Figure 1.
Isobaric sampling and transfer of the Pompeii worms (step = circled number in a and b).
a, 1: in situ sampling of Alvinellas inside a “crocodile” cylinder (C), further closed and inserted in the recovery cell PERISCOP (P). 2: PERISCOP (closed) ascends through the water column. 3: On the ship, samples are transferred from PERISCOP (P) to BALIST (B). 4: thermal exposures. b, Pressure (black line) and temperature (red lines) recordings inside the "crocodile" (arbitrary time units). The asterisk and arrow indicate the beginning and end of the 3 thermal exposures (20, 42 and 55°C, dotted, plain and bold lines respectively). Numbers circled in green refer to the steps described in fig. 1a. c, d, see a, step 1 (Photographic credit Ifremer/MESCAL 2012). e, see a, step 3. A viewport (arrow) allows sample observation inside BALIST.
Figure 2.
In vivo experiments on Alvinella pompejana.
Views of a portion of A. pompejana tubes inside the BALIST aquarium during the 10 first minutes of the 55°C-exposure experiment. In the middle of the figure, an individual is observed leaving its tube (approximate diameter of tube opening = 1 cm).
Figure 3.
Temperature effect on survival, cell mortality and hsp70 gene expression in A. pompejana.
a, Survival of A. pompejana specimens after the recovery from the PERISCOP sampling device (‘sampling’, n = 9) and the subsequent in vivo experiments in the BALIST aquarium (‘20°C’, n = 19; ‘42°C’, n = 24; ‘55°C’, n = 18). b, Coelomocytes death in animals from Fig. 3a. c, Hsp70 gene expression (mean for n = 5 individuals ± s.e.m.). Among the four A. pompejana’s hsp70 genes (Alvinella database [12]), two forms showed significant changes according to temperature, and the form that showed the most significant changes is presented here. d, Normalized fold hsp70 expression in gills, posterior part and coelomocytes of experimented animals with respect to ‘sampling’ specimens.
Figure 4.
Morphological consequences of a 55°C-exposure in A.
pompejana.°C-exposed (left column) versus 55°C-exposed (right column) specimens. a, b, General view of specimens after the in vivo experiments; c, d, Sections of the dorsal region showing the delamination of the epidermis (e) and cuticle (c) at 55°C; e, f, Sections of the ventral tube secreting region showing the disappearance of the tegument and disorganization of the underlying tissues at 55°C; g, h, Sections of muscles (m) showing the disorganization of cells at 55°C. Bar represents approximately 1 cm in a, b and 50 µm in c-h.