Exam 2 Material:

Why does permafrost thaw lead to increased greenhouse gases?

decomposition releases CO₂ and CH₄.

Which of the following are examples of climate feedback loops?

A. Permafrost thaw releasing methane
B. Amazon dieback releasing CO₂
C. Ice melting decreasing albedo
D. Forest fires releasing carbon

• Permafrost thaw → releases greenhouse gases → more warming → more thaw.

• Ice melting → less sunlight reflected → more warming → more ice melt.

Why are oceans absorbing most excess heat from climate change?

High heat capacity of water

Which species are considered climate “losers” in freshwater systems?

Trout and smallmouth bass

In lakes experiencing climate warming, which species is most likely to expand its range?

Smallmouth bass

What is the main purpose of climate envelope modeling?

To predict the future distribution of species under climate change

What happens when permafrost thaws, and how does it affect climate change?

Thawing permafrost releases carbon stored for thousands of years as CO₂ or CH₄, creating a positive feedback loop that accelerates climate warming.

Why does summer stratification occur in lakes?

Summer stratification occurs because warmer surface water is less dense than cooler water below, which prevents mixing.

What happens during spring turnover in lakes?

Ice melts and surface water warms to 4 °C, allowing oxygen to mix into deeper layers.

Are shallow lakes more prone to oxygen depletion in deep layers than deep lakes?

No. Shallow lakes are less prone because wind and mixing circulate oxygen more easily; deep lakes are more at risk.

Which fish are most vulnerable to warming and longer summer stratification?

Cold-water fish like trout and salmon.