Dykning med Ildkoraller

Koh Lantas Marineliv | Milleporidae

Ildkoralarter er sessile (stationære, fikserede på ét sted) Medusozoa, som er i stand til at producere calciumkarbonatskeletter og danne kolonier, der ligner de hårde koraller, men de er ikke ægte koraller. Vi kan se enorme kolonier af ildkoraller, når vi dykker fra Koh Lanta omkring Koh Rok.

Nogle arter er vigtige revbyggere, og flere Millepora-arter er i stand til meget hurtigt at danne skeletter af kalciumkarbonat. Disse skeletter er dækket af utallige porer, som indeholder polypperne. Hver fødepolyp er omgivet af mange defensive brodpolypper, som indeholder batterier af nematocystceller. Ved berøring trænger nematocysterne ind i menneskehuden og indsprøjter en kraftig gift, der skaber den 'ildlignende' forbrænding.

Ud over at fange byttedyr med deres stikkende nematocystpolypper får ildkoraller næringsstoffer via deres særlige symbiotiske forhold til alger, der kaldes zooxanthellae, ligesom de hårde koraller.

2 arter fundet på denne side:

Branching Fire Coral (Millepora tenella)
Leaf Fire Coral (Millepora platyphylla)

Branching Fire Coral

(Millepora tenella)

Millepora tenella @ Koh Rok

Branching Fire Coral is commonly seen at all of the dive sites around Koh Lanta. A Branching Fire Coral colony begins by encrusting a surface to form a base, and then growing outward in multiple branches.

This is a fast growing species and is capable of taking over large areas of a reef.

The colonies consist of thick, golden brown branches, with the growth zones at the tips of the branches being white.

Branching Fire Coral @ Koh Rok

Branching Fire Coral feed on plankton, and similar to true corals, due to their symbiotic relationship with zooxanthellae, they are subject to bleaching if the colourful zooxanthellae algae leave the polyps due to high sea water temperatures for example.

Fire corals can deliver a very painful burn-like sting - do not touch fire coral, you will regret it.

Leaf Fire Coral

(Millepora platyphylla)

Millepora platyphylla @ Koh Rok

Leaf Fire Coral grows vertically in leaf or plate-like branches. This species likes to grow on the top of the reef, in turbulent water (in the wave action zone) and enjoys strong sunlight which is necessary for the symbiotic zooxanthellae algae’s photosynthesis.

Leaf Fire Coral @ Koh Rok

Leaf Fire Coral is densely branched and provides shelter and home for a wide range of other species, including shrimp, frogfish, moray eels, and other small fish seeking refuge from potential predators.

As with other Fire Corals, Leaf Fire Coral can deliver a very nasty poisonous burn if touched.

Fire corals grow quickly and can push out other hard coral species to dominate some areas of a reef. Whilst this can be destructive, it can also contribute toward the survival of hard corals during Crown of Thorns outbreaks, as Crown of Thorns sea stars tend to avoid Fire Corals.