Watersheds of the coastal temperate rainforests of Pacific North America export large amounts of organic carbon (OC) to the coastal ocean. While it has been suggested that terrestrially derived organic matter could subsidize marine food webs and affect ocean biogeochemistry along the coastal margin, little work has been done to quantify and characterize OC across the freshwater to marine continuum. We conducted monthly and targeted rainfall event surveys of dissolved and particulate organic carbon (DOC and POC) quantity and quality (δ¹³C, dissolved organic matter characterization) across a freshwater to marine salinity gradient between Calvert and Hecate Islands, British Columbia, Canada. Freshwater DOC concentrations (9.97 ± 0.25 mg L⁻¹) far exceeded those in marine waters (1.24 ± 0.03 mg L⁻¹), while POC concentrations were similar across all sites (0.23 ± 0.01 mg L⁻¹). δ¹³C‐DOC and ‐POC in freshwaters were constant, but varied seasonally at the marine stations with freshwater and marine processes. Rainfall events facilitated the rapid export of terrestrial DOC and POC to coastal waters, altering water quality and potentially subsidizing microbial productivity across marine surface waters. On an annual basis, primary production in marine waters (21–42 Gg C) exceeded total freshwater OC contributions (1.8–2.2 Gg C); however, freshwater exports were more important during the autumn and winter months, when rainfall was highest and primary production was limited by shorter days and deep turbulent mixing. Our results highlight the importance of storms for connecting the coastal temperate rainforest with surface coastal waters, especially during the summer when connectivity between the freshwater and marine ecosystems is otherwise low.

中文翻译：

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溶解和颗粒有机碳的陆地出口影响了太平洋沿海温带雨林的近岸生态系统

北美太平洋沿海温带雨林的流域向沿海海洋出口大量有机碳（OC）。尽管有人提出，陆生有机物可能会补贴海洋食物网并影响沿海边缘的海洋生物地球化学，但为量化和表征整个淡水至海洋连续性中的OC所做的工作很少。我们进行了溶解和颗粒有机碳（DOC和POC）的数量和质量（δ每月和有针对性的降雨事件调查¹³ C，溶解的有机物质的表征）跨过淡水到卡尔弗特和赫卡特群岛，British Columbia，加拿大之间海洋盐度梯度。淡水DOC浓度（9.97±0.25 mg L ^-1）远远超过海水（1.24±0.03 mg L ^-1），而所有场所的POC浓度均相似（0.23±0.01 mg L ^-1）。δ ¹³淡水中的C-DOC和POC保持不变，但随着淡水和海洋过程的变化，在海洋站的季节性变化。降雨事件促进了陆地DOC和POC向沿海水域的快速出口，改变了水质，并有可能补贴整个海洋表层水域的微生物生产力。每年，海水的初级生产（21-42 Gg C）超过了淡水OC的总贡献量（1.8-2.2 Gg C）；然而，在秋季和冬季，降雨最多，而较短的日子和剧烈的湍流混合限制了初级生产，因此淡水出口在秋季和冬季更为重要。我们的结果强调了风暴对于将沿海温带雨林与地表沿海水域联系起来的重要性，