Seasonal and diurnal patterns of soil respiration in an evergreen coniferous forest: Evidence from six years of observation with automatic chambers

Makita, Naoki; Kosugi, Yukio; Sakabe, Ayaka; Kanazawa, Akito; Ohkubo, S.; Tani, Makoto

doi:10.1371/journal.pone.0192622

Cited by 44 publications

(23 citation statements)

References 69 publications

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“…It is known to have increased in the recent years [55,56]. Observational data of R s (e.g., [57]) show that the process intensity increases with temperature. Rate of chemical reactions, metabolic rate, as well as microorganism activity, generally increase with temperature.…”

Section: Physical Interpretationmentioning

confidence: 99%

Atmospheric Temperature and CO2: Hen-or-Egg Causality?

Koutsoyiannis¹,

Kundzewicz²

2020

Sci

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It is common knowledge that increasing CO2 concentration plays a major role in enhancement of the greenhouse effect and contributes to global warming. The purpose of this study is to complement the conventional and established theory that increased CO2 concentration due to human emissions causes an increase of temperature, by considering the reverse causality. Since increased temperature causes an increase in CO2 concentration, the relationship of atmospheric CO2 and temperature may qualify as belonging to the category of “hen-or-egg” problems, where it is not always clear which of two interrelated events is the cause and which the effect. We examine the relationship of global temperature and atmospheric carbon dioxide concentration at the monthly time step, covering the time interval 1980–2019, in which reliable instrumental measurements are available. While both causality directions exist, the results of our study support the hypothesis that the dominant direction is T → CO2. Changes in CO2 follow changes in T by about six months on a monthly scale, or about one year on an annual scale. We attempt to interpret this mechanism by involving biochemical reactions, as at higher temperatures soil respiration, and hence CO2 emission, are increasing.

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Section: Physical Interpretationmentioning

confidence: 99%

Atmospheric Temperature and CO2: Hen-or-Egg Causality?

Koutsoyiannis¹,

Kundzewicz²

2020

Sci

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“…As concluded by the previous studies among various semi-arid ecosystems, we can also emphasize that the S M has the potential to modulate the relationship of the S T with the S R and hence is considered the single best predictive variable of S R (Conant et al 2004;Rey et al 2005;Jia et al 2006;Almagro et al 2009;Jha and Mohapatra 2011;Tucker and Reed 2016). However, with the poor correlation between the S M and S T (Table 1), it is assumed that stimulation of S R was controlled not only by the optimal S M and S T values but also by the seasonal variation in fine root growth, microbial activity, and respiration (Adachi et al 2006;Makita et al 2018;Wang et al 2019). A significant positive relationship was found between the S R and S MA in the MFC, AF, and VF (Fig.…”

Section: Factors Controlling the Variation In S Rmentioning

confidence: 99%

Soil moisture controls the spatio-temporal pattern of soil respiration under different land use systems in a semi-arid ecosystem of Delhi, India

et al. 2020

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Background: Soil respiration (S R) is a critical process for understanding the impact of climatic conditions and land degradation on the carbon cycle in terrestrial ecosystems. We measured the S R and soil environmental factors over 1 year in four land uses with varying levels of disturbance and different vegetation types viz., mixed forest cover (MFC), Prosopis juliflora (Sw.) forest cover (PFC), agricultural field (AF), and vegetable field (VF), in a semi-arid area of Delhi, India. Our primary aim was to assess the effects of soil moisture (S M), soil temperature (S T), and soil microbial activity (S MA) on the S R. Methods: The S R was measured monthly using an LI-6400 with an infrared gas analyser and a soil chamber. The S M was measured using the gravimetric method. The S T (10 cm) was measured with a probe attached to the LI-6400. The S MA was determined by fluorescein diacetate hydrolysis. Results: The S R showed seasonal variations, with the mean annual S R ranging from 3.22 to 5.78 μmol m −2 s −1 and higher S R rates of~15-55% in the cultivated fields (AF, VF) than in the forest sites (MFC, PFC). The VF had significantly higher S R (P < 0.05) than the other land uses (AF, PFC, MFC), which did not vary significantly from one another in S R (P < 0.05). The repeated measures ANOVA evaluated the significant differences (P < 0.05) in the S R for high precipitation months (July, August, September, February). The S M as a single factor showed a strong significant relationship in all the land uses (R 2 = 0.67-0.91, P < 0.001). The effect of the S T on the S R was found to be weak and non-significant in the PFC, MFC, and AF (R 2 = 0.14-0.31; P > 0.05). Contrasting results were observed in the VF, which showed high S R during summer (May; 11.21 μmol m −2 s −1) and a significant exponential relationship with the S T (R 2 = 0.52; P < 0.05). The S R was positively related to the S MA (R 2 = 0.44-0.5; P < 0.001). The interactive equations based on the independent variables S M , S T , and S MA explained 91-95% of the seasonal variation in S R with better model performance in the cultivated land use sites (AF, VF). Conclusion: S M was the key determining factor of the S R in semi-arid ecosystems and explained~90% of the variation. Precipitation increased S R by optimizing the S M and microbial activity. The S MA , along with the other soil factors S M and S T , improved the correlation with S R. Furthermore, the degraded land uses will be more susceptible to temporal variations in S R under changing climatic scenarios, which may influence the carbon balance of these ecosystems.

