Atmospheric dust is a primary source of iron (Fe) to the open ocean, and its flux is particularly important in the high nutrient, low chlorophyll (HNLC) Southern Ocean where Fe currently limits productivity. Alleviation of this Fe limitation in the Subantarctic Zone of the Atlantic by increased dust‐borne Fe supply during glacial periods has been shown to increase primary productivity. However, previous work has found no such increase in productivity in the Pacific sector. In order to constrain the relative importance of Southern Ocean Fe fertilization on glacial‐interglacial carbon cycles, records of dust fluxes outside of the Atlantic sector of the Southern Ocean at the Last Glacial Maximum (LGM) are required. Here we use grain size and U‐series analyses to reconstruct lithogenic and CaCO₃ fluxes and Nd, Sr, and Pb isotopes to ascertain the provenance of terrigenous material delivered to four deep water cores in the SW Pacific Ocean over the last ~30 kyr. We find evidence for an increase in the relative proportion of fine‐grained (0.5–12 μm) terrigenous sediment and higher detrital fluxes during the LGM compared to the Holocene. The provenance of the LGM dust varied spatially, with an older, more “continental” signature (low ε_Nd, high ⁸⁷Sr/⁸⁶Sr) sourced from Australia in the northern cores, and a younger, more volcanogenic source in the southern cores (high ε_Nd, low ⁸⁷Sr/⁸⁶Sr), likely sourced locally from New Zealand. Given this increase in lithogenic flux to the HNLC subantarctic Pacific Southern Ocean during the LGM, factors besides Fe supply must have regulated the biological productivity here.

中文翻译：

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在最后一次冰雪盛期期间输送到西南太平洋的粉尘流量和物源

大气尘埃是通向大洋的主要铁（Fe）来源，其通量在高营养，低叶绿素（HNLC）的南洋中特别重要，那里的铁目前限制了生产力。冰川期粉尘携带的铁的供应增加，减轻了大西洋亚极地区的这种铁含量的限制，可以提高初级生产力。但是，以前的工作并未发现太平洋地区生产率的这种提高。为了限制南大洋铁肥在冰川-冰间碳循环中的相对重要性，需要记录南极大西洋大西洋地区末次冰盛期（LGM）的尘埃通量。在这里，我们使用粒度和U系列分析来重构成岩作用和CaCO ₃通量，以及Nd，Sr和Pb同位素来确定在过去30到30 yr内将源陆物质运至西南太平洋的四个深水核心。我们发现有证据表明，与全新世相比，LGM期间细粒（0.5-12μm）陆源沉积物的相对比例增加，碎屑通量更高。的LGM灰尘出处空间上变化的，与旧的，更多的“欧式”签名（低ε_的Nd，高⁸⁷ SR / ⁸⁶ SR）在北部芯从澳大利亚采购，在南部核的更年轻，更有火山源（高ε_的Nd，低⁸⁷ SR / ⁸⁶Sr），可能来自新西兰本地。鉴于在LGM期间流向HNLC亚南极太平洋南洋的成岩通量增加，除铁供应外，其他因素也必定会调节这里的生物生产力。