Do males and females respond differently to ocean acidification? An experimental study with the sea urchin Paracentrotus lividus

Abstract

Seawater pH lowering, known as ocean acidification, is considered among the major threats to marine environment. In this study, post-spawning adults of the sea urchin Paracentrotus lividus were maintained at three pH values (8.0, 7.7, 7.4) for 60 days. Physiological, biochemical, cellular, behavioural and reproductive responses were evaluated in males and females. Significant differences between sexes were observed, with higher ammonia excretion and lower catalase activity in males. Respiration rate (after 21 days), catalase activity in gonads and total coelomocyte count showed the same increasing trend in males and females under low pH. Ammonia excretion, gonadosomatic index and lysozyme activity exhibited opposite responses to low pH, with an increasing trend in males and decreasing in females. Results demonstrated that exposure to low pH could result in different response strategies of male and female sea urchins at a physiological, biochemical and immunological level. Reduced female gonadosomatic index under low pH suggested decreased energy investment in reproduction.

Ocean acidification does not overlook sex: Review of understudied effects and implications of low pH on marine invertebrate sexual reproduction

“…OA had negative effects on gonad growth, maturation, egg size, and gamete development in some echinoderm species (Siikavuopio et al, 2007;Kurihara, 2008;Stumpp et al, 2012;Kurihara et al, 2013;Suckling et al, 2014;Suckling et al, 2015;Verkaik et al, 2016;Dworjanyn and Byrne, 2018;Hu et al, 2018;Hue et al, 2020;Marcěta et al, 2020;Anand et al, 2021), while other studies reported no change in gamete development and quality (Wood et al, 2008;Uthicke et al, 2013;Hazan et al 2014; Uthicke et al, 2014;Dell'Acqua et al, 2019;Karelitz et al, 2019;Wong et al, 2019;Hue et al, 2020;Uthicke et al, 2020).…”

Environmental Factors and Genetic Diversity as Drivers of Early Gonadal Maturation: A Gonadosomatic Index Based Investigation on Indian Shad, Tenualosa ilisha Population of Bangladesh

“…For other habitats this relationship ranged between weak positive to moderate negative possibly for the reason that high pH driven waterbodies acidification differentially affect physiology, reproduction, biochemistry, and survival of organisms (McClellan-Green et al, 2007;Ellis et al, 2014;Lane et al, 2015) of those habitats. Especially the female T. ilisha possibly becomes vulnerable to stress from alteration of their resource energy location and high production cost of eggs compared to sperm like of other fish (Marčeta et al, 2020). Moderate positive relationships between GSI and salinity of two saline habitats (Tetulia River and Bay of Bengal) of this study suggest that gonadal development of T. ilisha was promoted by salinity.…”

Ocean warming and acidification modify top-down and bottom-up control in a tropical seagrass ecosystem

“…Additionally, in terms of energy budget, it can be infered that increased respiration and NH 4 + excretion rates with no significant change in feeding rate at high p CO 2 could decrease the amount of energy available for growth and reproduction of the sea urchin. Indeed some previous studies have indicated that exposure of sea urchin to high p CO 2 resulted in a decrease of feeding rate and delay in gonad development 21 , or increased respiration and reduced gonadosomatic index particularly in female sea urchins 35 , 36 . Furthermore, a decrease in the available energy for T. gratilla could be particularly significant under the combination of ocean warming and acidification, considering the significant decrease in feeding rate with the synergistic increase in respiration rate under high temperature and p CO 2 environment, especially when T. gratilla was fed with experimental seagrass.…”