Kelp forests are highly productive coastal habitats and are emerging as important sources of organic matter for other ecosystems. Although their high rates of productivity and detritus release are expected to lead to substantial export of carbon, few studies have actually quantified rates of export or the persistence of detritus. We addressed this in eight subtidal kelp forests (Laminaria hyperborea) spanning the length (9° of latitude) of the United Kingdom. Specifically, we quantified detritus production, retention/export from source and adjacent habitats, and in situ decomposition rates. Detritus released via both dislodgment of whole plants and “May cast” shedding of old growth was highly variable between sites with greatest values recorded in our colder, northern sites. This was attributable to greater plant size biomass in northern regions, rather than plant density or dislodgement rates. On average, the annual production of kelp detritus was 4706 ± 700 g FW m⁻² yr⁻¹ or 301 g C m⁻² yr⁻¹. Low retention of detritus within the kelp forest and adjacent sedimentary habitats indicated very high rates of export (> 98% across the study). A litterbag experiment showed detritus may take > 4 months to decompose, suggesting great potential for long distance transport. Overall, our findings suggest that L. hyperborea forests export large amounts of detritus subsidies across their range, which can potentially shape the structure of distant benthic communities and constitute a relevant and largely overlooked flux in the coastal carbon cycle, which may represent an important component of natural carbon sequestration.

中文翻译：

---

检查东北大西洋开放海岸潮下带珊瑚礁上的海带碎屑的生产、出口和直接命运

海带森林是高产的沿海栖息地，并且正在成为其他生态系统的重要有机物质来源。尽管预计它们的高生产率和碎屑释放率会导致大量碳出口，但很少有研究真正量化了出口率或碎屑的持久性。我们在八个潮下带海带森林（海带海带）中解决了这个问题) 跨越英国的长度（纬度 9°）。具体来说，我们量化了碎屑的产生、来源和邻近栖息地的保留/出口，以及原位分解率。通过整株植物的脱落和旧生长的“五月浇注”脱落释放的碎屑在我们较冷的北部地点记录的最大值的地点之间变化很大。这归因于北部地区更大的植物大小生物量，而不是植物密度或移位率。平均而言，海带碎屑的年产量为 4706 ± 700 g FW m ^-2  yr ^-1或 301 g C m ^-2  yr ^-1. 海带森林和邻近沉积栖息地内的碎屑保留率低表明出口率非常高（整个研究> 98％）。垃圾袋实验表明，碎屑可能需要 4 个月以上的时间才能分解，这表明长距离运输的潜力很大。总体而言，我们的研究结果表明L. hyperborea森林在其范围内输出大量碎屑补贴，这可能会塑造遥远底栖生物群落的结构，并构成沿海碳循环中相关且很大程度上被忽视的通量，这可能是一个重要组成部分的天然碳封存。