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Liu P, Barr AG, Zha T, Black TA, Jassal RS, Nesic Z, Helgason WD, Jia X, Tian Y. Re-assessment of the climatic controls on the carbon and water fluxes of a boreal aspen forest over 1996-2016: Changing sensitivity to long-term climatic conditions. Glob Chang Biol 2022; 28:4605-4619. [PMID: 35474386 DOI: 10.1111/gcb.16218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2021] [Accepted: 03/19/2022] [Indexed: 06/14/2023]
Abstract
Recent evidence suggests that the relationships between climate and boreal tree growth are generally non-stationary; however, it remains uncertain whether the relationships between climate and carbon (C) fluxes of boreal forests are stationary or have changed over recent decades. In this study, we used continuous eddy-covariance and microclimate data over 21 years (1996-2016) from a 100-year-old trembling aspen stand in central Saskatchewan, Canada to assess the relationships between climate and ecosystem C and water fluxes. Over the study period, the most striking climatic event was a severe, 3-year drought (2001-2003). Gross ecosystem production (GEP) showed larger interannual variability than ecosystem respiration (Re ) over 1996-2016, but Re was the dominant component contributing to the interannual variation in net ecosystem production (NEP) during post-drought years. The interannual variations in evapotranspiration (ET) and C fluxes were primarily driven by temperature and secondarily by water availability. Two-factor linear models combining precipitation and temperature performed well in explaining the interannual variation in C and water fluxes (R2 > .5). The temperature sensitivities of all three C fluxes (NEP, GEP and Re ) declined over the study period (p < .05), and, as a result, the phenological controls on annual NEP weakened. The decreasing temperature sensitivity of the C fluxes may reflect changes in forest structure, related to the over-maturity of the aspen stand at 100 years of age, and exacerbated by high tree mortality following the severe 2001-2003 drought. These results may provide an early warning signal of driver shift or even an abrupt status shift of aspen forest dynamics. They may also imply a universal weakening in the relationship between temperature and GEP as forests become over-mature, associated with the structural and compositional changes that accompany forest ageing.
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Affiliation(s)
- Peng Liu
- School of Soil and Water Conservation, Beijing Forestry University, Beijing, China
- Beijing Engineering Research Center of Soil and Water Conservation, Beijing Forestry University, Beijing, China
| | - Alan G Barr
- Global Institute for Water Security, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Tianshan Zha
- School of Soil and Water Conservation, Beijing Forestry University, Beijing, China
- Beijing Engineering Research Center of Soil and Water Conservation, Beijing Forestry University, Beijing, China
| | - T Andrew Black
- Biometeorology and Soil Physics Group, University of British Columbia, Vancouver, British Columbia, Canada
| | - Rachhpal S Jassal
- Biometeorology and Soil Physics Group, University of British Columbia, Vancouver, British Columbia, Canada
| | - Zoran Nesic
- Biometeorology and Soil Physics Group, University of British Columbia, Vancouver, British Columbia, Canada
| | - Warren D Helgason
- Chemical and Biological Engineering, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Xin Jia
- School of Soil and Water Conservation, Beijing Forestry University, Beijing, China
- Beijing Engineering Research Center of Soil and Water Conservation, Beijing Forestry University, Beijing, China
| | - Yun Tian
- School of Soil and Water Conservation, Beijing Forestry University, Beijing, China
- Beijing Engineering Research Center of Soil and Water Conservation, Beijing Forestry University, Beijing, China
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Liu P, Black TA, Jassal RS, Zha T, Nesic Z, Barr AG, Helgason WD, Jia X, Tian Y, Stephens JJ, Ma J. Divergent long-term trends and interannual variation in ecosystem resource use efficiencies of a southern boreal old black spruce forest 1999-2017. Glob Chang Biol 2019; 25:3056-3069. [PMID: 31055880 DOI: 10.1111/gcb.14674] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 04/23/2019] [Accepted: 04/25/2019] [Indexed: 05/14/2023]
Abstract
