Resumen Algunos ecosistemas terrestres antárticos se ven considerablemente afectados por el cambio climático, sobre todo en la región norte de la Península Antártica, que ha tenido el mayor aumento de temperatura en los últimos 60 años. Este calentamiento ha sido más pronunciado desde 2017 y ha provocado el retroceso de numerosos glaciares. Ello ha provocado la incipiente formación de suelos, que se encuentran sometidos a la acción de factores de formación (clima, biota, topografía), acción de animales (aves, mamíferos) y actividades humanas, y que evolucionan hacia una mayor producción y diversidad biológica. En este trabajo se determinó (en febrero de 2022) la composición química de los suelos en diferentes áreas de la Península Hurd y de Punta Hannah (parte meridional de la isla Livingston). En estos suelos los elementos mayoritarios (%) fueron Si, Fe, Ca, K, y Al y los minoritarios (ppm) Ti, Zr, Mn, Sr, P, y S. Estos componentes han permitido agrupar suelos según diferentes condiciones e impactos naturales, además de observar el tipo y la distribución de la vegetación como indicador del desarrollo edáfico.

Abstract Some Antarctic terrestrial ecosystems are greatly affected by climate change, especially in the northern Antarctic Peninsula region which has had the greatest temperature increase in the last 60 years. This increase has been more pronounced since 2017 and has caused a retreat of many glaciers. The retreat has caused the generation of soils, which are subjected to environmental effects (radiation, wind, temperatures), animal actions (birds, mammals) and human activities, and which evolve to greater biological production and diversity. Preliminary data on the chemical composition of soils were collected on February 2022 from different areas of Hurd Peninsula and Hannah Point (southern Livingston Island). The percentage of major elements (%) such as Si, Fe, Ca, K, and Al or minoritary (ppm) Ti, Zr, Mn, Sr, P, and S can be used to group soils according to different natural conditions and impacts. Furthermore, type and distribution of vegetation can be an indicator of soil development.

Abstract The geomorphic dynamics on ice-free areas are crucial for understanding soil formation, vegetation and landscape stability in maritime Antarctic. We aimed to describe the soil formation on different landforms, following the Holocene glacial retreat at Stinker Point. Twenty profiles were sampled and classified, grouped into three landforms units: middle platforms and scarps, till/glacial deposits and present/Holocene raised beaches. Soil chemical and physical attributes were determined, and the vegetation type identified and quantified. Soils from till and glacial deposits can be separated by the age of exposure: older soils are stony, skeletic; and recently exposed till has soils with moderate depth, alkaline reaction and very high base saturation. Soils at the middle platforms are shallow, coarse-grained, skeletic, with abundant vegetation. Soils from the present-day beaches are alkaline, very coarse with no horizon differentiation, whereas soils on Holocene beaches are acid and nutrient-rich due to past or present-day influence of fauna. Soils from Stinker Point are generally shallow, skeletic and strongly related to the landforms and biogenic influences. Compared with other islands of the South Shetlands, in Elephant Island soil development is less pronounced, being this mainly attributed to the metamorphic nature of parent material, with greater resistance to weathering.

The rapid changes that are taking place in the climate of the Antarctic Peninsula are triggering hydrological processes which had been limited or inactive for relatively long periods of time. These processes are evident in ice-free areas on the northern edge of the Antarctic Peninsula, such as Cape Lamb, and lead to intense draining of the surface and groundwater system throughout the brief Antarctic summer. The result is a movement of large amounts of water, sediments and nutrients that would be immobilized in other scenarios. This study proposes a model of the operation of the surface and groundwater system that could be valid for several ice-free areas in the region, based on the interpretation of field observations in Cape Lamb, the most extensive ice-free area on Vega Island. The model proposed is further supported by the interpretation of 56 chemical analyses of samples representing groundwater, active layer water, glacier ice and snowfall. The hydrochemical interpretation is supported primarily by four indicators (pH, electrical conductivity, D/18O ratio and SO4/Cl ratio) which have proven to be the most appropriate hydrochemical variables to differentiate the origin and interaction of the waters in the various sections of the system.

Los rapidos cambios climaticos ocurridos en la peninsula Antartica han reactivado procesos hidrogeologicos que han sido limitados o han estado inactivos durante un relativamente largo periodo de tiempo. Estos procesos se evidencian en las zonas descubiertas de hielo del norte de la peninsula Antartica, como en cabo Lamb, donde se desarrolla el sistema hidrico superficial y subterraneo a lo largo de todo el verano antartico. El resultado es la movilizacion de grandes cantidades de agua, sedimentos y nutrientes hacia otros escenarios. Este estudio propone un modelo de comportamiento del agua superficial y subterranea que resulta validado para las zonas libres de hielo de la region basado en las observaciones de campo e interpretacion de la informacion tomada en cabo Lamb, que constituye la zona descubierta mas extensa de la Isla Vega. El modelo propuesto se basa en la interpretacion de 56 analisis quimicos que se consideran representativos del agua superficial, subterranea, el agua de la capa activa, el hielo glaciar y la nieve. La interpretacion hidroquimica esta determinada en principio por cuatro parametros (pH, conductividad electrica, relacion de D/18O y relacion SO4/Cl) demostrando que estas variables son las mas apropiadas para diferenciar el origen e interaccion de las aguas en las diferentes partes del sistema hidrogeologico.