Groundwater pollution by agrochemicals such as nitrogen fertilizers can cause complex biogeochemical transformations to take place in groundwater-dependent ecosystems. To explore the interaction between nitrogen load and groundwater-dependent, spring-fed ecosystems, a study was conducted in Latvia in an area of suspected high nitrate (NO₃⁻) vulnerability due to its geological settings. A map of NO₃⁻ vulnerability along the margins of the carbonate aquifer in Latvia is presented. The map is based on a conceptual model that was developed during an extensive case study involving hydrological, hydrochemical, and habitat investigation of springs discharging from a karst aquifer and spring-fed ecosystems. Areas that should be prime targets for restricting fertilizer application are highlighted on the map. Although the case study revealed increased nitrogen pollution (up to 51 mg L⁻¹, standard deviation of 9 mg L⁻¹, in the springs discharging from the karst aquifer), no clear evidence of adverse effects due to NO₃⁻ pollution on the groundwater-dependent ecosystems using biotic indicators was found, highlighting the resilience of spring-fed ecosystems against high nitrogen inputs. In the case study, downstream groundwater-dependent ecosystems retained 70% of the reactive nitrogen during the vegetation season, but only a small proportion during the cold season. Thus, NO₃⁻ pollution can be partly mitigated by restoring wetlands along valley slopes where natural groundwater discharge takes place. The conceptual model developed for groundwater NO₃⁻ vulnerability is applicable to other areas in the Baltic region and other places with similar climatic and geological conditions.

氮肥等农用化学品对地下水的污染会导致依赖地下水的生态系统发生复杂的生物地球化学变化。为了探索氮负荷与依赖地下水、泉水喂养的生态系统之间的相互作用，在拉脱维亚的一个因地质环境而被怀疑为高硝酸盐 (NO ₃ ^- ) 脆弱性的地区进行了一项研究。NO ₃的地图^-介绍了拉脱维亚碳酸盐含水层边缘的脆弱性。该地图基于一个概念模型，该模型是在广泛的案例研究中开发的，该研究涉及对从岩溶含水层和泉水喂养的生态系统排放的泉水进行水文、水化学和栖息地调查。地图上突出显示了应该成为限制施肥的主要目标的区域。尽管案例研究显示氮污染增加（高达 51 mg L ^-1，标准偏差为 9 mg L ^-1，在从岩溶含水层排放的泉水中），但没有明确证据表明 NO ₃ ^-造成的不利影响使用生物指标发现依赖地下水的生态系统受到污染，突出了春季生态系统对高氮输入的恢复能力。在案例研究中，下游依赖地下水的生态系统在植被季节保留了 70% 的活性氮，但在寒冷季节只保留了一小部分。因此，可以通过恢复自然地下水排放的山谷斜坡沿线的湿地来部分缓解NO ₃ ^-污染。为地下水NO ₃ ^-脆弱性开发的概念模型适用于波罗的海地区的其他地区以及具有类似气候和地质条件的其他地方。