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“…Soil respiration (SR) is the largest biological carbon (C) flux after photosynthesis in terrestrial ecosystems, and is estimated to release 50–77 Pg C yr -1 globally [ 1 – 3 ]. This major natural flux largely determines the C balance between the terrestrial biosphere and the atmosphere [ 4 – 6 ] and plays a critical role in the carbon cycle. Soil is the largest C pool in the terrestrial biosphere and has been increasingly recognized to play a crucial role in mitigating global warming resulting from climate change [ 7 – 9 ].…”

Section: Introductionmentioning

confidence: 99%

Soil respiration variation along an altitudinal gradient in the Italian Alps: Disentangling forest structure and temperature effects

et al. 2021

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On the mountains, along an elevation gradient, we generally observe an ample variation in temperature, with the associated difference in vegetation structure and composition and soil properties. With the aim of quantifying the relative importance of temperature, vegetation and edaphic properties on soil respiration (SR), we investigated changes in SR along an elevation gradient (404 to 2101 m a.s.l) in the southern slopes of the Alps in Northern Italy. We also analysed soil physicochemical properties, including soil organic carbon (SOC) and nitrogen (N) stocks, fine root C and N, litter C and N, soil bulk densities and soil pH at five forest sites, and also stand structural properties, including vegetation height, age and basal area. Our results indicated that SR rates increased with temperature in all sites, and 55–76% of SR variability was explained by temperature. Annual cumulative SR, ranging between 0.65–1.40 kg C m-2 yr-1, decreased along the elevation gradient, while temperature sensitivity (Q10) of SR increased with elevation. However, a high SR rate (1.27 kg C m-2 yr-1) and low Q10 were recorded in the mature conifer forest stand at 1731 m a.s.l., characterized by an uneven-aged structure and high dominant tree height, resulting in a nonlinear relationship between elevation and temperature. Reference SR at 10°C (SRref) was unrelated to elevation, but was related to tree height. A significant negative linear relationship was found between bulk density and elevation. Conversely, SOC, root C and N stock, pH, and litter mass were best fitted by nonlinear relationships with elevation. However, these parameters were not significantly correlated with SR when the effect of temperature was removed (SRref). These results demonstrate that the main factor affecting SR in forest ecosystems along this Alpine elevation gradient is temperature, but its regulating role can be strongly influenced by site biological characteristics, particularly vegetation type and structure, affecting litter quality and microclimate. This study also confirms that high elevation sites are rich in SOC and more sensitive to climate change, being prone to high C losses as CO2. Furthermore, our data indicate a positive relationship between Q10 and dominant tree height, suggesting that mature forest ecosystems characterized by an uneven-age structure, high SRref and moderate Q10, may be more resilient.

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Seasonal and diurnal patterns of soil respiration in an evergreen coniferous forest: Evidence from six years of observation with automatic chambers

Cited by 44 publications

References 69 publications

Atmospheric Temperature and CO2: Hen-or-Egg Causality?

Atmospheric Temperature and CO2: Hen-or-Egg Causality?

Soil moisture controls the spatio-temporal pattern of soil respiration under different land use systems in a semi-arid ecosystem of Delhi, India

Soil respiration variation along an altitudinal gradient in the Italian Alps: Disentangling forest structure and temperature effects

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