A multidisciplinary research detected the presence of new toxic compounds from the Gulf of Penas to the Madre de Dios Archipelago. Its effects could account for potential negative effects on marine organisms.
During the expedition, surface water was collected through resins that trap toxins and keep them preserved. © Diego Nahuelhuén.
Andrea Navarro, IDEAL Center. It is not known when or how they arrived, but the truth is that they are there, in one of the most pristine areas of the planet.
Harmful Algal Blooms (HAB), commonly known as “red tides”, are a natural phenomenon that occurs due to the exponential increase of microalgae in the oceans, considered the basis of the trophic webs of aquatic ecosystems. These microscopic organisms poison shellfish and fish. Due to their high toxicity, they can cause the death of human beings who consume them.
According to a report by the Food and Agriculture Organization of the United Nations (FAO), marine toxins “represent a significant and growing threat to human health in many areas of the world.” Historically, one of the places considered most vulnerable to HAB events is the fjords and channels of the extreme south of Chile.
To date, in southern Patagonia, the scientific community had identified, at least, the presence of seven different marine toxins: diarrheic, paralyzing, amnesic and others that co-occur when extracting diarrheic toxins, such as yessotoxins, pectenotoxins, spirolides and gymnodimines. However, a multidisciplinary team of scientists found two new types that had not been registered in the northern part of the Magallanes Region.
The finding was made in an oceanographic campaign led by the Center for Dynamic Research on High Latitude Marine Ecosystems (IDEAL) of the Austral University of Chile (UACh), the University of Magallanes (UMAG) and the Institute of Fisheries Development (IFOP.) On board the scientific vessel “Cabo de Hornos,” a group of 23 researchers carried out a transect from the Gulf of Penas to the Madre de Dios Archipelago.
During the expedition, surface water was collected through resins that trap toxins and keep them preserved. Afterwards, the samples were transferred to the laboratories of the Alfred Wegener Institut (AWI) in Bremerhaven, Germany. There, using a very specific analytical technique called tandem mass spectrometry coupled with liquid chromatography, individual molecules were chemically detected.
As a result, the researchers found azaspiracids (which in other parts of the world is produced by species of microalgae of the genus Azadinium and Amphidoma) and pinnatoxins (generated by the microalgae Vulcanodinium rugosum.) The former generates symptoms such as nausea, vomiting, severe diarrhea and stomach spasms in humans. The latter belong to the group of cyclic imines, whose effects in experimental bioassays are toxic, which is why their potential effect on people is being investigated.
Azaspiracids have only been known for 25 years and despite the fact that they have been little studied, there is evidence that they have a wide worldwide distribution as well as the microalgae that produce them. For its part, the species that synthesizes pinnatoxin has been reported with a wide tolerance to salinities (euryhaline) and withstanding extreme temperatures (thermophilic,) conditions that do not occur in the Magallanes Region.
Since the factors that produce its proliferation in southern Patagonia are still unknown, its consequences on the marine ecosystem are uncertain. © Diego Nahuelhuén.
“It is not yet possible to know the biological origin or the primary source of the toxins. To determine how they got there, we need time series to allow us to continue investigating. Despite this, these registries will be essential to incorporate new species into the monitoring protocols,” warns the AWI chemical toxicologist, Dr. Bernd Krock.
“Researching these toxins takes a lot of time and dedication. From the taxonomic point of view through microscopy there is a lot of work to be done. It is also necessary to detect toxins in seawater and organisms,” affirms the IFOP phytoplanctologist, Dr. Gemita Pizarro.
Implications for the marine ecosystem
Since the factors that produce its proliferation in southern Patagonia are still unknown, its consequences on the marine ecosystem are uncertain. Despite this, one of the hypotheses that the team of scientists uses is that it could have negative effects on the higher trophic levels.
“In recent years, from the Gulf of Penas to the south, there have been deaths in invertebrates, fish and marine mammals that could eventually be related to these new toxic species in the area,” explains the CIGA researcher from UMAG and the IDEAL Center, Dr. Máximo Frangópulos.
“What are the environmental conditions for various toxins to be found in the interior waters and oceans of Patagonia? This is a relevant finding that allows addressing new questions and lines of research on the origin and the factors that are triggering them,” concludes the oceanographer of the IDEAL Center and academic of the Institute of Aquaculture of the UACh, Dr. José Luis Iriarte.