Bubbling Under the Surface: The Growing Problem of Declining Oxygen

Flashcards summarizing key concepts discussed in Dr. Michael Collins's lecture on the importance of oxygen and the issues surrounding hypoxia in marine environments.

What is the biological importance of oxygen?

Nearly all complex animal life relies on oxygen for efficient energy generation.

What is cellular respiration?

The process by which animals liberate energy from food through reactions to generate ATP.

What are the ATP yields for anaerobic vs aerobic respiration?

Anaerobic produces ~2 ATP; aerobic produces ~29-30 ATP.

What is normoxia?

Normal oxygen levels of 6-12 mL O2 L-1.

What is hypoxia?

Oxygen levels lower than normoxia, specifically < 2 mL O2 L-1.

What is hyperoxia?

Oxygen levels higher than normoxia, specifically > 6-12 mL O2 L-1.

What is anoxia?

Total absence of oxygen.

How does temperature affect oxygen in water?

Warmer temperatures promote stratification that prevents mixing of oxygen.

What natural phenomena can cause oxygen variation in shallow coastal environments?

Daily tidal cycles can lead to highly variable oxygen levels.

What is anthropogenic hypoxia?

Hypoxia caused by human activities, leading to increased severity, frequency, and duration.

What are the consequences of hypoxia for marine ecosystems?

Outward migration of fauna, mortality of sensitive species, and reduced biodiversity.

How does algal bloom formation lead to hypoxia?

Nutrient runoff causes blooms that deplete oxygen when decomposed by microbes.

What is the predicted reduction in ocean oxygen by 2100?

A further 7% reduction is predicted.

How do species differ in their hypoxia tolerance?

Tolerance varies based on evolutionary adaptations and metabolic strategies.

What is metabolic depression in response to hypoxia?

A shutdown of metabolic processes to avoid ATP imbalance and promote cellular survival.

What are dead zones?

Areas of hypoxia where marine life cannot sustain due to low oxygen levels.