title: Sustained hydrostatic pressure tolerance of the shallow water shrimp Palaemonetes varians at different temperatures: insights into the colonisation of the deep sea.
abstract: We investigated the tolerance of adult specimens of the shallow-water shrimp Palaemonetes varians to sustained high hydrostatic pressure (10 MPa) across its thermal tolerance window (from 5 to 27 °C) using both behavioural (survival and activity) and molecular (hsp70 gene expression) approaches. To our knowledge, this paper reports the longest elevated hydrostatic pressure exposures ever performed on a shallow-water marine organism. Behavioural analysis showed a 100% survival rate of P. varians after 7 days at 10 MPa and 5 or 10 °C, whilst cannibalism was observed at elevated temperature (27 °C), suggesting no impairment of specific dynamic action. A significant interaction of pressure and temperature was observed for both behavioural and molecular responses. Elevated pressure was found to exacerbate the effect of temperature on the behaviour of the animals by reducing activity at low temperature and by increasing activity at high temperature. In contrast, only high pressure combined with low temperature increased the expression of hsp70 genes. We suggest that the impressive tolerance of P. varians to sustained elevated pressure may reflect the physiological capability of an ancestral species to colonise the deep sea. Our results also support the hypothesis that deep-sea colonisation may have occurred during geological periods of time when the oceanic water column was warm and vertically homogenous.
authors.affiliation: University of Southampton, Ocean and Earth Science, National Oceanography Centre, Southampton, European Way, Southampton, SO14 3ZH, UK. delphine.cottin@univ-lyon1.fr
authors.forename: Delphine
authors.initials: D
authors.lastname: Cottin
authors.forename: Alastair
authors.initials: A
authors.lastname: Brown
authors.forename: Andrew
authors.initials: A
authors.lastname: Oliphant
authors.forename: Nélia C
authors.initials: NC
authors.lastname: Mestre
authors.forename: Juliette
authors.initials: J
authors.lastname: Ravaux
authors.forename: Bruce
authors.initials: B
authors.lastname: Shillito
authors.forename: Sven
authors.initials: S
authors.lastname: Thatje
mesh_terms: D000064:Acclimatization / Q000235:genetics; D000818:Animals; D060829:Arthropod Proteins / Q000235:genetics / Q000378:metabolism; D001522:Behavior, Animal; D002190:Cannibalism; D017753:Ecosystem; D015870:Gene Expression; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D006874:Hydrostatic Pressure; D009792:Oceans and Seas; D033541:Palaemonidae / Q000378:metabolism / Q000502:physiology*; D013312:Stress, Physiological; D013696:Temperature
chemical_list: D060829:Arthropod Proteins; D018840:HSP70 Heat-Shock Proteins