Importance of vegetation type for mercury sequestration in the northern Swedish mire, Rödmossamyran :
Importance of vegetation type for mercury sequestration in the northern Swedish mire, Rödmossamyran :
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植被类型对于瑞典北部 Rödmossamyran 沼泽固汞的重要性：
DOI：
10.1016/j.gca.2010.09.026
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发表时间：
2010
影响因子：
5
通讯作者：
R. Bindler
中科院分区：
文献类型：
--
作者：
J. Rydberg;J. Karlsson;R. Nyman;Ida Wanhatalo;Kerstin Näthe;R. Bindler
即使MARES已被证明是关于大气汞沉积的时间趋势的相对可靠的档案，但在人为对全球汞循环的贡献的大小方面，不同地点之间存在很大差异。多项研究还显示，同一沼泽区内汞的累积存在显著差异。这就提出了一个问题，除了汞的沉积，还有哪些因素会影响泥炭中这种元素的固存。其中一个因素可能是植被类型，它有可能影响汞的截留和保留。为了评估植被类型的小范围差异如何影响汞的固定，我们在瑞典北部沼泽的三个横断面上采集了泥炭和活植物的样本。沼泽有两种明显不同的植被类型，中部是以泥炭藓为主的开阔区域，而周围的沼泽除了泥炭苔藓外，还有一层灌木和稀疏的松树覆盖。在我们的数据中可以观察到几个主要的模式：(1)泥炭和泥炭苔藓在松树覆盖的沼泽中的汞含量(浓度和库存)都高于开阔的泥炭沼泽区域(泥炭和植物分别高出100%和71%)。这些差异明显超过了铅-210观测到的33%的差异，铅-210被认为是大气汞沉积的良好类似物。(2)同一植被类型内不同泥炭剖面之间汞浓度的差异在很大程度上可以归因于泥炭分解的差异。(3)在开阔的泥炭藻区并存生长时，次生苔藓的汞含量显著高于中心苔藓(分别为24±3和18±2ngHgg−1)。基于这些观察，我们认为物种组成、植被类型和分解可以影响泥炭记录中的汞固定，并且这些特性随时间或空间的任何变化都有可能改变泥炭中记录的汞沉积信号。
Even if mires have proven to be relatively reliable archives over the temporal trends in atmospheric mercury deposition, there are large discrepancies between sites regarding the magnitude of the anthropogenic contribution to the global mercury cycle. A number of studies have also revealed significant differences in mercury accumulation within the same mire area. This raises the question of which factors, other than mercury deposition, affect the sequestration of this element in peat. One such factor could be vegetation type, which has the potential to affect both interception and retention of mercury. In order to assess how small-scale differences in vegetation type can affect mercury sequestration we sampled peat and living plants along three transects on a northern Swedish mire. The mire has two distinctly different vegetation types, the central part consists of an open area dominated by Sphagnum whereas the surrounding fen, in addition to Sphagnum mosses, has an understory of ericaceous shrubs and a sparse pine cover. A few main patterns can be observed in our data; (1) Both peat and Sphagnum-mosses have higher mercury content (both concentration and inventory) in the pine-covered fen compared to the open Sphagnum area (100% and 71% higher for peat and plants, respectively). These differences clearly exceed the 33% difference observed for lead-210, which is considered as a good analogue for atmospheric mercury deposition. (2) The differences in mercury concentration between peat profiles within a single vegetation type can largely be attributed to differences in peat decomposition. (3) When growing side by side in the open Sphagnum area, the moss species Sphagnum subsecundum has significantly higher mercury concentrations compared to S. centrale (24±3 and 18±2ngHgg−1, respectively). Based on these observations we suggest that species composition, vegetation type and decomposition can affect the mercury sequestration in a peat record, and that any changes in these properties over time, or space, have the potential to modify the mercury deposition signal recorded in the peat.