Mangroves and Coral Reefs Lecture Notes

This flashcard set covers the biological characteristics, ecological stressors, productivity levels, and geomorphological structures of tropical mangrove and coral reef ecosystems.

Mangroves

Terrestrial, salt-tolerant trees that grow in tropical, low-energy intertidal environments with sedimentary soils.

Stilt roots

Also known as prop roots, these structures provide stabilization for mangrove trees in loose, unconsolidated sediments and help them withstand storms and wave action.

Pneumatophores

Commonly called snorkel roots, these structures have pores that allow mangrove trees to take in oxygen while the soil is inundated with water.

Water logging

The primary stressor for mangroves (the opposite of desiccation for seaweeds) which can cause the trees to drown if they cannot obtain enough oxygen or perform photosynthesis.

Mangrove Productivity

Relatively low compared to other benthic systems, typically less than $500\,g\,C\,m^{-2}\,yr^{-1}$ due to the high energetic costs of salt excretion and respiration.

Blue carbon sinks

Ecosystems such as mangroves and salt marshes where dead organic material is deposited and buried in sediment, effectively removing $CO_2$ from the atmosphere.

Avicennia

The single species of mangrove found in New Zealand, which grows up to $10\,meters$ in northern regions but remains much smaller in southern, colder latitudes.

Scleractinia

The special order of stony or hard corals that build colonial structures with calcium carbonate skeletons.

Hermatypic

A term used to describe corals that are reef-building.

Coral Reef Productivity

Considered the most productive marine ecosystem, with values ranging from $3,700$ to $4,000\,g\,C\,m^{-2}\,yr^{-1}$.

Zooxanthellae

Microscopic microalgae (typically dinoflagellates like Symbiodinium) that live inside coral tissues in a mutualistic relationship, providing organic matter and oxygen in exchange for nutrients and protection.

Coral bleaching

A stress response where corals expel their zooxanthellae (often due to heat waves/increased temperature), revealing the white calcium carbonate skeleton beneath.

Mesenteric filaments

Filaments inside a coral's gut that can be expelled to digest organic material or to attack and kill neighboring corals in competition for space.

Acropora

A genus of branching corals known for fast growth rates but high vulnerability to physical damage during hurricanes.

Fringing reef

A reef type that grows directly adjacent to the land, characterized by a reef flat and a reef slope close to the shore.

Barrier reef

A reef system separated from the mainland or island by a large, deep lagoon that may contain patch reefs.

Atoll

A ring-shaped reef structure found in the open ocean with no central land mass, formed by the gradual erosion and subsidence of a volcanic island.

Darwin's Theory of Atoll Formation

A physical process where a volcanic island develops a fringing reef, then erodes into a barrier reef with a lagoon, and eventually disappears entirely, leaving only a ring of coral.

Halimeda

A genus of green algae that produces calcium carbonate; when it breaks down, it contributes significantly to the production of sand in reef environments.

Crustose coralline algae

Slow-growing, encrusting algae that serve as 'cement' to stabilize reef rubble and compact the structure into a hard, fixed reef.

Cleaner station

A specific location on a reef where larger fish congregate to have ectoparasites removed by smaller cleaner fish (such as wrasses) in a mutualistic interaction.

Great Barrier Reef

The world's largest reef system, consisting of over $3,000$ individual reefs and $900$ islands, with its modern structure dating back approximately $10,000$ years.