Seawater carbonate chemistry and shell morphology and survival of the girdled dogwhelk, Trochia cingulata (Linnaeus, 1771)

• Main Authors: Martin, N, Clusella-Trullas, Susana, Robinson, Tamara B
• Format: Dataset
• Language: English
• Published: PANGAEA 2022
• Subjects: Alkalinity; total; standard error; Animalia; Aragonite saturation state; Benthic animals; Benthos; Bicarbonate ion; Breaking force; 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; Containers and aquaria (20-1000 L or < 1 m**2); Elands_Bay; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Growth/Morphology; Index; Laboratory experiment; Mollusca; Mortality; Mortality/Survival; OA-ICC; Ocean Acidification International Coordination Centre; Other studied parameter or process; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); pH; Potentiometric; Potentiometric titration; Salinity; Shell thickness; Single species; South Atlantic; Species; Ocean acidification; Dogwhelk
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.945426; https://doi.org/10.1594/PANGAEA.945426

Despite the existing body of research that considers altered ocean temperature and acidification as co-occurring stressors, our understanding of the consequences of such shifts remains limited. This is particularly problematic in relation to predators such as whelks, as they can exert strong top-down control of communities yet, as calcifying ectotherms, they are likely to be vulnerable to climate change. This study assessed the effects of simultaneous changes in water temperature and pH on the South African girdled dogwhelk Trochia cingulata. For 12 weeks, whelks were exposed to three temperatures, 9 °C (cooling), 13 °C (current) and 17 °C (warming), each at three target pH levels, 8.0 (current), 7.7 (intermediate) and 7.5 (extreme). For each treatment shell thickness, strength and shape were measured after 6 and 12 weeks, while mortality was recorded daily. Survival was not affected by pH and was highest at 9 °C. Almost all whelks exposed to warming died within 2 weeks. After 6 weeks, shell strength declined significantly as acidity increased, regardless of temperature, and shells of whelks held at 9 °C were thinner. By 12 weeks, whelks exposed to cooling and extreme pH had the weakest shells. Notably, temperature no longer influenced shell thickness, but whelks held at 9 °C became globular in shape. These changes in shell morphology likely resulted from the increased cost of shell maintenance in cool, acidic conditions. The differences observed at 6 and 12 weeks demonstrate how responses can change over time, a point that should be kept in mind when assessing species sensitivities to changing environments. The dominant effect of temperature highlights that T. cingulata is particularly vulnerable to warming, while regional cooling may pose a challenge with respect to shell morphology.