Abstract:
Eolian dust and riverine discharge are identified as two key components of terrestrial input to the oceans. They supply micronutrients to the oceans and modify marine carbon biogeochemistry and global climate through dust-land-ocean interactions. However, it is challenging to accurately constrain regional terrestrial inputs in the past, with currently available models and geochemical proxies. The present study utilizes sedimentary wtCaCO3% records to estimate lithogenic fluxes. The depth-dependance of CaCO3 preservation in the Holocene and Last Glacial Maximum (LGM) sediments in two major basins of the tropical Northeast Atlantic Ocean is described using a carbonate dissolution model. Results show that during the LGM, reduced dust deposition and slight drops of fluvial input are found in the Canary Basin and Cape Verde margins, respectively. To supplement, carbonate deposition during the LGM indicates that the deep subtropical Northeast Atlantic is seized by more sluggish deep waters relative to today.
摘要:
风尘和河流排放被确定为陆地输入海洋的两个关键组成部分。它们向海洋提供微量营养素,并通过沙尘-陆地-海洋的相互作用改变海洋碳生物地球化学和全球气候。然而,过去准确限制区域陆地投入是一项挑战,目前可用的模型和地球化学代理。本研究利用沉积的wtCaCO3%记录来估算成岩通量。使用碳酸盐溶解模型描述了热带东北大西洋两个主要盆地中全新世和最后冰川最大(LGM)沉积物中CaCO3保存的深度依赖性。结果表明,在LGM期间,加那利盆地和佛得角边缘的灰尘沉积减少,河流输入略有下降,分别。作为补充,LGM期间的碳酸盐沉积表明,与今天相比,深亚热带东北大西洋被更缓慢的深水所占据。