The interface between lotic and lentic ecosystems is often a zone of intense metabolic activity, as primary production in streams and rivers can be light limited whereas nutrients often limit primary production in lake ecosystems. Our objective was to model the influence that rivermouths (the lotic-lentic interface) could have on the loads of soluble reactive phosphorus (SRP) and dissolved inorganic nitrogen (N) passing from the tributary to the nearshore zone of a lake. To achieve this objective, we modeled the combined role of water column nutrient transformation rates with sediment nutrient flux rates. For sensitivity analysis, we picked plausible parameter ranges based on values previously measured in the Fox rivermouth (a tributary to Lake Michigan). Sensitivity analysis of the model demonstrated that overall the importance of water column processing rates increases with increasing nutrient concentration and discharge. We then applied the model to the Fox rivermouth, simulating the change in nutrients on four dates where all of the necessary parameters had been estimated. This modeling suggests that the Fox rivermouth is often a net sink for SRP and source for ammonia (NH₄), with water column processing driving SRP removal and both water column and sediment flux driving NH₄ dynamics. Removal of SRP in the water column means conversion to particulate and/or organic P, and those P pools are generally considered to be less bioavailable than SRP, so it may be that rivermouths disconnect upstream sources of nutrients from nearshore food webs. These results demonstrate that the interface zone between lotic and lentic systems has the potential to substantially alter the load and character of nutrients as river waters pass through rivermouths to adjacent nearshore areas.

Lotic 和 lentic 生态系统之间的界面通常是一个代谢活动强烈的区域，因为溪流和河流中的初级生产可能受到光照限制，而营养物质通常会限制湖泊生态系统中的初级生产。我们的目标是模拟河口（lotic-lentic 界面）对从湖泊支流到近岸区域的可溶性活性磷 (SRP) 和溶解无机氮 (N) 负荷的影响。为了实现这一目标，我们模拟了水柱养分转化率与沉积物养分通量率的综合作用。对于敏感性分析，我们根据先前在 Fox 河口（密歇根湖的一条支流）中测量的值选择了合理的参数范围。模型的敏感性分析表明，总体而言，水柱处理速率的重要性随着养分浓度和排放量的增加而增加。然后，我们将该模型应用于 Fox 河口，模拟了四个日期的营养物质变化，其中所有必要的参数都已估算完毕。该模型表明 Fox 河口通常是 SRP 的净汇和氨 (NH₄ )，水柱处理驱动 SRP 去除，水柱和沉积物通量驱动 NH ₄动力学。去除水体中的 SRP 意味着转化为颗粒和/或有机 P，而这些 P 池通常被认为比 SRP 的生物可利用性低，因此河口可能会断开上游营养源与近岸食物网的连接。这些结果表明，当河水通过河口到达邻近的近岸区域时，激流和滞留系统之间的界面区有可能显着改变营养物质的负荷和特性。