Kelp forests are extensive, widely distributed and highly productive. However, despite their importance, reliable estimates of net primary productivity (NPP) are currently unknown for most species and regions. In particular, how performance and subsequent NPP change throughout a species range is lacking. Here, we attempted to resolve this by examining growth and performance of the boreal kelp, Laminaria digitata, from range centre and trailing edge regions in the United Kingdom. During the peak growth season (March/April), range-centre individuals were up to three times heavier and accumulated biomass twice as fast as their trailing-edge counterparts. This was not apparent during the reduced growth season (August/September), when populations within both regions had similar biomass profiles. In total, annual NPP estimates were considerably lower for trailing-edge (181 ± 34 g C m−2 year−1) compared to range-centre (344 ± 33 g C m−2 year−1) populations. Our first-order UK estimates of total standing stock and NPP for L. digitata suggest this species makes a significant contribution to coastal carbon cycling. Further work determining the ultimate fate of this organic matter is needed to understand the overall contribution of kelp populations to regional and global carbon cycles. Nevertheless, we highlight the need for large-scale sampling across multiple populations and latitudes to accurately evaluate kelp species’ contributions to coastal carbon cycling.

中文翻译：

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冷水海带的范围中心和后缘种群之间的生态表现不同：对估计净初级生产力的影响

海带森林面积广阔，分布广泛，生产力高。然而，尽管它们很重要，但对于大多数物种和地区，净初级生产力 (NPP) 的可靠估计目前尚不清楚。特别是，缺乏性能和随后的 NPP 在整个物种范围内如何变化。在这里，我们试图通过检查来自英国范围中心和后缘区域的北方海带 (Laminaria digitata) 的生长和性能来解决这个问题。在生长高峰期（3 月/4 月），范围中心个体的体重是其后缘个体的三倍，生物量的积累速度是其后缘个体的两倍。这在生长季节减少（8 月/9 月）期间并不明显，因为这两个地区的种群具有相似的生物量分布。总共，与范围中心（344 ± 33 g C m-2 year-1）种群相比，后缘种群（181 ± 34 g C m-2 year-1）的年度 NPP 估计值要低得多。我们对 L. digitata 的总常备存量和 NPP 的一阶英国估计表明该物种对沿海碳循环做出了重大贡献。需要进一步的工作来确定这种有机物质的最终命运，以了解海带种群对区域和全球碳循环的总体贡献。尽管如此，我们强调需要跨多个种群和纬度进行大规模采样，以准确评估海带物种对沿海碳循环的贡献。digitata 表明该物种对沿海碳循环做出了重大贡献。需要进一步的工作来确定这种有机物质的最终命运，以了解海带种群对区域和全球碳循环的总体贡献。尽管如此，我们强调需要跨多个种群和纬度进行大规模采样，以准确评估海带物种对沿海碳循环的贡献。digitata 表明该物种对沿海碳循环做出了重大贡献。需要进一步的工作来确定这种有机物质的最终命运，以了解海带种群对区域和全球碳循环的总体贡献。尽管如此，我们强调需要跨多个种群和纬度进行大规模采样，以准确评估海带物种对沿海碳循环的贡献。