Incorporating organismal hydrogen (δ²H or δD) and oxygen (δ¹⁸O) stable isotope ratios into aquatic food web research can help elucidate relative reliance on shoreline inputs and/or feeding at different trophic levels; however, their interpretation is complicated by the fact that aquatic organisms derive hydrogen and oxygen from both their diet and the ambient water in which they reside. We examined spatial and seasonal patterns in δ²H and δ¹⁸O of field-collected water and small-bodied fishes. Samples were gathered from nearshore Lake Michigan, a dynamic region of a large, increasingly oligotrophic freshwater lake. We examined seasonal and spatial δ²H and δ¹⁸O values of surface and bottom water, and compared spatial δ²H and δ¹⁸O values of young-of-year yellow perch (Perca flavescens) and seasonal δ²H and δ¹⁸O values of round goby (Neogobius melanostomus). Nearshore δ²H and δ¹⁸O water values were more variable than previously-described offshore values. Variation in nearshore water δ²H and δ¹⁸O values was likely related to differential precipitation and/or discharges from tributaries, and there may be a surface dilution effect which led to lower δ¹⁸O values in nearshore surface waters than bottom waters. In our study, fish tissue δ²H and δ¹⁸O also varies more spatially than seasonally, and some findings suggest that fish tissue δ²H may reflect feeding at higher trophic levels. Though characteristics of the study system affect their interpretation, we suggest that δ²H and δ¹⁸O can be another tool to assess food web structure, with δ²H in particular having potential to resolve questions when δ¹³C or δ¹⁵N are inconclusive.

将有机体氢（δ ² H 或 δD）和氧（δ ^{18 O）稳定同位素比率纳入水生食物网研究，有助于阐明对}海岸线输入和/或不同营养级摄食的相对依赖；然而，由于水生生物从它们的饮食和它们所居住的环境水中获取氢和氧，这一事实使他们的解释变得复杂。我们检查了田间收集的水和小体鱼类的 δ ² H 和 δ ^{18 O 的}空间和季节模式。样本是从密歇根湖近岸采集的，这是一个大型的、日益贫营养的淡水湖的动态区域。我们检查了季节性和空间 δ ² H 和 δ ¹⁸地表水和底层水的O值，并比较了幼年黄鲈（Perca flavescens ）的空间δ ² H和δ ¹⁸ O值和圆虾虎鱼（Neogobius melanostomus ）的季节性δ ² H和δ ¹⁸ O值。近岸 δ ² H 和 δ ¹⁸ O 水值比先前描述的近海值变化更大。近岸水 δ ² H 和 δ ¹⁸ O 值的变化可能与降水差异和/或支流流量有关，可能存在地表稀释效应导致 δ ^18降低近岸地表水的 O 值高于底层水。在我们的研究中，鱼类组织 δ ² H 和 δ ¹⁸ O 的空间变化也比季节变化更大，一些研究结果表明，鱼类组织 δ ² H 可能反映了更高营养水平的摄食。尽管研究系统的特征会影响其解释，但我们建议 δ ² H 和 δ ¹⁸ O 可以作为评估食物网结构的另一种工具，特别是当 δ ¹³ C 或 δ ¹⁵ N 存在时，δ ² H 具有解决问题的潜力。没有定论。