Submarine canyons can facilitate the transfer of land‐derived organic matter to the deep sea. Here, we investigated links between variability in organic matter availability from land and marine sources and infauna communities in two contrasting canyon systems off New Zealand and used stable isotope analyses to identify potential food sources of benthic invertebrates. Kaikōura Canyon, a steep, short canyon close to the shore, was characterized by high food availability and varying proportions of marine‐ and land‐derived organic matter, whereas Hokitika Canyon, a narrow and lower‐gradient canyon that extends further from the coast, was characterized by low food availability and mostly land‐derived sediment organic matter throughout. Both macrofaunal and meiofaunal abundance and biomass were greater in Kaikōura Canyon than in Hokitika Canyon. Correlation analyses suggested that land‐derived organic matter may contribute to increased meiofaunal abundance in Kaikōura Canyon. Carbon and nitrogen isotopic analyses, however, did not provide unequivocal support for the uptake of land‐derived material by large benthic invertebrates in Kaikōura Canyon. Infaunal abundance and biomass were low throughout Hokitika Canyon despite similar concentrations of land‐derived organic matter in sediments of both canyons, which suggests that variations in marine‐derived organic matter inputs is the main driver of community differences among canyons. Refractory vascular plant material by itself may not provide an adequate food supply to infaunal organisms, but may represent a complementary food resource when more labile marine phytodetritus is also readily available.

中文翻译：

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新西兰海底峡谷中无生物群落的结构与沉积物有机物的起源有关

海底峡谷可以促进陆生有机物向深海的转移。在这里，我们调查了来自新西兰以外的两个形成对比的峡谷系统中陆地和海洋资源以及动物群落中可利用的有机物的可变性之间的联系，并使用稳定的同位素分析来确定底栖无脊椎动物的潜在食物来源。Kaikōura峡谷是一个靠近海岸的陡峭而短的峡谷，其特点是食物供应量高，并且海洋和陆地来源的有机物的比例各不相同，而Hokitika峡谷是一个狭窄且低梯度的峡谷，从海岸延伸得更远，其特点是粮食供应量低，并且整个过程中大部分为陆源沉积物有机物。Kaikōura峡谷的大型动物和牛角藻的丰度和生物量均大于Hokitika峡谷。相关分析表明，陆生有机质可能会增加Kaikōura峡谷中的动植物丰度。然而，碳和氮同位素分析并未为凯库拉峡谷中大型底栖无脊椎动物对陆源物质的吸收提供明确支持。尽管两个峡谷的沉积物中陆源性有机物的浓度相似，但整个霍基蒂卡峡谷的土壤丰度和生物量仍然较低，这表明海洋源性有机物输入的变化是峡谷间群落差异的主要驱动力。难治性维管束植物材料本身可能无法为霉菌生物体提供足够的食物供应，但是当还容易获得更加不稳定的海洋植物碎屑时，它可能是一种补充性食物资源。