Pulses and Polar Bears' Ecosystem

The video discusses the threats to polar bear habitats due to changes in sea ice and permafrost. It highlights the importance of maternity denning in the Hudson Bay area, where polar bears use permafrost features like pulses for denning. Climate change threatens these features, potentially reducing their availability and suitability for polar bears. The formation and life cycle of pulses are explained, along with the impact of climate change on their structure and longevity.

What is one of the main threats to polar bears mentioned in the introduction?

• Overfishing

• Air pollution

• Changes in sea ice

• Deforestation

Where does most maternity denning occur in the Hudson Bay system?

• On sandy beaches

• In permafrost features

• On floating icebergs

• In dense forests

What is the natural life cycle duration of pulses in the Hudson Bay lowlands?

• 50-100 years

• 300-400 years

• 100-150 years

• 200-300 years

How do pulses initially form in the Hudson Bay lowlands?

• As a lens of ice that doesn't melt one year

• From volcanic activity

• By the accumulation of sand

• Through human intervention

What happens to pulses as they grow larger?

• They push the peat above the water surface

• They turn into icebergs

• They become barren

• They sink below the water table

What is a significant threat to pulses due to climate change?

• They will attract more predators

• They will become too cold

• They will no longer reach sufficient height

• They will become too large

Why might pulses become less attractive to polar bears?

• They will be covered in snow

• They will be too far from the sea

• They will be too hot

• They will have a shorter life cycle

What happens when the lens of ice in a pulse starts to melt?

• The pulse becomes a permanent structure

• The pulse grows larger

• The peat dries out and slumps off

• The pulse becomes more stable

What is the consequence of deteriorating pulses for polar bears?

• They will become more aggressive

• They will migrate to warmer areas

• They will lose a key maternity denning structure

• They will have more denning options

What is the primary reason pulses are important for polar bears?

• They offer a place to hibernate

• They are a source of water

• They provide food

• They serve as maternity dens