Scientists have discovered a deep-water bamboo coral forest in the
South China Sea, where tall, whip-shaped coral colonies grow alongside sea fans, sponges and other marine animals.
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colonies → discover → fans
The forest lies at depths of 1,200 to 1,380 metres near the Xisha Islands, also known as the Paracel Islands.
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forest → lie → Islands
The discovery was made during a research expedition in May 2018 using the manned submersible ‘ShenhaiYongshi’.
uncertain
discovery → make → ShenhaiYongshi
According to research published in Scientific Reports titled ‘
Discovery of Deep-Water Bamboo Coral Forest in the South China Sea’, the coral colonies became denser at shallower depths.
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colonies → accord → depths
The findings provide the first set of observations of deep-water bamboo coral forests in Southeast Asia and open new opportunities to study these ecosystems and their conservation needs.
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findings → provide → ecosystems
The coral forest was discovered at the foot of the submerged Ganquan reef, near the western edge of the Xisha Islands.
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forest → discover → Islands
During an expedition in May 2018, researchers used the manned submersible ‘ShenhaiYongshi’ to explore underwater areas between 600 and about 1,400 metres deep.
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researchers → use → areas
The expedition was originally planned to explore drowned coral reefs, so the discovery of a dense bamboo coral forest came as a surprise to the researchers.
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discovery → plan → researchers
Researchers spotted patches of tall, slender bamboo corals along the submersible's route.
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Researchers → spot → route
The colonies often stood more than two metres tall, with their curling upper sections extending their total length to as much as five metres.
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sections → stand → metres
The discovery marked the first recorded observation of deep-water bamboo coral forests in Southeast Asia.
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discovery → mark → Asia
How does the bamboo coral forest support other marine life
The forest is dominated by bamboo corals temporarily identified as ‘Lepidisis sp’.
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forest → support → sp
These corals belong to the family Isididae and have whip-shaped, unbranched colonies with articulated skeletons.
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corals → belong → skeletons
Researchers also recorded two forms of cold-water gorgonian corals, Anthogorgia sp. and Calyptrophora sp.
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Researchers → record → corals
The Anthogorgia colonies were about 20 centimetres tall, while the broader Calyptrophora colonies reached around 40 centimetres.
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colonies → reach → centimetres
Sponges were also an important part of the forest, with some areas of the seabed covered by dense groups of sponges.
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areas → cover → sponges
Cirrate octopuses, crinoids and other animals were also observed during the expedition.
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octopuses → observe → expedition
The researchers noted that the bamboo coral forest appeared to provide habitat for a range of animals living near the seabed.
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forest → note → seabed
What did researchers discover about coral density at different depths
Researchers recorded a clear change in coral density along the lower slope of Ganquan reef.
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Researchers → discover → reef
Their observations showed that density increased from 24.8 colonies per 100 square metres at a depth of 1,380 metres to 220 colonies per 100 square metres at 1,200 metres.
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density → show → metres
Across 10 dives, the team recorded 638 metres of seabed video, covering an estimated area of 1,856 square metres.
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team → record → metres
The recordings lasted a total of 51.7 minutes.
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recordings → last → minutes
Researchers counted 1,877 coral colonies across 23 video sequences, including bamboo corals, sea fans and other coral forms.
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Researchers → count → corals
The study also recorded a maximum density of 225.6 colonies per 100 square metres at a depth of 1,199 metres on the Ganquan slope.
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study → record → slope
How do underwater conditions support the growth of the bamboo coral forest
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conditions → support → forest
The researchers linked the forest's presence to the underwater landscape, the submerged reef surface and active currents carrying nutrient-rich water.
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researchers → link → water
They also observed intense showers of marine snow, made up of organic material falling from the upper layers of the ocean.
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They → observe → ocean
These currents were reflected in the movement of the whip-shaped bamboo corals and the orientation of the sea fans.
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currents → reflect → fans
Other deep-water gorgonian corals were found during dives in a canyon at a depth of 2,000 metres and around a mud volcano at about 600 metres.
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corals → find → metres
However, the densely populated forest was found only along the Ganquan reef slope during the expedition.
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forest → find → expedition
The Aporia
