| 摘要: |
| 气溶胶中微量元素的大气输送过程对海洋初级生产力有重要意义，其中铁对海洋生物至关重要，也可能成为影响赤潮的关键因子。本文在综述了大气中酸性物质对气溶胶铁的酸化，在铁从不溶态转变为可溶态的关键过程基础上，提出了东海赤潮的发生可能与大气酸化气溶胶铁密切相关。酸化后的可溶性铁在东海赤潮区下沉可能与沿岸洋流从冬、夏季环流转换提供水动力条件共同作用。该设想将为探索赤潮灾害发生机理提供一些参考，对最终预警预报赤潮发生，减低赤潮灾害的损失，保护海洋生态环境具有重要意义。 |
| 关键词: 气溶胶 铁 酸溶解 东海赤潮 |
| DOI：10.7515/JEE211005 |
| CSTR： |
| 分类号: |
| 基金项目:国家自然科学基金项目（41775142） |
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| Acidification of iron in atmospheric aerosols and red tides in the East China Sea |
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ZHAO Xiuyi, TIAN Rongxiang
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College of Earth Sciences, Zhejiang University, Hangzhou 310027, China
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| Abstract: |
| Background, aim, and scope Iron is an essential nutrient element for animal and plant life activities, and the atmospheric transport of iron in aerosols is of great significance to the ocean primary productivity. In addition, iron has a greater impact on marine ecosystems and the global atmosphere, and it was found that the acid dissolution of iron in aerosols transforms iron from insoluble to bioavailable during atmospheric transport, which may affect harmful algae blooms. Materials and methods This paper reviews the acidification of aerosol iron in the atmosphere and the key process of transforming iron from insoluble to soluble. It is proposed that the occurrence of harmful algae blooms in the East China Sea may be a result of joint action, including the atmospheric acidification of aerosol iron as harmful algae bloom biosoluble iron, the acidification of soluble iron with the aerosol sinking in the harmful algae bloom zone of the East China Sea, and the conversion of coastal currents from the winter circulation to the summer circulation to provide hydrodynamic conditions. Results During atmospheric transportation, acid dissolves iron in aerosol particles, making it bioavailable and increasing the amount of bioavailable iron imported into the ocean. The sulfuric acid components, oxalates, and nitrogen-containing acidic components in the atmospheric environment will all have an impact on the acid dissolution process. The correlation between bioavailability and solubility of dissolved iron and the difference of solubility of dissolved iron in aerosols from different sources and the effect on primary productivity were discussed. Discussion By summarizing the current status and the possible causes of harmful algae blooms in the East China Sea, it is found that the sources of restrictive nutrients required for large-scale harmful algae blooms in the East China Sea is not entirely derived from terrestrial input and marine upwelling. Furthermore, atmospheric aerosol transmission source is likely to be important. Based on analysis of aerosol transport and harmful algae bloom occurrence, we found that the three necessary conditions of “nutrition” and “meteorology and hydrology” are related to the transport of iron and other restrictive nutrients by atmospheric aerosols, indicating that the transport of atmospheric aerosol iron may play a key role in the triggering of harmful algae bloom in the East China Sea. Conclusions Firstly, we described the acid dissolution process of iron in aerosol and the possible influencing factors of the acid dissolution process in aerosol and atmospheric environment, including the contribution of sulfur-containing acid components, oxalates and nitrogen-containing acid components to the dissolution process. Secondly, it shows that the bioavailability of metallic iron is closely related to its solubility. Finally, the importance of atmospheric transport as a source of restricted nutrients is pointed out. The correlation between aerosol transport and the occurrence of harmful algae bloom is preliminarily verified, which provides favorable evidence for subsequent studies. Recommendations and perspectives In order to further gain insights into the key processes of iron transport by atmospheric aerosol on the initiation of harmful algae blooms in the East China Sea, the method of combining atmospheric science and biogeochemical research can be used. Firstly, based on the observation data of harmful algae bloom and aerosol events in the East China Sea over a long time scale, the spatial and temporal relationship between the two was established through numerical analysis. Then, the potential relationship between iron and other nutrients transported by atmospheric aerosol and explosive proliferation of harmful algae bloom algae was quantitatively analyzed by using isotope tracer technology. In addition, the transport and deposition of iron by atmospheric aerosol were simulated. Finally, the key role of transport of atmospheric aerosol iron and phosphorus in causing harmful algae bloom in the East China Sea is analyzed and evaluated. On this basis, a harmful algae bloom early warning and forecast system supported by weather forecast model and nested grid air quality model is explored to be similar to weather forecast. It is of great significance for the final warning and forecast of harmful algae bloom occurrence, reducing the loss of harmful algae bloom and protecting the marine ecological environment. |
| Key words: aerosol iron acid dissolution red tides in the East China Sea |
