Storage and removal of nutrients by wetlands and riparian areas is an important process in understanding catchment nutrient fluxes and in helping to mitigate current issues of eutrophication in many regions. In cold climates, strong seasonality affects natural wetlands and those constructed for water treatment alike, raising important questions about how ecosystems can be managed to maximize nutrient retention in the landscape, particularly in light of rapid and ongoing wetland loss. This study assessed how freeze-thaw cycles (FTCs) affect the release of phosphorus (P) from common riparian macrophytes (Typha spp). The goal was to understand whether the freeze-thaw processes could drive enhanced nutrient release as has been shown for agricultural residues, but which has not previously been assessed in riparian vegetation. Given the rapid expansion of Phragmites australis in parts of the study area, this study also tested the effects of FTC on P release from Phragmites tissue. A common experimental protocol was used across 11 wetlands in three regions of Canada. These results demonstrate the potential for FTCs to induce P release from macrophyte tissue, although this is not observed in all cases. The impact of FTCs on P release was greatest and most consistent when samples were collected earlier in the growing season. Release rates were positively correlated with plant P content. This suggests that the degree of plant senescence may play a role in determining the response to FTCs. Typha and Phragmites showed similar responses to FTCs, suggesting that the importance of this process does not depend on the dominant taxon. Sequential FTCs led to further enhancement of P release from macrophyte tissue. The results from this study suggest that specific management such as harvesting Typha during the growing season, may mitigate the potential for P release due to FTCs.

湿地和河岸地区对养分的存储和清除是了解流域养分通量并帮助减轻许多地区当前富营养化问题的重要过程。在寒冷的气候中，强烈的季节性影响自然湿地和用于水处理的自然湿地，这引发了有关如何管理生态系统以最大程度地保留景观中养分的重要问题，尤其是考虑到湿地的迅速和持续丧失。这项研究评估了冻融循环（FTC）如何影响常见河岸大型植物（香蒲）中磷（P）的释放spp）。目的是了解冻融过程是否可以促进增加的养分释放，如农业残留所显示的那样，但以前尚未在河岸植被中进行过评估。鉴于芦苇在研究区域的某些区域迅速扩展，本研究还测试了FTC对芦苇中P释放的影响组织。在加拿大三个地区的11个湿地上使用​​了通用的实验方案。这些结果证明了FTC可能诱导大型植物组织释放P，尽管并非在所有情况下都观察到。当在生长季节较早时采集样品时，FTC对P释放的影响最大，而且最一致。释放速率与植物磷含量呈正相关。这表明植物衰老的程度可能在确定对FTC的反应中起作用。香蒲和芦苇对FTC的反应类似，这表明此过程的重要性不取决于主导的分类单元。顺序性FTC导致大型植物组织中P的释放进一步增强。这项研究的结果表明，在生长季节进行特定管理（例如收获香蒲）可能会减轻由于FTC释放磷的可能性。