Understanding the ecological implications of species coexistence is central to biodiversity studies and to identify environmental and anthropogenic drivers of ecosystem dynamics, where ecological network analysis offers valuable insights. This study examines the complexity, structure, and potential responses to disturbances of the Strait of Magellan's topological food web. Based on a dataset of 438 predator–prey interactions among 139 trophic species (nodes), the food web was characterized using a two‐scale approach. At the network level, descriptors including connectance, degree distribution, and small‐world pattern, were used to evaluate overall architecture. At the node level, species' roles were assessed using degree, betweenness, closeness, condensed in a novel Keystone Species Index (KSI), and topological role. Potential resilience to ongoing perturbations was inferred by relating these network‐ and node‐level properties. Overall, the network exhibits low connectance and an asymmetrical degree distribution, with a few species concentrating most interactions. Its small‐world pattern, characterized by high clustering and short path lengths, suggests that local disturbances could propagate rapidly. More than half of the species are omnivorous, potentially buffering the system against fluctuations in prey availability. According to the KSI antopological role results, polychaetes, Fuegian sprat Sprattus fuegensis ‘sardina fueguina', and Patagonian blenny Eleginops maclovinus ‘róbalo patagónico', act as central conduits for matter and energy flow, linking benthic and pelagic production to higher trophic levels. The combination of low connectance, an asymmetric degree distribution, and small‐world properties suggests that the food web is fragile to perturbations affecting highly connected species, with the potential to trigger trophic cascades. These findings highlight the importance of understanding trophic interactions for effective conservation and ecosystem management and provide new insights for the Strait of Magellan's ecosystem.

Microplastic (MP) pollution is a significant threat to marine environments not only due to its widespread presence but also because of the alarming emergence of ingestion records among benthic organisms. In this study, MP prevalence was assessed in the stomach of the crustaceans Lithodes santolla and Grimothea gregaria and the gastropods Nacella deaurata and N. concinna. Particles were analyzed with Fourier-transform infrared (FTIR) spectroscopy. Overall, the analysis revealed that the particles were mainly microfibers composed of cellulose/rayon (60%), followed by MPs (30%), and undetermined not registered in the library (10%). Higher prevalence was found in marine benthic grazers compared to scavengers, with the latter showing low particle prevalence in their stomach contents. Grazers presented a significantly higher abundance per individual but a lower size of ingested particles compared to scavengers. When grouped by trophic levels, tertiary consumers presented significantly lower abundances per individual but larger sizes of the ingested particles. Pearson’s correlations showed no significant associations between particle abundance/size and species body size. The results of this study may suggest that continued MP pollution in marine environments and the associated accidental ingestion by marine organisms will alter the energy flow and organic matter availability in benthic food webs, with species that perform certain functional traits more susceptible to being affected.

Benthic communities are a fundamental component of coastal marine ecosystems, regulating energy flow, mediating trophic transfer, and supporting a wide range of ecological functions closely linked to habitat characteristics. In Marine Protected Areas (MPAs), integrative approaches that simultaneously address trophic and functional dimensions are essential to assess ecosystem functioning and resilience to environmental disturbances. This study aimed to characterize and compare the trophic structure and functional diversity of benthic communities in sub-Antarctic fjords and channels of the Magellan region (southern Chile), all of which are located within MPAs and represent contrasting environmental settings characterized by either proglacial influence or a documented history of recurrent harmful algal bloom (HAB) occurrence and paralytic shellfish toxin (PST) exposure. We hypothesized that benthic communities under these contrasting environmental stressors would differ in carbon assimilation pathways, community isotopic niche breadth, and functional organization. Trophic structure was evaluated using stable isotope analysis (δ¹³C and δ¹⁵N), Bayesian mixing models to estimate basal carbon source contributions, and community-level isotopic metrics. Functional diversity was quantified using biological and ecological traits to calculate community- and species-level functional indices. Our results revealed marked differences in trophic organization among localities, whereas global functional diversity indices were consistently low and similar across environmental settings. Communities from localities characterized by recurrent HAB/PST exposure showed limited trophic reliance on pelagic-derived organic matter, maintaining benthic-based energy pathways, whereas proglacial localities exhibited higher allochthonous subsidies and broader isotopic niches. Functional uniqueness and specialization metrics indicated strong functional redundancy and a high dependence on a small set of functionally distinctive species. These findings establish a baseline for remote MPAs and demonstrate the value of integrating trophic and functional metrics in long-term monitoring and adaptive management frameworks.

Marian Cove, a proglacial Antarctic fjord, has been strongly affected by glacier retreat, generating a pronounced environmental gradient that shapes the structure and composition of benthic communities. Given its ecological relevance, this review aims to compile and synthesize existing information on the ecology, biodiversity, and functional dynamics of these communities, identifying patterns of ecological succession, trophic coupling, and resilience in response to glacier retreat. A systematic literature search was conducted using Google Scholar and Web of Science, covering the past three decades and applying inclusion criteria restricted to peer-reviewed studies focused on the ecological or trophic aspects of Antarctic macrobenthos. The reviewed studies reveal that high sedimentation rates and turbidity near the glacier favor low-diversity pioneer communities, while outer sectors host more diverse and functionally complex assemblages. Local benthic production and functional redundancy emerge as primary mechanisms of ecological resilience under increasing disturbance, with functionally redundant species adapted to the environmental gradient and key taxa maintaining energy fluxes and local biodiversity. Comparisons between Marian Cove and other Antarctic fjords, such as Potter Cove, highlight convergent ecological mechanisms operating under different levels of glacial disturbance, where local benthic production and redundancy sustain ecosystem resilience. This review synthesizes three decades of research in a representative Antarctic fjord and underscores the need for long-term monitoring, standardized methodologies, and international collaboration to anticipate critical thresholds of ecological stability in proglacial ecosystems facing accelerated climate change.

Understanding the intricate ecological implications of species coexistence through trophic network analysis is crucial for biodiversity studies and for deciphering the environmental drivers of ecosystem dynamics. This study examines, in detail, the complexity, structure, and potential responses of the Strait of Magellan’s trophic network to both environmental and anthropogenic disturbances. Based on an extensive dataset of prey-predator interactions, we characterized the network’s topology and its theoretical resilience using a complex network methodology, analyzing the system at both the network-wide (holistic) and species-specific (reductionist) levels. Our analysis of 140 trophic species and 438 interactions reveals a network with low connectivity (0.022) and an asymmetrical distribution of links, where a few species disproportionately perform most interactions. The network exhibits a ”small-world” architecture, with high clustering and short path lengths, suggesting a rapid propagation of local disturbances. A significant proportion (over 50%) of species are omnivorous, a trait likely contributing to ecosystem stability amidst fluctuating prey availability. Key taxa – polychaetes, Fuegian sprat ( Sprattus fuegensis ) “sardina”, squat lobster ( Grimothea gregaria ) “langostino”, and Patagonian blenny ( Eleginops maclovinus ) “róbalo” – emerge as central conduits for matter and energy flow, effectively linking benthic and pelagic primary productivity to higher trophic levels and significantly underpinning ecosystem function. While the network shows potential robustness to general fluctuations, its concentrated interaction structure makes it vulnerable to the loss or migration of these pivotal species. These findings highlight the importance of understanding trophic relationships to inform effective conservation and ecosystem management strategies in this sensitive Sub-Antarctic marine region. This study provides a foundational understanding of the Strait of Magellan’s marine trophic architecture.