A team of researchers conducted experiments in which they subjected two species to temperatures that simulate future scenarios of climate change. The results were published in the journal Science of the Total Environment.
Daniela Jofré, IDEAL Center. The red sea urchin (Loxechinus albus) and the “dwarf sea urchin” (Pseudechinus magellanicus) are two marine species that, although they have a different distribution throughout South America, converge in the southern part of the Magallanes Region, this place being the habitat of lower temperature where both genders share the same ecosystem.
As a result of this, a team of researchers carried out various experiments with the aim of determining how these two species respond not only to the increase in ocean temperature, but to one of the indirect effects generated by the change in temperature: the lack of food for marine organisms. The results were published in the scientific journal Science of the Total Environment.
Considering the accelerated process of global warming, a significant increase in sea temperature is expected, which would bring with it a series of consequences and important changes associated with the relationships between species that could generate a shortage of nutrients for some organisms.
The study was in charge of the ecophysiologist Dr. Camille Détrée, postdoctoral fellow at the Center for Dynamic Research on High Latitudes Marine Ecosystems (IDEAL) of the Austral University of Chile (UACh,) who evaluated the strategy of these two species of sea urchin against alleged climate change scenarios.
The specimens were subjected for 60 days to two stress factors, related to the increase and decrease in temperature and lack of food. Furthermore, the physiological response and oxygenation capacity, coupled with the expression of genes associated with metabolism against these conditions was analysed.
The two species were exposed to different factors: a warm treatment (14°C, corresponding to the predictions for ocean warming in the region,) a cold treatment (1°C, corresponding to average summer temperature in Antarctica,) and a restriction of nutrients, with a contribution of half of the food they consume. “We wanted to see how its total energy was affected, because when the sea urchin looks for food and consumes it, it gains and loses part of this component. Both genders need a percentage that allows them to grow and reproduce,” explained Dr. Détrée.
The research determined that both species respond satisfactorily to an increase in ocean temperature. However, the food shortage associated with this phenomenon would negatively influence L. albus and P. magellanicus, since they would not have enough energy to grow and reproduce.
This unfavourable panorama would especially affect the red sea urchin, since it is currently extracted commercially from the Los Ríos Region to the south. In the Magallanes Region, its closed period is from August to February. “In the case of L. albus, this species would also have external pressure due to its fishing,” said the researcher.
The sea urchins were also subjected to minimum temperatures, considering a possible migration to the white continent, in a scenario where the Antarctic Circumpolar Current is not an impediment to the entry and colonization of these species. However, the specimens showed a higher mortality rate under these levels of environmental stress.
“Ingestion, absorption and respiration measurements made it possible to determine the energy budget of the two species of sea urchins, key information to know if they will be successful in a given environment. In addition, together with the knowledge of gene expression, this study makes a powerful tool to determine the ability to face projected scenarios according to climate change models,” concluded Dr. Jorge Navarro, academic at the Institute of Marine and Limnological Sciences of the UACh, researcher at the IDEAL Center and co-author of the study.