Net ecosystem exchange (NEE) of carbon dioxide (CO(2)) was measured in a cool temperate peatland in northwestern Turkey on a continuous basis using eddy covariance (EC) sensors and multiple (non-)linear regression-M(N)LR-models. Our results showed that hourly NEE varied between -1.26 and 1.06 mg CO(2) m(-2) s(-1), with a mean value of 0.11 mg CO(2) m(-2) s(-1). Nighttime ecosystem respiration (R(E)) was on average measured as 0.23 ± 0.09 mg CO(2) m(-2) s(-1). Two best-fit M(N)LR models estimated daytime R(E) as 0.64 ± 0.31 and 0.24 ± 0.05 mg CO(2) m(-2) s(-1). Total R(E) as the sum of nighttime and daytime R(E) ranged from 0.47 to 0.87 mg CO(2) m(-2) s(-1), thus yielding estimates of gross primary productivity (GPP) at -0.35 ± 0.18 and -0.74 ± 0.43 mg CO(2) m(-2) s(-1). Use of EC sensors and M(N)LR models is one of the most direct ways to quantify turbulent CO(2) exchanges among the soil, vegetation and atmosphere within the atmospheric boundary layer, as well as source and sink behaviors of ecosystems.
Keywords: biogeochemical model; carbon cycle; diurnal variation; flux tower.