María Soledad Astorga-España

The North American beaver ( Castor canadensis ) has become a major invasive threat in the sub-Antarctic forests of the Fuegian Archipelago. By constructing dams, beavers flood and kill extensive forest areas, convert riparian forests (RFs) into wetlands, and substantially alter hydrological and biogeochemical processes. This study presents an integrated austral summer assessment of greenhouse gas(GHG) fluxes in a beaver-created wetland and an adjacent intact RF. Fluxes were measured from water, soil, and tree stem surfaces. CH ₄ emissions were markedly higher in the beaver-degraded area than in the intact forest, with total ecosystem emissions of 20.36 and −1.59 mg CH ₄ m ⁻² d ⁻¹ , respectively. In contrast, CO ₂ emissions were greater in the intact RF (39.3 g CO ₂ m ⁻² d ⁻¹ ) than in the beaver-degraded forest (4.32 g CO ₂ m ⁻² d ⁻¹ ). Annualizing these summer fluxes yielded total GHG emissions that were 179 t CO _2-eq ha ⁻¹ yr ⁻¹ higher in the intact forest than in the beaver-created wetland. However, this difference does not account for forest gross primary production, which was not measured and for which no comparable estimates are available for sub-Antarctic forests. Consequently, although the intact RF likely functions as a net carbon sink, its magnitude could not be reliably estimated. In contrast, the beaver-created wetland, devoid of living trees, remained a net source of approximately 17 t CO _2-eq ha ⁻¹ yr ⁻¹ . These results indicate that beaver-induced deforestation may represent a substantial source of GHGs in southernmost forest ecosystems.

Reciprocal relationships between fishers and marine life have been documented in Indigenous fishing contexts, but there are few case studies that describe the mechanisms of such relationships, and even fewer that explore other contexts, such as that of artisanal fishers in Latin American countries. We studied the artisanal hake fishery in the sub‐Antarctic channels of Chilean Patagonia, a global hotspot for albatross and petrel diversity. We aimed to uncover nature's contributions to hake fishers and, reciprocally, the potential fishers' contributions to marine life with a particular emphasis on seabirds. We adopted a bifocal observational strategy. From a human perspective, ethnographic methods (e.g., semi‐structured interviews) are analysed with Nature's Contributions to People and reciprocal contribution frameworks. From the seabirds' view, we assessed offal consumption through experimental and observational methods. We randomly threw offal items into the sea and observed the seabird responses (whether they consumed offal). Hake fishers' relationships with the marine environment are multidimensional, particularly with seabirds. Based on fishers' perceptions, we identified four key contributions of seabirds to humans: they serve as value indicators of fishing distribution and concentration areas, offer companionship and recreation during fishing activities, enhance scenic emotionality through the presence of albatrosses and assist in the function of sea cleaning. In reciprocal contributions, artisanal fishers viewed hake offal as a beneficial food source for the seabirds, especially the liver. Fishers described that fishing in the right way can reduce bycatch and effort. The fishers' main contribution to seabirds is through offering them the offal of hake catches. We observed that seabirds consumed hake liver 99% of the time, while they consumed stomach less frequently (24%). We identified that southern giant petrels and black‐browed albatrosses consumed more liver, while kelp gulls ate more stomach. The liver comprises 51.6% fat, essential for high trophic level marine predators such as black‐browed albatrosses. Adopting reciprocal contributions and NCP served as a catalyst for understanding fishers' positive actions but also is a promoter to research multiple views of nature–human relationships in fishing settings. Values of nature, like reciprocity, could enrich ecosystem‐based management strategies. Read the free Plain Language Summary for this article on the Journal blog.

The COVID-19 pandemic has caused an unprecedented health and economic crisis, highlighting the importance of developing new molecular tools to monitor and detect SARS-CoV-2. Hence, this study proposed to employ the carrageenan extracted from Gigartina skottsbergii algae as a probe for SARS-CoV-2 virus binding capacity and potential use in molecular methods. G. skottsbergii specimens were collected in the Chilean subantarctic ecoregion, and the carrageenan was extracted —using a modified version of Webber’s method—, characterized, and quantified. After 24 h of incubation with an inactivated viral suspension, the carrageenan’s capacity to bind SARS-CoV-2 was tested. The probe-bound viral RNA was quantified using the reverse transcription and reverse transcription loop-mediated isothermal amplification (RT-LAMP) methods. Our findings showed that carrageenan extraction from seaweed has a similar spectrum to commercial carrageenan, achieving an excellent proportion of binding to SARS-CoV-2, with a yield of 8.3%. Viral RNA was also detected in the RT-LAMP assay. This study shows, for the first time, the binding capacity of carrageenan extracted from G. skottsbergii, which proved to be a low-cost and highly efficient method of binding to SARS-CoV-2 viral particles.

Se estudió la composición química proximal, los parámetros morfométricos y la cantidad de parte comestible en cholga (A. ater) y chorito (M. chilensis) recolectados en estaciones del estrecho de Magallanes, de lugares adyacentes a parques Nacionales. En chorito, las muestras provenientes de bahía Gente Grande, que es el único sector de muestreo, cercano a la costa de la Isla de Tierra del Fuego, en el lado oriental del estrecho de Magallanes, se determinaron los parámetros morfométricos mayores. Mientras que la mayoría de los parámetros morfométricos mayores determinados en cholga son de las muestras provenientes de puerto Edén, en el lado occidental del estrecho de Magallanes. La carne de fresca de chorito y cholga presentó un alto contenido de humedad. Las proteínas son el componente bioquímico con mayor porcentaje, seguido por los hidratos de carbono y en menor cantidad las grasas, en ambos moluscos estudiados. Importante destacar también, que las cholgas presentan mayor cantidad de carbohidratos y energía (Kcal/100 g) que los choritos. Las diferencias observadas entre los choritos y las cholgas, en los parámetros morfométricos, la cantidad de carne fresca y la composición química, se atribuyen a las características propias de cada especie, las cuales al ser comparadas en este estudio con tablas de composición de alimentos nacionales e internacionales muestran una buena calidad de los organismos para el consumo humano.