Quantification of carbon uptake inhibited by the phosphorus limitation in tropics: Application of Dynamic Land Ecosystem Model

Abstract:

Tropical regions act as an important carbon (C) sink resulting in partial mitigation of the increased carbon dioxide (CO₂) concentration in the atmosphere. The C sink capacity is constrained by the nutrient availability particularly of phosphorus (P) which is strongly bound to iron and aluminum oxides in highly weathered tropical soils. However, most ecosystem models neglect the P limitation mechanism that can result in overestimation of the C uptake in the terrestrial biosphere. In this study, we incorporated a P module into the process based model, the Dynamic Land Ecosystem Model (DLEM 2.0) used it to estimate the net carbon exchange (NCE: net primary productivity – heterotrophic respiration) in the tropics during 1901–2010. Specific objectives of the research are to determine the spatial and temporal patterns of NCE in the context of multiple environmental changes (e. g. land cover and land use change, elevated carbon dioxide (CO₂) concentration, climate, and atmospheric nitrogen deposition) as well as to quantify the magnitude of carbon uptake inhibited by P limitation in pan tropics during 1901–2010. The simulation results from DLEM 2.0 were validated against field observations on carbon, nitrogen, and phosphorus ratios in the foliage and plant litter pools in different geographical locations across the globe. This abstract will be updated with the results in the next few months. Our results will provide insights into P limitation influence on C uptake in the tropics.