Coral Reef Diagnostics

N. GBR - Green (AULK20)

Khaled bin Sultan Living Oceans Foundation — Global Reef Expedition
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Part of the regional summaries: Australia (GBR) - Far North: Green stations (no-take reefs) and Australia (GBR)

05
Coral Health Index: TBD
Country
Australia
Survey date(s)
2014-09-06
Coordinates
-15.2672, 145.5805
Coral cover
51%
Benthic transects+photo-quadrats
Observations
not yet tagged for this site
Heat stress
Today’s heat load
24.8°C0.0°C-weeks
3 Oct 2026 · No heat stress
5-year thermal stress load
5-year mean max. degree heating weeks (DHW)
7.8°C-weeksi
2021–2025
NOAA Coral Reef Watch — Northern GBR virtual station
i 5-year mean max. DHW is the mean of the annual maximum DHWs over the five complete years named above, not conditions today.
More infoNorthern GBR (NOAA CRW virtual station)
Survey depth (expedition team)
6.9 m
Living Oceans Foundation (LOF) benthic survey depth; no dive by Anderson at this station
Sea surface temp. (satellite)
24.6°C
satellite sea surface temperature (SST) on the survey date (NOAA Coral Reef Watch, Northern GBR), not an in-water reading; it is the warmest-pixel (90th percentile) reading in the station area and can run 1–1.5°C above the reef

Two other CRD dive sites within 5 km shown in orange — click a marker to open its page.

🗺 Detailed map of the Global Reef Expedition dive sites, Lark, Williamson, and unnamed reef 15-043, northern Great Barrier Reef (Khaled bin Sultan Living Oceans Foundation; opens in a new window)

Site description

Setting

Global Reef Expedition station AULK20 on Lark Reef, northern Great Barrier Reef (-15.2672, 145.5805), surveyed on 6 September 2014, in a no-take Marine National Park (Green) Zone.

Coral cover

Stressors

Regional context only: surveyed about eighteen months before the 2016 mass bleaching, an event that severely bleached hundreds of reefs on the northern Great Barrier Reef (Hughes et al. 2017); 5-year mean annual maximum thermal stress at the Northern GBR virtual station is 7.8 degree heating weeks.

Comparisons with other data

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

Nearby citizen-science imagery within 2 km (not a survey of this site, and not total coral cover):

  • Great Reef Census (citizen science, AI + volunteer image analysis): branching Acropora 6.1%, plating Acropora 8.4%, massive corals 3.9% of colonizable substrate, 38 images, 2024-11-06, 1.44 km.

The Great Reef Census scores three coral shapes only, so every other coral is left out, and its denominator is colonizable substrate (sand, water, and shadow excluded): these values are not hard coral cover and should not be added together or compared with the cover figures on this page. The photographs are taken by volunteer snorkelers 3–5 m above the reef. In the program's own validation (Lawson et al. 2025, Environmental Monitoring and Assessment 197:814, doi:10.1007/s10661-025-14261-6, open access), each analysis method on its own differed from expert estimates by up to about 9.5 percentage points on average for these coral types (AI alone: plating Acropora −9.1 points; AI plus volunteers: branching Acropora +9.5 points); the program's “~99% accurate” figure is the average over about 8,000 images after choosing the better method for each coral type, and site values from fewer images carry more error. Sites with fewer than 40 images have fewer images than the 40–80 the method needs to estimate site-level values to within 5 percentage points. Source: Great Reef Census / Citizens of the Great Barrier Reef; Lawson et al. 2026, Limnology & Oceanography Letters, doi:10.1002/lol2.70168 (data CC BY-NC 4.0, doi:10.7910/DVN/KCULSD).

Data & links

Data are from the Khaled bin Sultan Living Oceans Foundation Global Reef Expedition and Coral Reef Diagnostics.

© Coral Reef Diagnostics.