نتایج جستجو برای: Acrotelm

تعداد نتایج: 17  

Journal: :Proceedings. Biological sciences 2001
L R Belyea R S Clymo

The role of peatlands in the global carbon cycle is confounded by two inconsistencies. First, peatlands have been a large reservoir for carbon sequestered in the past, but may be either net sources or net sinks at present. Second, long-term rates of peat accumulation (and hence carbon sequestration) are surprisingly steady, despite great variability in the short-term rates of peat formation. He...

2003
J. HOLDEN

1 Runoff production in blanket peat catchments of the northern Pennine hills, UK was measured through monitoring and experimentation at the plot, hillslope and catchment scale. Water flow from soil pipes was measured in one of the study catchments and overland flow, throughflow and water table were measured in runoff plots; rainfall simulation and tension-infiltrometry provided information on i...

2001
Zicheng Yu Ian D. Campbell Dale H. Vitt Michael J. Apps

This article reviews the existing conceptual and simulation models for peatlands and develops a model framework for simulating peatland dynamics in boreal regions. Clymo’s peat bog growth model has been used as the conceptual foundation in published simulation models, but in these models the structural and functional layers of litter, acrotelm and catotelm are not dynamically integrated. Organi...

2006
Zicheng Yu

Northern peatlands have accumulated up to about 450 Gt of carbon, mostly during the Holocene (the last 12,000 years) after the last glaciation (Gorham 1991; Clymo et al. 1998). Although northern peatlands have a relatively low average net accumulation rate (e.g., 19.4 g C m–2 year–1 in western interior Canada; Vitt et al. 2000), their extent, high-latitude location, and the large size of their ...

2008
J. P. Cagampan J. M. Waddington

The natural carbon storage function of peatland ecosystems can be severely affected by the abandonment of peat extraction, influencing peatland drainage, leading to large and persistent sources of atmospheric CO2. Moreover, these cutover peatlands have a low and variable water table position and high tension at the surface, creating harsh ecohydrological conditions for vegetation re-establishme...

Journal: :FEMS microbiology letters 2004
Johan W H Weijers Stefan Schouten Marjolein van der Linden Bas van Geel Jaap S Sinninghe Damsté

The presence and distribution of isoprenoid glycerol dialkyl glycerol tetraethers (GDGTs), lipids that constitute the membranes of Archaea, have been investigated in a 50-cm long core from a Swedish peat bog. In the acrotelm, the periodically water saturated and thus oxic upper layer of the peat bog, only minor amounts of GDGTs were found. These amounts increase considerably in the catotelm, th...

Leaf size indices of the tree species in the peatland of Agusan del Sur in Mindanao in Philippines was examined to deduce the variation of forest structure and observed forest zonation.  Using raunkiaer and webb’s leaf size classification, the leaf morphometrics of seven tree species consistently found on the established sampling plots were determined.  The species includes Ternstroemia phi...

Journal: :global journal of environmental science and management 0
l.g. aribal department of forest biological sciences, college of forestry and environmental science, central mindanao university, musuan, bukidnon, philippines j.g. bonggay department of forest biological sciences, college of forestry and environmental science, central mindanao university, musuan, bukidnon, philippines e.s. fernando department of forest biological sciences, college of forestry and natural resources, university of the philippines, los baños, laguna, philippines

leaf size indices of the tree species in the peatland of agusan del sur in mindanao in philippines was examined to deduce the variation of forest structure and observed forest zonation.  using raunkiaer and webb’s leaf size classification, the leaf morphometrics of seven tree species consistently found on the established sampling plots were determined.  the species includes ternstroemia philipp...

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