Temperature and the Physiology of Intracellular and Extracellular Acid-Base Regulation in the Blue Crab Callinectes Sapid Us

Abstract

The 14C-DMO/3H-inulin method for pHi was critically assessed in intact Callinectes and found to be reliable provided adequate equilibration time and significant radiolabel excretion were taken into account. An unusually high ‘mean whole body pHi’ (7.54 at 20°C compared with a pHa of 7.80) was due to a highly alkaline fluid compartment (pHi = 8.23) in the carapace. At 20°C the pHi of the heart was 7.35 and skeletal muscle pHi was 7.30, and there were small but consistent differences in the pHi of different muscle types. The change in pHa with temperature was −0.0151 u°C−1 between 10 and 30°C, slightly less than the slope for the neutral pH of water (ΔpN/ΔT ≃ −0.0175 u °C−1). With data corrected to constant PiCoCo2 this was associated with a change in [HCO3−]a between 10 and 20°C (−0.13 mequivl−1°C−1, constant PaCoCo2) and a change in PaCoCo2 between 20 and 30°C (+0.13Torr°C−1, constant [HCO3−]a). The disturbing effect of relatively small PiCOCO2 changes on this pattern was demonstrated. ΔpHi/ΔT slopes for all tissues except carapace were not significantly different from pHa/ΔT but generally lower than ΔpN/ΔT. The slope for the. carapace was very flat and greatly influenced the ‘mean whole body pHi’ slope (−0.0062u°C−1). In haemolymph in vitro at constant Picoco2 ‘passive’ Δ[HCO3−]/ΔT (−0.17mequivI −1°C−1) was comparable to that in vivo between 10 and 20°C, independent of absolute PCOCO2. and directly related to total protein concentration. Haemolymph non-bicarbonate buffer value (β) was similarly related to protein, but increased with temperature. Crabs subjected to an acute 20→10°C shift showed initial overshoots of pHa and pHi associated with undershoot of PaCOCO2, all of which were corrected over 24 h as [HCO3−]a rose. During this period there was a significant net uptake

An intertidal life: Combined effects of acidification and winter heatwaves on a coralline alga (Ellisolandia elongata) and its associated invertebrate community

“…In particular, adverse effects due to acidic conditions are expected upon growth rate and molting frequency (Whiteley, 2011). The calcification process, in fact, is linked to molting cycles: calcium carbonate does not deposit before the molt, and is likely taken up from the surrounding medium through the gills (Wood & Cameron, 1985;Neues et al, 2007).…”

OSMOREGULATION, IONIC EXCHANGE, BLOOD CHEMISTRY, AND NITROGENOUS WASTE EXCRETION IN THE LAND CRABCARDISOMA CARNIFEX:A FIELD AND LABORATORY STUDY

“…The only other measurements of acidic equivalent fluxes in crabs using comparable methodology are also in Callinectes sapidus, which is both carnivorous and euryhaline. Interestingly, this species in intermoult condition exhibits Jn e + t ^ +380 ^equiv kg" 1 h "' (Cameron, 1979), declining to =0/Ltequiv-kg ' -h" 1 in seawater (Wood and Cameron, 1985), a comparable trend to that seen in C. carnifex (Table III).…”