Follow the coral

Background to this study - a coral baseline from more benign times

If you want to skip this until later, go back to the opening page, scroll down below the beautiful coral scene, then select one of the tasks

Starting in the early 1980s, the Australian Institute of Marine Science (AIMS) established around 30 permanent sites to learn about the dynamic behavior of coral communities. The communities vary in composition across different reef-zones and environments, from sheltered nearshore reefs in turbid waters, through to the slopes and surf zones of outer reefs. AIMS photographed the sites most years from 1980 to 2000, and had them digitized soon after that.

Now, some of these sites are included in a new study, and with your help, we will learn how changes recorded in the new study compare to the various 'shifting baselines' recorded within the 1980-2000 series. During that period, there was much variability in the sites' exposure to and recovery after disturbances.

Location of the study areas

To make sure that we covered all the major environments and types of coral communities, we established the 'AIMS cross-shelf series' at latitude 19 degrees South, and the 'Lizard Island and Yonge Reef series', at latitude 15 degrees South. In the figure below, each triangle marks a 'site', which is the location of several 'photo-transects' (see Terminology below). See the Field Guides for more detail about the study sites and their physical environments.

The AIMS cross-shelf series

Pandora Reef is a 'turbid coastal reef' in waters that often gets stirred up and made muddy by south-east winds. Rib and John Brewer are 'mid-shelf' reefs where the water is rarely turbid, and Myrmidon Reef (an 'outer-shelf reef') sits way out in clear waters, pounded by massive waves from the Coral Sea.

Lizard Island and Yonge Reef

The reef at Lizard Island is a 'fringing reef' built on the island's rocky shores, Yonge Reef is a 'ribbon reef' perched close to where the edge of the shallow continental shelf (<100 m) plunges to > 2000 m).

Terminology

In this study, 'reefs' have several 'sites', which contain one or more 'photo-transects', each running along a depth contour - usually between 20 m and 2 m. We drove steel pegs into the reef and, each time we visited the site, ran a surveyor's tape measure between them and took near vertical photos at each 1 m mark. This strip of photos is called a 'photo-transect'.

The strip of images below shows part of the first photo-transect we took back in 1980. Each image covers about 1 square meter. Your task is to help us follow changes in abundance of the various types of corals, sponges and algae at that site through the years. You simply mark a 'thing' and answer two questions about its abundance. We provide the identifications.

A few words about corals, reefs and resilience

To float over a healthy coral reef in clear tropical waters is to witness an amazing creation of nature. Before you, you see hard corals that stand rigidly in the surging waves, and soft corals, sea fans and sea whips that move with the surge. Both hard and soft corals have an amazing diversity of shapes and sizes that provide a place to live for countless crabs, snails, clams, urchins, fishes and other tropical species.

Hard corals are the building blocks of coral reefs. Over thousands of years, hard corals have built coral reefs by settling on the dead skeletons of previous generations of hard corals that are cemented together by ‘coralline algae’, just like bricks in a house are cemented together by mortar. But this ‘house’ is riddled with creatures called ‘bioeroders’. Bioeroders (such as sponges, worms and mollusks) are a normal part of coral reef biodiversity: they bore into and hollow out living and dead corals, and the reef structure itself. From time to time, both living and bored corals are smashed by storm waves and broken into rubble and sand. Rubble and sand are also important as coral reef habitats, but here our focus is the coral and the reef structure itself.

In the composite view above and the diagram below, this healthy reef is extending itself over the shallow sandy seafloor to its right. It takes a critical destructive wave to spread the rubble to where new coral larvae can settle and viable fragments can resume their growth.

Episodic disturbance is a normal aspect of Great Barrier Reef coral communities. The most common are mass coral predation by crown-of-thorns sea-stars (Acanthaster planci), heatwaves causing coral bleaching, and destructive waves generated by cyclones (hurricanes). The disturbance episode may be of short duration, whereas recovery can be very slow, depending on rates of settlement and survival of new corals. 'Resilience' refers to the extent to which, and rate at which, the pre-disturbance state of the coral community is regained.

For more information on episodic disturbances see:
https://www.aims.gov.au/docs/research/biodiversity-ecology/threats/cots.html
https://www.gbrmpa.gov.au/__data/assets/pdf_file/0016/14308/GBRMPA-ExtremeWeatherAndtheGBR-2010-11.pdf
https://www.aims.gov.au/coral-bleaching

The archive of images available to this study will, with your help, allow us to document, for the first time, differences in coral community resilience in different types of coral reef, and different zones within those reefs. You will help us gather two simple measures of the main types, abundance and sizes of corals from 1980 to 2000. These decades were before coral bleaching became a major recurrent disturbance on the Great Barrier Reef (though some of our sites were affected). Most coral death documented in these images was caused by predation by Acanthaster planci.

How did we collect the images?

We used a twin underwater camera rig to take stereo pairs using Kodachrome film. These images were digitized in 2002.

The rig setup allows stereoscopic viewing and photogrammetry, but here we request your help with monoscopic images only.

Before you start

Please click on the Tutorial Tab for detailed instructions.

Coral Abundance

Here, you follow changes in the types and abundance of things growing in the sites from 1980 to 2000. There were remarkable changes during the study period, so don't worry if there is nothing obvious in the scene you are looking at. Your data for these 'empty' scenes will help us just as much as your data for those scenes that have lots of obvious corals, etc., in revealing the big picture.

We've made things easy for you: you count stuff; we identify it.

Further Reading
You can access the following relevant publications by their 'TD ##' code at:

https://1drv.ms/u/s!Ah0IPTbzqn4sg95EdOszyzEfmHZKNQ?e=H1pA18

1. Done TJ (1982) Patterns in the distribution of coral communities across the central Great Barrier Reef. Coral Reefs 1: 95-107. (TD 08)

2. Done TJ (1992) Constancy and change in some Great Barrier Reef coral communities: 1980-1990. American Zoologist 32: 655-662 (TD 26)

3. Ninio R, Meekan M, Done T, Sweatman H (2000) Temporal patterns in coral assemblages on the Great Barrier Reef from local to large spatial scales. Marine Ecology Progress Series 194: 75-74 (TD 41a)

4. Done TJ, Turak E, Wakeford M, DeVantier L, McDonald A, Fisk D. (2007) Decadal changes in turbid-water coral communities at Pandora Reef: loss of resilience or too soon to tell? Coral Reefs 26:789–805 (TD 57)

5. Wakeford M, Done TJ, Johnson CR (2008). Decadal trends in a coral community and evidence of changed disturbance regime. Coral Reefs 27: 1-13 (TD 58)

6. Done TJ, DeVantier LM, Turak E, Fisk DA, Wakeford M, van Woesik R (2010) Coral growth on three reefs: development of recovery benchmarks using a space for time approach. Coral Reefs 29:815–833. (TD 62)