Lecture 7: Detecting Pollutants & Their Impacts

Question 1

What is paleoecology? How is it used for long-term tracking of pollutants?

Answer 1

= the ecology of fossil animals and plants.
used to study the relationship b/w pollutants and previous generations of animals/ plants

Question 2

the concept of uniformitarianism=

Answer 2

the present is the key to the past

Question 3

analogy=

Answer 3

application of modern organismic features to ancient organisms, including:
- enviro tolerance
- abundance of organisms
- understand past enviro/ communities

Question 4

how is lake history preserved?

Answer 4

in the lake bed (preserved in the sediment)

Question 5

paleolimnology=

Answer 5

the study of lake sediments

Question 6

the paleolimnological approach:
(6 steps)

Answer 6

1. select study lake
2. select coring site and retrieve sediment core (deepest part)
3. section and date sediment core (slice it, then date using isotopic/ radioactive dating)
4. sub-sample sediments and isolate indicator of interest
5. collect indicator data
6. analyze data

Question 7

What are the following used for?
- diatoms
- chrysophytes
- chironomids

Answer 7

environmental indicators in aquatic systems
- we look for these organisms in sediment because they preserve well (silica skeletons)

Question 8

What are 3 environmental indicators from land that we use?

Answer 8

• pollen
• mineral particles
• insect remains

Question 9

what can environmental indicators on the land tell us?

Answer 9

• if/ when the forest around the lake burned
• conditions of the lake surroundings

Question 10

What are 3 environmental indicators from the atmosphere that we use? Where do they end up?

Answer 10

• 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

Question 11

when taking cores from the bottom of lakes, the content of the ___ is also usually sampled

Answer 11

water

Question 12

when analyzing sediment cores, light layers are from ___ and darker layers are from ___

Answer 12

summer= light
winter= dark

Question 13

1 varve=

Answer 13

1 year of sediment deposition

Question 14

organic varves are ___ b/c they contain

clastic varves are ___ b/c they contain

Answer 14

darker –> organic material

lighter –> sediment only (in glacial lakes/ arctic)

Question 15

if a sediment core shows us a shift in organism abundance, what could that suggest?

Answer 15

change in acidity (acid rain)
some thrive in higher acidity, some die

Question 16

T/F
Ice cores can be stored and reused as our technology improves

Answer 16

true!

Question 17

Explain the mesocosm approach of determining ecological impacts

Answer 17

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

Question 18

what’s a problem with the mesocosm approach?

Answer 18

you lose contact with the natural environment (isolated enviro becomes too different from natural enviro)

Question 19

Explain The Whole Ecosystem Experimentation Approach

Answer 19

do an experiement on a whole ecosystem (for example a whole lake, instead of an isolated part inside the lake)

Question 20

What is the ELA?

Answer 20

experimental lakes area in ontario- experiments done on entire lakes
started by gov of canada

Question 21

what’s an example of a famous study done at ELA?

Answer 21

Lake 266
eutrophication study to prove phosphorus was causing it
divided lake into 2 parts, added P to one part and not the other

Question 22

What is the forest (terrestrial) equivalent of the ELA?

Answer 22

Hubbard Brook Experimental forest (est 1955)

Question 23

what kind of experiments happen at the Hubbard Brook forest?

Answer 23

• long-term studies on air, plants, soil, animals, invasive species
• clear cutting
• ongoing experiment: how increased CO2 affects growth of forest

Question 24

give a summary of each:
Mesocosm:

Whole-Ecosystem:

Answer 24

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