Preliminary results suggest that Pseudechinus magellanicus, a species that is abundant in the extreme southern waters of Chile and Argentina, could tolerate a future scenario of ocean warming.
These sea urchins are distributed along the Pacific Coast from Puerto Montt (Chile) southward, and in the Atlantic Ocean from the Río de la Plata (Argentina) also to the south. © Camille Detree.
Daniela Jofré, IDEAL Center. These creatures exist in great abundance in the Southern Ocean, and play an important role in marine ecosystems. However there is very little known about their biology. These are commonly known as the “dwarf sea urchin,” whose scientific name is Pseudechinus magellanicus. This is a species that has not been widely studied.
These sea urchins are distributed along the Pacific Coast from Puerto Montt (Chile) southward, and in the Atlantic Ocean from the Río de la Plata (Argentina) also to the south. They are commonly found in Patagonian coastal waters. Unlike the “red sea urchin,” which is exploited in large quantities and makes Chile one of the largest exporters worldwide, the “dwarf sea urchin” is not edible.
In a scenario involving climate change, where an increase in temperature is predicted in the Southern Ocean, the physiological response of the “dwarf spiny urchin” and its possible survival could affect the entire ecosystem. This situation is being researched by Dr. Camille Detree, a scientist at the Research Center – Dynamics of High Latitude Marine Ecosystems (IDEAL) of the Austral University of Chile (UACh).
After analyzing specimens from the Straits of Magellan and the Yendegaia Fjord (Beagle Channel), in Chile’s Magallanes and Antarctic Region, Dr. Detree is leading the first study in the country that analyzes the adaptability of the species when confronted with temperature and salinity variations, among other factors.
“P. magellanicus is near the limits of its distribution in the Beagle Channel, so studying its thermal tolerance is an essential part of understanding the strategy that this population might employ in responding to climate change. Will it tolerate such changes? Will this species migrate to a colder environment, or perish in trying to do so? Those were some of our questions,” said Dr. Detree.
The specimens were exposed to temperatures from a range of -1° C (winter temperature in the Antarctic) to the highest temperature level. © Camille Detree.
For this research, laboratory experiments were carried out in which sample specimens were subjected to several temperature levels to assess their “recovery capability.” The specimens were exposed to temperatures from a range of -1° C (winter temperature in the Antarctic) to the highest temperature level, where the urchins were unable to recover within the period of one hour.
Dr. Detree proposed the hypothesis that the “dwarf spiny urchin” enjoyed a wide thermal range, being able to function and survive at lower temperatures. However, the results of their study were surprising: the recovery time increased with lower temperature, at -1 ° C. In contrast, the “turnover capacity” was similar for individuals held at a temperature of 7°C to 17°C. At 19°C, the recovery time started to increase and mortality occurred at 22°C, the upper thermal limit for this population. These results suggest that P. magellanicus in the Beagle Channel could likely tolerate a future warming scenario.
Dr. Detree also concluded that “Although it seems that this sea urchin could tolerate a degree of ocean warming, it is necessary to continue looking into other factors associated with global climate change, such as the acidification of the seas and freshening, which together could affect the urchins’ thermal tolerance.”