Light transport in coral skeletons.

<p><b>A</b> – Visual demonstration of differences in light transport shown for three taxa as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0061492#pone.0061492-Enrquez2" target="_blank">[10]</a> by focusing a laser on (a) highly-absorbing black surface and on skeletons of (b) <i>Leptastrea transversa</i>, (c) <i>Leptoria phrygia</i>, and (d) <i>Seriatopora caliendrum</i>. Microscopic light-scattering properties of skeletons were measured using LEBS with a white light source. <b>B</b> – Schematic representation of the redistribution of light between sun-exposed versus shaded areas. Differences in light transport are shown for corals with (a) very high skeleton and a (b) low skeleton. Skeletons capable of longer light transport (i.e. longer or low ) are able to illuminate otherwise shaded areas in the colony and this increased redistribution between sun-exposed versus shaded areas of a colony may further amplify the light available to the algae: (I) downwelling light, (II) diffuse reflectance, (III) photon path (arrows) and sub-micron scatters (black dots), (IV) diffuse reflectance illuminating a shaded algal cell in the coral tissue: the skeleton serves as a secondary light source <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0061492#pone.0061492-Enrquez1" target="_blank">[9]</a>.</p

Evolutionary correlation between scattering coefficient and coral bleaching.

<p>A composite phylogeny shown in mirror image, with character states for (left) and BRI (right) mapped to illustrate their significant correlation (p<0.05) throughout the evolutionary history of corals. High bleaching susceptibility appears to be less common toward the base of the coral tree (box A) and higher in the <i>Montipora-Acropora</i> clade (box B) and the “Robusta” coral clade (box C).</p

Fractal dimension of different biogenic (biomineralized) and non-biogenic materials as measured by LEBS.

<p>Fractal dimension of different biogenic (biomineralized) and non-biogenic materials as measured by LEBS.</p

Excess light dynamics.

<p><b>A</b> – Relationship between excess light (<i>E</i>) and concentration of absorbing particles (<i>ρ</i>). Data collected using ‘flat coral models’: Bottom layer: ∼1 mm skeleton slices (<i>Pocillopora damicornis</i> - open circles; <i>Seriatopora hystrix</i> - squares, <i>Porites lobata</i> - diamonds) on top of a highly scattering standard or the standard alone - triangles. Top layer: set of five 1 mm polymer layers containing progressively lower concentrations of fluorescent 6 µm microspheres (<i>ρ</i>) mimicking light absorbing symbionts densities in healthy tissue (100% cover = 7.8×10⁶ microspheres/cm²) and in corals undergoing bleaching response up to 93% bleached (0.7×10⁶ microspheres/cm²). <b>B</b> – association with the rate of excess light increase (Δ_E) for 13 skeletons of 10 coral species. Δ_E was calculated for each ‘flat coral’ construct from data as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0061492#pone-0061492-g002" target="_blank">Fig. 2A</a>.</p

Relationship between growth-form averaged- and fractal dimension (D_f).

<p>Example colonies of various growth forms: (a) thin-branching: <i>Seriatopora hystrix</i>, (b) medium-branching: <i>Stylophora subseriata</i>, and (c) thick-branching <i>Acropora variolosa</i> (average diameter of branches shown in figure), (d) laminar/foliaceous: <i>Echinopora lamellosa</i> and (e) massive: <i>Galaxea</i> sp.</p