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.

Impact of Extreme Weather Events on Aboveground Net Primary Productivity and Sheep Production in the Magellan Region, Southernmost Chilean Patagonia

Spatio-temporal patterns of climatic variability have effects on the environmental conditions of a given land territory and consequently determine the evolution of its productive activities. One of the most direct ways to evaluate this relationship is to measure the condition of the vegetation cover and land-use information. In southernmost South America there is a limited number of long-term studies on these matters, an incomplete network of weather stations and almost no database on ecosystems productivity. In the present work, we characterized the climate variability of the Magellan Region, southernmost Chilean Patagonia, for the last 34 years, studying key variables associated with one of its main economic sectors, sheep production, and evaluating the effect of extreme weather events on ecosystem productivity and sheep production. Our results show a marked multi-decadal character of the climatic variables, with a trend to more arid conditions for the last 8 years, together with an increase in the frequency of extreme weather events. Significant percentages of aboveground net primary productivity (ANPP) variance is explained by high precipitation, mesic temperatures, and low evapotranspiration. These conditions are, however, spatially distributed in the transition zone between deciduous forests and steppe and do not represent a general pattern for the entire region. Strong precipitation and wind velocity negatively affect lamb survival, while temperature and ANPP are positively correlated. The impact of extreme weather events on ANP and sheep production (SP) was in most of the cases significantly negative, with the exception of maximum temperature that correlated with an increase of ANPP, and droughts that showed a non-significant negative trend in ANPP. The examination of these relationships is urgent under the current scenario of climate change with the acceleration of the environmental trends here detected.

High similarity in the microbiota of cold-water sponges of the Genus Mycale from two different geographical areas

Sponges belonging to genus Mycale are common and widely distributed across the oceans and represent a significant component of benthic communities in term of their biomass, which in many species is largely composed by bacteria. However, the microbial communities associated with Mycale species inhabiting different geographical areas have not been previously compared. Here, we provide the first detailed description of the microbiota of two Mycale species inhabiting the sub-Antarctic Magellan region (53°S) and the Western Antarctic Peninsula (62–64°S), two geographically distant areas (>1,300 km) with contrasting environmental conditions. The sponges Mycale (Aegogropila) magellanica and Mycale (Oxymycale) acerata are both abundant members of benthic communities in the Magellan region and in Antarctica, respectively. High throughput sequencing revealed a remarkable similarity in the microbiota of both sponge species, dominated by Proteobacteria and Bacteroidetes, with both species sharing more than 74% of the OTUs. In contrast, 16% and 10% of the OTUs were found only in either M. magellanica or M. acerata, respectively. Interestingly, despite slight differences in the relative abundance, the most dominant OTUs were present in both species, whereas the unique OTUs had very low abundances (less than 1% of the total abundance). These results show a significant overlap among the microbiota of both Mycale species and also suggest the existence of a low level of specificity of the most dominant symbiont groups.