11: Pollutants & their effects on marine mammals

Question 1

Do we have definitive proof that pollutants have a direct effect on the health of marine mammals or their role in the mortality of an animal

Answer 1

There has yet to be a definitive proof that pollutants have a direct affect on health of marine mammals or what role they play in the mortality of an animal

Question 2

What is the term for when pollutants are passed on from prey to predator through the food chain ?

Answer 2

Biomagnification

Question 3

What happens to the concentration of a compound or pollutant through the biomagnification?
(list 4 variables)

Answer 3

1. route of exposure
2. chemical and physical properties of the compound/pollutant
3. metabolic capacity of the predator
4. the predators physiological condition

Question 4

The impact of pollutants on marine mammals is
generally divided in 3 main effects.
List and explain each:

Answer 4

• the organ or system affected
• the organs where the pollutant is stored
• the species affected

Question 5

Contrast the effects of the following key factors that determine organ/tissue
concentrations of pollutants with examples:
1) Type of food/prey
2) Age of predator
3) Reproductive status
4) Gender
 5) Geographical location of prey 
6) Feeding habits

Answer 5

1. Algae vs. fish
2. young vs. old
3. lactating vs. prego
4. male vs. females
5. high concentration in rivers/bays vs. deep oceans
6. herbivore, larger hinters such as seals

Question 6

impaired reproduction most often found in____________

Answer 6

seals

Question 7

impaired development in young most often found in____________

Answer 7

polar bears

Question 8

indirect mortality most often found in____________ by what method of intake?

Answer 8

dolphin - ingestion

Question 9

direct mortality most often found in____________ and what is cause?

Answer 9

sea otter; thermoregulation

Question 10

Give 3 most important reasons for why heavy metal pollution

is extremely difficult to study in wild marine mammal species?

Answer 10

1) it is difficult to obtain animal samples due to extreme or harsh habitat
2) most studs are complicated b the lack of controlled conditions
3) marine mammals have the ability to tolerate high amounts of heavy metals such has mercury, lead or cadmium

Question 11

What 3 organs are heavy metals most commonly stored in?

Answer 11

liver, kidney, and muscles

Question 12

What are the 2 systems most commonly affected by mercury?

Answer 12

neurological disease

young being unable to develop

Question 13

What has been documented to happen to some humans who ingested marine animals contaminated with mercury? give examples..

Answer 13

this si due to biomagnification
i.e.: minamata disease in japan
or inuit in canada

Question 14

In the case of mercury, can marine mammals detoxify mercury ?
explain why/how

Answer 14

1) demethylating (removing methyl group CH3) the highly toxic organic mercury into a less toxic inorganic mercury
2) by combing mercury with selenium which produces an inactive salt

Question 15

Are PCBs (persistent organic pollutants) common in marine mammals? and if so what 2 populations have the highest concentrations ?

Answer 15

yes;

males and diseased individuals

Question 16

PCBs are usually found in species closest to ___________

Give some examples:

Answer 16

sources of contamination such as sea otters, seals and polar bears .

Question 17

give 3 most common systemic effects of PCB contamination.

Answer 17

reproduction, impaired growth in young and the brain

Question 18

describe how PCBs are thought to impact hearing in mammals, is this relevant in marine mammals?

Answer 18

affect thyroid hormone transportation i notes brain –> impact hearing
very impotent in marine mammals since they opened on song/hearing to locate food

Question 19

Organochlorines or hydrocarbonated insecticides (DDTs) - is there a sex effect on accumulation and why?

Answer 19

accumulate more in males than females
females reduce their organochlorine levels by passing on their pollutants to their young through placental transfer or lactation

Question 20

what is thought to be the main system affected by this pollutant what is the consequence of that?

Answer 20

immunosuppressive system –> vulnerable to disease

Question 21

What species has the highest concentrations of organochlorines ?
Describe the anatomical effects seen in females of this species and any genetic abnormalities

Answer 21

Polar bears; female bears have normal opening vaginas but also small penis with baculum (penis bone) and no y chromo

Question 22

Organochlorines structurally affect which 3 main organs? which 3 organs are they stored ?

Answer 22

kidneys, adrenal glands, reproductive tract

stored in fatty tissue such as blubber, lover and brain

Question 23

What was the effect on Harbor seals fed PCBs and a specific type of DDT?

Answer 23

reproductive rate showed a 60% decrease in pups births.

Question 24

What is the suggested effect of PCBs in cetaceans

Answer 24

unclear on affect

Question 25

petroleum products:

List 3 differing properties of oil?

Answer 25

colour, viscoisity, and specific gravity (weight)

Question 26

What are the 3 different categories of crude oil?

Describe the implications of each and their behavior in water once spilled.

Answer 26

light, medium or heavy
some flat and evaporate or sink just below the surface or sink toe ht bottom and each form of oil will move differently with currents and tides

Question 27

What is the main effect in marine mammal of exposure to oil? describe why and what species are most susceptible & why

Answer 27

sea otters -> lethargic, respiratory distress, diarrhea, and liver r kidney failure from igestion

seals die b/c brain lesions of inhaling oil vapors

hypothermia in sea otters, polar bears and seals (esp critical for seas since they have no fat or blubber)

Question 28

A specific contaminant or the amount not contaminant may affect a species in different degrees.

Answer 28

1) age
ii) fat reserves
iii) breeding stages
iv) prey