Claudio Gonzalez – The history of Austral currents under a snail’s shell
Back from Macquarie Island, a marine biologist from Chile’s Milenio Base Institute fulfills a scientific and personal dream by collecting rare specimens of mollusks.
The moon passes and the sea recedes. Rocks covered in shells emerge. Claudio Gonzalez, a biologist specializing in invertebrates, loves this landscape. He has been criss-crossing southern Chile and Antarctica for 18 years, in search of shellfish specimens to study on the coast revealed at low tide. The animals he looks for on the American side of the Southern Ocean are linked to the populations of the sub-Antarctic islands, such as Macquarie Island, on the opposite side of the White Continent. “I’d seen this island described in books many times, but this time I saw it, with its whales, orcas and fabulous birds.” Claudio Gonzalez has just returned from an expedition during which he was able to set foot on the island for the first time in his career. “It was a life experience. A dream come true.”
He is one of the principal investigators of the Instituto Milenio Base, a ten-year Chilean project that cuts across several fields of knowledge, linking some twenty Chilean and foreign institutions to answer the scientific questions of the Antarctic Treaty system.
Since its inception in 2022, the initiative and the French company Ponant have signed agreements enabling the network’s scientists to embark on cruises. “They allow us to work in the field while they do their tourist activities,” explains the researcher, back at the Universidad Austral de Chile in possession of rare samples of gastropods and other mollusks. “In this way, we were able to travel to the sub-Antarctic islands of New Zealand and Australia.”
Permits are required to access these nature reserves. “Unfortunately, we were unable to land at the Antipodes and Snares,” he explains. “Tourism is not permitted there.” For Claudio Gonzalez to be able to disembark, it is essential that tourists be able to do so too. On the other hand, the doors to Auckland, Campbell and Macquarie Islands have been opened to them.
Approaching the most eagerly awaited of them all, Macquarie, the tail of an Indonesian typhoon lifted the ocean. The ship was delayed, and Claudio Gonzalez lost a day. Finally, arriving on site on a Wednesday morning, he disembarked… at high tide. “High tide, when you’re working in the tidal zone, is a headache. Collection options are more difficult when the water’s up to your waist. We had to put our heads under water and into the waves to get the specimens out,” he explains.
In the afternoon, the forecast on the other side of the island is more favorable, and the tide is low. But the wind changes direction and the swell rises. The landing is cancelled. “What a frustration not to have been able to land,” he confides. Claudio Gonzalez remembers relativizing by recalling the Rolling Stones: “You can’t always get what you want, but if you try once in a while, you find, you get what you need.” In hindsight, he feels he came away with what he needed.
“When I was a PhD student, I had managed to obtain a tissue sample of the Macquarie endemic species, Nacella macquariensisand now I have 15 specimens,” he explains. “It was a fantastic scientific experiment.” He also brought back small gastropods barely 8 mm in size, such as Laevilitorina venusta. This one doesn’t produce larvae, but juveniles that cling to macroalgae to travel. When these break off, they float and circulate for almost a year around Antarctica. “A 2001 estimate noted 8 million rafts circulating in the circumpolar current at any given moment”, notes the researcher.
On South American islands such as Hornos and Diego Ramírez, through Crozet and Kerguelen to Macquarie, populations of gastropods and other mollusks are more or less connected. “The island is a particularly isolated point in the range of the animal species I study, and has a high level of endemism,” he explains. “We’re working on evolutionary markers found in the snail genome. We’ll be able to determine whether the current distribution of these species is the result of contemporary dispersal or whether this happened 100,000 years ago.”
The fruits of his latest collection are currently being analyzed, and Claudio Gonzalez plans to set off again, hoping that the tide will be with him and thus add a few inhabited shells to his “coquillier”.