Long-term trends in ecosystem resource use efficiencies (RUEs) and their controlling factors are key pieces of information for understanding how an ecosystem responds to climate change. We used continuous eddy covariance and microclimate data over the period 1999-2017 from a 120-year-old black spruce stand in central Saskatchewan, Canada, to assess interannual variability, long-term trends, and key controlling factors of gross ecosystem production (GEP) and the RUEs of carbon (CUE = net primary production [NPP]/GEP), light (LUE = GEP/absorbed photosynthetic radiation [APAR]), and water (WUE = GEP/evapotranspiration [E]). At this site, annual GEP has shown an increasing trend over the 19 years (p < 0.01), which may be attributed to rising atmospheric CO2 concentration. Interannual variability in GEP, aside from its increasing trend, was most strongly related to spring temperatures. Associated with the significant increase in annual GEP were relatively small changes in NPP, APAR, and E, so that annual CUE showed a decreasing trend and annual LUE and WUE showed increasing trends over the 19 years. The long-term trends in the RUEs were related to the increasing CO2 concentration. Further analysis of detrended RUEs showed that their interannual variation was impacted most strongly by air temperature. Two-factor linear models combining CO2 concentration and air temperature performed well (R2 ~0.60) in simulating annual RUEs. LUE and WUE were positively correlated both annually and seasonally, while LUE and CUE were mostly negatively correlated. Our results showed divergent long-term trends among CUE, LUE, and WUE and highlighted the need to account for the combined effects of climatic controls and the 'CO2 fertilization effect' on long-term variations in RUEs. Since most RUE-based models rely primarily on one resource limitation, the observed patterns of relative change among the three RUEs may have important implications for RUE-based modeling of C fluxes.
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Affiliation(s)
- Peng Liu
- Yanchi Research Station, School of Soil and Water Conservation, Beijing Forestry University, Beijing, China
- Key Laboratory of State Forestry Administration on Soil and Water Conservation, Beijing Forestry University, Beijing, China
- Biometeorology and Soil Physics Group, University of British Columbia, Vancouver, BC, Canada
| | - T Andrew Black
- Biometeorology and Soil Physics Group, University of British Columbia, Vancouver, BC, Canada
| | - Rachhpal S Jassal
- Biometeorology and Soil Physics Group, University of British Columbia, Vancouver, BC, Canada
| | - Tianshan Zha
- Yanchi Research Station, School of Soil and Water Conservation, Beijing Forestry University, Beijing, China
- Key Laboratory of State Forestry Administration on Soil and Water Conservation, Beijing Forestry University, Beijing, China
| | - Zoran Nesic
- Biometeorology and Soil Physics Group, University of British Columbia, Vancouver, BC, Canada
| | - Alan G Barr
- Climate Research Division, Environment and Climate Change Canada, Saskatoon, SK, Canada
- Global Institute for Water Security, University of Saskatchewan, Saskatoon, SK, Canada
| | - Warren D Helgason
- Chemical and Biological Engineering, University of Saskatchewan, Saskatoon, SK, Canada
| | - Xin Jia
- Yanchi Research Station, School of Soil and Water Conservation, Beijing Forestry University, Beijing, China
- Key Laboratory of State Forestry Administration on Soil and Water Conservation, Beijing Forestry University, Beijing, China
| | - Yun Tian
- Yanchi Research Station, School of Soil and Water Conservation, Beijing Forestry University, Beijing, China
- Key Laboratory of State Forestry Administration on Soil and Water Conservation, Beijing Forestry University, Beijing, China
| | - Jilmarie J Stephens
- Biometeorology and Soil Physics Group, University of British Columbia, Vancouver, BC, Canada
| | - Jingyong Ma
- Yanchi Research Station, School of Soil and Water Conservation, Beijing Forestry University, Beijing, China
- Key Laboratory of State Forestry Administration on Soil and Water Conservation, Beijing Forestry University, Beijing, China
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Pappas C, Matheny AM, Baltzer JL, Barr AG, Black TA, Bohrer G, Detto M, Maillet J, Roy A, Sonnentag O, Stephens J. Boreal tree hydrodynamics: asynchronous, diverging, yet complementary. Tree Physiol 2018; 38:953-964. [PMID: 29741658 DOI: 10.1093/treephys/tpy043] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 04/17/2018] [Indexed: 06/08/2023]
