An interdisciplinary group of scientists performed a transect of 13 sampling stations at a site that is considered crucial for cetaceans.
Daniela Jofré, IDEAL Center. The Gerlache Strait, located in the western part of the Antarctic Peninsula, is not only a passage for scientific and tourist ships that arrive year after year on the white continent. During the summer, it becomes a key feeding site for humpback whales (Megaptera novaeangliae), also known as yubarta.
Despite its importance for one of the largest species in the cetacean genus, the place has been little studied by the scientific community.
A team of researchers from various disciplines from the Center for Dynamic Research of High Latitude Marine Ecosystems (IDEAL) of the Austral University of Chile (UACh) carried out a transect of 13 oceanographic stations. On board the Karpuj vessel, belonging to the Chilean Antarctic Institute (INACH), the scientists measured diverse variables such as temperature, salinity, pH and oxygen, among others.
The main objective of the research was to find out how oceanographic conditions vary along the strait and to relate these conditions to the greater or lesser productivity of the system.
“Considering the important percentage of whales that come to this place to feed, we believe that this is a fairly productive area in relation to phytoplankton. As it is a strait protected by mountains and glaciers, the contribution of iron due to the entry of melting water should be important,” says Dr. Juan Höfer, researcher at the IDEAL Center and academic at the Pontifical Catholic University of Valparaíso (PUCV).
In turn, the scientists collected samples for trace metal analysis and study of the present microbial community. The first results indicate that the waters present in the northern Gerlache area come from the Weddell Sea, located to the east of the Antarctic Peninsula, being different from the waters found in the southern area of the strait.
“We know that the strait supports a large whale population, but the question is why? One hypothesis is that the waters that pass through the strait receive micronutrients, such as iron, from shallow sediments or glaciers, which added to the nutrients that come from the Southern Ocean would create optimal chemical conditions for life to grow,” states Dr. Mark Hopwood, researcher at the Center for Ocean Research (GEOMAR) in Germany.
“The Gerlache Strait is included in the General Protection Zone within the proposed Marine Protected Area promoted by Chile and Argentina. Our data show the uniqueness of this Antarctic zone and will give important information to understand its operation,” concludes Dr. Mireia Mestre, researcher at the IDEAL Center and the University of Concepción (UdeC).