Geochemical Markers of Temperature and Sedimentary Organic Matter Composition as Indicators of Environmental Change in Admiralty Bay, Antarctica.

• Grant number: 24/22739-2
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: September 01, 2025
• End date: March 31, 2029
• Field of knowledge: Physical Sciences and Mathematics - Oceanography - Chemical Oceanography
• Principal Investigator: Cesar de Castro Martins
• Grantee: Yasmym Schutz de Vincenzi Weirich
• Host Institution: Instituto Oceanográfico (IO). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 19/12551-8 - Benthic connections of high Southern Latitudes: BECOOL, AP.PFPMCG.TEM

Abstract

The Antarctic Peninsula is considered a region of great importance for studying ongoing climate change due to its geographical location, severe natural conditions, and minimal human interference. To this end, the study of processes that lead to short- and long-term environmental oscillations, driven by natural and/or anthropogenic factors, can be conducted through the characterization of sedimentary organic matter (OM). This is because OM contains molecular components with a stable chemical structure resistant to diagenetic processes. Given that sea surface temperature variation is linked to synergistic effects on biogeochemical cycles, the application of biogeochemical markers to study environmental change processes, such as temperature variations and OM production, provides direct evidence of how the Antarctic environment responds over time to such changes. Traditionally, these changes are evaluated using total organic carbon (TOC), total nitrogen (TN), and their respective isotopic ratios (¿13C and ¿15N). However, more robust responses can be obtained through (bio)molecular markers, such as n-alkanes, n-alcohols, sterols, highly branched isoprenoids, and GDGTs, due to their specificity with the source of OM production and the biochemical responses of organisms to environmental variations, such as temperature fluctuations and ice melting. Thus, this project will study the distribution of sedimentary OM, its different sources, and its variability across various temporal and spatial scales in Admiralty Bay, Antarctic Peninsula. This will enable the analysis of (paleo)climatic variation and its relationship with the modification of biogeochemical cycles in the region and the dynamics of the global marine carbon cycle. (AU)