Kelp forests are highly productive coastal habitats that serve as biodiversity hotspots and provide valuable ecosystem services. Despite being one the largest marine biomes, kelp forests have been drastically understudied relative to other marine systems. Notably, while the role of kelp as habitat-forming, or ‘foundation species', is well-documented, a comprehensive understanding of kelp forest food web structure is lacking, particularly regarding the importance of kelp-derived energy/nutrients to consumers. Here, we provide a biogeographic perspective on the energetic underpinning of kelp forests based on published literature. We targeted studies which used geochemical proxies – stable isotope analysis – to examine the transfer of carbon from kelp to local consumers. These studies (n = 94) were geographically skewed, with > 40% from Northern European Seas and Temperate Northeast Pacific. Quantitative estimates for the percentage of kelp energy (or kelp + macroalgae if sources were pooled) incorporated by local consumers came from 43 publications, which studied 141 species and 35 broader taxonomic groups. We examined these data for trends among functional groups and across upwelling regimes. No patterns are evident at present, perhaps due to the paucity or variability of available data. However, energetic subsides from kelps clearly support a wide range of diverse taxa around the globe. We also characterized biogeographic patterns in δ¹³C values of kelps and particulate organic matter (POM, a phytoplankton proxy), to evaluate potential limitations of stable isotope analysis in disentangling the relative contributions of pelagic versus benthic resources to coastal food webs. Globally, kelps and POM differed by > 4.5‰, but there was substantial variation among regions and kelp species. Accordingly, we discuss advances in stable isotope techniques which are facilitating more precise analysis of these complex energetic pathways. We end by proposing four main avenues of critical future research that will shed light on the resilience of these communities to global change.

中文翻译：

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表征海带森林食物网中的能量流动：地球化学回顾并呼吁进一步研究

海带森林是高产的沿海栖息地，可作为生物多样性热点并提供有价值的生态系统服务。尽管是最大的海洋生物群落之一，但相对于其他海洋系统，海带森林的研究却大大不足。值得注意的是，虽然海带作为栖息地形成或“基础物种”的作用已得到充分证明，但缺乏对海带森林食物网结构的全面了解，特别是关于海带衍生的能量/营养素对消费者的重要性。在这里，我们根据已发表的文献提供了关于海带森林能量支撑的生物地理学观点。我们针对使用地球化学代理（稳定同位素分析）的研究来检查碳从海带转移到当地消费者的过程。这些研究（n = 94）在地理上存在偏差，> 40% 来自北欧海域和温带东北太平洋。当地消费者纳入的海带能量（或海带 + 大型藻类，如果资源合并）百分比的定量估计来自 43 份出版物，这些出版物研究了 141 个物种和 35 个更广泛的分类群。我们检查了这些数据以了解功能组和上升流状态之间的趋势。目前没有明显的模式，可能是由于可用数据的缺乏或可变性。然而，海带的能量消退显然支持全球范围内广泛的不同分类群。我们还描述了 δ 中的生物地理模式 它研究了 141 个物种和 35 个更广泛的分类群。我们检查了这些数据以了解功能组和上升流状态之间的趋势。目前没有明显的模式，可能是由于可用数据的缺乏或可变性。然而，海带的能量消退显然支持全球范围内广泛的不同分类群。我们还描述了 δ 中的生物地理模式 它研究了 141 个物种和 35 个更广泛的分类群。我们检查了这些数据以了解功能组和上升流状态之间的趋势。目前没有明显的模式，可能是由于可用数据的缺乏或可变性。然而，海带的能量消退显然支持全球范围内广泛的不同分类群。我们还描述了 δ 中的生物地理模式海带和颗粒有机物（POM，一种浮游植物代理）的^{13 C 值，以评估稳定同位素分析在解开中上层与底栖资源对沿海食物网的相对贡献方面的潜在局限性。}在全球范围内，海带和 POM 差异 > 4.5‰，但地区和海带种类之间存在显着差异。因此，我们讨论了稳定同位素技术的进步，这些技术有助于更精确地分析这些复杂的能量通路。最后，我们提出了关键的未来研究的四个主要途径，这些途径将阐明这些社区对全球变化的复原力。