Predicting riverine dissolved silica fluxes to coastal zones from a hyperactive region and analysis of their first-order controls
Predicting riverine dissolved silica fluxes to coastal zones from a hyperactive region and analysis of their first-order controls
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DOI：
10.1007/s00531-008-0381-5
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发表时间：
2010-01-01
影响因子：
2.3
通讯作者：
Kempe, Stephan
中科院分区：
文献类型：
--
作者：
Hartmann, Jens;Jansen, Nils;Kempe, Stephan
硅酸盐风化和由此产生的溶解物质输运以两种方式影响全球碳循环。首先通过吸收大气/土壤中的二氧化碳，其次通过河流系统向海洋生态系统提供营养物溶解二氧化硅（DSi）。以前的研究表明，以火山活动为主的地区是dsi运动的过度活跃甚至是“热点”。在此，我们提出了一种预测海岸带dsi通量的新方法，强调“一级”控制因素（岩性、径流、地形、土地覆盖和温度）。这种方法适用于日本群岛，该地区的特点是火山比例很高（占表面积的29.1%）。提出的dsi -通量模型基于516个集水区的数据，覆盖了日本列岛约56.7%的面积。岩性的空间分布——最重要的一级控制因素之一——取自一张新的日本高分辨率地图。结果表明，日本列岛是一个超活跃区，其dsi产率为3.3 t SiO2 km(-2) a(-1)，是世界平均水平的6.6倍，但区域差异较大。大约10%的面积超过世界平均dsi产量的10倍。坡度是除岩性和径流外另一个重要的控制dsi通量的因素，可以超过径流对dsi产出量的影响。尽管日本群岛的监测区域从北纬31度延伸到北纬46度，但温度并没有被确定为一个重要的一阶模型变量。这可能是由于群岛的区域环境使坡度、径流和岩性与温度相关，温度信息在一定程度上被这些因素所替代。土地覆盖数据也不能改善预测模型。这在一定程度上可能是由于卫星图像对土地覆盖信息的误读。讨论了这些结果对地球系统和全球碳循环模拟的意义。
Silicate weathering and resulting transport of dissolved matter influence the global carbon cycle in two ways. First by the uptake of atmospheric/soil CO2 and second by providing the oceanic ecosystems via the fluvial systems with the nutrient dissolved silica (DSi). Previous work suggests that regions dominated by volcanics are hyperactive or even "hot spots" concerning DSi-mobilization. Here, we present a new approach for predicting DSi-fluxes to coastal zones, emphasizing "first-order" controlling factors (lithology, runoff, relief, land cover and temperature). This approach is applied to the Japanese Archipelago, a region characterized by a high percentage of volcanics (29.1% of surface area). The presented DSi-flux model is based on data of 516 catchments, covering approximately 56.7% of the area of the Japanese Archipelago. The spatial distribution of lithology-one of the most important first order controls-is taken from a new high resolution map of Japan. Results show that the Japanese Archipelago is a hyperactive region with a DSi-yield 6.6 times higher than the world average of 3.3 t SiO2 km(-2) a(-1), but with large regional variations. Approximately 10% of its area exceeds 10 times the world average DSi-yield. Slope constitutes another important controlling factor on DSi-fluxes besides lithology and runoff, and can exceed the influence of runoff on DSi-yields. Even though the monitored area on the Japanese Archipelago stretches from about 31A degrees to 46A degrees N, temperature is not identified as a significant first-order model variable. This may be due to the fact that slope, runoff and lithology are correlated with temperature due to regional settings of the Archipelago, and temperature information is substituted to a certain extent by these factors. Land cover data also do not improve the prediction model. This may partly be attributed to misinterpreted land cover information from satellite images. Implications of results for Earth System and global carbon cycle modeling are discussed.