It has been observed in high-latitude marine environments of the Southern Hemisphere that the variability in the ecological patterns of macrobenthic communities show variations at different spatial scales (i.e. cm to km), mainly influenced by environmental stress gradients. We examined macrobenthic communities of intertidal and subtidal habitats in a glacial fjord using taxonomic, ecological and oceanographic approaches, estimating vertical and horizontal variation using a nested design with different spatial scales ranging from centimeters to kilometers (quadrats, patches, shore and sites respectively). We found that vertical patterns in taxon richness and community structure were significant in both habitats. These patterns also showed horizontal variability at different spatial scales, becoming more pronounced at smaller scales (quadrats). The dominant taxa in the intertidal (macroalga) and subtidal (macroinvertebrate) communities also exhibited a scale-dependent distribution pattern, indicating that the greatest horizontal variation occurs at small spatial scales. Annual and opportunistic green algae such as Ulva intestinalis and Cladophora flexuosa were dominant in the intertidal, while the dominant taxa in the subtidal were the filter-feeding bivalve Aulacomya atra and the suspensivorous hydrozoan Symplectoscyphus marionensis. The results were related to biological interactions and local abiotic factors characteristic of an estuarine system influenced by glaciers, with lower salinity and temperature and higher turbidity in sites close to glaciers. The information generated on diversity patterns is very relevant and can serve as a baseline in the evaluation of ecological patterns of shallow macrobenthic communities in environmental gradients influenced by glaciers in the Magellanic Subantarctic ecoregion.

This study aimed at testing the existence of local adaptation in the gametophytes of giant kelp, in regions separated by up to 4000km and strong thermal divergence.

La ecorregión subantártica de Magallanes posee una heterogénea costa de fiordos y canales, con una gran extensión de ecosistemas intermareales sujetos al efecto de condiciones climáticas extremas características de zonas de altas latitudes. Trabajos de investigación recientes sugieren que la estructura de los ensambles intermareales que habitan en ambientes extremos, como subantárticos y antárticos, presenta altas variaciones horizontales y verticales que se acentúan a escalas espaciales finas. Éste podría ser un patrón general en hábitats intermareales de altas latitudes del hemisferio sur, y en este trabajo evaluamos la hipótesis que la variabilidad horizontal y vertical de los ensambles bentónicos intermareales en ambientes extremos subantárticos es mayor a escalas finas. En marzo-abril de 2017 se analizó la variabilidad espacial sobre los ensambles bentónicos intermareales de bahía Yendegaia, Reserva de la Biosfera Cabo de Hornos, como modelo de estudio con un diseño anidado con diferentes escalas espaciales que van desde centímetros a kilómetros. El análisis de los componentes de varianza y pseudo-varianza mostró una significativa variación horizontal y vertical a escalas finas. Se identificaron seis comunidades con una marcada zonación vertical. Las especies más representativas fueron el molusco Perumytilus purpuratus y las algas Porphyra/Pyropia sp1. y Ulva flexuosa, las que tuvieron una alta variación vertical en escalas finas. Estos patrones apoyan la hipótesis testeada, sin embargo, es probable que factores físicos locales del hábitat relacionados con cambios abióticos también influyan significativamente sobre las variaciones espaciales a pequeñas escalas en las comunidades de bahía Yendegaia. Por lo tanto, se propone extender este tipo de investigaciones incorporando la variabilidad temporal y datos ambientales en bruto. Estos estudios permitirán detectar los factores locales más influyentes sobre la variación espacial de los ensambles bentónicos intermareales subantárticos.

The potential for biological colonisation of Antarctic shores is an increasingly important topic in the context of anthropogenic warming. Successful Antarctic invasions until now have been recorded exclusively from terrestrial habitats. While non‐native marine species such as crabs, mussels and tunicates have already been reported from Antarctic coasts, none have as yet established there. Among the potential marine invaders of Antarctic shallow waters is Halicarcinus planatus (Fabricius, 1775), a crab with a circum‐Subantarctic distribution and substantial larval dispersal capacity. An ovigerous female of this species was found in shallow waters of Deception Island, South Shetland Islands in 2010. A combination of physiological experiments and ecological modelling was used to assess the potential niche of H. planatus and estimate its future southward boundaries under climate change scenarios. We show that H. planatus has a minimum thermal limit of 1 °C, and that its current distribution (assessed by sampling and niche modelling) is physiologically restricted to the Subantarctic region. While this species is presently unable to survive in Antarctica, future warming under both strong mitigation' and 'no mitigation' greenhouse gas emissions scenarios will favour its niche expansion to the Western Antarctic Peninsula (WAP) by 2100. Future human activity also has potential to increase the probability of anthropogenic translocation of this species into Antarctic ecosystems.

Two species of scallop, Austrochlamys natans (“ Ostión del Sur ”) and Zygochlamys patagonica (“ Ostión patagonico ”) are presently exploited in the southern part of the Magallanes Province (MP). The lack of clarity in taxonomic identification and ecological aspects is generating both erroneous extraction statistics and an unperceived harvesting pressure on A. natans and Z. patagonica . We aim to discriminate these Magallanes scallops accurately, improve our understanding of their complex natural history and discuss possible implications for their management and conservation status, given the current fisheries statistics. To achieve these goals, we present a complete review of the historical identification of the Magallanes scallop and a multi-locus molecular phylogeny which allowed us to recover the phylogenetic position of A. natans . We sampled 54 individuals from five localities across the southern Pacific coast of the MP. We calculated the depth of the byssal notch (BND) and shell height (VH) ratio from morphological characters and conducted phylogenetic reconstructions with mitochondrial (12S and 16S) and nuclear markers (28S) using Bayesian and maximum likelihood analyses. Both morphology and molecular phylogeny identified two distinct entities, Z. patagonica and a distinct, highly divergent lineage that corresponds to A. natans . Our study provides integrative evidence to alert the current fishery management and the need for further conservation studies.