Characterizing spatial and temporal variability of food web dynamics is necessary to predict how wetter and more nutrient-rich conditions expected with climate change will influence the fate of organic matter within northern peatlands. The goals of this study were to (1) document spatial and temporal variability in the contribution of periphyton to peatland food webs using isotope analysis (¹³C and ¹⁵N), and (2) quantify the influence of increased nutrient availability on primary and secondary production across a gradient of rich, moderate, and poor fen peatlands common to the northern boreal biome. We established replicate m² plots within each fen located in interior Alaska to quantify periphyton (algae and bacteria) and macroinvertebrate biomass with and without nutrient addition throughout a growing season (May–August). Stable isotope analysis showed that periphyton contributed = 65% of organic matter to the food web over time and across fens compared to = 7% from plants or detritus. The transfer of basal resources was reflected in an increase in herbivore biomass as algal biomass increased over time in all fens, followed by an increase in predatory macroinvertebrates during the latter part of the growing season. Furthermore, all measures of periphyton and macroinvertebrate biomass were enhanced by nutrient addition. These data provide insight into patterns of natural variation within the aquatic food web of boreal peatlands and show that basal resources within this ecosystem, which are generally considered to be “detritus-based,” are actually driven by periphyton with minimal input from plant detrital pathways.

中文翻译：

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北方泥炭地食物网的绿化：附生植物支持北部泥炭地的二次生产

表征食物网动力学的时空变化对于预测气候变化预期的更湿润和更多营养的条件将如何影响北部泥炭地有机物的命运是必要的。这项研究的目的是（1）使用同位素分析（¹³ C和¹⁵ N）记录围生植物对泥炭地食物网的贡献的时空变化，以及（2）量化养分利用率增加对初级和次级的影响北部北方生物群系常见的富，中，贫芬泥炭地的梯度生产。我们建立了复制m ²在阿拉斯加内部的每个within内绘制一个图，以量化整个生长季节（5月至8月）添加或不添加营养素的浮游生物（藻类和细菌）和大型无脊椎动物生物量。稳定的同位素分析表明，与之相比，随着时间的推移和跨，附生植物对食物网的有机物贡献率为65％。=来自植物或碎屑的7％。基础资源的转移反映在草食动物生物量的增加中，因为所有中藻类生物量均随时间增加，随后在生长期的后期，捕食性大型无脊椎动物增加。此外，添加养分可以增强所有围生植物和大型无脊椎动物生物量的测量。这些数据提供了对北方泥炭地水生食物网内自然变化模式的洞察力，并表明该生态系统内的基础资源（通常被认为是“碎屑为基础”）实际上是由浮游植物驱动的，而植物碎屑途径的投入却很少。 。