Effects of ocean acidification and salinity variations on the physiology of osmoregulating and osmoconforming crustaceans

Abstract

Survival, osmoregulatory pattern, oxygen consumption, energy spent on metabolism, ammonia excretion, type of oxidized energy substrate, and hepatosomatic index were evaluated in decapods (an osmoregulating crab, Callinectes danae, and an osmoconforming seabob shrimp, Xiphopenaeus kroyeri) exposed to carbon dioxide-induced water acidification (pH 7.3, control pH 8.0) and different salinities (20, 25, 30, 35, and 40‰) for 3 days. Compared to the animals kept at controlled pH, exposure to reduced pH resulted in the loss of osmoregulatory capacity in C. danae at all salinities, except for some hyporegulation at 40‰, and reduced oxygen consumption and ammonia excretion at 20 and 40‰. Xiphopenaeus kroyeri remained an osmoconformer in all evaluated conditions, except for some hyporegulation at 40‰, and when exposed to the reduced pH, it presented changes in oxygen consumption at all salinities and reductions in ammonia excretion at 20 and 35‰ compared to the control animals. Both species use protein as the main energy substrate and decrease the hepatosomatic index when exposed to reduced pH relative to the control. The observed changes may be associated with changes in the activity of enzymes related to osmoregulation, the use of amino acids as osmotic effectors of cell volume control and recovery, and the Bohr effect, and, because the gills are multifunctional organs related to osmoregulation, the changes may be related to acid-base control, nitrogen excretion, and respiration, with a change in one of these functions bringing about changes in the others.

Effects of Elevated pCO2 on the Survival and Growth of Portunus trituberculatus

“…The enhanced survival of swimming crabs under OA was expected and observed in this study, despite the lack of enhanced survival in other crabs (Ceballos-Osuna et al, 2013;Long et al, 2013a;Ragagnin et al, 2018;Ramaglia et al, 2018). Based on the SEM, crab survival was mainly explained by the carbonate system, antioxidative enzymes, seawater bacteria, gut bacteria, and digestive enzymes (Figure 7).…”

“…The impacts of OA are raising increasing concerns with regard to crustaceans because of the sensitivity of calcifying animals ( Hendriks et al, 2010 ). Among them, crabs present species-specific responses to OA, such as different impacts on calcification ( Walther et al, 2010 ; Long et al, 2013a ; Wei et al, 2015 ), and survival was shown to be reduced in crabs following a longer term exposure (months) to OA, although shorter term exposure (less than 1 month) did not have any apparent effects ( Ceballos-Osuna et al, 2013 ; Long et al, 2013a ; Ragagnin et al, 2018 ; Ramaglia et al, 2018 ). In addition, OA can also induce negative effects on crab fertilization, embryonic development, and behavior ( de la Haye et al, 2011 , 2012 ; Ceballos-Osuna et al, 2013 ; Long et al, 2013b ; Dodd-Luke et al, 2015 ).…”

Effects of salinity acclimation on the growth performance, osmoregulation and energy metabolism of the oriental river prawn, Macrobrachium nipponense (De Haan)

“…The process of actively regulating osmotic pressure needs to consume more energy stored in the crustacean to maintain normal physiological activity, the oxygen consumption and ammonia excretion rate will increase, which led to a negatively affect in growth (Ramaglia, de Castro & Augusto, ; Spanopoulos‐Hernández, Martínez‐Palacios, Vanegas‐Pérez, Rosas & Ross, ). It is now generally accepted that crustaceans have the lowest levels of metabolism when salinity is near the isotonic point, the organism can save the energy required for osmotic pressure regulation for growth (Le et al., ).…”

Does physiological tolerance to acute hypoxia and salinity change explain ecological niche in two intertidal crab species?

“…1A). In other crab species, increases in MO 2 with declining salinity are commonly reported (Taylor et al., 1977b; Shumway, 1983; Normant and Gibowicz, 2008), although some authors have reported MO 2 increases in hypersaline waters (Ramaglia et al., 2018) or a lack of change in MO 2 with salinity (Winch and Hodgson, 2007; Theuerkauff et al., 2018). Differences between studies are likely due to diverse experimental protocols (most notably whether the measurement occurs after acute exposure or after acclimation) and differences in the osmoregulatory capacity of the test species.…”