Climate Change Ocean & Marine Systems 2

Question 1

Which coastal ecosystems are recognized as the most effective stores of 'blue carbon'?

Accepted Answer

Mangroves, seagrasses, and salt marshes

Answer

Mangroves, seagrasses, and salt marshes sequester carbon at rates far exceeding most terrestrial ecosystems per unit area and store it for centuries in their soils.

Question 2

What are the two primary physical mechanisms driving global sea level rise in a warming climate?

Accepted Answer

Thermal expansion of seawater and melting of land-based ice sheets and glaciers

Answer

Sea level rises because warming seawater expands (thermal expansion) and because melting glaciers and ice sheets transfer previously land-locked water into the ocean.

Question 3

Marine heatwaves are formally defined as periods when sea surface temperatures exceed what threshold?

Accepted Answer

The 90th percentile of local climatological temperatures for at least 5 consecutive days

Answer

The scientific definition requires temperatures above the local 90th percentile climatological threshold for at least 5 consecutive days, ensuring comparisons are relative to local baseline conditions.

Question 4

Which major Atlantic circulation system is considered most vulnerable to weakening as Arctic ice melts add freshwater to the North Atlantic?

Accepted Answer

Atlantic Meridional Overturning Circulation (AMOC)

Answer

AMOC is driven by the sinking of cold, salty water in the North Atlantic; freshwater input from melting ice reduces salinity and density, potentially slowing or disrupting this circulation.

Question 5

What is ocean deoxygenation and why does climate change accelerate it?

Accepted Answer

The widespread loss of dissolved oxygen driven by warming reducing gas solubility and increased stratification limiting replenishment

Answer

Warmer water holds less dissolved gas (lower oxygen solubility), and stronger stratification prevents oxygen-rich surface waters from mixing into the deeper ocean.

Climate Change Practice Test

Climate Change Practice Test

Climate Change Ocean & Marine Systems 2