A pioneering research of its kind suggests that the brown alga, commonly known as huiro, generates a strategy of acclimatization to new environmental conditions. The results were published in the prestigious scientific journal Science of the Total Environment.
Andrea Navarro, IDEAL Center. It is home to one of the most productive ecosystems on Earth and provides ecosystem services worth trillions of dollars. The huiro or giant kelp, whose scientific name is Macrocystis pyrifera, is a species of macroalgae that can form large underwater forests, which fulfill a vital ecological function: They provide shelter, food and reproduction for countless organisms. Under optimal conditions they reach growth rates of around 5% per day. For example, a 10 m long plant can grow 50 cm per day during spring and summer.
Globally, it is estimated that as a result of climate change, the decline of the huiro forests has reached 38% in the last 50 years. However, in Chilean Patagonia there are very isolated backgrounds that indicate that no major variations have been detected. Taking these data into account, a team of researchers from the Center for Dynamic Research of High Latitude Marine Ecosystems (IDEAL) of the Austral University of Chile (UACh) carried out a pioneering study of its kind, which results were recently published in the scientific journal Science of the Total Environment.
The work focused on physiologically characterizing the huiro forests in the fjords and channels of the extreme south of Chile and understanding how they are dealing with climate change. The main objective of the study was to determine how these large macroalgae are able to cope with the impact and spatial variability of the different environmental forces, such as the limitation of light and turbidity, present in a marine system at high latitudes.
For the above, the researchers took the Yendegaia Fjord as the study area, located in the Beagle Channel, in the Magallanes and Chilean Antarctic Region. After carrying out diverse fieldwork, the team of scientists carried out a series of analyzes both in vivo and in the laboratory that allowed obtaining a physiological characterization of the populations impacted by the effluents from the Stopanni Glacier, which shows evidence of retreat and is located 11 kilometers from the sea.
The results of the study indicate that the huiro forests settled in the Patagonian systems generate a unique acclimatization strategy to the new environmental variables caused by climate change. The alga is adapted to a condition of limited light: When there are stress factors such as greater turbidity in the water and high levels of particulate matter, the refraction is greater and, therefore, the quantity and quality of light necessary for the photosynthesis is very limited. However, these large areas of huiro maintain the ability to carry out their metabolic activity, optimizing the capture of all available light at different depth levels.
“This is the first approximation of the in vivo physiological state of Macrocystis pyrifera in the subantarctic zone and particularly in the Beagle Channel. We propose that the Yendegaia Fjord is currently showing us what will happen to other types of glaciers in Patagonia in the future. The picture we envision today is possibly the same as we will have in 30 years, considering the most pessimistic future scenarios of climate change. In spite of everything, the alga will still be there,” says doctor (c), Mauricio Palacios, author of the study.
The research revealed that huiro forests present local adaptations, which are manifested in the active production of anti-stress phenolic substances, called florotannins. Through chemical analysis and transmission electron microscopy, it was shown that all the samples collected along the Yendegaia Fjord contained an abundant presence of these substances. So far, it has been documented that these compounds possess a series of properties, some of them anti-stress against ultraviolet radiation, temperature and the action of herbivores. This confirms that the alga is constantly protecting itself.
The scientific work, in addition to being one of the few that has evaluated the physiological activity in vivo, takes on special relevance in a context where the Intergovernmental Panel on Climate Change (IPCC) projects that the huiro forests will retract their distribution. towards the polar zones. The Patagonian region could be a climatic refuge for these macroalgae.
“An important aspect that this study also raises is that as global warming moves back the glaciers, new areas of the seabed will emerge that can be colonized by macroalgae, probably expanding their distribution and that will have consequences for future biodiversity in these extreme regions,” concluded Dr. Iván Gómez, deputy director of the IDEAL Center and co-author of the study.