ocean warming Flashcards
How do natural disturbances affect coral reef ecosystems?
Natural disturbances play a critical role in structuring ecosystems. Corals have adapted to these regimes over millennia, but rapid human-driven changes negatively impact ecosystem states.
How can intermediate levels of disturbance impact coral reef diversity?
Intermediate levels of disturbance may promote diversity by preventing dominance of a single species, allowing coexistence of multiple species.
How have human activities shifted disturbance regimes on coral reefs?
Human activities have led to shifts in disturbance regimes, resulting in reduced coral cover and possible shifts to alternate ecosystem states.
What are the key human disturbances that cause coral reef decline?
1) Fishing: Overfishing and destructive fishing.
2) Coastal development: Pollution, sedimentation, and land reclamation.
3) Biological disturbances: Predators and diseases.
What is coral bleaching and what causes it?
Coral bleaching is the visible loss of the microscopic algae that inhabit coral. It results from temperature stress, which disrupts the coral-algae symbiosis, exposing the white limestone skeleton through coral tissue.
What has been the main driver of global coral reef loss since the 1980s?
Coral bleaching, driven by rising sea temperatures, has been the primary cause of global coral reef loss since the 1980s.
What could happen if corals don’t increase their thermal tolerance?
Without an increase in thermal tolerance of 0.2–1.0°C per decade, coral bleaching could become an annual or biannual event in the next 30–50 years, leading to mass coral mortality.
What are the mechanisms by which corals might adapt to climate change?
1)Acclimatization: Prior exposure to sub-lethal stress helps corals cope with future stress.
2) Shifts in reef community structure: Replacement of susceptible species with more stress-tolerant species.
3) Adaptation: Evolutionary changes in the coral host or its symbionts through natural selection.
What is the role of acclimatization in coral adaptation to climate change?
Acclimatization occurs when corals exposed to non-lethal stress develop resistance to future stress. This process could delay the arrival of severe bleaching scenarios, but rapid adaptation has not been observed.
Can corals rapidly adapt to bleaching?
Current evidence does not support the idea that corals can rapidly adapt to bleaching. While acclimatization may delay impacts, long-term adaptation through natural selection is slow.
