Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada.
PLoS One. 2010 Apr 8;5(4):e10073. doi: 10.1371/journal.pone.0010073.
Stable isotope analysis was used to determine the relative proportions of terrestrial and marine subsidies of carbon to invertebrates along a tidal gradient (low-intertidal, mid-intertidal, high-intertidal, supralittoral) and to determine the relative importance of terrestrial carbon in food web pathways leading to chum salmon fry Oncorhynchus keta (Walbaum) in Howe Sound, British Columbia. We found a clear gradient in the proportion of terrestrially derived carbon along the tidal gradient ranging from 68% across all invertebrate taxa in the supralittoral to 25% in the high-intertidal, 20% in the mid-intertidal, and 12% in the low-intertidal. Stable isotope values of chum salmon fry indicated carbon contributions from both terrestrial and marine sources, with terrestrially derived carbon ranging from 12.8 to 61.5% in the muscle tissue of chum salmon fry (mean 30%). Our results provide evidence for reciprocal subsidies of marine and terrestrially derived carbon on beaches in the estuary and suggest that the vegetated supralittoral is an important trophic link in supplying terrestrial carbon to nearshore food webs.
稳定同位素分析被用于确定潮汐梯度（低潮带、中潮带、高潮带、超潮带）中无脊椎动物的陆地和海洋碳补助的相对比例，并确定在通往不列颠哥伦比亚省豪湾的马苏大麻哈鱼（Oncorhynchus keta (Walbaum)）幼鱼的食物网途径中陆地碳的相对重要性。我们发现，沿着潮汐梯度，陆地衍生碳的比例有一个明显的梯度，从超潮带所有无脊椎动物类群的 68%到高潮带的 25%、中潮带的 20%和低潮带的 12%。马苏大麻哈鱼幼鱼的稳定同位素值表明，碳的贡献来自陆地和海洋两个来源，马苏大麻哈鱼幼鱼肌肉组织中的陆地衍生碳含量在 12.8%至 61.5%之间（平均值为 30%）。我们的研究结果为河口海滩上海洋和陆地衍生碳的互惠补助提供了证据，并表明植被茂盛的超潮带是向近岸食物网提供陆地碳的重要营养环节。