Abstract
Water stress has been identified as a key mechanism of the contemporary increase in tree mortality rates in northwestern North America. However, a detailed analysis of boreal tree hydrodynamics and their interspecific differences is still lacking. Here we examine the hydraulic behaviour of co-occurring larch (Larix laricina) and black spruce (Picea mariana), two characteristic boreal tree species, near the southern limit of the boreal ecozone in central Canada. Sap flux density (Js), concurrently recorded stem radius fluctuations and meteorological conditions are used to quantify tree hydraulic functioning and to scrutinize tree water-use strategies. Our analysis revealed asynchrony in the diel hydrodynamics of the two species with the initial rise in Js occurring 2 h earlier in larch than in black spruce. Interspecific differences in larch and black spruce crown architecture explained the observed asynchrony in their hydraulic functioning. Furthermore, the two species exhibited diverging stomatal regulation strategies with larch and black spruce employing relatively isohydric and anisohydric behaviour, respectively. Such asynchronous and diverging tree-level hydrodynamics provide new insights into the ecosystem-level complementarity in tree form and function, with implications for understanding boreal forests' water and carbon dynamics and their resilience to environmental stress.
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Affiliation(s)
- Christoforos Pappas
- Département de géographie and Centre d'études nordiques, Université de Montréal, Montréal, QC, Canada
| | - Ashley M Matheny
- Department of Geological Sciences, Jackson School of Geosciences, University of Texas at Austin, Austin, TX, USA
- Department of Civil, Environmental, and Geodetic Engineering, Ohio State University, Columbus, OH, USA
| | | | - Alan G Barr
- Climate Research Division, Environment Canada and Global Institute for Water Security, University of Saskatchewan, Saskatoon, SK, Canada
| | - T Andrew Black
- Faculty of Land and Food Systems, Biometeorology and Soil Physics Group, University of British Columbia, Vancouver, BC, Canada
| | - Gil Bohrer
- Department of Civil, Environmental, and Geodetic Engineering, Ohio State University, Columbus, OH, USA
| | - Matteo Detto
- Center for Tropical Forest Science-Forest Global Earth Observatory, Smithsonian Tropical Research Institute, Panamà, Republic of Panamà
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA
| | - Jason Maillet
- School of Environment and Sustainability, University of Saskatchewan, Saskatoon, SK, Canada
| | - Alexandre Roy
- Département de géographie and Centre d'études nordiques, Université de Montréal, Montréal, QC, Canada
| | - Oliver Sonnentag
- Département de géographie and Centre d'études nordiques, Université de Montréal, Montréal, QC, Canada
| | - Jilmarie Stephens
- Faculty of Land and Food Systems, Biometeorology and Soil Physics Group, University of British Columbia, Vancouver, BC, Canada
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He L, Chen JM, Liu J, Mo G, Bélair S, Zheng T, Wang R, Chen B, Croft H, Arain M, Barr AG. Optimization of water uptake and photosynthetic parameters in an ecosystem model using tower flux data. Ecol Modell 2014. [DOI: 10.1016/j.ecolmodel.2014.09.019] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Dietze MC, Vargas R, Richardson AD, Stoy PC, Barr AG, Anderson RS, Arain MA, Baker IT, Black TA, Chen JM, Ciais P, Flanagan LB, Gough CM, Grant RF, Hollinger D, Izaurralde RC, Kucharik CJ, Lafleur P, Liu S, Lokupitiya E, Luo Y, Munger JW, Peng C, Poulter B, Price DT, Ricciuto DM, Riley WJ, Sahoo AK, Schaefer K, Suyker AE, Tian H, Tonitto C, Verbeeck H, Verma SB, Wang W, Weng E. Characterizing the performance of ecosystem models across time scales: A spectral analysis of the North American Carbon Program site-level synthesis. