Vol. 57, 2018 (update: 2018.07.03; 08.08) Salinity Variation in a Mangrove Ecosystem: A Physiological Investigation to Assess Potential Consequences of Salinity Disturbances on Mangrove CrabsDimitri Theuerkauff1,2,#, Georgina A. Rivera-Ingraham1,#, Jonathan A.C. Roques1,2, Laurence Azzopardi1,2, Marine Bertini1, Mathilde Lejeune1, Emilie Farcy1, Jehan-Hervé Lignot1,*, and Elliott Sucré1,2 doi:10.6620/ZS.2018.57-36
1UMR
MARBEC (University of Montpellier, CNRS, IFREMER, IRD), Montpellier,
France. E-mail: Dimitri.theuerkauff@umontpellier.fr (Theuerkauff);
g.rivera-ingraham@gmail.com (Rivera-Ingraham);
Jonathan.roques@bioenv.gu.se (Roques);
Laurence.azzopardi@univ-mayotte.fr (Azzopardi);
Marine.bertini@umontpellier.fr (Bertini); Emilie.farcy@umontpellier.fr
(Farcy); Elliott.sucre@univ-mayotte.fr (Sucré) (Received 14 December 2017; Accepted 21 June
2018; Communicated by Benny K.K. Chan) Theuerkauff,
Georgina A. Rivera-Ingraham, Jonathan A.C. Roques, Laurence Azzopardi,
Marine Bertini, Mathilde Lejeune, Emilie Farcy, Jehan-Hervé Lignot, and
Elliott Sucré (2018) Salinity is one of the main environmental
factors determining coastal species distribution. However, in the
specific case of mangrove crabs, salinity selection cannot be
understood through ecological approaches alone. Yet understanding this
issue is crucial in the context of mangrove conservation, since this
ecosystem is often used as biofilter of (low-salinity) wastewater.
Crabs are keystone species in this mangrove ecosystem and are
differentially affected by salinity. We hypothesize that crab salinity
selection may be partly explained by specific salinity-induced
physiological constraints associated with osmoregulation, energy and
redox homeostasis. To test this, the response to salinity variation was
analysed in two landward mangrove crabs: the fiddler crab Tubuca
urvillei, which inhabits low-salinity areas of the mangrove, and
the
red mangrove crab Neosarmatium
meinerti, which lives in areas with
higher salinity. Results confirm that both species are strong
hypo-/hyper-osmoregulators that deal easily with large salinity
variations. Such shifts in salinity do not induce changes in energy
expenditure (measured as oxygen consumption) or in the production of
reactive oxygen species. However, T.
urvillei
is physiologically suited to habitats with brackish water, since it
presents i) high hemolymph osmolalities over a wider range of
salinities and lower osmoregulatory capacity in seawater, ii) high Na+/K+-ATPase
(NKA) activity in the posterior osmoregulatory gills and iii) a thicker
osmoregulatory epithelium along the posterior gill lamellae. Therefore,
while environmental salinity alone cannot directly explain fiddler and
red mangrove crab distributions, our data suggest that salinity
selection is indeed influenced by specific physiological adjustments. Key words: Bioenergetics,
Osmoregulation, Salinity-induced oxidative stress, Mangrove, Decapods. *Correspondence:
E-mail: jehan-herve.lignot@umontpellier.fr |