Abstract. Salt marshes and seagrass meadows can sequester and store high quantities of organic carbon (OC) in their sediments relative to other marine and terrestrial habitats. Assessing carbon stocks, carbon sources, and the transfer of carbon between habitats within coastal seascapes are each integral in identifying the role of blue carbon habitats in coastal carbon cycling. Here, we quantified carbon stocks, sources, and exchanges in seagrass meadows, salt marshes, and unvegetated sediments in six bays along the Pacific coast of California. The salt marshes studied here contained approximately twice as much OC as did seagrass meadows, 23.51 ± 1.77 kg OC m⁻³ compared to 11.01 ± 1.18 kg OC m⁻³, respectively. Both seagrass and salt marsh sediment carbon stocks were higher than previous estimates from this region but lower than global and U.S.-wide averages, respectively. Seagrass-derived carbon was deposited annually into adjacent marshes during fall seagrass senescence. However, isotope mixing models estimate that negligible amounts of this seagrass material were ultimately buried in underlying sediment. Rather, the vast majority of OC in sediment across sites was likely derived from planktonic/benthic diatoms and C3 salt marsh plants.

中文翻译：

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太平洋西海岸的蓝碳股票和交易所

摘要。相对于其他海洋和陆地生境，盐沼和海草草甸可以隔离并在其沉积物中存储大量有机碳（OC）。评估碳储量，碳源以及沿海海域内栖息地之间的碳转移在确定蓝色碳栖息地在沿海碳循环中的作用中都是不可或缺的。在这里，我们量化了加州太平洋沿岸六个海湾的海草草甸，盐沼和无植被沉积物中的碳储量，来源和交换。此处研究的盐沼中的OC约为海草草甸的OC的两倍，为23.51±1.77 kg OC m ^-3，而11.01±1.18 kg OC m ^-3， 分别。海草和盐沼沉积物碳储量均高于该地区先前的估计，但分别低于全球和美国范围内的平均水平。每年秋天的海草衰老期间，海草来源的碳每年都会沉积到相邻的沼泽中。但是，同位素混合模型估计可忽略不计的这种海草材料最终被埋在下面的沉积物中。相反，跨地点沉积物中的绝大部分OC可能来自浮游/底生硅藻和C3盐沼植物。