N. GBR - Green (AU3479)

Setting

Global Reef Expedition station AU3479 on Unnamed Reef 34, far northern Great Barrier Reef (-11.1548, 143.0872), the first of Anderson's three dives there on 17 September 2014, in a no-take Marine National Park (Green) Zone. His notes describe a very murky site (4-5 m visibility, "possibly less") on a gently sloping sand slope; corals appeared to be absent below 12 m, so he ran his five transects at 8.5-10 m.

General benthic features

His notes describe shallows characterized by huge thickets of Millepora fire coral, Porites cylindrica, and P. lobata or other massive poritids, with live coral cover reaching 60-70% in many areas but only four or five species. On his transects he listed soft corals, fungiids, Lobophyllia, Caulastrea, large Pachyseris, Pocillopora acuta, large massive Porites, Acropora, Isopora, several favid species, blue coral, and encrusting sponges; a well-developed patch, at the base of the reef system (9.7 m), held 10-15 species. The 21 posted frames are from the shallow reef. Dense thickets of upright branching colonies, brown with pale tips, fill the first eight and rise toward the surface under schools of damselfish (e.g., Image 1, Image 2, Image 3, Image 4, Image 5, Image 6, Image 7, Image 8), and in two more a thicket runs in front of a very large, evenly pale massive dome (e.g., Image 9, Image 10).

12345678910

Other frames show large massive and encrusting colony mounds and a steep face of massive colonies pocked with boring holes (e.g., Image 11, Image 12, Image 13), a big brown dome (e.g., Image 14), a mix of massive and branching colonies (e.g., Image 15), a rounded knobby massive colony beside a long-spined sea urchin (e.g., Image 16), pink-orange lobed colonies (e.g., Image 17), and a branching colony over a brown massive colony (e.g., Image 18).

1112131415161718

Porites was the most common coral genus on this station's transects (18% of the benthos), followed by Montipora (7.3%), Favites (2.7%), Goniopora (2.3%), Pavona (1.7%), and Lobophyllia, Pectinia, and Platygyra (1.3% each); bare substrate covered 30%, the largest non-coral class. Among the algal classes on this station's transects, sediment-laden turf (17%) led, followed by turf (3.3%) and macroalgae (0.7%).

Coral cover

• Reference: Khaled bin Sultan Living Oceans Foundation, Global Reef Expedition (in situ transect)
• His by-eye estimates on the five transects were 5% and under 5% at 10 m, 10-15% at 9.7 m, 15-20% at 9 m, and 20-25% at 8.5 m, well below the 60-70% he estimated in the shallow thickets.
• The expedition's in situ point-count transects at this station recorded 46% live coral cover against 21% total algal cover.
• Transect mean 46 ± 2.9% SE (n = 3 transects; Living Oceans Foundation per-transect benthic data); the headline above is the expedition's station value.

Stressors

At 10 m much of the hard bottom was coral rubble blanketed in clay silt and overgrown by fleshy macroalgae; his notes describe it as "coral rubble covered by clay silt and fleshy macroalgae," with some living hard coral still present at 10 m and much more at 8-9 m. On his 9 m transect the rubble was poorly cemented and silt-covered, and staghorn strands showed partial mortality. His notes for this dive do not mention bleaching, disease, or crown-of-thorns starfish.

Fish and other fauna

His notes log an aggressive, large (2 m) gray reef shark and one cushion star (Culcita) as a sighting, with feeding not recorded; neither is in the posted frames. Giant clams sit among the corals in one frame (e.g., Image 19), and two close views show a clam's folded, patterned mantle (e.g., Image 20, Image 21).

192021

Comparisons with other data

No prior survey data from this site. If you would like to share yours, please email us.

Other notes

By their capture times, the 21 downward photo-quadrats matched to this reef by boat GPS position and date were taken on the second dive here (AU3481), and that page shows them.