Effects of temperature and salinity on the sub-Antarctic snail Xymenopsis muriciformis (King and Broderip, 1832): Medium-term exposure to different climate change scenarios

As a consequence of climate change, benthic marine species that inhabit the sub-Antarctic oceans could be impacted as a result of changes in temperature and salinity that are affecting areas of high latitudes, where stenoic marine species are common. Therefore, the physiological performance of the species is essential to understand the ability of species to persist within their current range and to predict their rates of redistribution in response to the impacts of climate change impact. Xymenopsis muriciformis, an endemic sub-Antarctic benthic snail of the Strait of Magellan (53 degrees 47'S; 70 degrees 58'W), was used as a model species to understand the physiological response of a species that inhabits the Southern Oceans, where environmental conditions are very stable. We tested a medium-term exposure to the effects of climate change, including changes in temperature and salinity. The organisms were acclimatized for three months in the laboratory, at a temperature of 9 degrees C and salinity of 30 psu (control). The experiment was carried out for 60 days, where the ingestion rate and oxygen uptake were measured every 10 days. At the end of the experiments, the physiological condition of the organisms was determined by applying the metabolic indicators: carbohydrate indices (CHI), total lipids (TLI) and lipofuscins (LI), which were obtained by histological-histochemical analysis. The results indicated that temperature had significant effects on the ingestion rate and oxygen consumption, while salinity and the interaction between salinity and temperature had no significant effects. Organisms exposed to low temperatures (1 degrees C) and (5 degrees C), expected for the southern hemisphere summer, exhibited cellular degradation, which would limit the access and colonization of Antarctic environments. The organisms exposed to the 15 degrees C treatment (expected for the Magellan region), presented a significantly higher amount of lipofuscins in the vesicular connective tissue cells with morphological characteristics in the autophagosomes. We concluded that the snail X. muriciformis is a characteristic stenoic species, highly sensitive to temperature variations, as those projected in climate change scenarios for the Antarctic and sub-Antarctic regions.

Automated summary

Climate change affects benthic marine species in the sub-Antarctic oceans, and understanding their physiological responses is crucial for predicting their redistribution in response to climate change impacts. This study used Xymenopsis muriciformis as a model species and found that temperature had significant effects on the ingestion rate and oxygen consumption, while salinity and the interaction between salinity and temperature did not have significant effects. Furthermore, organisms exposed to low temperatures showed cellular degradation, while those exposed to higher temperatures exhibited higher amounts of lipofuscins.