A study conducted in the Reloncaví Fjord, in the Los Lagos region of Chile, and published in the scientific journal JGR Biogeosciences, reports that the “choritos” (Chilean blue mussels) – an important commercial resource in the country – may be able to survive in waters that are “corrosive.”

Maximiliano Vergara, marine biologist at IDEAL Center.

Andrea Navarro, IDEAL Center. The Reloncaví Fjord, located in Chile’s Los Lagos region, is considered a strategic area for oceanography in Chile. In addition to its scenic beauty, this is the northernmost fjord in not only Patagonia, but anywhere in the southern hemisphere. The Puelo River flows through the center of this region, providing large contributions of fresh water.

It is here that a team of Chilean scientists installed the first carbonate study system with high data collection precision to capture information about ocean acidification, a phenomenon occurring as a result of pollution caused by greenhouse gases. The work involved researchers from the Research Center – Dynamics of High Latitude Marine Ecosystems (IDEAL) of the Austral University of Chile (UACh). Through the use of an oceanographic buoy, they were able to obtain continuous data from the Reloncaví Fjord from December 2014 to September 2016.

After measuring dissolved oxygen, temperature, salinity, depth, pH and carbon dioxide, the results of the study were published in the scientific journal JGR Biogeosciences. These findings contrast with the previous scientific view: that calcifying organisms – those that form a shell – could not survive ocean acidification.

Maximiliano Vergara, marine biologist and doctoral candidate at the IDEAL Center as well as leader of the study, explained that “After studying the chemistry of the Reloncaví Fjord we found that, contrary to what was believed, mussels are in fact able to survive in a corrosive environment. That is to say, they’re naturally adapted to ocean acidification.”

An important industry in southern Chile is aquaculture. This includes “mytiliculture,” or mussel farming, one of the largest sectors in terms of export volume. It is estimated that more than 70% of the sources for the Chilean blue mussel are from the Reloncaví Fjord, making it the largest such supplier for the country. On the other hand, this same study revealed a critical degree of calcium availability during the winter months. Due to the current strong variability of the ocean, this is an indicator of potential risk for calcification of mitilid (mussel) larvae that develop in the spring, as well as salmon raised in these waters.

It is estimated that more than 70% of the sources for the Chilean blue mussel are from the Reloncaví Fjord. © Maximiliano Vergara

Climate change

Climate change projections forecast 20% less rainfall, which could affect the dynamics and structure of organisms that live in the water column, such as mussels. “Knowing at what times of the year there may be more or less corrosivity can help reduce stress during harvesting. In Chile, it is essential to continue working on these monitoring systems, which can be used for forecasting,” according to Vergara.