Physiological response of the cold-seep mussel Bathymodiolus childressi to acutely elevated temperature

Abstract

It is predicted that deep-sea animals adapted to thermally stable conditions should be highly sensitive to temperature change and should not have inducible heat-shock responses. This premise was tested with the cold-seep mussel Bathymodiolus childressi Gustafson, 1998 from 750 m depth in the Gulf of Mexico at a site known as Brine Pool NR-1 (27°43.4157N, 91°16.756W). Mussels were collected during February 2003. Site temperature, measured in different months between 1995 and 2005, ranged between 6.5 and 7.2°C. Although Brine Pool NR-1 is stenothermal, hydrogen sulfide, oxygen, and salinity vary over temporal and spatial scales. In laboratory experiments, B. childressi survived increases up to approximately 20°C above ambient temperature for 6 h before suffering greater than 50% mortality. Although a high thermal tolerance was observed, B. childressi did not express an inducible 70 kDa heat-shock protein. However, high constitutive levels of hsp70 were present in B. childressi suggesting a necessity to remediate protein damage from stressors other than elevated temperature; these constitutive proteins probably confer an indirect thermal tolerance. © Springer-Verlag 2006.