Shell nacre ultrastructure and depressurisation dissolution in the deep-sea hydrothermal vent mussel Bathymodiolus azoricus.
This study describes the micro-morphological features of the shell nacre in the vent mytilid Bathymodiolus azoricus collected along a bathymetric gradient of deep-sea hydrothermal vents of the mid-Atlantic ridge (MAR). Pressure-dependent crystallisation patterns were detected in animals subjected to post-capture hydrostatic simulations. We provide evidence for the following: (1) shell micro morphology in B. azoricus is similar to that of several vent and cold-seep species, but the prismatic shell layers may vary among bathymodiolids; (2) nacre micro-morphology of mussels from three vent sites of the MAR did not differ significantly; minor differences do not appear to be related to hydrostatic pressure, but rather to calcium ion availability; (3) decompression stress may cause drop off in pH of the pallial fluid that damages nascent crystals, and in a more advanced phase, the aragonite tablets as well as the continuous layer of mature nacre; and (4) adverse effects of decompression on calcium salt deposition in shells was diminished by re-pressurisation of specimens. The implications of the putative influence of hydrostatic pressure on biomineralisation processes in molluscs are discussed.
Kadar
Eniko
E
Department of Oceanography and Fisheries, IMAR Centre of the University of the Azores, Cais de Santa Cruz, 9901-862, Horta, Portugal. enikokadar@notes.horta.uac.pt
Checa
Antonio G
AG
Damasceno-Oliveira
Alfredo
A
Oliveira
Alfredo N D P
AN
Machado
Jorge P
JP
D000818:Animals; D001267:Atlantic Ocean; D002113:Calcification, Physiologic; D002119:Calcium Carbonate / Q000737:chemistry* / Q000378:metabolism; D003460:Crystallization; D006863:Hydrogen-Ion Concentration; D006874:Hydrostatic Pressure; D008855:Microscopy, Electron, Scanning; D008968:Molecular Conformation; D049879:Mytilidae / Q000378:metabolism / Q000648:ultrastructure*; D013696:Temperature
D002119:Calcium Carbonate