The coastline of Peru lacks long-lived marine organisms useful for paleoclimatic reconstructions generating a need for novel archives. Short-lived (<5 years) bivalves are commonly found in geological and archaeological deposits and thus can provide “snapshots” of past climatic variability (i.e., seasonal range), similar to data obtained by individual foraminifera analysis, rather than continuous, cross-dated time series (e.g., trees and corals). Previous studies have found success using the short-lived intertidal clam Mesodesma donacium. However, M. donacium are vulnerable to die-offs from the warmer sea surface temperatures (SST) associated with El Niño events and are functionally extinct in northern Peru thus limiting the possibility of modern analog studies for that region. Here we investigate the short-lived (1–3 years) surf clam, Donax obesulus, commonly found in northern Peru, as a paleoclimate archive. Donax obesulus populations are able to survive the warmer SSTs present during El Niño years although they are vulnerable to colder SSTs associated with La Niñas. We assessed the environmental drivers underlying subannual δ¹⁸O variability in D. obesulus from live collected shells from fish markets and coastal beaches near the Nepeña Valley, Peru in 2012 (La Niña), 2014 (ENSO-neutral), and 2016 (El Niño). Forward modeling of pseudo-shell δ¹⁸O reveals that SST variations are a dominant driver with secondary contributions from seasonally-varying seawater δ¹⁸O (δ¹⁸O_sw). By accounting for varying δ¹⁸O_sw, we isolated the temperature dependent variable resulting in a paleotemperature equation for D. obesulus δ¹⁸O. We verified our results with the δ¹⁸O record of a D. obesulus shell collected in 2006. Our results suggest that the paleotemperature equation we developed is useful for reconstructing El Niño-Southern Oscillation (ENSO)-related climatic variations in this region and the pseudo-shell approach may be useful for understanding shell δ¹⁸O in other locations.

秘鲁的海岸线缺乏可用于古气候重建的长寿海洋生物，因此需要新的档案。短寿命（<5 年）双壳类动物常见于地质和考古沉积物中，因此可以提供过去气候变化（即季节性范围）的“快照”，类似于个体有孔虫分析获得的数据，而不是连续的、交叉的日期时间序列（例如，树木和珊瑚）。以前的研究已经发现使用短命的潮间带蛤Mesodesma donacium取得了成功。然而，M. donacium容易受到与厄尔尼诺事件相关的温暖海面温度 (SST) 的死亡影响，并且在秘鲁北部功能性灭绝，从而限制了对该地区进行现代模拟研究的可能性。在这里，我们调查了秘鲁北部常见的短命（1-3 年）冲浪蛤，Donax obesulus，作为古气候档案。Donax obesulus种群能够在厄尔尼诺年期间出现的较暖海温中存活下来，尽管它们容易受到与拉尼娜现象相关的较冷海温的影响。我们评估了D. obesulus 年亚年 δ ¹⁸ O 变异性的环境驱动因素2012 年（拉尼娜现象）、2014 年（ENSO 中性）和 2016 年（厄尔尼诺现象）从秘鲁 Nepeña 山谷附近的鱼市和沿海海滩收集到的活贝壳。伪壳 δ ¹⁸ O 的正向建模表明 SST 变化是主要驱动因素，其次要贡献来自季节性变化的海水 δ ¹⁸ O (δ ¹⁸ O _sw )。通过考虑变化的 δ ¹⁸ O _sw，我们分离了温度相关变量，从而得出了D. obesulus δ ¹⁸ O的古温度方程。我们用D. obesulus的 δ ¹⁸ O 记录验证了我们的结果2006 年收集的贝壳。我们的结果表明，我们开发的古温度方程可用于重建该地区与厄尔尼诺-南方涛动 (ENSO) 相关的气候变化，而伪贝壳方法可能有助于了解其他地区的贝壳 δ ¹⁸ O地点。