scholarly journals Decreased carbon limitation of litter respiration in a mortality-affected piñon–juniper woodland

2013 ◽  
Vol 10 (3) ◽  
pp. 1625-1634 ◽  
Author(s):  
E. Berryman ◽  
J. D. Marshall ◽  
T. Rahn ◽  
M. Litvak ◽  
J. Butnor
Keyword(s):  
Soil Respiration ◽  
Microbial Respiration ◽  
Root Exudation ◽  
Mineral Soil ◽  
Carbon Limitation ◽  
Substrate Availability ◽  
Litter Respiration ◽  
Labile C ◽  
Juniper Woodland ◽  
C Limitation

Abstract. Microbial respiration depends on microclimatic variables and carbon (C) substrate availability, all of which are altered when ecosystems experience major disturbance. Widespread tree mortality, currently affecting piñon–juniper ecosystems in southwestern North America, may affect C substrate availability in several ways, for example, via litterfall pulses and loss of root exudation. To determine piñon mortality effects on C and water limitation of microbial respiration, we applied field amendments (sucrose and water) to two piñon–juniper sites in central New Mexico, USA: one with a recent (< 1 yr), experimentally induced mortality event and a nearby site with live canopy. We monitored the respiration response to water and sucrose applications to the litter surface and to the underlying mineral soil surface, testing the following hypotheses: (1) soil respiration in a piñon–juniper woodland is water- and labile C-limited in both the litter layer and mineral soil; (2) piñon mortality reduces the C limitation of litter respiration; and (3) piñon mortality enhances the C limitation of mineral soil respiration. Litter respiration at both sites responded to increased water availability, yet surprisingly, mineral soil respiration was not limited by water. Consistent with hypothesis 2, C limitation of litter respiration was lower at the recent mortality site compared to the intact canopy site. Applications to the mineral soil showed evidence of reduction in CO2 flux on the girdled site and a non-significant increase on the control. We speculate that the reduction may have been driven by water-induced carbonate dissolution, which serves as a sink for CO2 and would reduce the net flux. Widespread piñon mortality may decrease labile C limitation of litter respiration, at least during the first growing season following mortality.

scholarly journals Decreased carbon limitation of litter respiration in a mortality-affected piñon-juniper woodland

2012 ◽  
Vol 9 (10) ◽  
pp. 14475-14501 ◽  
Author(s):  
E. Berryman ◽  
J. D. Marshall ◽  
T. Rahn ◽  
M. Litvak ◽  
J. Butnor
Keyword(s):  
Soil Respiration ◽  
Temperature Sensitivity ◽  
Water Availability ◽  
Microbial Respiration ◽  
Mineral Soil ◽  
Substrate Availability ◽  
Litter Respiration ◽  
Labile C ◽  
Juniper Woodland ◽  
C Limitation

Abstract. Microbial respiration depends on microclimatic variables and carbon (C) substrate availability, all of which are altered when ecosystems experience major disturbance. Widespread tree mortality, currently affecting piñon-juniper ecosystems in Southwestern North America, may affect C substrate availability in several ways; for example, via litterfall pulses and loss of root exudation. To determine piñon mortality effects on C and water limitation of microbial respiration, we applied field amendments (sucrose and water) to two piñon-juniper sites in central New Mexico, USA: one with a recent (< 1 yr), experimentally-induced mortality event and a nearby site with live canopy. We monitored the respiration response to water and sucrose applications to the litter surface and to the underlying mineral soil surface, testing the following hypotheses: (1) soil respiration in a piñon-juniper woodland is water- and labile C-limited in both the litter layer and mineral soil; (2) water and sucrose applications increase temperature sensitivity of respiration; (3) the mortality-affected site will show a reduction in C limitation in the litter; (4) the mortality-affected site will show an enhancement of C limitation in the mineral soil. Litter respiration at both sites responded to increased water availability, yet surprisingly, mineral soil respiration was not limited by water. Temperature sensitivity was enhanced by some of the sucrose and water treatments. Consistent with hypothesis 3, C limitation of litter respiration was lower at the recent mortality site compared to the intact canopy site. Results following applications to the mineral soil suggest the presence of abiotic effects of increasing water availability, precluding our ability to measure labile C limitation in soil. Widespread piñon mortality may decrease labile C limitation of litter respiration, at least during the first growing season following mortality.

scholarly journals Influence of Long-Term Thinning on the Biomass Carbon and Soil Respiration in a Larch (Larix gmelinii) Forest in Northeastern China

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Huimei Wang ◽  
Wei Liu ◽  
Wenjie Wang ◽  
Yuangang Zu
Keyword(s):  
Soil Respiration ◽  
Temperature Sensitivity ◽  
Forest Ecosystems ◽  
Mineral Soil ◽  
Biomass Accumulation ◽  
Northeastern China ◽  
Microbial Composition ◽  
Litter Respiration ◽  
Few Data

