caa a22 4500 445383933 CHVBK 20180317143026.0 cr unu---uuuuu 170323e20110601xx s 000 0 eng 10.1007/s10021-011-9426-x doi (NATIONALLICENCE)springer-10.1007/s10021-011-9426-x Menge Duncan National Center for Ecological Analysis and Synthesis, 93101, Santa Barbara, California, USA aut Conditions Under Which Nitrogen Can Limit Steady-State Net Primary Production in a General Class of Ecosystem Models [Elektronische Daten] [Duncan Menge] Human activity is drastically altering global nitrogen (N) availability. The extent to which ecosystems absorb additional N—and with it, additional CO2—depends on whether net primary production (NPP) is N-limited, so it is important to understand conditions under which N can limit NPP. Here I use a general dynamical model to show that N limitation at steady-state—such as in old-growth forests—depends on the balance of biotically controllable versus uncontrollable N inputs and losses. Steady-state N limitation is only possible when uncontrollable inputs (for example, atmospheric deposition) exceed controllable losses (for example, leaching of plant-available soil N), which is the same as when uncontrollable losses (for example, leaching of plant-unavailable soil N) exceed controllable inputs (biological N fixation). These basic results are robust to many model details, such as the number of plant-unavailable soil N pools and the number and type of N fixers. Empirical data from old-growth tropical (Hawai'i) and temperate (Oregon, Washington, Chile) forests support the model insights. Practically, this means that any N fixer—symbiotic or not—could overcome ecosystem N limitation, so understanding N limitation requires understanding controls on all N fixers. Further, comparing losses of plant-available N to abiotic inputs could offer a rapid diagnosis of whether ecosystems can be N-limited, although the applicability of this result is constrained to ecosystems with a steady-state N cycle such as old-growth forests largely devoid of disturbance. The Author(s), 2011 nitrogen fixation nationallicence lichen nationallicence ecosystem theory nationallicence dissolved organic nitrogen nationallicence nitrogen deposition nationallicence biogeochemical theory nationallicence nitrogen loss nationallicence Ecosystems Springer-Verlag 14/4(2011-06-01), 519-532 1432-9840 14:4<519 2011 14 10021 https://doi.org/10.1007/s10021-011-9426-x text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10021-011-9426-x text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Menge Duncan National Center for Ecological Analysis and Synthesis, 93101, Santa Barbara, California, USA aut NATIONALLICENCE 773 0- Ecosystems Springer-Verlag 14/4(2011-06-01), 519-532 1432-9840 14:4<519 2011 14 10021 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer