# A 1.5-Kilometre Coral Ribbon in the Indian Ocean, and a Question Only DNA Can Answer

- Link: https://www.o0justjoseph0o.com/cocos-islands-coral-ribbon-1-5-kilometres/
- Published: 2026-11-11T18:04:57+05:00
- Author: admin

On the deep outer slope of a tropical reef in the middle of the Indian Ocean, there
lives a coral colony 1.5 kilometers (just under a mile) long, and potentially thousands
of years old.

That is how ScienceAlert described the find on 11 November 2026. The report rests
on fieldwork by marine biologist JP Hobbs, who mapped the colony over 12 dives at
depths of 14 to 65 metres near the Cocos (Keeling) Islands, an Australian territory
in the Indian Ocean.

The coral is a _Pachyseris_ rose coral. Colonies of this genus normally grow to 
about 2 metres across. This one was traced as a ribbon roughly 1.5 kilometres long
along the slope.

The length is a mapped figure, not a complete one. A 10-metre break interrupts the
formation, and the survey left it out. That means the structure may once have stretched
more than 2 kilometres — and that 1.5 km is the conservative reading of what the
divers recorded.

What the divers could not establish is what the ribbon is. It may be a single clonal
animal, one organism that has copied itself outward over a very long time. It may
instead be several related colonies that grew into one another and fused. The DNA
that would settle the question has not been sequenced. Fifty tissue samples have
gone to the Queensland Museum, where Peter Cowman is leading the genomic work.

“If it is one organism, made up of many clones that have accumulated, replicated
and expanded over the years,” Cowman said, “it could be hundreds or even thousands
of years old.”

— Peter Cowman, Queensland Museum, to ScienceAlert.

The conditional matters. If it is one organism, the age could be in the hundreds
or thousands of years. If it is a merger of colonies, each part has its own history,
and the ribbon is old without being a single old individual.

“I think if it is one single individual, it might be one of the largest corals that
has been found.” — Peter Cowman, to ScienceAlert.

“One of the largest” is a cautious comparison, not a record. Nobody has measured
this colony against every other known coral and certified a ranking. Cowman’s phrasing
is doing exactly the work it should: describing a possibility, not announcing a 
title.

There is also no paper. The find has not been through peer review, and no independent
second outlet was available to check the reporting. This is one outlet’s original
reporting on unpublished fieldwork. It should be read as reported, not established.

If the DNA does show a single individual, the implications go beyond size. A coral
that has persisted for centuries or millennia on a deep outer slope would be evidence
that this part of the reef has been stable for a very long time — the kind of long-
run stability reef scientists rarely get to observe directly.

For now, the honest description is narrower than the headline invites. A rose coral,
normally a couple of metres wide, has been mapped as a 1.5-kilometre ribbon in deep
water. It might be one animal. It might be several. It is probably old. The samples
are in the lab, and the answer is not in yet.

Source: ScienceAlert, 11 November 2026.
 Photo: Jerry Reid / U.S. Fish and Wildlife
Service, public domain, via Wikimedia Commons — illustrative image, not the colony
described.