The iron isotopic composition and the elemental ratios (Cd/Ti) in the size-fractionated aerosols collected over the East China Sea

Aerosol deposition is one of the major processes providing bioavailable Fe to the surface ocean. However, the quantification of aerosol Fe flux in the surface ocean is highly challenging operationally. In this study, we measured both Fe isotopic composition and specific elemental ratios in 5 size-fraction aerosols collected over the East China Sea (ECS) to quantify the relative contribution of lithogenic and anthropogenic aerosol Fe. Both the isotopic and elemental ratios indicate that anthropogenic aerosol Fe mainly originates from high temperature combustion activities, with the end member of the δ56Fe to be -4.5 ‰. We found that the Cd/Ti ratio is a much more reliable proxy to quantify the contribution of anthropogenic aerosol Fe in coarse aerosols than δ56Fe in the ECS. Attributed to extremely high deposition velocities and low solubilities for large size aerosols, lithogenic aerosols are still the dominant dissolved aerosol Fe source in the ECS., Method
Sampling site and procedures
The aerosol samples were collected in a small islet in the ECS, Pengjia islet (PJ, 1.1 km2, 25.63°N, 122.08°E), which is located at 66 km from the northernmost of Taiwan (Fig. 1). There are only about 30 governmental staff stayed on the volcanic islet for meteorological observation and coastal guarding. Based on aerosol optical depth data, PJ receives aerosols from the north during the northeast monsoon season and from the south during the southwest monsoon season (Fig. 1). This makes it an ideal time series sampling site to investigate the impact of East Asian aerosols on the surface water of the Northwestern Pacific Ocean (NWPO). Size-fractionated aerosol samples were collected by polytetrafluoroethylene filters (TE-230-PTFE, Tisch Environmental Inc., US) installed on the high volume aerosol sampler (TISCH Environmental Inc., US, MODEL-TE-5170) and coupled with a cascade impactor (TISCH Environmental Inc., US, Series 235). The cascade impactor separ..., , # The iron isotopic composition and the elemental ratios (Cd/Ti) in the size-fractionated aerosols collected over the East China Sea

The files (Table 2, Table S2, Table Cd to Ti ratio, and Table S3) shown in the following link are the key data set for the manuscript submitted to *Journal of Geophysical Research: Oceans*.

The manuscript entitled, \"Contribution of anthropogenic and lithogenic aerosol Fe in the East China Sea\" are written by Chih-Chiang Hsieh and Tung-Yuan Ho. 

[https://doi.org/10.5061/dryad.rv15dv4h3](https://doi.org/10.5061/dryad.rv15dv4h3)

## Description of the data and file structure

The details of the dataset contents and the experimental procedures for obtaining the data are described in the manuscript.

The file of Table 2 is the data of the Fe isotopic compositions of total, ultrapure water leached, and buffer leached of the size-fractionated aerosol samples collected in the East China Sea. The file of Table S2 is the contribut...