Fig 1.
Coral fragments were transplanted between locations on the reef flat (red) and reef slope (blue) of Heron Island in the Southern Great Barrier Reef of Australia.
For clarity, sites of colony origin are referred to as “reef slope” (blue zip tie) and “reef flat” (red zip tie), and locations of experimental positioning (transplantation) are referred to as “deep” and “shallow”, however, they describe the same habitat. In total 250 fragments of Acropora formosa were collected, 25 of these were stored as representative fragments to be used for initial measurements. The remaining 200 fragments had holes drilled and zip ties threaded through; these were attached to live rock for transplantation onto a metal rack. Created in Adobe Illustrator.
Fig 2.
End-point examples of Acropora formosa fragments following a reciprocal transplantation experiment conducted at Heron Island (Southern Great Barrier Reef).
(a) Fragments experimentally located as transplants to the “deep” reef slope, and (b) Fragments experimentally located as transplants to the “shallow” reef flat. Zip-ties represent location of colony Origin (slope = blue, flat = red). Tissue dieback can be observed at the base of fragments where zip-ties have been attached, differential levels of dieback are due to a lack of uniformity in the live rock corals were attached to. The red circle in (a) highlights dieback with algal growth, and in (b) highlights dieback with the absence of coralites and tissue. (c) in situ photograph of experimental rack on the reef flat.
Table 1.
Summary of statistical models.
Fig 3.
Fragment mortality potential, initial bulk volume of fragments and abiotic conditions associated with the reciprocal transplantation exercise conducted between the reef flat and reef slope of Heron Island (Southern GBR).
(a) In situ 24hr mean temperature (°C) and (b) in situ daytime mean PAR (photosynthetically activate radiation, μmol m−2 s−1) between 6:00 h and 18:00 h. Abiotic conditions for the deep site (depth = 7-8m, blue line), and the shallow site (depth = 1-3m, red line) were recorded from October 2017 –February 2018. Shading on both abiotic condition figures represent 25th percentile (Q1) on the bottom, and 75th percentile (Q3) on the top, of daily data recorded at each location. The dashed line in figure (a) represents the local MMM + 1 (28.3°C) which is associated with bleaching threshold. Grey area under curve indicates Q3 degree heating week (DHW) accumulation on the reef flat. (c) Initial differences in bulk volume (ml) between A. formosa fragments from each location of Origin (p<0.05). (d) The probability of fragment mortality by their location of Origin4, error bars represent a 95% confidence interval, grey dots show data points, and red dots indicate the mean value in data set.
Fig 4.
Change in bulk volume (ml/ml) of A. formosa fragments form Heron Island.
(Southern GBR) by (a) location of Transplantation (P <0.05), and (b) location of Origin (P <0.05). Change in living surface area (LSA, cm2/cm2) of A. formosa fragments by (c) location of Transplantation (P<0.05), and (d) location of Origin (P<0.05) for fixed rate of change in volume. The percentage change in buoyant weight for (e) percentage change in living surface area and (f) percentage change in total protein. For both (e) and (f) the black line indicates mean value, and the shaded band the confidence interval. (g) Change in buoyant weight (g/g) for fixed changes in living surface area between location of Transplantation (shallow and deep), and location of Origin (flat and slope). (h) Change in total proteins (mg/mg) for fixed changes in living surface area between location of Transplantation (shallow and deep), and location of Origin (flat and slope). Error margins in all graphs represent a 95% confidence interval. All variables are reported as percentage relative change from initial over the experimental period, as indicated by “% Δ” in all axis titles.