Acute metabolic responses of two marine brachyuran crabs to dilute seawater: The aerobic cost of hyper regulation.

Autor: Rios LP; Programa de Pós-Graduação em Zoologia, Universidade Federal do Paraná, Curitiba, Paraná, Brazil., Freire CA; Departamento de Fisiologia, Setor de Ciências Biológicas, Universidade Federal do Paraná, Curitiba, Paraná, Brazil.
Jazyk: angličtina
Zdroj: Journal of experimental zoology. Part A, Ecological and integrative physiology [J Exp Zool A Ecol Integr Physiol] 2023 Jul; Vol. 339 (6), pp. 519-534. Date of Electronic Publication: 2023 Mar 26.
DOI: 10.1002/jez.2697
Abstrakt: Hepatus pudibundus ("flecked box crab") is a stenohaline osmoconfomer, and restricted to marine habitats. Callinectes danae ("swimming crab Dana") lives in coastal/estuarine waters and is a weak hyper regulator. There is no consensus on which strategy is more expensive metabolically face salinity challenges: conformation with higher dependence on cell volume regulation, or hyper regulation, alleviating the need for intense cell volume regulation. Crabs were probed for their acute response to dilute seawater through exposures to salinities 35‰, 30‰, 25‰, and 20‰ for 2, 4, and 6 h. Hemolymph osmolality, lactate, and ions (chloride, sodium, magnesium, potassium) were assayed, as well as muscle water content. Water dissolved oxygen, ammonia, and pH levels were also measured. H. pudibundus conformed for osmolality and displayed increase in muscle hydration along the decrease in salinity down to 25‰, while C. danae efficiently maintained hemolymph osmo ionic stability, consumed more oxygen, acidified more the water, and released more ammonia. In 25‰, both species spent energy: H. pudibundus putatively controlling cell volume, and C. danae regulating hemolymph concentrations. In 20‰, H. pudibundus closed itself, avoiding the contact of the interface epithelia with the external environment and producing much lactate, whereas C. danae spent more energy (aerobic) in extracellular osmo ionic stability. Under these conditions, anisosmotic extracellular regulation (together with additional cell volume regulation) is more oxygen consuming than osmoconformation with a putatively more intense challenge to cell volume. The exposure to hyposalinity limits the occupation of estuarine environments by H. pudibundus in short and middle term.
(© 2023 Wiley Periodicals LLC.)
Databáze: MEDLINE
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