Table 1.
Abundance of some invertebrate species at Conero Promontory (NW Adriatic Sea) before, during and after the disease.
Table 2.
Filtration rates of some species from the study area before and after the disease of 2009 and almost two years after the disease of 2011.
Fig 1.
Effects of the disease on some benthic species.
A-B) Appearance of Aplysina aerophoba before (A) and during (B) the disease. C) The anemone Aiptasia sp. was contracted during the disease (C) but it appeared in healthy conditions about one month later (D). E-F) Colonies of Eudendrium racemosum lacking of polyps (E) and of Cornularia cornucopiae with contracted anthocodia (F). G) Hydroids completely recovered within a month from the disease (picture G by F. Betti). Scale bars A-F 5 cm, G 10 cm.
Fig 2.
Underwater pictures of different areas occupied by Chondrosia reniformis before, during and after the disease.
A) Picture of a healthy individual of C. reniformis taken before the disease. B) During the disease, almost the total surface of C. reniformis showed necrotic areas characterized by white and putrefied tissues. C-D) Large areas visible in November 2013 after the detachment of dead C. reniformis; the rocky wall is covered with calcareous tubes of serpulids (C) and cirripeds (D). E-F) Recovery of the area after almost two years; the areas where C. reniformis was the dominant species (CrAs) were colonized by pioneer species such as the tubeworm Spirobranchus triqueter and the bryozoan Schizobrachiella sanguinea (E); the areas where C. reniformis was not the dominant species (OAs) were mainly occupied by cnidarians (cn), encrusting sponges (es) and the encrusting alga Titanoderma sp. (ea). Scale bars A-F 5 cm.
Fig 3.
Trend of weekly average values of wave height (m) and superficial temperature (°C) of 2011.
The blue area indicates the prolonged period of calm sea conditions and high temperature (from June to the first week of October).
Table 3.
Duration of periods of calm sea and high temperature from 2000 to 2013.
Fig 4.
Average daily temperature from July to September of the years 2010–2012.
The trend relative to the year with episodes of disease (2011) were showed by a continuous red line. Temperature kept high (≥23°C) throughout September.
Fig 5.
The bar charts show the comparison of the abundance of the most representative species before (June 2009) and after the disease (June 2013 and 2014) both in the areas where C. reniformis was the dominant species (CrAs) (A) and in the other areas (OAs) (B). C) Abundance of fauna associated to C. reniformis before (June 2009), immediately after (November 2011) and almost two years after the disease (June 2013).
Fig 6.
Reduction of Chondrosia reniformis and Irciniidae/Spongiidae communities after the two disease events.
Scheme illustrating a 0.5 x 0.5 m marked area subdivided in 9 sub-quadrats of 16.7 cm side in four different moments: before (June 2009) (A) and after (B) (October 2009) the first outbreak and after the second outbreak (November 2011 (C) and June 2013 (D)). The surfaces covered with Chondrosia reniformis and Irciniidae/Spongiidae were indicated in red and brown, respectively; numbers indicate the total cover of each species. Pictures E-F shows the central area of the quadrat (16.7 cm side) colonized by different assemblages in June 2009 (D) and June 2013 (D). Cr: Chondrosia reniformis, En: Eupolymnia nebulosa, Es: Encrusting sponges, Ms: Microcosmus sp., Pn: Phallusia nigra, IS: Irciniidae/Spongiidae, St: Spirobranchus triqueter, Sv: Serpula vermicularis. Figure F by F. Betti.