Biological mechanisms and effectiveness of algae in contaminated waters ​

 

The huiro, a species of brown algae, uses several biological mechanisms to absorb and neutralize pollutants present in the waters of Puchuncaví. According to Dr. Contreras, these algae have polysaccharides in their cell walls that act as a first defense barrier, adsorbing metals and metalloids. When metals enter cells, they are accumulated through proteins and small compounds. In addition, enzymes and antioxidant compounds eliminate free radicals that are formed by the presence of heavy metals. However, not all brown algae have the same tolerance to these conditions; Lessonia spicata, for example, shows less resistance to anthropogenic pollution, which explains its reduced population in impacted areas such as Horcón.

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The restoration of the huero on the seabed not only recovers the algal biomass, but also has a profound effect on local biodiversity. Lessonia spicata, as a community structurer, facilitates the settlement of various species, directly regulating coastal food chains. The loss of scapes would reduce the number of herbivores and, subsequently, carnivores in the region, affecting the ecological balance. In addition, these algae contribute to carbon sequestration and participate in vital biogeochemical cycles, offering multiple ecosystem services.

 

Long-term effects and indicators of success ​

 

Underwater reforestation with huero could have significant long-term effects on the chemical and microbiological composition of water in contaminated areas. “The key indicator of success is the increase in the number and abundance of species in the area,” says Dr. Contreras. Previous studies in Chile and other coastal regions have shown that recovering brown algae not only sequesters metals, making them less available to other organisms, but also contributes directly to the Sustainable Development Goals, helping to restore vital ecosystems and combating climate change. . The ability of algae to filter pollutants and grow varies depending on season and weather conditions. "We have observed that the physiological responses of the hummingbird change during the year, influenced by climatic, oceanographic and herbivory factors," explains Contreras. For example, the most active reproductive period occurs in autumn, with a notable presence of female gametophytes in impacted areas such as Horcón. Additionally, growing conditions in these high-impact areas show high mortality, which limits repopulation success. Although Dr. Contreras recognizes that the challenge is considerable, the restoration of these ecosystems – she affirms – is fundamental for the health of the ocean and the mitigation of climate change. "The need to increase the abundance of these organisms is urgent to recover biological systems and confront climate change," he emphasizes. The initiative in Caleta Horcón is an example of how collaboration between scientists and local communities can offer innovative solutions to protect our oceans.