Abstract Proxy records of past sea-level change provide a means of extending sea-level histories from tide gauges into the pre-industrial period. This is especially valuable in the South Atlantic region where sea-level data are limited to only a few tide-gauge records. Multi-proxy approaches to sea-level reconstruction are relatively rare but have distinct benefits when groups of micro-organisms are sparse or under-represented in modern or fossil sediments. Here, we address this challenge by utilising surface foraminifera, testate amoebae and diatoms from a salt marsh at Swan Inlet, East Falkland. All three micro-organism groups occupied distinct vertical niches in the contemporary salt-marsh. We investigated the relative performance of each group of micro-organisms in providing a sea-level reconstruction using individual (group-specific) regression models and with a multi-proxy regression model that combined all three groups. Foraminifera alone were not a suitable proxy. Surveyed sample elevations were closely matched by estimated elevations using Weighted-Average (WA) and Weighted-Average Partial-Least-Squares (WA- PLS) regressions. Relative sea-level reconstructions were derived by applying each model to microfossil assemblages recovered from a core (SI-2) from the same site. The combined transfer function yielded reconstructive precision (± 0.08 m) comparable to our best single-proxy transfer function (± 0.06 m) but only 17% of palaeo-samples were identified as having “close” or “good” analogues in the combined training data set. We highlight the benefit of a pragmatic approach to sea-level reconstructions whereby additional proxies should be employed if the use of only one proxy performs poorly across the width of the elevation gradient.

中文翻译：

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使用盐沼有孔虫、硅藻和遗嘱变形虫重建福克兰群岛（马尔维纳斯群岛）的海平面变化

摘要 过去海平面变化的代理记录提供了一种将海平面历史从潮汐测量仪扩展到前工业时代的手段。这在南大西洋地区尤其有价值，那里的海平面数据仅限于少数潮汐测量记录。海平面重建的多代理方法相对较少，但当微生物群在现代或化石沉积物中稀少或代表性不足时具有明显的好处。在这里，我们通过利用来自东福克兰斯旺湾盐沼的表面有孔虫、变形虫和硅藻来应对这一挑战。所有三个微生物群体都在当代盐沼中占据了不同的垂直生态位。我们使用个体（特定于组）回归模型和结合所有三组的多代理回归模型研究了每组微生物在提供海平面重建方面的相对性能。单独的有孔虫不是合适的代理。调查的样本海拔与使用加权平均 (WA) 和加权平均偏最小二乘 (WA-PLS) 回归的估计海拔密切匹配。通过将每个模型应用于从同一地点的岩心 (SI-2) 中回收的微化石组合，推导出相对海平面重建。组合传递函数产生的重建精度 (± 0.08 m) 与我们最好的单代理传递函数 (± 0.06 m) 相当，但只有 17% 的古样本在组合训练中被确定为具有“接近”或“良好”的类似物数据集。