Alor - Pasir Merah (Red Sand)

Setting

Visibility is good throughout with strong ambient light.

General benthic features

The opening frames confirm the site's name: a reddish-brown sediment/rubble plain (a mix of fine sand and small coral fragments giving it a distinctive rust-red hue) with only isolated small coral colonies (a pale mounding head, a purple encrusting patch, small faviid heads) and a black damselfish with an orange-tipped tail (e.g., Image 16, Image 51).

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Further along the dive, the habitat becomes a dense low-relief coral garden: massive Porites and Platygyra-type brain corals with maze-like grooved surfaces, foliose plating colonies with pale rims, a golden-brown giant clam (Tridacna) with a fluted, spotted mantle wedged among coral, large anemones (one brown carpet-type, one smaller) each hosting anemonefish, and a partially buried large gray-spotted pufferfish resting in a sandy hollow beneath overhanging coral (e.g., Image 2, Image 17, Image 21, Image 40).

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Black bushy growth consistent with black coral, a maroon/purple crinoid feather star, and a blue Linckia sea star recur on the reef structure (e.g., Image 30, Image 44).

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Coral cover is patchy rather than uniform: dense clusters of massive and plating corals alternate with open white sand patches hosting only scattered small colonies, consistent with a mixed sand/coral mosaic rather than continuous reef framework (e.g., Image 22, Image 32, Image 42).

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Coral cover

Coral cover: 16% — a blind Claude computer-vision point count of 174 of Anderson's unedited photographs (20 points per photo; water, fish, and obstructions excluded). Other computer-vision methods are listed in the method table.

Stressors

No bleaching or disease is visible on any photographed coral; all colonies show normal brown/tan/olive pigmentation, aside from expected white skeletal rims on actively growing plate margins.

Comparisons with other data

Also on record for this site: A heterogeneous volcanic slope of sand, rubble, and red or pink encrusted substrate interspersed with coral outcrops (e.g., Image 5, Image 7, Image 23).

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Anthias, chromis, and other damselfishes were locally dense above the slope (e.g., Image 18, Image 39, Image 54).

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A reef-to-wall transition with locally enhanced water movement; the gas vents reported for the site were not clearly captured (e.g., Image 27).

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Other notes

A guideline/rope runs through at least two frames, and one wide frame shows a large school of dozens of small dark fish (chromis/damsel-type) streaming along the reef edge in blue water with two divers visible in the distance (e.g., Image 8, Image 12, Image 13).

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