The Maldivian archipelago, in the equatorial Indian Ocean, provides a unique location to assess long-term basin-wide South Asian Monsoon (SAM) processes as well as its response during climatic extremes. This insight is beneficial to better understand future SAM influences on the Maldives Inner Sea physicochemical characteristics and its diverse tropical ecosystems in a warming world. This study uses samples from International Ocean Discovery Program Expedition 359, drilled within the Inner Sea drift deposits. Multiple foraminiferal species (n = 15) and proxies (δ¹⁸O, δ¹³C, and Mg/Ca) are used to assess glacial-interglacial SAM dynamics influencing the Inner Sea conditions across Marine Isotope Stages (MIS) 1–2 and 10–13. The summer SAM is modulated by insolation and atmospheric CO₂ and has a predominant impact on the northern Indian Ocean surface salinity. As with present-day observations, a strong summer monsoon resulted in large basin-wide δ¹⁸O_sw (salinity) gradients during the interglacials. Moreover, at the MIS11 minimum (MIS11c), a recognized analog for the present-day, sea surface temperatures (SSTs) were warmer than the present with a stronger summer SAM. This led to an expanded surface mixed layer and strong thermocline, resulting in a highly stratified water column and prominent oxygen minimum zone in the Inner Sea during MIS11c. SSTs in the Maldives are projected to increase at the end of this century and based on the reality that current warming (anthropogenically driven) is much faster than seen during MIS11, the Maldivian tropical coral reef and benthic shoal ecosystems will be subject to increasing stress.

中文翻译：

---

季风和热带气候对马尔代夫内海物理化学和温跃层特征的强迫：来自海洋同位素阶段 1-2 和 10-13 的见解

马尔代夫群岛位于赤道印度洋，为评估长期全盆地南亚季风 (SAM) 过程及其在极端气候下的响应提供了独特的位置。这一见解有利于更好地了解未来 SAM 对马尔代夫内海物理化学特征及其在变暖世界中多样化热带生态系统的影响。这项研究使用了来自国际海洋发现计划远征 359 的样本，这些样本在内海漂移沉积物中钻孔。多种有孔虫物种 ( n  = 15) 和代理 (δ ¹⁸ O, δ ¹³C 和 Mg/Ca) 用于评估影响海洋同位素阶段 (MIS) 1-2 和 10-13 的内海条件的冰期-间冰期 SAM 动力学。夏季 SAM 受日照和大气 CO ₂调制，对北印度洋表面盐度有主要影响。与目前的观测结果一样，强烈的夏季风导致大面积的 δ ¹⁸ O _sw（盐度）间冰期梯度。此外，在 MIS11 最小值 (MIS11c) 是当今公认的类似物，海面温度 (SST) 比现在更温暖，夏季 SAM 更强。这导致扩大的表面混合层和强温跃层，导致在 MIS11c 期间内海出现高度分层的水柱和显着的最低氧区。马尔代夫的 SST 预计将在本世纪末增加，并且基于当前变暖（人为驱动）比 MIS11 期间看到的要快得多的现实，马尔代夫热带珊瑚礁和底栖浅滩生态系统将承受越来越大的压力。