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2011jg001661] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Grant RF, Margolis HA, Barr AG, Black TA, Dunn AL, Bernier PY, Bergeron O. Changes in net ecosystem productivity of boreal black spruce stands in response to changes in temperature at diurnal and seasonal time scales. Tree Physiol 2009; 29:1-17. [PMID: 19203928 DOI: 10.1093/treephys/tpn004] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Net ecosystem productivity (NEP) of boreal coniferous forests is believed to rise with climate warming, thereby offsetting some of the rise in atmospheric CO(2) concentration (C(a)) by which warming is caused. However, the response of conifer NEP to warming may vary seasonally, with rises in spring and declines in summer. To gain more insight into this response, we compared changes in CO(2) exchange measured by eddy covariance and simulated by the ecosystem process model ecosys under rising mean annual air temperatures (T(a)) during 2004-2006 at black spruce stands in Saskatchewan, Manitoba and Quebec. Hourly net CO(2) uptake was found to rise with warming at T(a) < 15 degrees C and to decline with warming at T(a) > 20 degrees C. As mean annual T(a) rose from 2004 to 2006, increases in net CO(2) uptake with warming at lower T(a) were greater than declines with warming at higher T(a) so that annual gross primary productivity and hence NEP increased. Increases in net CO(2) uptake measured at lower T(a) were explained in the model by earlier recovery of photosynthetic capacity in spring, and by increases in carboxylation activity, using parameters for the Arrhenius temperature functions of key carboxylation processes derived from independent experiments. Declines in net CO(2) uptake measured at higher T(a) were explained in the model by sharp declines in mid-afternoon canopy stomatal conductance (g(c)) under higher vapor pressure deficits (D). These declines were modeled from a hydraulic constraint to water uptake imposed by low axial conductivity of conifer roots and boles that forced declines in canopy water potential (psi(c)), and hence in g(c) under higher D when equilibrating water uptake with transpiration. In a model sensitivity study, the contrasting responses of net CO(2) uptake to specified rises in T(a) caused annual NEP of black spruce in the model to rise with increases in T(a) of up to 6 degrees C, but to decline with further increases at mid-continental sites with lower precipitation. However, these contrasting responses to warming also indicate that rises in NEP with climate warming would depend on the seasonality (spring versus summer) as well as the magnitude of rises in T(a).
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Affiliation(s)
- R F Grant
- Department of Renewable Resources, University of Alberta, Edmonton, AB T6G 2E3, Canada
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Krishnan P, Black TA, Barr AG, Grant NJ, Gaumont-Guay D, Nesic Z. Factors controlling the interannual variability in the carbon balance of a southern boreal black spruce forest. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2007jd008965] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Gaumont-Guay D, Black TA, Barr AG, Jassal RS, Nesic Z. Biophysical controls on rhizospheric and heterotrophic components of soil respiration in a boreal black spruce stand. Tree Physiol 2008; 28:161-171. [PMID: 18055427 DOI: 10.1093/treephys/28.2.161] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We conducted a root-exclusion experiment in a 125-year-old boreal black spruce (Picea mariana (Mill.) BSP) stand in 2004 to quantify the physical and biological controls on temporal dynamics of the rhizospheric (R(r)) and heterotrophic (R(h)) components of soil respiration (R(s)). Annual R(r), R(h) and estimated moss respiration were 285, 269 and 57 g C m(-2) year(-1), respectively, which accounted for 47, 44 and 9% of R(s) (611 g C m(-2) year(-1)), respectively. A gradual transition from R(h)-dominated (winter, spring and fall) to R(r)-dominated (summer) respiration was observed during the year. Soil thawing in spring and the subsequent increase in soil water content (theta) induced a small and sustained increase in R(h) but had no effect on R(r). During the remainder of the growing season, no effect of theta was observed on either component of R(s). Both components increased exponentially with soil temperature (T(s)) during the growing season, but R(r) showed greater temperature sensitivity than R(h) (Q(10) of 4.0 and 3.0, respectively). Temperature-normalized variations in R(r) were highly correlated with eddy covariance estimates of gross ecosystem photosynthesis, and the correlation was greatest when R(r) was lagged by 24 days. Within diurnal cycles, variations in T(s) were highly coupled to variations in R(h) but were significantly decoupled from R(r). The patterns observed at both time scales strongly suggest that the flow of photosynthates to the rhizosphere is a key driver of belowground respiration processes but that photosynthate supply may control these processes in several ways.
