Seawater carbonate chemistry and polyspermy of a broadcast spawning bivalve

• Main Authors: Han, Yu, Shi, Wei, Tang, Y, Zhao, Xinguo, Du, Xueying, Sun, Shuge, Zhou, Weishang, Liu, Guangxu
• Format: Dataset
• Language: English
• Published: PANGAEA 2021
• Subjects: Adenosine triphosphate; per unit protein; Alkalinity; total; standard deviation; Animalia; Aragonite saturation state; Benthic animals; Benthos; Bicarbonate ion; Bottles or small containers/Aquaria (<20 L); Calcite saturation state; Calculated using CO2SYS; Calculated using seacarb after Nisumaa et al. (2010); Carbon; inorganic; dissolved; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Coast and continental shelf; EXP; Experiment; Fluorescence intensity; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Laboratory experiment; Microfilament migration; Mollusca; North Pacific; OA-ICC; Ocean Acidification International Coordination Centre; Partial pressure of carbon dioxide; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); pH; Polyspermy; Potentiometric; Potentiometric titration; Pacific; Ocean acidification
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.929201; https://doi.org/10.1594/PANGAEA.929201

Ensuring that oocytes are fertilized by a single sperm during broadcast spawning is crucial for the fertilization success of many marine invertebrates. Although the adverse impacts of ocean acidification (OA) on various marine species have been revealed in recent years, its impact on polyspermy and the underlying mechanisms involved remain largely unknown. Therefore, in the present study, the effect of OA on polyspermy risk was assessed in a broadcast spawning bivalve, Tegillarca granosa. In addition, the impacts of OA on the two polyspermy blocking processes, the fast block (membrane depolarization) and the permanent block (cortical reaction), were investigated. The results show that the exposure of oocytes to two future OA scenarios (pH 7.8 and pH 7.4) leads to significant increases in polyspermy risk, about 1.70 and 2.38 times higher than the control, respectively. The maximum change in the membrane potential during oocyte membrane depolarization markedly decreased to 15.79% (pH 7.8) and 34.06% (pH 7.4) of the control value. Moreover, the duration of oocyte membrane depolarization was significantly reduced to approximately 63.38% (pH 7.8) and 21.91% (pH 7.4) of the control. In addition, cortical granule exocytosis, as well as microfilament migration, were significantly arrested by OA treatment. Exposure to future OA scenarios also led to significant reductions in the ATP and Ca2+ content of the oocytes, which may explain the hampered polyspermy blocking. Overall, the present study suggests that OA may significantly increase polyspermy risk in T. granosa by inhibiting membrane depolarization and arresting cortical granule exocytosis.