The Gulf of Aqaba is an oligotrophic marine system with an oxygen-rich water column. Aeolian dust from the Arabian, Sinai, and Sahara deserts is an important source of sedimentary material to the gulf, especially at 700 m water depth. The head of the gulf is affected by sediment transport from the Arava desert during winter flash floods. In this work, we have studied the speciation of iron in the dust, dry creek sediments and sediments of the Gulf of Aqaba at various water depths in order to understand sources and transformations of iron. Two sources of iron, dust and flash floods transported material, were found to possess distinct geochemical signatures: dust was found to be enriched in total and highly reactive iron relative to the sediments in creek beds. Combination of these two sources leads to an increase of highly reactive iron in sediments with water depth. This increase, in turn, results in formation of a lateral redox gradient with sulfidic pore-waters near the shore, and ferruginous-manganous pore-waters and cryptic sulfur cycling at the deeper water sites. Another result of dry aeolian deposition of desert dust to the sediments of the Gulf of Aqaba, overlaid by deep well‑oxygenated waters, is anomalously high ratios of highly reactive to total iron, which have been proposed to be diagnostic for anoxic, iron-rich water columns, when applied as a paleoproxy.

亚喀巴湾是一种贫营养海洋系统，带有富氧水柱。来自阿拉伯，西奈和撒哈拉沙漠的风尘是海湾的沉积物质的重要来源，特别是在水深700 m时。在冬季山洪暴发期间，海湾的头部受到阿拉瓦沙漠中泥沙运移的影响。在这项工作中，我们研究了灰尘，干小河沉积物和亚喀巴湾不同水深沉积物中铁的​​形态，以了解铁的来源和转化。铁，粉尘和山洪的两种来源被发现具有明显的地球化学特征：相对于小河床中的沉积物，粉尘中铁和高反应性铁的含量最高。这两种来源的结合导致沉积物中高反应性铁随水深的增加而增加。这种增加反过来导致在岸边形成硫化物孔隙水，在较深水位形成铁锰锰孔隙水和隐含硫循环，形成横向氧化还原梯度。沙漠粉尘在亚喀巴湾的沉积物中被干燥的风尘沉积，并被深层充氧水覆盖，这是高反应性铁与总铁的比例异常高，已提出可用于诊断缺氧，富含铁的铁水柱，用作古过氧化物。