Amino acid ?13C and ?15N patterns from sediment trap time series and deep-sea corals: Implications for biogeochemical and ecological reconstructions in paleoarchives

Recent work using compound-specific stable isotopes of amino acids (CSI-AA) in proteinaceous deep-sea corals opens a new realm high-fidelity reconstruction for biogeochemical and ecological changes the ocean. However, underlying these CSI-AA paleoceanographic applications are series fundamental assumptions, which hold first that baseline-proxy AA isotope values fixed at base food webs represent integrated ?13C ?15N primary production, second they unaltered during subsequent export incorporation from particles into corals. We explored long-term data on sediment trap time together with contemporaneous, geographically close bamboo (Isidella sp.) California margin, directly testing assumptions time. Our show essential (?13CEAA) source AAs (?15NPhe) sinking quantitatively track bulk production. These baseline proxies varied independently carbon flux, trophic position (TPCSI-AA) microbial alteration, suggesting were well preserved consumed by Paired comparisons between revealed minor elevations ?13CEAA (by ?2‰) ?15NPhe ?1‰) available coral specimens. hypothesize difference is due to geographic offset production expected (more offshore) site onshore) specimens, whereas likely related fractionation. Using empirical models derived series, we demonstrate can reconstruct known nitrogen values, exported TPCSI-AA very good fidelity. Together, findings major advance our understanding behavior modern paleoarchives, be used underpin rapidly evolving use CSI-AA-based tools multiple studies archives.