A stable isotope simulator that can be coupled to existing mass balance models
Rastetter, Edward B.
Kwiatkowski, Bonnie L.
McKane, Robert B.
MetadataShow full item record
KeywordC-13; Food web model; Harvard Forest, Massachusetts, USA; Isotope dynamics; Isotope simulation; Mass balance model; N-15; Nitrogen cycle; Stable isotopes
To facilitate the simulation of isotope dynamics in ecosystems, we developed software to model changes in the isotopic signatures of the stocks of an element using the output from any parent model that specifies the stocks and flux rates of that element based on a mass balance approach. The software alleviates the need to recode the parent model to incorporate isotopes. This parent model can be a simple mass balance spreadsheet of the system. The isotopic simulations use a linear, donor-controlled approximation of the fluxes in the parent model, which are updated for each time step. These approximations are based on the output of the parent model, so no modifications to the parent model are required. However, all fluxes provided to the simulator must be gross fluxes, and the user must provide the initial isotopic signature for all stocks, the fractionation associated with each flux, and the isotopic signature of any flux originating from outside the system. We illustrate the use of the simulator with two examples. The first is based on a model of the carbon and nitrogen mass balance in an eight-species food web. We examine the consequences of using the steady-state assumption implicit in multi-source mixing models often used to map food webs based on 13C and 15N. We also use the simulator to analyze a pulse chase 15N-labeling experiment based on a spreadsheet model of the nitrogen cycle at the Harvard Forest Long Term Ecological Research site. We examine the constraints on net vs. gross N mineralization that are necessary to match the observed changes in the isotopic signatures of the forest N stocks.
Author Posting. © The Authors, 2005. This is the author's version of the work. It is posted here by permission of Ecological Society of America for personal use, not for redistribution. The definitive version was published in Ecological Applications 15 (2005): 1772–1782.
Showing items related by title, author, creator and subject.
Stable isotope and modelling evidence for CO2 as a driver of glacial–interglacial vegetation shifts in southern Africa Bragg, F. J.; Prentice, C.; Harrison, S. P.; Eglinton, Geoffrey; Foster, P. N.; Rommerskirchen, F.; Rullkotter, J. (Copernicus Publications on behalf of the European Geosciences Union, 2013-03-22)Atmospheric CO2 concentration is hypothesized to influence vegetation distribution via tree–grass competition, with higher CO2 concentrations favouring trees. The stable carbon isotope (δ13C) signature of vegetation is ...
Doney, Scott C.; Lindsay, Keith; Fung, Inez Y.; John, Jasmin G. (American Meteorological Society, 2006-07-01)A new 3D global coupled carbon–climate model is presented in the framework of the Community Climate System Model (CSM-1.4). The biogeochemical module includes explicit land water–carbon coupling, dynamic carbon allocation ...
Poussart, Pascale F.; Schrag, Daniel P. (2005-05-04)Despite the existence of a number of climate proxies, the terrestrial expression of tropical climate variability over the past few centuries remains poorly resolved. We explore the applicability of stable isotope ...