The Strait of Magellan—a Gateway to New Worlds

The year 2020 marks the five hundredth anniversary of the “discovery” of the Strait of Magellan. The unveiling of this passage between 1519 and 1522 allowed the planet to be circumnavigated for the first time in the history of humanity. All maritime routes could now be connected, and the idea of the Earth, in its geographical, cosmographic, and philosophical dimensions, gained its definitive meaning. This discovery can be considered one of the founding events of the modern world and of the process of globalization that still continues today. This new connectivity awoke an immediate interest in Europe that led to the emergence of a political consciousness of possession, domination, and territorial occupation generalized on a global scale, and the American continent was the starting point for this. This consciousness also inspired a desire for knowledge about this new form of inhabiting the world. Various fields of knowledge were redefined thanks to the new spaces and measurements produced by the discovery of the southern part of the Americas, which was recorded in books on cosmography, natural history, cartography, and manuscripts, circulating mainly between the Americas and Europe. All these processes transformed the Strait of Magellan into a geopolitical space coveted by Europeans during the 16th century. As an interoceanic connector, it was used to imagine commercial routes to the Orient and political projects that could sustain these dynamics. It was also conceived as a space to speculate on the potential wealth in the extreme south of the continent. In addition, on the Spanish side, some agents of the Crown considered it a strategic place for imperial projections and the defense of the Americas.

Beta Diversity of Antarctic and Sub-Antarctic Benthic Communities Reveals a Major Role of Stochastic Assembly Processes

Community assembly is the result of both, deterministic and stochastic processes. The former encompasses niche-based local-scale mechanisms such as environmental filtering and biotic interactions; the latter includes ecological drift, probabilistic colonisation, and random extinctions. Using standardised sampling protocols, we show that the spatial variation in species composition (beta diversity) of shallow subtidal macrobenthic communities of sub-Antarctic (Strait of Magellan and Yendegaia Fjord [Beagle Channel]) and Antarctic (Fildes Bay [King George Island, West Antarctic Peninsula]) localities reflects a high contribution of stochastic processes to community assembly. Null model analyses indicated that random sampling from species pools of different sizes drove the observed among-locality differences in incidence- and abundance-based beta diversity. We analysed a normalised stochasticity ratio (NST), which delimits between more deterministic (<50%) and more stochastic (>50%) assembly. NST was notably larger than 50%, with mean values of 69.5% (95% CI = 69.2–69.8%), 62.5% (62.1–62.9%), and 72.8% (72.5–73.2%) in Strait of Magellan, Yendegaia Fjord, and Fildes Bay, respectively. Accordingly, environmental factors, such as depth, seawater temperature, salinity, and underwater light penetration, accounted for a small fraction of the spatial variation in community composition across the three localities. In this region, therefore, stochastic processes could have stronger effects on community assembly than deterministic niche-based factors. As anthropogenic biotic homogenisation continues apace, our study can give useful insights into the major ecological processes in Southern Ocean’ coastal marine communities.

First record of Rocinela aff. australis (Isopoda, Aegidae) in the Patagonian toothfish Dissostichus eleginoides (Pisces, Nothotenidae) from southern Chile

An isopod of the family Aegidae, provisionally referred to as Rocinela aff. australis Schiœdte & Meinert, 1879, is reported from the Patagonian tootfish Dissostichus eleginoides Smitt, 1898, from off the Biobio region, Chile. One specimen was collected, its body suboval, symmetrical, the dorsum weakly vaulted, stout, and with a few pits on the body. The specimen collected clearly belongs to the genus Rocinela and within that genus would most closely resemble Rocinela australis, but its actual specific status, whether an established species of the genus (and if so, which one) or possibly proving to be an as yet undescribed species, will have to await close examination by a specialist in marine isopod taxonomy. For the time being, we refer to the specimen as “Rocinela aff. australis”, since, compared with existing Rocinela spp., it matches best with that species both in general morphology and in geographical occurrence. This species, then, was reported until now only for the Strait of Magellan, Magellan region, and the southern Argentinean Atlantic coast. Thus, if the specimen would prove to really belong to Rocinela australis, then this report would constitute the most northern record of that species.

Freshwater Invertebrates of Southwestern South America: Diversity, Biogeography, and Threats

This chapter reviews the current state of knowledge of invertebrates of rivers, lakes, and wetlands in western South America, from southern Peru to the Strait of Magellan in southern Chile. A characterization of the diverse groups of insects, mollusk crustaceans, and other smaller groups is presented, and a biogeographic analysis of them is made with emphasis on their main forcing factors, ecology, and threats in the Anthropocene. This fauna presents Gondwanic characteristics, with clear North–South latitudinal patterns, covering from the Desert of Atacama in the North, one of the most arid deserts of the world, to the rainy and cold regions of the southern end of South America. The central zone of this territory includes one of the global biodiversity “hot spots,” which currently presents serious threats associated with changes in habitat, introduction of invasive species, climate change, and overexploitation of aquatic resources.

Diversity of benthic marine mollusks of the Strait of Magellan, Chile (Polyplacophora, Gastropoda, Bivalvia): a historical review of natural history

An increase in richness of benthic marine mollusks towards high latitudes has been described on the Pacific coast of Chile in recent decades. This considerable increase in diversity occurs specifically at the beginning of the Magellanic Biogeographic Province. Within this province lies the Strait of Magellan, considered the most important channel because it connects the South Pacific and Atlantic Oceans. These characteristics make it an interesting area for marine research; thus, the Strait of Magellan has historically been the area with the greatest research effort within the province. However, despite efforts there is no comprehensive and updated list of the diversity of mollusks within the Strait of Magellan up to now. This study consisted of a complete bibliographic review of all available literature that included samples of mollusks in the Strait of Magellan. More than 300 articles were reviewed, covering 200 years of scientific knowledge. There were 2579 records belonging to 412 taxa, of which 347 are valid species. Of the total valid species, 44 (~13%) are considered of doubtful presence in the Strait. This work increases the known richness of mollusks of the Strait of Magellan by 228%; it is also the first report that integrates all available diversity studies of the three most speciose classes of benthic mollusks (Gastropoda, Bivalvia and Polyplacophora) from the Strait of Magellan.