Experiments show for the first time that volcanic ash affects the size of mussels and increases energy expenditure.
How does volcanic ash affect a food commonly found on the coasts of Chile, such as Mytilus chilensis, better known as chorito or mussel? That was the question answered by a group of researchers from the the Austral University of Chile (UACh) and the Center for the Dynamic Research of Marine Ecosystems of High Latitudes (IDEAL).
In this research, which included the work of Dr. Jorge Navarro, Dr. Jan Pechenik, Dr. Óscar Chaparro, and marine biologist Luis Salas, was published in the scientific journal Marine Pollution.
The effects of ash particles resulting from volcanic activity in the atmosphere are known. However, once they settle out and reach the oceans, the resulting effects caused on these mussels have so far been unknown.
A total of 360 mussels were used, grouped into 180 juveniles and 180 adults, which were given a diet of microalgae and ash for 15 days to identify potentially lethal impacts of volcanic ash particles.
The mussels were collected at Caleta de Amargo, in the Los Ríos Region of Chile. Some of the mussels were used to measure respiratory levels, feeding capacity, and body weight loss. Analysis of electronic microscopy of the gills identified potential physical injury due to the abrasive action of the volcanic ash.
Luis Salas and Oscar Chaparro agree that consuming the ash would be like ingesting ground glass. “We thought the mussels would die, but that didn’t happen. All the experimental animals survived, ” Salas said.
One of the results revealed the greater the number of suspended volcanic particles, the less the mussels could distinguish between nutritive particles (microalgae) and ash particles, and thus they would spend excessive energy in the feeding process. As a result, the presence of ash particles in the water can produce a reduction of around 19% and 40% of the body mass of mussels, in adults and juveniles, respectively.
Dr. Navarro, from the IDEAL Center, explained that the consequence of ash particles not only imply the loss of body mass, but also could have an effect on reproduction in adult organisms, due to the lower amount of energy that is channeled to the formation of reproductive cells.
The current study has generated new understanding, which will serve to promote additional studies elsewhere in Chile, a country where there are 2900 volcanoes, and where periodic eruption events take place, such as the occurrence in Patagonia, when the Chaitén volcano erupted in 2011. “Without a doubt that event could also have negative effects on Patagonian ecosystems where there are filtering organisms, including both plankton and benthic species,” said Dr. Navarro.
“The reduction in the amount of body mass is a reflection of the fact that the mussels were not eating properly, despite the abundance of available microalgae. If this continues over time, it could result in a difficult survival situation for these mussels. The physical damage we expected to see did not occur, since these mussels have a mechanism that prevents physical damage to the gills, ” explained Chaparro.
This study, which was presented in Brazil and Peru at oceanography seminars, and for the first time is released in Chile, will allow us to understand how primary consumers, such as mussels, are affected by volcanic eruptions. Luis Salas explains that the role of mussels in the food chain is very important, because they are responsible for filtering the suspended particulate matter and then transforming it into food for other species of the seabed.