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.
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
Eniko
E
Kadar
Antonio G
AG
Checa
Alfredo
A
Damasceno-Oliveira
Alfredo N D P
AN
Oliveira
Jorge P
JP
Machado
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