Benthic foraminiferal surface porosity (the mean percentage of surface area covered by pores; higher porosity: lower oxygenation) and iodine to calcium ratio (I/Ca, higher I/Ca: higher oxygenation) are both promising paleoceanographic proxies that will advance through testing in down-core studies. Here we report the first down-core comparison (~45 kyr) of these proxies for a core from the southern Brazilian margin (26°40.22′ S, 46°26.46′ W, 475 m water depth). Both proxies are most sensitive to low-O₂ conditions (<50 μmol/kg), and not well-constrained at higher O₂ concentrations. Porosity values are generally low (<15%) and I/Ca ranges between ~4 and ~ 6 μmol/mol throughout the core. The two proxies are overall consistent, suggesting that bottom-water oxygen concentrations at the site remained above 50 μmol/kg during the last 45 kyr. Several non-O₂ factors (e.g., iodate reduction rates, water mass mixing, temperature, foraminiferal shell robustness) could influence the proxies and require further investigation.

底栖有孔虫表面孔隙率（孔隙覆盖的表面积的平均百分比；较高的孔隙率：较低的氧合）和碘钙比（I/Ca，较高的 I/Ca：较高的氧合）都是有希望的古海洋学代理，将通过测试推进核心研究。在这里，我们报告了巴西南部边缘（南纬 26°40.22'、西经 46°26.46'、水深 475 米）的岩心的这些代表的第一次岩下比较（~45 kyr）。两种代理对低 O ₂条件（<50 μmol/kg）最敏感，在较高 O ₂条件下不受很好的限制浓度。孔隙度值通常较低 (<15%)，整个岩心的 I/Ca 范围在 ~4 到 ~6 μmol/mol 之间。这两个指标总体上是一致的，表明在过去的 45 kyr 期间，该地点的底水氧浓度保持在 50 μmol/kg 以上。几个非 O ₂因素（例如，碘酸盐还原率、水团混合、温度、有孔虫壳的坚固性）可能会影响代理并需要进一步调查。