In order to determine the origins of dissolved inorganic nutrients and dissolved organic matter in coastal waters off Jeju Island, Korea, we measured the concentrations of ²²²Rn, nutrients, fluorescent dissolved organic matter (FDOM), and dissolved organic carbon in coastal waters during September 2016 and October 2017. The lower salinity waters occurring in the southern coastal waters off Jeju (SCW) were characterized by higher nutrients and humic-like FDOM, while those in the western coastal waters off Jeju (WCW) showed no trend. A significant negative correlation between salinity and ²²²Rn in the SCW (r² = 0.62, n = 7 for 2016; r² = 0.56, n = 14 for 2017) indicates that freshwaters occurring in the SCW originate from fresh groundwater. However, depleted ²²²Rn activities in the fresh surface waters of the WCW indicate that those in the WCW originate mainly from the remote Changjiang diluted water. In general, the coastal ecosystem in the SCW is characterized by the dominance of brown seaweeds, and the WCW is by scleractinian corals. Our results imply that high nutrient concentrations in the SCW provide favorable conditions for the growth of seaweeds, while relatively low nutrient concentrations and high FDOM concentrations in the WCW provide favorable conditions for survival of corals.

中文翻译：

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利用Rad追踪济州岛沿海水域营养物和溶解有机物的不同淡水源

为了确定韩国济州岛沿海水域中溶解的无机养分和溶解有机物的来源，我们测量了9月沿海水域中²²² Rn，养分，荧光溶解性有机物（FDOM）和溶解性有机碳的浓度。 2016年和2017年10月。济州岛（SCW）南部沿海水域中盐度较低的水域以较高的养分和类似腐殖质的FDOM为特征，而济州岛（WCW）西部沿海水域中盐度水域则没有趋势。盐分与SCW中的²²² Rn之间呈显着负相关（ 2016年r ²  = 0.62，n = 7; r ²  = 0.56，n = 2017年为14）表示SCW中出现的淡水来自淡水。然而，WCW淡水中²²² Rn活性的减少表明WCW中的Rn活性主要来自偏远的长江稀释水。通常，SCW的沿海生态系统的特征是棕色海藻占优势，而WCW的特征是巩膜珊瑚。我们的结果表明，SCW中较高的养分浓度为海藻的生长提供了有利条件，而WCW中相对较低的养分浓度和较高的FDOM浓度为珊瑚的生存提供了有利条件。