Thinning management is used to improve timber production, but only a few data are available on how it influences ecosystem C sink capacity. This study aims to clarify the effects of thinning on C sinks of larch plantations, the most widespread forests in Northeastern China. Both C influx from biomass production and C efflux from each soil respiration component and its temperature sensitivity were determined for scaling-up ecosystem C sink estimation: microbial composition is measured for clarifying mechanism for respiratory changes from thinning treatment. Thinning management induced 6.23 mol C m−2 yr−1increase in biomass C, while the decrease in heterotrophic respiration (Rh) at the thinned sites (0.9 mol C m−2 yr−1) has enhanced 14% of this biomass C increase. This decrease inRhwas a sum of the 42% decrease (4.1 mol C m−2 yr−1) in litter respiration and 3.2 mol C m−2 yr−1more CO2efflux from mineral soil in thinned sites compared with unthinned control. Increases in temperature, temperature sensitivity, alteration of litters, and microbial composition may be responsible for the contrary changes inRhfrom mineral soil and litter respiration, respectively. These findings manifested that thinning management of larch plantations could enhance biomass accumulation and decrease respiratory efflux from soil, which resulted in the effectiveness improvement in sequestrating C in forest ecosystems.

scholarly journals Historical climate controls soil respiration responses to current soil moisture

2017 ◽  
Vol 114 (24) ◽  
pp. 6322-6327 ◽  
Author(s):  
Christine V. Hawkes ◽  
Bonnie G. Waring ◽  
Jennifer D. Rocca ◽  
Stephanie N. Kivlin
Keyword(s):  
Climate Change ◽  
Soil Moisture ◽  
Soil Respiration ◽  
Carbon Cycling ◽  
Large Scale ◽  
Microbial Respiration ◽  
Rainfall Gradient ◽  
Soil Microbial ◽  
Historical Climate ◽  
Moisture Dependence

Ecosystem carbon losses from soil microbial respiration are a key component of global carbon cycling, resulting in the transfer of 40–70 Pg carbon from soil to the atmosphere each year. Because these microbial processes can feed back to climate change, understanding respiration responses to environmental factors is necessary for improved projections. We focus on respiration responses to soil moisture, which remain unresolved in ecosystem models. A common assumption of large-scale models is that soil microorganisms respond to moisture in the same way, regardless of location or climate. Here, we show that soil respiration is constrained by historical climate. We find that historical rainfall controls both the moisture dependence and sensitivity of respiration. Moisture sensitivity, defined as the slope of respiration vs. moisture, increased fourfold across a 480-mm rainfall gradient, resulting in twofold greater carbon loss on average in historically wetter soils compared with historically drier soils. The respiration–moisture relationship was resistant to environmental change in field common gardens and field rainfall manipulations, supporting a persistent effect of historical climate on microbial respiration. Based on these results, predicting future carbon cycling with climate change will require an understanding of the spatial variation and temporal lags in microbial responses created by historical rainfall.

scholarly journals Stoichiometry constrains microbial response to root exudation- insights from a model and a field experiment in a temperate forest

2013 ◽  
Vol 10 (2) ◽  
pp. 821-838 ◽  
Author(s):  
J. E. Drake ◽  
B. A. Darby ◽  
M.-A. Giasson ◽  
M. A. Kramer ◽  
R. P. Phillips ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Microbial Biomass ◽  
Field Experiment ◽  
Microbial Activity ◽  
Root Exudates ◽  
Microbial Respiration ◽  
Root Exudation ◽  
N Availability ◽  
Rhizosphere Soils ◽  
Wide Range

Abstract. Plant roots release a wide range of chemicals into soils. This process, termed root exudation, is thought to increase the activity of microbes and the exoenzymes they synthesize, leading to accelerated rates of carbon (C) mineralization and nutrient cycling in rhizosphere soils relative to bulk soils. The nitrogen (N) content of microbial biomass and exoenzymes may introduce a stoichiometric constraint on the ability of microbes to effectively utilize the root exudates, particularly if the exudates are rich in C but low in N. We combined a theoretical model of microbial activity with an exudation experiment to test the hypothesis that the ability of soil microbes to utilize root exudates for the synthesis of additional biomass and exoenzymes is constrained by N availability. The field experiment simulated exudation by automatically pumping solutions of chemicals often found in root exudates ("exudate mimics") containing C alone or C in combination with N (C : N ratio of 10) through microlysimeter "root simulators" into intact forest soils in two 50-day experiments. The delivery of C-only exudate mimics increased microbial respiration but had no effect on microbial biomass or exoenzyme activities. By contrast, experimental delivery of exudate mimics containing both C and N significantly increased microbial respiration, microbial biomass, and the activity of exoenzymes that decompose low molecular weight components of soil organic matter (SOM, e.g., cellulose, amino sugars), while decreasing the activity of exoenzymes that degrade high molecular weight SOM (e.g., polyphenols, lignin). The modeling results were consistent with the experiments; simulated delivery of C-only exudates induced microbial N-limitation, which constrained the synthesis of microbial biomass and exoenzymes. Exuding N as well as C alleviated this stoichiometric constraint in the model, allowing for increased exoenzyme production, the priming of decomposition, and a net release of N from SOM (i.e., mineralization). The quantity of N released from SOM in the model simulations was, under most circumstances, in excess of the N in the exudate pulse, suggesting that the exudation of N-containing compounds can be a viable strategy for plant-N acquisition via a priming effect. The experimental and modeling results were consistent with our hypothesis that N-containing compounds in root exudates affect rhizosphere processes by providing substrates for the synthesis of N-rich microbial biomass and exoenzymes. This study suggests that exudate stoichiometry is an important and underappreciated driver of microbial activity in rhizosphere soils.

