Introduction to Marine Biology: Hidden Corals - Mesophotic Reefs

These flashcards cover key concepts related to mesophotic coral ecosystems discussed in the lecture on marine biology.

What are mesophotic coral ecosystems (MCEs)?

Light-dependent ecosystems found between 30-150 m, including reef-building corals, soft corals, sponges, and algae.

Why are mesophotic reefs significant?

They potentially serve as refuges for shallow-water corals, are biologically valuable, cover extensive areas, and provide socioeconomic services.

What colors of light are primarily available at mesophotic depths?

Mainly blue, green, and purple wavelengths, as longer wavelengths (red, orange, yellow) are absorbed first.

What is the temperature range typically experienced by mesophotic ecosystems?

Between 20-26 °C.

What hypothesis suggests that MCEs could serve as a refuge for shallow-water corals?

Deep Reef Refugia Hypothesis (DRRH) suggests deeper reefs may provide spatial refuge for corals and serve as a larvae source for recovery.

How does species diversity change with depth in mesophotic ecosystems?

Diversity decreases with increasing depth, with high species turnover and minimal overlap between depth zones.

What are the dominant organisms found in mesophotic communities?

Coral, sponge, and macroalgae species, with zooxanthellate corals forming the reef structure.

What significant environmental factor contributes to mesophotic coral bleaching?

Rising water temperatures and thermocline depth changes associated with climate change.

What challenges have historically limited research on mesophotic reefs?

Safety issues of SCUBA diving at deeper depths and the expense of using remotely operated vehicles (ROVs) or submersibles.

How do MCEs potentially buffer against climate change impacts?

MCEs may have escaped recent bleaching events and remain in relatively pristine conditions compared to shallow reefs.