Climate Change Ocean & Marine Systems

Question 1

What chemical process primarily causes ocean acidification as atmospheric CO2 levels rise?

Accepted Answer

CO2 reacts with seawater to form carbonic acid, releasing hydrogen ions

Answer

UV radiation breaks down salt compounds in seawater, lowering pH

Answer

Increased evaporation concentrates existing acids already present in the ocean

Answer

Nitrogen runoff from agriculture introduces acids into coastal ocean zones

Question 2

Approximately what percentage of human-caused CO2 emissions have the world's oceans absorbed since the industrial era?

Accepted Answer

About 25-30%

Answer

About 10%

Answer

About 50%

Answer

About 70%

Question 3

What is coral bleaching?

Accepted Answer

A stress response in which corals expel their symbiotic zooxanthellae algae, turning white

Answer

The natural death cycle that occurs when coral reefs reach old age

Answer

A process where algal blooms coat coral surfaces and block sunlight

Answer

Whitening caused by increased UV radiation penetrating the water column

Question 4

What is thermohaline circulation?

Accepted Answer

The global ocean conveyor belt driven by density differences from temperature and salinity variations

Answer

The seasonal surface temperature cycle driven by solar radiation

Answer

The upwelling of cold, nutrient-rich water along continental coastlines

Answer

The mixing of surface and deep water layers by wind action alone

Question 5

Since approximately 1870, global mean sea level has risen by roughly how much?

Accepted Answer

About 20-23 cm (8-9 inches)

Answer

About 5 cm (2 inches)

Answer

About 50 cm (20 inches)

Answer

About 1 meter (39 inches)

Question 6

Which statement about the effect of ocean warming on marine primary productivity is most accurate?

Accepted Answer

Warming increases stratification in tropical zones, reducing nutrient upwelling and lowering productivity

Answer

Warming uniformly increases phytoplankton productivity across all ocean regions

Answer

Warming has no significant effect on phytoplankton because they adapt rapidly

Answer

Warming only affects productivity in polar seas while tropical productivity remains stable

Question 7

What term describes hypoxic coastal ocean areas—often worsened by nutrient runoff and rising temperatures—where dissolved oxygen is insufficient to support most marine life?

Accepted Answer

Dead zones

Answer

Thermal vents

Answer

Benthic layers

Answer

Abyssal plains