Covariation between gross primary production and ecosystem respiration across space and the underlying mechanisms: A global synthesis

Abstract

a b s t r a c tGross primary production (GPP) and ecosystem respiration (RE) are two important processes in the terrestrial carbon cycle. Understanding the relationships between GPP and RE across space, as well as the underlying mechanisms, is helpful for understanding the terrestrial carbon cycle and predicting the global carbon budget. In this study, we investigated the correlation between the spatial variations in GPP and RE by compiling carbon flux data from 264 sites across the Asian, European, North American, South American, African, and Oceanian regions. The results indicated that GPP and RE covaried across space regionally and globally (P < 0.001). The spatial variations in GPP explained 66-98% of the variations in RE in the six regions (approximately explained 60-76% when considered the effects of self-correlation caused by current flux partitioning algorithm), and it explained 90% of RE variations at the global scale (about 70% when considered the effects of self-correlation). RE/GPP values were not significantly different among the six regions or between the two hemispheres. RE/GPP values consistently averaged at 0.87 ± 0.04 along the spatial variations in climate and vegetation index. This covariation between GPP and RE across space is largely attributed to the parallel responses of GPP and RE to the common climatic and vegetation factors, but the underlying mechanism lies in productivity as the primary and direct substrate supplier for respiration which fundamentally constrains RE. These results suggest that the variation in photosynthate availability is the dominant driver for respiration across space and that this process must be fully considered in the cross-site RE comparisons.

Terrestrial carbon balance in a drier world: the effects of water availability in southwestern North America

“…Mass conservation precludes the driest sites from functioning indefinitely as carbon sources, and caution should be applied in extrapolating these results, which represent a period of drought in southwestern North America (Seager & Vecchi, ; Scott et al ., ). Drought may shift a number of long‐lasting constraints such as plant community and soil carbon pools, possibly reducing GEP and increasing R eco (Van der Molen et al ., ), similar to the ‘disturbance offset’ suggested in other multisite flux data syntheses (Baldocchi, ; Chen et al ., ).…”

“…The spatial slope of R eco to GEP (0.64) for southwest North American semiarid ecosystems (Fig. ) was smaller than that reported in several prior studies (~0.7–0.9) (Law et al ., ; Baldocchi, ; Lasslop et al ., ; Chen et al ., ). It was more similar to that found in a recent synthesis across eddy covariance sites in China (0.68) with greater representation of semiarid ecosystems (Yu et al ., ).…”

Spatial Variation of Soil Respiration in a Cropland under Winter Wheat and Summer Maize Rotation in the North China Plain

“…A few reports have contended that spatial patterns of R s may be controlled more by photosynthesis and productivity than by soil temperature [4], [24], [25], [26]. Temporal patterns of R s have been simulated using continuous records of temperature, moisture, and other variables [12], [27], [28], [29].…”

“…Compared with methods for estimating the temporal variation of R s , methods for quantifying spatial variation of R s are limited and difficult [30]. The spatial difference in R s within a site and between sites is often not explained by climatic variables; instead, the difference is modulated by gradients in the biological activity and differences in the soil properties [26], [27], [31], [32]. These features may provide a basis to design field experiments and conduct data analysis to improve the estimation of soil CO 2 emission from an ecosystem.…”

Construction and progress of Chinese terrestrial ecosystem carbon, nitrogen and water fluxes coordinated observation

“…Integrative analysis of global carbon fluxes data showed that GPP and RE co-varied at the spatial pattern from regional to global scale (Yu et al, 2013b;Chen et al, 2013;Chen et al, 2015b) . The spatial pattern of GPP determined 90% of the global spatial pattern of RE and its underlying physiological mechanism due to the fact that production GPP functions as the direct substrate provider for respiration RE (Chen et al, 2015b).…”