The life cycle of Sea butterflies under threat from climate change, posing a potential risk to the Southern Ocean ecosystem.

The world’s oceans absorb nearly a quarter of all carbon dioxide (CO2).₂) emissions. During absorption, CO₂ It interacts with seawater and lower ocean pH levels. This is known as ocean acidification and results in lower concentrations of carbon ions. Some ocean dwellers use the carbon ion to build and maintain their shells. Among them are pterodactyls, which are important components of the marine ecosystem.

Certain aspects of wingspan, including life cycles and population dynamics, have not been well studied. This is due in part to their size–some species of sea butterflies measure less than one millimeter–and poor long-term survival in captivity. Now, a team of marine scientists has examined the life cycles, abundance and seasonal diversity of moulted sea butterflies in the northeastern Scotia Sea, an area experiencing some of the fastest climate change in the Southern Ocean.

said Dr Clara Manu, a researcher with the British Antarctic Survey and corresponding author of the study published in the journal Frontiers in Marine Sciences. “Knowledge about the life cycle of this essential organism may improve prediction of the effects of ocean acidification on the Antarctic ecosystem.”

Population stability is essential for the survival of the species

For their work, the scientists collected sea butterflies in a sediment trap, a sampler moored at a depth of 400 metres. Dr Vicki Beck, a researcher with the British Antarctic Survey, added a co-author of the study. “Using sediment trap samples, we have successfully reconstructed their life cycle over the course of a year.”

For the two dominant species collected — Limacina rangii and Limacina retroversa — the scientists noted divergent life cycles, resulting in different vulnerabilities in the changing oceans. L. rangii, a polar species, can be found in both adults and juveniles during the winter months. L. retroversa, a subarctic species, is shown to only occur in adults during the winter season.

During the cooler season, ocean water is more acidic than at other times of the year because cooler temperatures increase carbon dioxide₂ dissolution in the ocean. The researchers write that the life stages of sea butterflies that are thereafter are more vulnerable and more vulnerable to ocean acidification levels.

The fact that adults and juveniles of L. rangii coexist during the winter may give them a survival advantage. If one group is weak, the general population stability will not be in danger. However, with L. retroversa, if one population is removed, the entire population may be at risk.

Prolonged exposure is a challenge for survival

The researchers note that although species are affected differently, neither is likely to remain unharmed if exposed to unfavorable conditions for extended periods of time.

As the intensity and duration of ocean acidification events increase, they begin to overlap with spawning events in the spring. Scientists warned that this could put the most vulnerable life stage, the larvae, at particular risk and could endanger future populations.

To find out how such a scenario could play out in the Scotia Sea, the research team will continue to study the sea butterflies that live there. “The next step will be to focus on multi-year sediment trap samples to determine potential annual variation in the life cycle associated with environmental change,” said Dr Jessie Gardner of the British Antarctic Survey, lead author of the study.