scholarly journals The Transcriptional Response of Soil Bacteria to Long-Term Warming and Short-Term Seasonal Fluctuations in a Terrestrial Forest

2021 ◽  
Vol 12 ◽  
Author(s):  
Priyanka Roy Chowdhury ◽  
Stefan M. Golas ◽  
Lauren V. Alteio ◽  
Joshua T. E. Stevens ◽  
Andrew F. Billings ◽  
...  

Terrestrial ecosystems are an important carbon store, and this carbon is vulnerable to microbial degradation with climate warming. After 30 years of experimental warming, carbon stocks in a temperate mixed deciduous forest were observed to be reduced by 30% in the heated plots relative to the controls. In addition, soil respiration was seasonal, as was the warming treatment effect. We therefore hypothesized that long-term warming will have higher expressions of genes related to carbohydrate and lipid metabolism due to increased utilization of recalcitrant carbon pools compared to controls. Because of the seasonal effect of soil respiration and the warming treatment, we further hypothesized that these patterns will be seasonal. We used RNA sequencing to show how the microbial community responds to long-term warming (~30 years) in Harvard Forest, MA. Total RNA was extracted from mineral and organic soil types from two treatment plots (+5°C heated and ambient control), at two time points (June and October) and sequenced using Illumina NextSeq technology. Treatment had a larger effect size on KEGG annotated transcripts than on CAZymes, while soil types more strongly affected CAZymes than KEGG annotated transcripts, though effect sizes overall were small. Although, warming showed a small effect on overall CAZymes expression, several carbohydrate-associated enzymes showed increased expression in heated soils (~68% of all differentially expressed transcripts). Further, exploratory analysis using an unconstrained method showed increased abundances of enzymes related to polysaccharide and lipid metabolism and decomposition in heated soils. Compared to long-term warming, we detected a relatively small effect of seasonal variation on community gene expression. Together, these results indicate that the higher carbohydrate degrading potential of bacteria in heated plots can possibly accelerate a self-reinforcing carbon cycle-temperature feedback in a warming climate.

2021 ◽  
Author(s):  
Zhihan Yang ◽  
Xiaolu Tang ◽  
Xinrui Luo ◽  
Yuehong Shi

<p>Soil respiration (RS), consisting of soil autotrophic respiration (RA) and heterotrophic respiration (RH), is the largest outflux of CO<sub>2</sub> from terrestrial ecosystems to the atmosphere. The temperature sensitivity (Q<sub>10</sub>) of RS is a crucial role in benchmarking the intensity of terrestrial soil carbon-climate feedbacks. However, the heterogeneity of Q<sub>10</sub> of RS has not been well explored. To fill this substantial knowledge gap, gridded long-term Q<sub>10</sub> datasets of RS at 5 cm with a spatial resolution of 1 km were developed from 515 field observations using a random forest algorithm with the linkage of climate, soil and vegetation variables. Q<sub>10</sub> of RA and RH were estimated based on the linear correlation between Q<sub>10</sub> of RS and RA/RH. Field observations indicated that regardless of ecosystem types, Q<sub>10</sub> of RS ranged from 1.54 to 4.17 with an average of 2.52. Q<sub>10</sub> varied significantly among ecosystem types, with the highest mean value of 3.18 for shrubland, followed by wetland (2.66), grassland (2.49) and forest (2.48), whereas the lowest value of 2.14 was found in cropland. RF could well explain the spatial variability of Q<sub>10</sub> of RS (model efficiency = 0.5). Temporally, Q<sub>10</sub> of RS, RA and RH did not differ significantly (<em>p </em>= 0.386). Spatially, Q<sub>10</sub> of RS, RA and RH varied greatly. In different climatic zones, the plateau areas had the highest mean Q<sub>10</sub> value of 2.88, followed by tropical areas (2.63), temperate areas (2.52), while the subtropical region had the lowest Q<sub>10</sub> on average (2.37). The predicted mean Q<sub>10</sub> of RS, RA and RH were 2.52, 2.29, 2.64, respectively, with strong spatial patterns, indicating that the traditional and constant Q<sub>10</sub> of 2 may bring great uncertainties in understanding of soil carbon-climate feedbacks in a warming climate.</p>


2018 ◽  
Vol 22 (2) ◽  
pp. 100-108 ◽  
Author(s):  
Ji Young Eom ◽  
Seok Hee Jeong ◽  
Jung Hwa Chun ◽  
Jae Ho Lee ◽  
Jae Seok Lee

2020 ◽  
Author(s):  
Robert Calin-Jageman ◽  
Irina Calin-Jageman ◽  
Tania Rosiles ◽  
Melissa Nguyen ◽  
Annette Garcia ◽  
...  

