Biogeochemical and oceanographic conditions provide insights about current status of an Antarctic fjord affected by relatively slow glacial retreat

• Published in: Anais da Academia Brasileira de Ciências
• Main Authors: NATALIA VENTURINI, LUIS CERPA, NOELIA KANDRATAVICIUS, GASTÓN MANTA, BÁSLAVI CÓNDOR-LUJÁN, JENNIFER PEREIRA, RUBENS C.L. FIGUEIRA, PABLO MUNIZ
• Format: Article in Journal/Newspaper
• Language: English
• Published: Academia Brasileira de Ciências 2023
• Subjects: organic and inorganic elements; biopolymeric carbon; glacio-marine sedimentation; terrestrial inputs; unpolluted sediments; Science; Q; Antarctic; Carrasco; Collins Bay; Collins Glacier; Van Veen; Antarc*
• Online Access: https://doi.org/10.1590/0001-3765202320230451; https://doaj.org/article/975e4f4f324e416e90aa39a89ea00328

Abstract Understand the origin, transport, and character of organic matter entering Antarctic fjords is essential as they are major components of the global carbon cycle and budget. Macromolecular pools of particulate organic matter, bulk organic geochemistry, major and trace elements in surface sediments from Collins Bay were analysed as source indicators. Oceanographic conditions, bathymetry (multibeam) and grain size were considered as environmental controlling factors. Sediment samples were taken with a van Veen grab, during the ANTAR XXV Peruvian expedition (February 2018), onboard the R/V “BAP Carrasco” from the Peruvian Navy. Biopolymeric composition revealed the predominance of fresh marine protein-rich organic matter in the seafloor of Collins Bay, denoting high quality food resource for marine benthic heterotrophs. Based on Igeo values (between 0 and 1) Collins Bay can be considered unpolluted with natural levels of As, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn. Distribution of most of these elements with a gradient of decrease from the shallow inner fjord towards the outer deepest fjord, suggest their association with the deposition of detrital material and lithogenic particles supplied by Collins Glacier frontal ablation and runoff. This first comprehensive baseline information would assist in interpreting downcore sedimentary reconstructions and future climate-induce changes.