studies
- becomes diff from natural enviro
Whole-Ecosystem
- larger area
- no lost contact with natural enviro
- good for long term studies
