02597nas a2200205   4500008004100000245011500041210006900156300001500225490000700240520194100247100001702188700001702205700001402222700001302236700001602249700001702265700001502282700001702297856007702314       2009                        eng d00aLong-term patterns of mass loss during the decomposition of leaf and fine root litter: an intersite comparison0 aLongterm patterns of mass loss during the decomposition of leaf   a1320 -13380 v153 a<p>Decomposition is a critical process in global carbon cycling. During decomposition, leaf and fine root litter may undergo a later, relatively slow phase; past long-term experiments indicate this phase occurs, but whether it is a general phenomenon has not been examined. Data from Long-term Intersite Decomposition Experiment Team, representing 27 sites and nine litter types (for a total of 234 cases) was used to test the frequency of this later, slow phase of decomposition. Litter mass remaining after up to 10 years of decomposition was fit to models that included (dual exponential and asymptotic) or excluded (single exponential) a slow phase. The resultant regression equations were evaluated for goodness of fit as well as biological realism. Regression analysis indicated that while the dual exponential and asymptotic models statistically and biologically fit more of the litter type&ndash;site combinations than the single exponential model, the latter was biologically reasonable for 27&ndash;65% of the cases depending on the test used. This implies that a slow phase is common, but not universal. Moreover, estimates of the decomposition rate of the slowly decomposing component averaged 0.139&ndash;0.221 year&minus;1 (depending on method), higher than generally observed for mineral soil organic matter, but one-third of the faster phase of litter decomposition. Thus, this material may be slower than the earlier phases of litter decomposition, but not as slow as mineral soil organic matter. Comparison of the long-term integrated decomposition rate (which included all phases of decomposition) to that for the first year of decomposition indicated the former was on average 75% that of the latter, consistent with the presence of a slow phase of decomposition. These results indicate that the global store of litter estimated using short-term decomposition rates would be underestimated by at least one-third.</p>1 aHarmon, M.E.1 aSilver, W.L.1 aFasth, B.1 aChen, H.1 aBurke, I.C.1 aParton, W.J.1 aHart, S.C.1 aCurrie, W.S.  uhttps://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2486.2008.01837.x01489nas a2200241   4500008004100000245009000041210006900131300001300200490000800213520073000221100001700951700001700968700001600985700001701001700001701018700001701035700001501052700001601067700001701083700001501100700001401115856011801129       2007                        eng d00aGlobal-scale similarities in nitrogen release patterns during long-term decomposition0 aGlobalscale similarities in nitrogen release patterns during lon  a361 -3640 v3153 aLitter decomposition provides the primary source of mineral nitrogen (N) for biological activity in most terrestrial ecosystems. A 10-year decomposition experiment in 21 sites from seven biomes found that net N release from leaf litter is dominantly driven by the initial tissue N concentration and mass remaining regardless of climate, edaphic conditions, or biota. Arid grasslands exposed to high ultraviolet radiation were an exception, where net N release was insensitive to initial N. Roots released N linearly with decomposition and exhibited little net N immobilization. We suggest that fundamental constraints on decomposer physiologies lead to predictable global-scale patterns in net N release during decomposition.1 aParton, W.J.1 aSilver, W.L.1 aBurke, I.C.1 aGrassens, L.1 aHarmon, M.E.1 aCurrie, W.S.1 aKing, J.Y.1 aAdair, E.C.1 aBrandt, L.A.1 aHart, S.C.1 aFasth, B.  uhttp://knz.lternet.edu/content/global-scale-similarities-nitrogen-release-patterns-during-long-term-decomposition