Sonne slides 101-151

Question 1

What reproductive issues were observed in Baltic seals due to pollutants?

Answer 1

Females had:
- uterine stenoses, preventing egg transport

Also:
- kidney damage
- tooth loss caused by bone inflammation.

Question 2

What is the Testicular Dysgenesis Syndrome (TDS)?

Answer 2

Male reproduction-related condition

Symptoms and embryonal-based disorders:

• hypospadias (opening of the urethra is on the underside of the penis instead of at the tip)
• cryptorchidism, absence of at least 1 testicle from the scrotum
• poor semen quality
• testicular cancer

Question 3

How did the Baltic seal disease complex become a template for Arctic research?

Answer 3

It showed how simultaneous marine and terrestrial issues, like DDT, mercury, and reproductive problems, can inform studies on polar bears and other Arctic species.

Question 4

What causes the decrease in polar bear skull bone density (osteoporosis), and why does it affect only males?

Answer 4

Males face stronger selection pressures due to less calcium recycling, while females mobilize calcium for pups during hibernation, preserving their bone density.

Question 5

How does PCB exposure vary geographically in polar bears?

Answer 5

PCB concentrations increase demographically from west to east in the Arctic, reflecting regional pollution sources

Question 6

What is the role of the hypothalamic-pituitary-adrenal/gonadal axis (HPA/G-axis)?

Answer 6

It regulates endocrine functions, including stress responses and reproductive hormones, but can be disrupted by pollutants like mercury.

Question 7

How do pollutants like PFAS affect polar bear testosterone levels?

Answer 7

High PFAS concentrations lower testosterone, reducing fertility and altering male behavior, such as decreased mating interest.

Question 8

Why do female polar bears avoid osteoporosis, CVD, and DMII despite extreme physiological stress?

Answer 8

Their endocrine systems are adapted to preserve bone density and overall health during reproductive cycles, even under massive calcium demands.

Question 9

What does melatonin do in polar bears, and how is it linked to hormonal changes?

Answer 9

Produced by the pineal gland, melatonin regulates seasonal cycles, influencing reproductive hormone levels like testosterone and estrogen during maturation

Question 10

How do pollutants disrupt endocrine systems in female polar bears?

Answer 10

Pollutants like DDT increase male hormone production in females, causing abnormal genital development and reproductive issues.

Question 11

How does mercury impact brain function in humans and wildlife?

Answer 11

Mercury exposure reduces antibody production, slows cognitive functions, and disrupts neurological development, as seen in studies on polar bears and children.

Question 12

What are the effects of PFAS on cognitive and motor functions?

Answer 12

PFAS impair both motor and cognitive abilities by disrupting the nervous system and testosterone regulation, affecting behavior and brain health.

Question 13

Why are tissues from wildlife essential for studying ecotoxicology?

Answer 13

Wildlife tissues, like polar bear brains, provide critical insights into pollutant effects on hormones, immune systems, and neurological health.

Question 14

How does mercury exposure in polar bear-based diets affect humans?

Answer 14

Communities consuming polar bears, like those in the Faroe Islands, experience reduced brain function and slower cognitive responses, particularly in children.

Question 15

How do endocrine-disrupting pollutants affect polar bear behavior?

Answer 15

Pollutants like PFOS and mercury lower testosterone, disrupting mating behaviors and reducing reproductive success.

Question 16

What is the connection between mercury, the pituitary gland, and brain function?

Answer 16

Mercury disrupts the pituitary gland’s steroid production, leading to impaired brain development and function, particularly in exposed children.

Question 17

What did research on Baltic seals reveal about the impact of chemical cocktails?

Answer 17

A mix of pollutants caused severe health issues like reproductive failure, kidney damage, and tooth loss, showing the importance of studying combined toxic effects.

Question 18

Why is the concept of “cocktail pollution” important?

Answer 18

It highlights how multiple pollutants interact to exacerbate toxic effects, such as impaired immunity and reproductive health, which might not be apparent from single pollutant studies.

Question 19

What is the target organ if you want to learn more about the effects of pollutants in polar bears?