Soil respiration in pure and mixed stands of European beech and Norway spruce following removal of organic horizons

2005 ◽  
Vol 35 (11) ◽  
pp. 2756-2764 ◽  
Author(s):  
Werner Borken ◽  
Fritz Beese
Keyword(s):  
Soil Respiration ◽  
Norway Spruce ◽  
Forest Type ◽  
Mineral Soil ◽  
European Beech ◽  
Large Contribution ◽  
Mixed Stands ◽  
Organic C ◽  
C Stocks ◽  
Beech Stand

Soil respiration was measured in adjacent pure and mixed stands of European beech (Fagus sylvatica L.) and Norway spruce (Picea abies (L.) Karst.) at Solling, Germany. Forest type had a significant effect on soil respiration, which was highest in the pure beech stand and lowest in the pure spruce stand. Both throughfall and soil temperature increased with the proportion of beech. Additionally, microbial respiration and biomass in the organic (O) horizons increased sequentially from the pure spruce to the pure beech stand, suggesting that abiotic and biotic factors enhanced the decomposition of litter under beech. Because the spruce litter decomposition rate was low, carbon (C) stocks of the O horizons increased with the proportion of spruce, from 1.6 to 5.1 kg C·m–2. The removal of the O horizons decreased soil respiration by 31%–45%, indicating a large contribution of the mineral soil and roots to total soil respiration. Turnover times of organic C in the O horizons ranged between 5.5 years in the pure beech stand and 20.6 years in the pure spruce stand. Our results suggest that tree species conversion may alter the turnover of soil organic matter, and thus the sequestration of organic C in the O horizons.

scholarly journals Effect of soil microorganisms and labile C availability on soil respiration in response to litter inputs in forest ecosystems: A meta‐analysis

2020 ◽  
Vol 10 (24) ◽  
pp. 13602-13612
Author(s):  
Yanjun Zhang ◽  
Junliang Zou ◽  
Delong Meng ◽  
Shuina Dang ◽  
Jinhong Zhou ◽  
...  
Keyword(s):  
Soil Respiration ◽  
Soil Microorganisms ◽  
Forest Ecosystems ◽  
Meta Analysis ◽  
Labile C

scholarly journals Temperature and substrate availability regulate soil respiration in the tropical mountain rainforests, Hainan Island, China

2013 ◽  
Vol 6 (5) ◽  
pp. 325-334 ◽  
Author(s):  
Zhang Zhou ◽  
Lai Jiang ◽  
Enzai Du ◽  
Huifeng Hu ◽  
Yide Li ◽  
...  
Keyword(s):  
Soil Respiration ◽  
Hainan Island ◽  
Substrate Availability ◽  
Tropical Mountain

scholarly journals Contribution of root respiration to soil respiration in a rape (Brassica campestris L.) field in Southwest China

2014 ◽  
Vol 60 (No. 1) ◽  
pp. 8-14 ◽  
Author(s):  
Q. Hao ◽  
C. Jiang
Keyword(s):  
Soil Respiration ◽  
Root Respiration ◽  
Southwest China ◽  
Brassica Campestris ◽  
Microbial Respiration ◽  
Belowground Biomass ◽  
Closed Chamber ◽  
Shoot Ratio ◽  
Root Shoot Ratio ◽  
Aboveground And Belowground Biomass

This study aimed to separate the respective contributions of root and microbial respiration to soil respiration in a rape field in Southwest China. The soil respiration was measured with a closed chamber technique and a regression method was used to apportion root and microbial respiration. Microbial and root respiration ranged from 70.67 to 183.77 mg CO<sub>2</sub>/m<sup>2</sup>/h and 21.99 to 193.09 mg CO<sub>2</sub>/m<sup>2</sup>/h, averaged 127.16 and 116.66 mg CO<sub>2</sub>/m<sup>2</sup>/h during the rape growing season, respectively. Root respiration coefficient ranged from 0.41 to 5.39 mg C-CO<sub>2</sub>/g C/h and was negatively correlated with root/shoot ratio, aboveground and belowground biomass, but positively correlated with root N content. The contribution of root respiration to soil respiration averaged 44.2%, ranging from 14.5% to 62.62%.

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