[[This is a Stage 2 Registered Report manuscript now accepted for publication at eNeuro. The accepted Stage 1 manuscript is posted here: https://psyarxiv.com/s7dft, and the pre-registration for the project is available here (https://osf.io/fqh8j, 9/11/2019). A link to the final Stage 2 manuscript will be posted after peer review and publication.]] There is fundamental debate about the nature of forgetting: some have argued that it represents the decay of the memory trace, others that the memory trace persists but becomes inaccessible due to retrieval failure. These different accounts of forgetting lead to different predictions about savings memory, the rapid re-learning of seemingly forgotten information. If forgetting is due to decay, then savings requires re-encoding and should thus involve the same mechanisms as initial learning. If forgetting is due to retrieval failure, then savings should be mechanistically distinct from encoding. In this registered report we conducted a pre-registered and rigorous test between these accounts of forgetting. Specifically, we used microarray to characterize the transcriptional correlates of a new memory (1 day after training), a forgotten memory (8 days after training), and a savings memory (8 days after training but with a reminder on day 7 to evoke a long-term savings memory) for sensitization in Aplysia californica (n = 8 samples/group). We found that the re-activation of sensitization during savings does not involve a substantial transcriptional response. Thus, savings is transcriptionally distinct relative to a newer (1-day old) memory, with no co-regulated transcripts, negligible similarity in regulation-ranked ordering of transcripts, and a negligible correlation in training-induced changes in gene expression (r = .04 95% CI [-.12, .20]). Overall, our results suggest that forgetting of sensitization memory represents retrieval failure.


2004 ◽  
Vol 188 (1-3) ◽  
pp. 197-210 ◽  
Author(s):  
Annett Wolf ◽  
Peter Friis Møller ◽  
Richard H.W. Bradshaw ◽  
Jaris Bigler

2010 ◽  
Vol 90 (5) ◽  
pp. 755-765 ◽  
Author(s):  
M. T. Tesfaendrias ◽  
M. R. McDonald ◽  
J. Warland

To identify carrot and onion cultivars that provide consistent marketable yields, we tracked the yields of five fresh market carrot [(Daucus carota L. subsp. sativus (Hoffm.) Arcang.] and six onion (Allium cepa L.) cultivars for at least 13 yr. Relationships between long-term weather variables and marketable yields were also investigated. The effects of cultivar, year and cultivar × year interactions on yield of carrots and onions were assessed. Cultivar and year had significant effects on carrot and onion yields, while the interaction was significant in only one of four data sets of carrot yield. Carrot cv. Cellobunch (95.4 t ha–1) and onion cv. Corona (74.1 t ha–1) had the highest mean marketable yields over the years studied. There was a slight positive correlation between mean yield of the assessed carrots and maximum temperatures in September (r = 0.44). Mean carrot yield was also somewhat negatively correlated with total rainfall in July (r = –0.43) and with number of days with rain in August (r = –0.43) and September (r = –0.44). Most onion cultivars showed stronger relationships between marketable yield and various weather patterns. Marketable yield of onions increased with an increase in the number of days with rainfall in June (r = 0.57). The mean marketable yield of the six onion cultivars decreased in relation to temperatures ≥30°C in June (r = –0.55) and August (r = –0.53). The mean yield of all the onions in the trials was negatively correlated (r = –0.78) with growing degree days (base 5°C, May to August). The results indicated that the data from long-term cultivar trials can be used to identify cultivars that yield well despite seasonal variations in weather. Key words: Daucus carota, Allium cepa, temperature, rainfall


2011 ◽  
Vol 63 (12) ◽  
pp. 2983-2991 ◽  
Author(s):  
M. Métadier ◽  
J. L. Bertrand-Krajewski

Continuous high resolution long term turbidity measurements along with continuous discharge measurements are now recognised as an appropriate technique for the estimation of in sewer total suspended solids (TSS) and Chemical Oxygen Demand (COD) loads during storm events. In the combined system of the Ecully urban catchment (Lyon, France), this technique is implemented since 2003, with more than 200 storm events monitored. This paper presents a method for the estimation of the dry weather (DW) contribution to measured total TSS and COD event loads with special attention devoted to uncertainties assessment. The method accounts for the dynamics of both discharge and turbidity time series at two minutes time step. The study is based on 180 DW days monitored in 2007–2008. Three distinct classes of DW days were evidenced. Variability analysis and quantification showed that no seasonal effect and no trend over the year were detectable. The law of propagation of uncertainties is applicable for uncertainties estimation. The method has then been applied to all measured storm events. This study confirms the interest of long term continuous discharge and turbidity time series in sewer systems, especially in the perspective of wet weather quality modelling.


1990 ◽  
Vol 70 (3) ◽  
pp. 363-377 ◽  
Author(s):  
D. ANN BROWN ◽  
S. P. MATHUR ◽  
ANTON BROWN ◽  
D. J. KUSHNER

Different numerical methods used to distinguish between organic soil types are evaluated. The research was initiated by the suggestion that acid leaching from mining wastes could be prevented by capping the tailings with a self-renewing methane-producing muskeg bog, in order to prevent the penetration of oxygen to the wastes. Thirty organic soils from bogs in the mining districts of Elliot Lake, Sudbury, and Timmins, Ontario, and Noranda, Quebec, were sampled and 28 soil characteristics were measured. These characteristics, whose values are normally or lognormally distributed, were analyzed by several different statistical methods. Some characteristics indicate the existence of two populations, and others are bivariantly correlated. Canonical discriminant analysis was more successful than cluster analysis in separating the bogs into well-defined geographical groups. However, principal component analysis proved best at grouping the organic soils according to their organic and inorganic components, and we suggest that this is a suitable method for the general discrimination of organic soil types. Methane was present in all the 17 bogs tested for it, and in two very wet bogs more than 2 mmol of methane per liter were extracted. Key words: Muskeg bog, organic soils, soil characterization, principal component analysis


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