Examinando por Autor "Edwin Loarte"
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Ítem “Declining glacier cover drives changes in aquatic macroinvertebrate biodiversity in the Cordillera Blanca, Perú”(Wiley, 2024-07-31) Edson Palacios Robles; Katy Medina; Edwin Loarte; Alberto Castañeda Barreto; Miriam Gamboa Mendoza; Rosario Polo Salazar; Pedro Tapia; Francesca Pellicciotti; Lee E. BrownOngoing climate change threatens the biodiversity of glacier-fed river ecosystems worldwide through shifts in water availability and timing, temperature, chemistry, and channel stability. However, tropical glacier-fed rivers have received little attention compared to those in temperate and Arctic biomes, despite their unique biodiversity potentially responding differently due to additional stress from higher altitude locations thus lower oxygen availability, diurnal freeze–thaw cycles, and annual monsoon rainfall disturbances. This study quantified aquatic biodiversity responses to decreasing glacier cover in the Cordillera Blanca range of the Peruvian Andes. Ten rivers were studied along a gradient of decreasing glacier cover in the Parón, Huaytapallana, and Llanganuco basins, with a specific focus on macroinvertebrates and physicochemical parameters in both the dry and wet seasons. We found higher temperatures, more stable and lower turbidity rivers as glacier cover decreased, which were related significantly to higher local diversity and lower β-diversity. Analysis of similarity revealed significant differences in the macroinvertebrate community among rivers with high, medium, or low glacier cover, illustrating turnover from specialists to generalists as glacial influence decreased. Redundancy analysis demonstrated that there were more species found to prefer stable beds and water temperatures in medium and low glacier cover in a catchment rivers. However, certain taxa in groups such as Paraheptagyia, Orthocladiinae, Anomalocosmoecus, and Limonia may be adapted to high glacial influence habitats and at risk of glacier retreat. Although species composition was different to other biomes, the Cordillera Blanca rivers showed similar benthic macroinvertebrate biodiversity responses to glacier retreat, supporting the hypothesis that climate change will have predictable effects on aquatic biodiversity in mountain ranges worldwide.Ítem Glacier influence on the composition and diversity of the marine phytoplankton community in Admiralty Bay, King George Island, Antarctica(Ciencias Marinas, 2024) Katy Medina Marcos; Edwin Loarte; Sofia Rodriguez-Venturo; Maribel Baylón Coritoma; Pedro M TapiaClimate change has contributed to rapid glacier retreat in the West Antarctic Peninsula, with potential implications for marine ecosystems, particularly phytoplankton communities. In this study, we examined the influence of glacier proximity on phytoplankton composition in Admiralty Bay, Antarctica, during the austral summer of 2020. In total, 12 sampling stations were established at various distances from the glacier front to collect water samples at 3 depths to quantitatively analyze phytoplankton. The community in all stations was found to be dominated by nanoflagellates (<20 µm) (95.5%), followed by diatoms (4.02%), and finally, dinoflagellates (0.47%). The diversity index (H') ranged from 0.07 to 1.04 bits·cell–1, with the highest indices observed at stations closer to the glacier fronts and the one closest to the coast (<3 km). Based on phytoplankton community composition, 3 clusters were identified: (1) the station closest to the coast, (2) stations located between 0.66 and 1.12 km from the glacier front, and (3) stations between 2.61 and 11.10 km from the glacier front. Overall, diversity exhibited a fourth-degree polynomial relationship (R2 = 0.35) with glacier distance. Therefore, it can be concluded that the composition of marine phytoplankton varies based on its proximity to glaciers in Admiralty Bay.