Eolian transport of mineral dust is one of the main inputs of iron (Fe) to the global ocean; however, the magnitude and biogeochemical impact of this supply depends on the solubility of the deposited dust. In particular, the effect of temperature on Fe‐bearing dust solubility has been scarcely investigated even though a seasonal gradient of sea surface temperature (SST) is a common feature in coastal zones adjacent to the major dust source regions of the world. In this work, the effect of temperature on the fractional solubility of Fe (FFeS) was evaluated experimentally using sieved soils (as a dust proxy) from the Baja California Peninsula and surface seawater from the Gulf of California (GC). Two incubations were performed at 17°C (winter) and 29°C (summer) considering the seasonal variability of SST in the GC. Differences in FFeS up to 3 orders of magnitude (0.003–4.49%) were linked to incubation temperature, dust load, and contact time between seawater and dust. After 72 hr of incubation, the effect of temperature was statistically significant (p < 0.05) for all dust treatments, with FFeS higher (4–24 times) at 29°C. High FFeS in warmer waters are a result of increased Fe‐bearing dust dissolution and decreased scavenging of Fe by dust particles. Since temperature appears to control the magnitude of FFeS in the GC, we suggest that this factor could have an effect on the atmospheric inputs of soluble Fe in marginal seas with similar seasonal SST contrasts; including the global ocean, where well‐defined latitudinal temperature gradients exist.

中文翻译：

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海面温度是否会影响铁在矿物粉尘中的溶解度？加利福尼亚湾案例研究

风尘对矿物粉尘的运输是向全球海洋中铁（Fe）的主要输入之一。但是，这种供应的数量和生物地球化学影响取决于沉积粉尘的溶解度。尤其是，尽管在邻近世界主要粉尘源区域的沿海地区普遍存在海面温度的季节性梯度，但很少研究温度对含铁粉尘溶解度的影响。在这项工作中，使用来自下加利福尼亚半岛的筛分土壤（​​作为除尘剂）和来自加利福尼亚湾（GC）的地表海水，通过实验评估了温度对Fe（FFeS）的分数溶解度的影响。考虑到GC中SST的季节性变化，在17°C（冬季）和29°C（夏季）进行了两次孵育。FFeS的差异最高达3个数量级（0.003-4.49％）与孵化温度，粉尘负荷以及海水与粉尘之间的接触时间有关。孵育72小时后，温度的影响具有统计学意义（p  <0.05），适用于所有粉尘处理，在29°C时FFeS较高（4–24倍）。在较温暖的水中，较高的FFeS是含铁粉尘溶解度增加和粉尘颗粒对铁的清除减少的结果。由于温度似乎控制着GC中FFeS的大小，因此我们认为该因素可能会影响具有相似的SST季节性变化的边缘海中可溶性Fe的大气输入。包括存在明确定义的纬度温度梯度的全球海洋。