Water and mass exchanges in mosses: Towards an understanding of the movement of solutes and hydrocarbons

泥炭地占加拿大土地面积的14%，气候和景观导致土壤持续潮湿。由于氧气扩散到潮湿的土壤中的能力很差，生长在那里的植被在死亡时会缓慢腐烂，导致有机碳的积累，或称“泥炭”。泥炭的形成是陆地最大的碳汇，具有全球意义。泥炭主要由苔藓形成，因为它们抗腐烂。加拿大的许多泥炭地因园艺泥炭收获和造成污染的工业活动而受到破坏。了解苔藓的水分动态及其如何影响碳吸收是本研究的目标之一。如果我们认识到苔藓的水需求，就可以管理收获的泥炭地，为苔藓提供最佳条件。被工业活动、管道爆裂或火车出轨污染的泥炭地需要采取补救或保护邻近地区的战略。然而，对溶解在水中的化学品或泥炭地中的石油基流体（碳氢化合物）的运输的了解非常少。随着对苔藓中水分运动的深入了解，我们可以关注溶解物质是如何运输的，以及它们是否可以迁移到不饱和的苔藓剖面并威胁到苔藓的死亡。本研究探讨这些运输过程。最后，随着溶解的化学物质的运输知识，这项研究将研究碳氢化合物（不容易溶解）如何在苔藓层中移动，什么过程抑制运动或鼓励其分解。该研究建议将重点放在魁北克省莱维斯附近的一个地点，2004年，一列货运列车出轨将约20万升汽油和取暖油泄漏到沼泽泥炭地。该场地仍然受到污染，但如果没有这项研究，就无法在充分了解过程的情况下就如何（或是否）补救作出任何决定。

Peatlands comprises ~14% of Canada's land area where climate and landscape result in persistently wet soil conditions. Because of poor oxygen diffusion into wet soil, the vegetation growing there decays slowly when it dies, resulting in the accumulation of organic carbon, or "peat". Peat formation is the largest terrestrial carbon sink, so is of global significance. Peat is dominantly formed by mosses because they are resistant to decay. Many peatlands in Canada are damaged by horticultural peat harvesting and by industrial activities that cause contamination. Understanding the moisture dynamics of mosses and how it affects carbon uptake is one goal of this study. Harvested peatlands can be managed to provide optimal conditions for mosses if we recognize their water needs. Peatlands that have been contaminated by industrial activities, burst pipelines or train derailments require strategies for remediation or protection of adjacent areas. However, knowledge of the transport of chemicals dissolved in water, or of petroleum-based fluids (hydrocarbons) in peatlands, is very poor. With the improved understanding of how water movement occurs in mosses, we can focus on how dissolved substances are transported, and whether they can migrate up the unsaturated moss profile and threaten to kill the mosses. This study examines these transport processes. Finally, with knowledge of transport of dissolved chemicals, this study will examine how hydrocarbons (which do not readily dissolve) move in the moss layer, what processes inhibit movement or encourage its breakdown. The research proposes to focus on a site near Lévis, QC, where in 2004 a freight train derailment spilled ~200,000 litres of gasoline and heating oil onto a bog peatland. The site is still contaminated, but without this study any decisions on how (or if) to remediate it will not be made with a good understanding of the processes.