# Coral Reef and Volcanic Islands

I have two questions regarding coral reef and volcanic islands.

When a new volcanic island is formed, how much time generaly passes before a coral reef starts to form around the island?

Another question: Are there any volcanic islands in warm pacific waters which do not show fringing or a barrier reef? If so, is this because the island was formed recently and is still too hot for a coral reef to flourish?

• Please edit your question to make which does not Fringing or barrier reef clear... May 22 '19 at 10:08
• @david welcome to Stackexchange! I've edited your question to tidy up the English a little. I think that I have maintained your intended question, but if I haven't then I apologise, and please either tell me here, or edit it yourself. May 23 '19 at 16:59
• This article says "However, they grow very slowly—anywhere from 0.3 cm to 10 cm per year The reefs we see today have been growing over the past 5 000 to 10 000 years". May 24 '19 at 1:35
• I read the article. Thanks Keith! May 24 '19 at 7:02

I just came upon this paper by Tomascik et al. (1996). It does not answer directly your question, but I found it sufficiently relevant to post it here anyway. It is a study of coral colonization after emplacement of a lava flow. They found that only five years after emplacement of an andesitic lava flow from Gunung Api in 1988, large parts of this new coastline was already covered by coral. They mention a previous study (Grigg and Maragos 1974) on Hawaii where it took 20$$-$$50 years for coral to colonize a submerged lava flow.

Of course, in those cases the coral could come from nearby reefs, while in the case of a new island it has to come from further away. So those fast colonization timescales are not directly applicable to your question.

based on Hunga Tonga, either within a decade or even before the volcano ever reaches the surface.

https://matangitonga.to/2019/12/09/Tonga-corals-hunga-volcano

• Nice one! Although in this case also coral could come from pretty close as the new land is connected to older islands. Dec 17 '19 at 13:04

Geologic evidence for coral go back 500 million years. Hawaiian islands are great examples as island chain, with Kauai 5.7 million and the youngest "Big Isle" at 110,000"

Normally coral reefs take many millennia, but fast colonization time scales coral can proliferate pretty fast. Soft corals are the fastest growing. It typically takes coral 25 to 75 years to reach sexual maturity.

Montipora capricornis (Leaf Plate) can also grow pretty quick....All in all it takes 1000 years to get a mature reef unrecognizable from natural ones 10,000+ years. Since corals build atop existing skeletons it's hard to gauge their age.