The biogeochemical heterogeneity of peatlands

泥炭地的生物地球化学异质性

• 批准号: RGPIN-2020-05310
• 负责人: Talbot, Julie
• 金额: $ 2.19万
• 依托单位: Université de Montréal
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=754707
• 关键词: biogeochemical; heterogeneity; peatlands

Peatlands are a type of wetland that cover about 12% of Canada's land area. They are characterized by the peat over which they form, a soil that is entirely made of the dead remains of plants and other organic matter. This peat can reach several meters high and it stores large amounts of carbon since about 50% of the peat's dry weight is carbon. It is therefore estimated that approximately one third of all the soil carbon on the planet is stored in peatlands, although they only cover about 2-3% of the global land area. This peat forms because peatlands are consistently wet, limiting the rate at which organic remains decompose. While this carbon storage has been intensively studied over the last two decades, much less is know about the role of nitrogen and phosphorus in peatlands, the two main nutrients upon which plant growth depends. The amount of nutrients available in some types of peatlands is very limited, and any change in the amount of nutrients they receive may change their vegetation composition and affect their capacity to accumulate carbon. Research on peatlands often concentrates on the central and uniform portions of these wetlands, considered to be representative of the processes occurring elsewhere. However, peatlands are not uniform. Their margin, which can be of variable width (from a few meters to more than a hundred meters) is a transition area that has unique chemical and hydrological characteristics that have seldom been studied. Many peatlands are also dotted with open water pools, small ponds that seem to be completely independent from one another and have also been seldom studied in the past. These ponds have been shown to emit carbon while the peat around it stores carbon. Peatlands that have been disturbed by peat extraction, often for horticultural uses, are often restored once the extraction stops, and in some test sites, pools have been re-created. In this research, I will try to understand how processes related to carbon, nitrogen and phosphorus cycling vary between different components of peatlands that have seldom been studied, margins and pools. I will also determine how do pools from restored peatlands chemically compare to pools from undisturbed peatlands. Finally, I will describe how the carbon, nitrogen and phosphorus content of peat varies worldwide and determine if these variations may inform us on the human disturbances to which the peatlands are exposed.

泥炭地是一种湿地，占加拿大陆地面积的12%。它们的特点是在其上形成泥炭，这是一种完全由植物和其他有机物质的尸体组成的土壤。这种泥炭可以达到几米高，它储存了大量的碳，因为大约50%的泥炭干重是碳。因此，据估计，地球上大约三分之一的土壤碳储存在泥炭地中，尽管它们只覆盖全球陆地面积的2-3%。这种泥炭的形成是因为泥炭地一直是潮湿的，限制了有机残留物分解的速度。虽然在过去的二十年里，人们对碳储存进行了深入的研究，但对氮和磷在泥炭地中的作用知之甚少，而氮和磷是植物生长所依赖的两种主要营养物质。某些类型的泥炭地可获得的养分量非常有限，它们所获得的养分量的任何变化都可能改变其植被组成，并影响其积累碳的能力。 对泥炭地的研究通常集中在这些湿地的中心和统一部分，被认为是其他地方发生的过程的代表。然而，泥炭地并不均匀。它们的边缘可以是不同的宽度（从几米到一百多米），是一个过渡区，具有独特的化学和水文特征，很少被研究。许多泥炭地也点缀着开放的水池，这些小池塘似乎彼此完全独立，过去也很少被研究。这些池塘已经被证明排放碳，而周围的泥炭储存碳。被泥炭开采破坏的泥炭地，通常用于园艺，一旦开采停止，往往会恢复，在一些试验地点，池已经重建。 在这项研究中，我将试图了解如何与碳，氮和磷循环的不同组成部分的泥炭地，很少被研究，边缘和池之间的变化。我还将确定如何从恢复泥炭地池化学比较池从原状泥炭地。最后，我将描述泥炭的碳，氮和磷含量在世界范围内的变化，并确定这些变化是否可以告诉我们人类干扰的泥炭地暴露。