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Affiliation(s)
- David Gaumont-Guay
- Biometeorology and Soil Physics Group, University of British Columbia, Vancouver, BC V6T 1Z4, Canada.
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Zha T, Niinisto S, Xing Z, Wang KY, Kellomäki S, Barr AG. Total and component carbon fluxes of a Scots pine ecosystem from chamber measurements and eddy covariance. Ann Bot 2007; 99:345-53. [PMID: 17218344 PMCID: PMC2803003 DOI: 10.1093/aob/mcl266] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
BACKGROUND AND AIMS Distinguishing between, and quantifying, the different components of ecosystem C fluxes is critical in predicting the responses of ecosystem C cycling to climate change. The aims of this study were to quantify the photosynthetic and respiratory fluxes of a 50-year-old Scots pine (Pinus sylvestris) ecosystem, and to distinguish respiration of branches with needles from that of stems, and that of soil. METHODS The CO2 flux of the ecosystem was continuously measured using the eddy covariance (EC) method, and its components (respiration and photosynthesis of a branch with needles, stem and soil surface) were measured with an automated chamber system, from 2001 to 2004. KEY RESULTS All values below are chamber based. The average temperature coefficient (Q10) of respiration was 2.7, 2.2 and 4.0, respectively, for branch (Rbran), stem (Rstem) and the soil surface (Rsoil). Respiration at a reference temperature of 15 degrees C (R15) was 1.27, 0.49 and 4.02 micromol CO2 m(-2) ground s(-1) for the three components, respectively. Over 4 years, the annual Rbran, Rstem and Rsoil ranged from 196 to 256, 56 to 83 and 439 to 598 g C m(-2) ground year(-1), respectively, with a 4-year average of 227, 72 and 507 g C m(-2) ground year(-1). Annual ecosystem respiration (Reco) was 731, 783, 909 and 751 g C m(-2) ground year(-1) in years 2001-2004, respectively, gross primary production (GPP) was 922, 1030, 1138 and 1001 g C m(-2) ground year(-1), and net ecosystem production (NEP) was 191, 247, 229 and 251 g C m(-2) ground year(-1). The average contribution of Rbran, Rstem and Rsoil to Reco was 29, 9 and 62 %, respectively. Overstorey photosynthesis accounted for 96 % of GPP. The average Reco/GPP ratio was 0.78. Net primary production (NPP) in the 4 years was 469, 581, 600 and 551 g C m(-2) year(-1), respectively, with the NPP/GPP ratio 0.54 averaged over the years. CONCLUSIONS Respiration from the soil is the dominant component of ecosystem respiration. Differences between years in Reco were due to differences in temperature during the growing season. Rsoil was more sensitive to temperature than Rbran and Rstem, and differences in Rsoil were responsible for the differences in Reco between years.
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Affiliation(s)
- Tianshan Zha
- Climate Research Division, Environment Canada, 11 Innovation Rd, Saskatoon SK, S7N 3H5, Canada.
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Barr AG, Betts AK, Black TA, McCaughey JH, Smith CD. Intercomparison of BOREAS northern and southern study area surface fluxes in 1994. ACTA ACUST UNITED AC 2001. [DOI: 10.1029/2001jd900070] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Barr AG, Betts AK, Desjardins RL, MacPherson JI. Comparison of regional surface fluxes from boundary-layer budgets and aircraft measurements above boreal forest. ACTA ACUST UNITED AC 1997. [DOI: 10.1029/97jd01104] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Betts AK, Barr AG. First International Satellite Land Surface Climatology Field Experiment 1987 sonde budget revisited. ACTA ACUST UNITED AC 1996. [DOI: 10.1029/96jd02247] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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