TY - JOUR

T1 - Contrasting responses to salinity and future ocean acidification in arctic populations of the amphipod Gammarus setosus

AU - Brown, James

AU - Whiteley, Nia

AU - Bailey, Allison

AU - Graham, Helen

AU - Hop, Haakon

AU - Rastrick, Samuel

PY - 2020/12/1

Y1 - 2020/12/1

N2 - Climate change is leading to alterations in salinity and carbonate chemistry in arctic/sub-arctic marine eco- systems. We examined three nominal populations of the circumpolar arctic/subarctic amphipod, Gammarus setosus, along a salinity gradient in the Kongsfjorden-Krossfjorden area of Svalbard. Field and laboratory ex- periments assessed physiological (haemolymph osmolality and gill Na+/K+-ATPase activity, NKA) and energetic responses (metabolic rates, MO2, and Cellular Energy Allocation, CEA). In the field, all populations had similar osmregulatory capacities and MO2, but lower-salinity populations had lower CEA. Reduced salinity (S = 23) and elevated pCO2 (~1000 μatm) in the laboratory for one month increased gill NKA activities and reduced CEA in all populations, but increased MO2 in the higher-salinity population. Elevated pCO2 did not interact with salinity and had no effect on NKA activities or CEA, but reduced MO2 in all populations. Reduced CEA in lower-rather than higher-salinity populations may have longer term effects on other energy demanding processes (growth and reproduction).

AB - Climate change is leading to alterations in salinity and carbonate chemistry in arctic/sub-arctic marine eco- systems. We examined three nominal populations of the circumpolar arctic/subarctic amphipod, Gammarus setosus, along a salinity gradient in the Kongsfjorden-Krossfjorden area of Svalbard. Field and laboratory ex- periments assessed physiological (haemolymph osmolality and gill Na+/K+-ATPase activity, NKA) and energetic responses (metabolic rates, MO2, and Cellular Energy Allocation, CEA). In the field, all populations had similar osmregulatory capacities and MO2, but lower-salinity populations had lower CEA. Reduced salinity (S = 23) and elevated pCO2 (~1000 μatm) in the laboratory for one month increased gill NKA activities and reduced CEA in all populations, but increased MO2 in the higher-salinity population. Elevated pCO2 did not interact with salinity and had no effect on NKA activities or CEA, but reduced MO2 in all populations. Reduced CEA in lower-rather than higher-salinity populations may have longer term effects on other energy demanding processes (growth and reproduction).

KW - Arctic

KW - Amphipod

KW - cellular energy budgets

KW - metabolic rates

KW - ocean acidification

KW - salinity

KW - Kongsfjorden

KW - Svalbard

U2 - 10.1016/j.marenvres.2020.105176

DO - 10.1016/j.marenvres.2020.105176

M3 - Article

VL - 162

JO - Marine Environmental Research

JF - Marine Environmental Research

SN - 0141-1136

M1 - 105176

ER -