Publication Date:
2024-03-15
Description:
Low pO2 values have been measured in the perivitelline fluids (PVF) of marine animal eggs on several occasions, especially towards the end of development, when embryonic oxygen consumption is at its peak and the egg case acts as a massive barrier to diffusion. Several authors have therefore suggested that oxygen availability is the key factor leading to hatching. However, there have been no measurements of PVF pCO2 so far. This is surprising, as elevated pCO2 could also constitute a major abiotic stressor for the developing embryo. As a first attempt to fill this gap in knowledge, we measured pO2, pCO2 and pH in the PVF of late cephalopod (Sepia officinalis) eggs. We found linear relationships between embryo wet mass and pO2, pCO2 and pH. pO2 declined from 〉12 kPa to less than 5 kPa, while pCO2 increased from 0.13 to 0.41 kPa. In the absence of active accumulation of bicarbonate in the PVF, pH decreased from 7.7 to 7.2. Our study supports the idea that oxygen becomes limiting in cephalopod eggs towards the end of development; however, pCO2 and pH shift to levels that have caused significant physiological disturbances in other marine ectothermic animals. Future research needs to address the physiological adaptations that enable the embryo to cope with the adverse abiotic conditions in their egg environment.
Keywords:
Alkalinity, total; Ammonium; Animalia; Aragonite saturation state; Bicarbonate ion; Calcite saturation state; Calculated; Calculated using CO2SYS; Calculated using seacarb after Nisumaa et al. (2010); Carbon, inorganic, dissolved; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Carbon dioxide, partial pressure; Conductivity meter (WTW, Weilheim, Gemany); Containers and aquaria (20-1000 L or 〈 1 m**2); EPOCA; EUR-OCEANS; European network of excellence for Ocean Ecosystems Analysis; European Project on Ocean Acidification; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Laboratory experiment; Laboratory strains; Mollusca; Nekton; Nitrate; Nitrite; Not applicable; OA-ICC; Ocean Acidification International Coordination Centre; Oxygen; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); Pelagos; pH; Reproduction; Salinity; Sepia officinalis; Sepia officinalis, embryo, mass, wet; Sepia officinalis, haemolymph, bicarbonate ion; Sepia officinalis, haemolymph O2; Sepia officinalis, haemolymph pCO2; Sepia officinalis, haemolymph pH; Single species; Temperature, water; WTW 340i pH-analyzer and WTW SenTix 81-electrode
Type:
Dataset
Format:
text/tab-separated-values, 338 data points
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