Reef Basics
These tiny animals live in colonies and form the basic structure of a coral reef.
Coral polyps
This shark species is commonly seen around Koh Tao dive sites like Chumphon Pinnacle.
Whale shark
This type of relationship describes the close interaction between coral and zooxanthellae, where both benefit.
Mutualism
(Also acceptable: Symbiosis)
This global phenomenon is causing rising sea temperatures that stress coral reefs.
Climate change
This term describes the immense variety of life forms found living within a coral reef ecosystem.
Biodiversity
These symbiotic algae live inside coral tissue and give corals their color.
Zooxanthellae
This species of sea turtle is frequently seen around Koh Tao reefs.
A green sea turtle
(Also acceptable: A hawksbill sea turtle)
This type of ecological relationship benefits one organism while the other is neither helped nor harmed.
Commensalism
This type of local diver or snorkeler behavior can physically damage coral reefs.
Physical contact
(Acceptable: touching coral, kicking with fins, anchor damage)
Corals that build reefs are classified in this biological class of animals.
Class: Anthozoa
Phylum: Cnidaria
Order: Scleractinia
This type of coral has large, fleshy polyps and lacks the rigid calcium carbonate skeleton found in reef-building corals.
Soft coral
This small reef fish removes parasites from larger fish at cleaning stations.
Cleaner wrasse
In addition to grazing algae, parrotfish contribute to reefs through this process of breaking down coral and producing sand.
Bioerosion
This type of land-based pollution increases nutrient levels and can lead to algal blooms on reefs.
Runoff
This ecological concept describes a reef’s ability to resist damage and recover after disturbances like bleaching events.
Reef resilience
This type of reef formation surrounds Koh Tao - fringing, barrier, or atoll.
A fringing reef
Population outbreaks of this echinoderm can devastate coral reefs.
Crown of Thorns Starfish
This term describes a specific reef location where cleaner organisms remove parasites from larger marine animals.
Cleaning station
This process lowers ocean pH and reduces corals’ ability to build calcium carbonate skeletons.
The biological process where a heterotrophic organism consumes algae, digests the cytoplasm, and retains the functional chloroplasts within its own cells to perform photosynthesis. These "stolen" plastids allow the host to gain energy from sunlight, acting as "solar-powered" organisms.
Kleptoplasty
This chemical compound is the primary material corals use to build their skeletons.
Calcium carbonate (CaCO₃)
This large reef-dwelling bivalve contains symbiotic algae similar to those found in corals.
Giant Clams
Herbivorous fish are critical for reef resilience after bleaching events because they
Prevent algae from overgrowing and outcompeting recovering corals
This human activity accelerates reef decline by removing algae-grazing fish.
Overfishing
These specialized, stinging organelles located on coral tentacles are used for defense, prey capture, and aggression
Nematocysts