Biogeochemical characteristics and fluxes of suspended particulate organic matter in response to low-tide rainfall
Biogeochemical characteristics and fluxes of suspended particulate organic matter in response to low-tide rainfall
复制标题
低潮降雨响应下悬浮颗粒有机物的生物地球化学特征及通量
DOI：
10.1002/lno.10741
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发表时间：
--
影响因子：
4.5
通讯作者：
Raymond Torres
中科院分区：
文献类型：
--
作者：
Si Chen;Raymond Torres
研究了低潮降雨对盐沼颗粒有机碳（POC）循环的影响。在降雨和无雨条件下采集了潮间沟的悬浮沉积物样品。体（碳、氮）和分子（例如，木质素）组成的变化。悬浮泥沙浓度的时间模式模拟降雨强度的波动，但所有POC不一定遵循这些模式。constituents.do例如，水柱中颗粒有机物浓度与雨强呈协变关系，而颗粒有机物（OM）含量与雨强的相关性很小。一般来说，降雨影响使水体中悬浮沉积物和有机成分的浓度提高了三个数量级。多变量统计分析表明，悬浮颗粒物与平静天气悬浮颗粒物、盐沼表层沉积物和溪岸表层沉积物的组成不同。降雨夹带的颗粒物中的碳和植物源有机质被耗尽，但富含木质素酚。bulk.organic这些观测结果表明，径流过程优先动员POC来自互花米草沼泽平台和有效地运输这些材料的潮间小溪低潮降雨事件。此外，降雨量的运输率为0.02060.002 gPOC m22 mmRain21，该POC周转率为。average.net每年有19%的POC从河口排入海洋。因此，在平静天气条件下进行的河口外输估算通常代表POC输出的最低水平。因此，低潮降雨可以预期大大提高交付沼泽源POC沿海海洋。
We evaluated the effects of low-tide rainfall on salt marsh particulate organic carbon (POC) cycling. Suspended.sediment samples from intertidal creeks were collected during rain and no-rain conditions. Bulk (carbon,.nitrogen) and molecular (e.g., lignin) compositions of organic constituents in particulates were analyzed. Temporal.patterns of suspended sediment concentration mimic fluctuations in rainfall intensity, but all POC constituents.do not necessarily follow these patterns. For example, particulate organic matter concentrations in water.column covaried with rain intensity yet organic matter (OM) contents in the particles showed trivial correlations.with rain. In general, rainfall effects raised the suspended sediment and organic constituent concentrations in.the water column by up to three orders of magnitude. Multivariate statistical analysis revealed that the rainfallentrained.particulates were compositionally distinct from calm weather suspended particulates, from salt marsh.surface sediment, and from creek bank surface sediment. Rainfall-entrained particulates are depleted in bulk.organic carbon and phytoplankton-derived OM but enriched in lignin phenols. These observations indicate that.rainfall-runoff processes preferentially mobilize POC derived from Spartina alterniflora from marsh platforms and.effectively transport these materials to intertidal creeks following low-tide rainfall events. Moreover, average.net transport rates by rainfall are 0.02060.002 gPOC m22 mmRain21, and this POC turnover rate amounts to. 19% of the annual POC export from estuary to ocean. Therefore, estuarine outwelling estimates typically.made under calm weather conditions represent minimum levels of POC export. Hence, low-tide rainfall can be.expected to substantially enhance the delivery of marsh-derived POC to the coastal ocean.