A global model of carbon, nitrogen and phosphorus cycles for the terrestrial biosphere

Abstract

Abstract. Carbon storage by many terrestrial ecosystems can be limited by nutrients, predominantly nitrogen (N) and phosphorus (P), in addition to other environmental constraints, water, light and temperature. However the spatial distribution and the extent of both N and P limitation at the global scale have not been quantified. Here we have developed a global model of carbon (C), nitrogen (N) and phosphorus (P) cycles for the terrestrial biosphere. Model estimates of steady state C and N pool sizes and major fluxes between plant, litter and soil pools, under present climate conditions, agree well with various independent estimates. The total amount of C in the terrestrial biosphere is 2767 Gt C, and the C fractions in plant, litter and soil organic matter are 19%, 4% and 77%. The total amount of N is 135 Gt N, with about 94% stored in the soil, 5% in the plant live biomass, and 1% in litter. We found that the estimates of total soil P and its partitioning into different pools in soil are quite sensitive to biochemical P mineralization. The total amount of P (plant biomass, litter and soil) excluding occluded P in soil is 17 Gt P in the terrestrial biosphere, 33% of which is stored in the soil organic matter if biochemical P mineralization is modelled, or 31 Gt P with 67% in soil organic matter otherwise.This model was used to derive the global distribution and uncertainty of N or P limitation on the productivity of terrestrial ecosystems at steady state under present conditions. Our model estimates that the net primary productivity of most tropical evergreen broadleaf forests and tropical savannahs Correspondence to: Y. P. Wang (Yingping.wang@csiro.au) is reduced by about 20% on average by P limitation, and most of the remaining biomes are N limited; N limitation is strongest in high latitude deciduous needle leaf forests, and reduces its net primary productivity by up to 40% under present conditions.

The carbon cycle in the Australian Community Climate and Earth System Simulator (ACCESS-ESM1) – Part 2: Historical simulations

“…In addition to other environmental constraints such as water, light and temperature, carbon storage by terrestrial ecosystems may also be limited by nutrients, predominantly nitrogen and phosphorus (Wang and Houlton, 2009;Wang et al, 2010;Zhang et al, 2013). However, few estimates are available of total nitrogen and phosphorus pool sizes and their global spatial distribution is even more uncertain.…”

“…This capability is important because nitrogen, phosphorus and carbon biogeochemical cycles are strongly coupled, and it has been demonstrated that nutrient limitation has a large impact on the productivity of terrestrial ecosystems (Wang et al, 2010;Goll et al, 2012;Zhang et al, 2013). Consequently, global land carbon uptake can be altered significantly.…”

“…For the ACCESS-ESM1 version, ocean carbon fluxes are simulated by the World Ocean Model of Biogeochemistry And Trophic dynamics (WOMBAT) (Oke et al, 2013) and land carbon fluxes are simulated by the Community Atmosphere Biosphere Land Exchange (CABLE) model (Kowalczyk et al, 2006;Wang et al, 2011), which optionally includes nutrient limitation (nitrogen and phosphorus) for the terrestrial biosphere through its biogeochemical module, denoted CASA-CNP (Wang et al, 2010). This capability is important because nitrogen, phosphorus and carbon biogeochemical cycles are strongly coupled, and it has been demonstrated that nutrient limitation has a large impact on the productivity of terrestrial ecosystems (Wang et al, 2010;Goll et al, 2012;Zhang et al, 2013).…”

Assessing carbon dioxide removal through global and regional ocean alkalinization under high and low emission pathways

“…The land surface scheme uses CABLE (Best et al, 2015) coupled to CASA-CNP (Wang et al, 2010;Mao et al, 2011) which simulates biogeochemical cycles of carbon, nitrogen, and phosphorus in plants and soils. The response of the land carbon cycle was shown to simulate the observed biogeochemical fluxes and pools on the land surface (Wang et al, 2010).…”

Relationships of phosphorus fractions to organic carbon content in surface soils in mature subtropical forests, Dinghushan, China

“…For example, Schlesinger et al (1998) proposed that P was limiting plant growth in soil at an early stage of development (110 years) on Rakata Island, Indonesia, perhaps as a result of the observed rapid accumulation of organic P. Wang et al (2006) found that soil organic C concentration was positively related to the concentrations of soil soluble organic-P fractions, whereas it was negatively related to the concentrations of soil soluble inorganic-P fractions in depressional and riparian freshwater wetlands in North-east China. Further studies on the relationships between soil organic C and P fractions are needed to clarify the relationship between soil organic C accumulation and soil P availability, which has important implications in understanding the limitation P places on the storage of C in terrestrial ecosystems (Wang et al 2010;Kirkby et al 2011).…”