Monitoring of seagrass meadows is essential to inform adaptive management and address widespread declines in seagrass ecosystems. Effective monitoring techniques require sensitive indicators that are capable of detecting sub-lethal stressors and differentiating stress responses from background environmental variation. Here we explore untargeted metabolomics as a means to measure multi-parameter molecular responses of seagrass to low-light stress. We subjected Zostera muelleri to reduced light scenarios (<10% natural light) in a six-week field experiment. Biomass loss was quantified over time and leaf samples were analysed by Nuclear Magnetic Resonance (NMR) spectroscopy to explore the effect of low-light exposure on metabolic activity. We identified several potential bioindicators of low-light stress: a reduction of soluble sugars and their derivatives, glucose, fructose, sucrose and myo-inositol, N-methylnicotinamide, organic acids and various phenolic compounds, and an increase in some amino acids. These signals were evident even amongst a noisy background of environmental variation and are consistent with inhibition of photosynthesis. Metabolite profiles showed a more consistent response to low-light stress than to biomass loss. These results suggest that metabolomics measurements may be useful bio-indicators of low-light stress in seagrass and that molecular indicators could inform on management of seagrass ecosystems.

监测海草草甸对于提供适应性管理和解决海草生态系统普遍下降至关重要。有效的监测技术需要灵敏的指示器，这些指示器必须能够检测亚致死压力源并将压力响应与背景环境变化区分开。在这里，我们探索无目标的代谢组学作为一种手段来测量海草对弱光胁迫的多参数分子响应。我们接受了Zostera muelleri在为期六周的野外实验中，减少了照明场景（自然光<10％）。随时间对生物量损失进行定量，并通过核磁共振（NMR）光谱分析叶片样品，以探索弱光照射对代谢活性的影响。我们确定了几种低光照潜在的生物指示剂：可溶性糖及其衍生物，葡萄糖，果糖，蔗糖和肌醇，N-甲基烟酰胺，有机酸和各种酚类化合物的减少以及某些氨基酸的增加。这些信号甚至在嘈杂的环境变化背景中也很明显，并且与光合作用的抑制作用一致。代谢物谱显示对弱光胁迫的响应比对生物量损失的响应更为一致。