000K utf8 1100 $c2025 1500 eng 2050 urn:nbn:de:gbv:8:3-2025-00430-2 2051 10.5194/bg-22-863-2025 3000 Hoogakker, Babette A.A. 3010 Anderson, Robert 3010 Auderset, Alexandra 3010 Barras, Christine 3010 Basak, Chandranath 3010 Bradbury, Harold J. 3010 Brinkmann, Inda 3010 Cardich, Jorge 3010 Castillo, Alexis 3010 Choquel, Constance 3010 Cook, Madelyn 3010 Costa, Kassandra 3010 Davis, Catherine 3010 Diz, Paula 3010 Donnenfield, Jonas 3010 Elling, Felix J. 3010 Erdem, Zeynep 3010 Filipsson, Helena L. 3010 Garrido, Sebastián 3010 Glock, Nicolaas 3010 Gottschalk, Julia 3010 Govindankutty Menon, Anjaly 3010 Groeneveld, Jeroen 3010 Hallmann, Christian 3010 Hardisty, Dalton S. 3010 Hendy, Ingrid 3010 Hennekam, Rick 3010 Hess, Anya V. 3010 Jacobel, Allison 3010 Kusch, Stephanie 3010 Lu, Wanyi 3010 Lynch-Stieglitz, Jean 3010 Martínez-García, Alfredo 3010 Matos, Lélia 3010 Meissner, Katrin J. 3010 Molina, Giulia 3010 Moretti, Simone 3010 Morford, Jennifer 3010 Muñoz, Práxedes 3010 Ni, Sha 3010 Nilsson-Kerr, Katrina 3010 Nuber, Sophie 3010 Radionovskaya, Svetlana 3010 Raven, Morgan Reed 3010 Ren, Abby 3010 Reyes Macaya, Dharma 3010 Sepúlveda, Julio 3010 Somes, Christopher J. 3010 Studer, Anja S. 3010 Tachikawa, Kazuyo 3010 Tapia, Raúl 3010 Tetard, Martin 3010 Vollmer, Tyler 3010 Wang, Xingchen 3010 Wang, Yi 3010 Wu, Shuzhuang 3010 Zhang, Yan 3010 Zheng, Xin-Yuan 3010 Zhou, Yuxin 4000 Reviews and syntheses: Review of proxies for low-oxygen paleoceanographic reconstructions$hCopernicus GmbH [Hoogakker, Babette A.A.] 4030 $nCopernicus GmbH 4209 A growing body of observations has revealed rapid changes in both the total inventory and the distribution of marine oxygen over the latter half of the 20th century, leading to increased interest in extending oxygenation records into the past. The use of paleo-oxygen proxies has the potential to extend the spatial and temporal range of current records, constrain pre-anthropogenic baselines, provide datasets necessary to test climate models under different boundary conditions, and ultimately understand how ocean oxygenation responds beyond decadal-scale changes. This review seeks to summarize the current state of knowledge about proxies for reconstructing Cenozoic marine oxygen: sedimentary features, sedimentary redox-sensitive trace elements and isotopes, biomarkers, nitrogen isotopes, foraminiferal trace elements, foraminiferal assemblages, foraminiferal morphometrics, and benthic foraminiferal carbon isotope gradients. Taking stock of each proxy reveals some common limitations as the majority of proxies functions best at low-oxygen concentrations, and many reflect multiple environmental drivers. We also highlight recent breakthroughs in geochemistry and proxy approaches to constraining pelagic (in addition to benthic) oxygenation that are rapidly advancing the field. In light of both the emergence of new proxies and the persistent multiple driver problem, the need for multi-proxy approaches and data storage and sharing that adhere to the principles of findability, accessibility, interoperability, and reusability (FAIR) is emphasized. Continued refinements of proxy approaches and both proxy–proxy and proxy–model comparisons are likely to support the growing needs of both oceanographers and paleoceanographers interested in paleo-oxygenation records. 4950 https://doi.org/10.5194/bg-22-863-2025$xR$3Volltext$534 4950 https://nbn-resolving.org/urn:nbn:de:gbv:8:3-2025-00430-2$xR$3Volltext$534 4961 https://macau.uni-kiel.de/receive/macau_mods_00005962 5051 333.7 5550 coastal marine waters 5550 deoxygenation 5550 Low-oxygen environments 5550 open marine waters