TY - JOUR
T1 - Assessing canopy performance using carbonyl sulfide measurements
AU - Yang, Fulin
AU - Qubaja, Rafat
AU - Tatarinov, Fyodor
AU - Rotenberg, Eyal
AU - Yakir, Dan
N1 - We are grateful to H. Sagi, A. Pelner, B. Ninyo‐Setter, S. Roahtyn, E. Ramati, Y. Preisler, G. Yosef, R. Stern, J. Muller, E. Schwartz, and M. Sprintsin for help in the field work. This work was supported by, the Minerva Foundation, the Israel Science Foundation (ISF), the JNF‐KKL, the C. Wills and R. Lewis program in Environmental Science, the National Natural Science Foundation of China (41775105) and by the German Research Foundation (DFG) as part of the German‐Israel collaborative project “Climate feedbacks and benefits of semi‐arid forests” (CliFF; grant no. YA 274/1‐1 and SCHM 2736/2‐1).
PY - 2018/8
Y1 - 2018/8
N2 - Carbonyl sulfide (COS) is a tracer of ecosystem photosynthesis that can advance carbon cycle research from leaf to global scales; however, a range of newly reported caveats related to sink/source strength of various ecosystem components hinder its application. Using comprehensive eddy-covariance and chamber measurements, we systematically measure ecosystem contributions from leaf, stem, soil, and litter and were able to close the ecosystem COS budget. The relative contributions of nonphotosynthetic components to the overall canopy-scale flux are relatively small (~4% during peak activity season) and can be independently estimated based on their responses to temperature and humidity. Converting COS to photosynthetic CO2 fluxes based on the leaf relative uptake of COS/CO2, faces challenges due to observed daily and seasonal changes. Yet, this ratio converges around a constant value (~1.6), and the variations, dominated by light intensity, were found unimportant on a flux-weighted daily time-scale, indicating a mean ratio of daytime gross-to-net primary productivity of ~2 in our ecosystem. The seasonal changes in the leaf relative uptake ratio may indicate a reduction in mesophyll conductance in winter, and COS-derived canopy conductance permitted canopy temperature estimate consistent with radiative skin temperature. These results support the feasibility of using COS as a powerful and much-needed means of assessing ecosystem function and its response to change.
AB - Carbonyl sulfide (COS) is a tracer of ecosystem photosynthesis that can advance carbon cycle research from leaf to global scales; however, a range of newly reported caveats related to sink/source strength of various ecosystem components hinder its application. Using comprehensive eddy-covariance and chamber measurements, we systematically measure ecosystem contributions from leaf, stem, soil, and litter and were able to close the ecosystem COS budget. The relative contributions of nonphotosynthetic components to the overall canopy-scale flux are relatively small (~4% during peak activity season) and can be independently estimated based on their responses to temperature and humidity. Converting COS to photosynthetic CO2 fluxes based on the leaf relative uptake of COS/CO2, faces challenges due to observed daily and seasonal changes. Yet, this ratio converges around a constant value (~1.6), and the variations, dominated by light intensity, were found unimportant on a flux-weighted daily time-scale, indicating a mean ratio of daytime gross-to-net primary productivity of ~2 in our ecosystem. The seasonal changes in the leaf relative uptake ratio may indicate a reduction in mesophyll conductance in winter, and COS-derived canopy conductance permitted canopy temperature estimate consistent with radiative skin temperature. These results support the feasibility of using COS as a powerful and much-needed means of assessing ecosystem function and its response to change.
U2 - https://doi.org/10.1111/gcb.14145
DO - https://doi.org/10.1111/gcb.14145
M3 - مقالة
SN - 1354-1013
VL - 24
SP - 3486
EP - 3498
JO - Global Change Biology
JF - Global Change Biology
IS - 8
ER -