Exam prep

Question 1

Contamination vs. Pollution

Answer 1

Contamination is the naturally occurring presence of elevated concentrations of substances. Is natural and not anthropogenic! E.g. oil seeps along the coast of California.

Pollution is the leakage of anthropogenic substances in the marine environment causing deleterious effects.
(Dissolved nutrients, oil spills, particulates like dredging, coal dust and microplastic, industrial waste like heavy metals, PCBs, organochlorine, and Debris like garbage, ships waste, fishing gear)
Also, hot water from power plants.

Question 2

What are sublethal effects

Answer 2

Deleterious effects caused by pollution that don’t kill the organism, but either deform them or cause them to become infertile etc.

Can be Acute or Chronic

Question 3

The types of perturbations, release of pollutant

Answer 3

Pulse: Release is sudden, big and of short duration. Quite common, like if you tip a bunch of barrels of something into the water column.

Press: Much longer duration, a chronic type of pollution, pollutant keeps “dribbling out”

Question 4

Types of responses of organisms to perturbations (pollutants) e.g. change in abundance

Answer 4

Pulse: Drop off quickly but bounce back, e.g. amphipods

Press: Much longer effect, chronic effect, population not as persistent as the one with the pulse response

Question 5

What is bioaccumulation?

Answer 5

The cummulative accumulation of substances that cannot be excreted in organic tissues. Can cause sublethal effects and when concentration is high enough can be lethal.

Question 6

Can you draw the response of organisms tolerance and vigour?

Answer 6

Graph has vigour on y-axis and concentration of contaminant on the x-axis.
First zone, is the zone of indifference. Vigour is high, accumulation may occur.
Second zone is the zone of stress. vigour drops to zero.
Third zone is the zone of intolerance. Species is absent. Vigour is zero.
(Phillips and Rainbow 1993)

Question 7

How can we measure pollution?

Answer 7

We measure pollution at different levels of biological organisation:

1. Individual or sub-organismal measures
   - Physiological (looking at anomalies in liver)
   - Biochemical
2. Whole organism - demographic characteristics
   - Reproductive output
   - Body size
   - Growth
3. Community and population level studies
   - abundance of populations
   - contribution to food web

Question 8

Sensitivity to toxins varies..

Answer 8

1. Among species
2. within species (depending on physiology and nutritional state, also on developmental stage; juveniles are often more sensitive than adults. larval forms are still growing, so the risk of becoming deformed is greater)

Question 9

Synergistic vs. Antagonistic effects

Answer 9

Synergistic effects: multiple toxins increase the effect (a major concern)

Antagonistic effects: multiple toxins decrease the effect

Question 10

How do we determine if an impact has taken place?

Answer 10

Sampling design:
BACI = Before After Control Impact, one control and one impact (Green 1979)

BACIP = Paired and multiple times Before and After, one control, one impact (Oaten 1986)

Beyond-BACI = One impact area, mutliple control sites (Underwood 1991) GOOD OPTION

MBACI = Multiple Before After Control Impact (Keough and Mapstone 1995) IDEAL IMPACT STUDY

Question 11

Acceptable impact studies and the statistical inferences you can make from them

Answer 11

Before and after at control and impact sites can give you temporal and spatial inferences

Sample after impact at control and impact sites can only give you spatial inferences

Question 12

Not acceptable impact studies

Answer 12

Temporal replication with no controls. Can give you temporal inferences, but this is not good.

Spatial replication of impact with no controls. Inferences will be based on experience. Not Good.

Question 13

How do we measure impacts on planktonic assemblages?

Answer 13

1. Lab experiments - Traditional approach
   (e. g. LD50)
2. Field studies (Impact studies, MBACI and all that)
3. Modelling (Oceanography and plankton)
4. Mesocosms
5. Monitoring with organisms (Like oysters or jellyfish)

Question 14

Measures of toxicity

Answer 14

Toxicity tests
LT50 - The time it takes for 50 % to be dead

LC50 - Lethal concentration where 50 % are dead

LD50 - Lethal dose where 50 % are dead

Question 15

What are fish larvae vulnerable to?

Answer 15

Metals (Cd, Hg, Pb, Zn, Cu)
pH
Organochlorines (DDT, DDE)
Industrial waste
Chlorine
Temperature
Oils

Effects can occur at very low concentrations

Question 16

Oceanography and pollutants!

Answer 16

Pollutants can concentrate at fronts

Abundance of larvae vs. current speed

Question 17

Bioindicators vs. biomonitors

Answer 17

Bioindicators: changes in biochemical, physiological or behavioural attributes of an organism providing a qualitative state of the environment

Biomonitor: Using an organism as a proxy for levels of a xenobiotic in the environment. e.g. oysters and jellyfish

Question 18

How can Climate Change impact plankton and why is it a concern?

Answer 18

Changes in the plankton can cause ecosystem wide cascades. Responses can be very quick and affect higher trophic levels.

• Change size structure
• Change timing of reproduction
• Change production
• Change zooplankton abundance
• Loss of key species through decalicification (e.g. coccolithophores)

Question 19

The East Australian current is..

Answer 19

The fastest warming part of the world