Answer 19

Liver

Question 20

Why are Ito cells (liver) and Vitamin A crucial for polar bears?

Answer 20

Ito cells store Vitamin A, essential for polar bear health.

A deficiency can lead to conditions like cancer, as observed in captivity studies.

Question 21

What was the significance of the sled dog study in polar bear diet research?

Answer 21

Sled dogs were fed diets with and without blubber to study pollutant effects, revealing how contaminants like PCBs impact metabolism and health.

Question 22

What is hypogonadism?

Answer 22

When the body’s sex glands (gonads) produce little or no hormones

Question 23

Why are sister pairs used in genetic studies of pollution effects?

Answer 23

Using sister pairs minimizes genetic variability, reducing the number of animals needed for laboratory studies and ensuring more reliable results.

Question 24

What are the differences between unhealthy fatty acids from pigs and healthy ones from whales?

Answer 24

Pig fatty acids are immune-suppressive, while whale fatty acids promote health, showcasing the role of dietary fatty acid composition in disease resistance.

Question 25

How does melatonin regulate polar bear reproduction?

Answer 25

Melatonin production, controlled by light cycles, triggers hormonal changes that initiate mating seasons in spring when food becomes available.

Question 26

How does PCB exposure correlate with hypothyroidism in sled dogs?

Answer 26

Sled dogs exposed to PCBs showed a significant link to hypothyroidism, with PCB exposure affecting thyroid hormone concentrations and metabolism.

Question 27

What is hypothyroidism?

Answer 27

Hypothyroidism is when your thyroid gland doesn’t make enough hormone. It can make you feel tired or gain weight unexpectedly.

Question 28

Why do polar bears in Svalbard produce fewer antibodies?

Answer 28

Higher PCB concentrations in Svalbard reduce immune responses, leaving polar bears less able to fight infections or survive without vaccination.

Question 29

How does light availability affect polar bear reproduction?

Answer 29

Polar bears’ reproduction is synchronized with seasonal light and seal abundance, highlighting their physiological reliance on evolutionary adaptations.

Question 30

What challenges do polar bears face without sea ice?

Answer 30

Without sea ice, polar bears lose access to prey like seals, disrupting their metabolism and endocrine systems, potentially forcing migration or adaptation.

Question 31

How do oil spills affect Arctic wildlife differently?

Answer 31

Oil kills birds by impairing thermoregulation, poisons polar bears when licked off their fur, and forces narwhals to dive or navigate around it

Question 32

How do selenium and Vitamin C mitigate mercury toxicity?

Answer 32

Selenium and Vitamin C bind to mercury in a 1:1 ratio, reducing its bioaccumulation. Inuit diets rich in narwhal skin provide both nutrients.

Question 33

What systems are most susceptible to PFAS exposure in humans?

Answer 33

PFAS disrupt immune, endocrine, and metabolic systems by lowering lymphocyte activity, reducing antibody production, and mimicking hormone structures.

Question 34

How do endocrine pollutants disrupt thyroid hormone function?

Answer 34

Endocrine pollutants mimic hormone structures, disrupting thyroid function in both mothers and offspring, impacting growth and development.

Question 35

Why is carbon sequestration nearly zero in the Amazon rainforest now?

Answer 35

Deforestation and environmental degradation have diminished the Amazon’s ability to act as a carbon sink, releasing stored carbon instead.

Question 36

How do fatty acids influence immune responses in polar bears?

Answer 36

Fatty acid consumption may reduce immune responses, as observed in polar bears exposed to contaminants that affect antibody production.

Question 37

What are future challenges for Inuit populations in the Arctic?

Answer 37

Inuits face increased disease risks due to climate change, reliance on contaminated marine food, and disruptions to traditional lifestyles.

Question 38

Why is sunrise critical for polar bear reproduction?

Answer 38

Sunrise signals the start of seal availability and reproductive cycles, with light-regulated hormones driving mating behaviors.

Question 39

What is the “future challenge” for researchers studying Arctic pollutants?

Answer 39

Researchers must address the impacts of climate change, pollution, and the resulting physiological and ecological changes in Arctic wildlife and human populations.