1-Results of one-way ANOVA comparing initial and final fluorescence variables (Yield, ETR) for the Control, Medium and Extreme temperature treatments, and 2- results of one-way ANOVA comparing different treatments fluorescence variables (Yield, ETR) for the initial and final time point of the experiment.

<p>*show significant differences p<0.05 and</p><p>**p<0.01.</p

The western Mediterranean Sea, showing the surveyed localities of <i>Ircinia fasciculata</i>.

<p>The western Mediterranean Sea, showing the surveyed localities of <i>Ircinia fasciculata</i>.</p

Percentage of the summer period with temperatures above 23°C, 24°C, 25°C and 26°C in Cabrera NP (a) and above 23°C, 24°C and 25°C in Scandola RN (b).

<p>Data from SOMLIT (temperature sensors) data series.</p

Aspects of <i>Ircinia fasciculata</i> mortality.

<p>a) First stage of the affectation on <i>I. fasciculata</i> (arrow head) compared with healthy <i>S. spinosulum</i> (arrow), b) small whitish spots on the <i>I. fasciculata</i> surface, c) completely dead <i>I. fasciculata</i> with the skeleton (spongin network) free of cellular material, (d) white bacterial veil on unhealthy <i>Sarcotragus spinosulum</i> surface.</p

Relationship between the percentage of time above a temperature threshold (26°C) from August 1 to September 30 and the percentage of affected <i>I. fasciculata</i> colonies in Cabrera NP.

<p>Relationship between the percentage of time above a temperature threshold (26°C) from August 1 to September 30 and the percentage of affected <i>I. fasciculata</i> colonies in Cabrera NP.</p

Temperature records (from 1 August to 30 September) at 15 m depth obtained in Scandola RN and Cabrera NP.

<p>TX and T max refer to the average mean and maximum temperatures, respectively, obtained for the available period in each study area.</p

Mean densities of <i>Ircinia fasciculata</i> (a) and <i>Sarcotragus spinosulum</i> (b) recorded in Cabrera NP (circles, C) and Scandola RN (triangles, S) during the monitoring period.

<p>Bars represent standard errors. Mean concentrations, which were not significantly different in a Tukey test, are joined by horizontal lines. N =  number of specimens sampled.</p

Several ultrastructural aspects of a healthy <i>Ircinia fasciculata</i>.

<p>A) Archeocyte of a subectosomal zone, surrounded by numerous cyanobacteria (c) and some heterotrophic bacteria (h); B) Detail of a healthy cyanobacteria, close to an archeocyte plenty of glycogen rosettes (g); C) “symbiotic” bacterial community, typically found in the sponge; D) collagen layer (co) between endopinacocytes (pi) separating two choanocyte chambers (ch: choanocytes); E) collagen bundles, surrounded by endopinacocytes (pi); F) basal section of a choanocyte, full of heterogeneous phagosomes (ph), which is characteristic of the species (n: nucleus).</p

Two-way ANOVA results for Cabrera NP <i>Ircinia fasciculata</i> and <i>Sarcotragus spinosulum</i> densities and % of injured specimens, with site (random) and time (fixed) factors.

<p>ANOVA results for Scandola RP <i>Ircinia fasciculata</i> and <i>Sarcotragus spinosulum</i> densities and % of injured specimens across time.</p

Localities and geographical position where the presence (+) or absence (−) of mass mortality was assessed.

*<p>Present study</p>**<p>Maldonado et al. 2010.</p