12.2 Wednesday, Jan. 4 Insights into the physiological adaptations of caridean shrimp to hydrothermal vent living: implications for colonization OLIPHANT, A*; THATJE, S; BROWN, A; MORINI, M; RAVAUX, J; SHILLITO, B; SMITH, F; REED, A; University of Southampton; University of Southampton; University of Southampton; Université Pierre et Marie Curie; Université Pierre et Marie Curie; Université Pierre et Marie Curie; University of Southampton; University of Southampton Andrew.Oliphant@noc.soton.ac.uk
Palaemonetes varians, a shallow-living palaemonid shrimp, and Mirocaris fortunata, a deep-sea hydrothermal vent bresiliid shrimp, both inhabit environments with highly fluctuating water temperatures. Given the close taxonomic relationship between palaemonid and bresiliid shrimp, physiological comparisons may provide insights into adaptations required for life in the vent environment. In this study, adult P. varians were subjected to a temperature/pressure regime from 5 to 30°C and from 0.1 to 30 MPa; oxygen consumption rates and behaviour in response to these conditions were assessed. P. varians showed increasing pressure sensitivity with decreasing temperature; however, shrimp were capable of tolerating pressures found outside their normal bathymetric distribution at all temperatures. Respiratory response of adult P. varians and M. fortunata to acute temperature shock demonstrated that M. fortunata had a lower oxygen consumption rate than P. varians at all temperatures, indicating lower metabolic costs and greater tolerance of highly fluctuating temperature. During temperature preference experiments, M. fortunata (19.2 ± 1.1°C) selected a higher average temperature than P. varians (18.3 ± 0.9°C). The similar temperature physiology of P. varians and M. fortunata, and P. varians’ pressure tolerance indicate that the common ancestor of both species was probably eurybathyal and eurythermal; physiological attributes which persist in these extant species.