scholarly journals The riverine source of CH<sub>4</sub> and N<sub>2</sub>O from the Republic of Congo, western Congo Basin

2017 ◽  
Vol 14 (9) ◽  
pp. 2267-2281 ◽  
Author(s):  
Robert C. Upstill-Goddard ◽  
Matthew E. Salter ◽  
Paul J. Mann ◽  
Jonathan Barnes ◽  
John Poulsen ◽  
...  
Keyword(s):  
Tropical Forest ◽  
Dry Season ◽  
Congo Basin ◽  
Wet Season ◽  
Swamp Forest ◽  
Republic Of Congo ◽  
Emission Fluxes ◽  
Sub Saharan ◽  
Ch4 And N2o ◽  
Land Types

Abstract. We discuss concentrations of dissolved CH4, N2O, O2, NO3− and NH4+, and emission fluxes of CH4 and N2O for river sites in the western Congo Basin, Republic of Congo (ROC). Savannah, swamp forest and tropical forest samples were collected from the Congo main stem and seven of its tributaries during November 2010 (41 samples; wet season) and August 2011 (25 samples; dry season; CH4 and N2O only). Dissolved inorganic nitrogen (DIN: NH4++ NO3−; wet season) was dominated by NO3− (63 ± 19 % of DIN). Total DIN concentrations (1.5–45.3 µmol L−1) were consistent with the near absence of agricultural, domestic and industrial sources for all three land types. Dissolved O2 (wet season) was mostly undersaturated in swamp forest (36 ± 29 %) and tropical forest (77 ± 36 %) rivers but predominantly supersaturated in savannah rivers (100 ± 17 %). The dissolved concentrations of CH4 and N2O were within the range of values reported earlier for sub-Saharan African rivers. Dissolved CH4 was found to be supersaturated (11.2–9553 nmol L−1; 440–354 444 %), whereas N2O ranged from strong undersaturation to supersaturation (3.2–20.6 nmol L−1; 47–205 %). Evidently, rivers of the ROC are persistent local sources of CH4 and can be minor sources or sinks for N2O. During the dry season the mean and range of CH4 and N2O concentrations were quite similar for the three land types. Wet and dry season mean concentrations and ranges were not significant for N2O for any land type or for CH4 in savannah rivers. The latter observation is consistent with seasonal buffering of river discharge by an underlying sandstone aquifer. Significantly higher wet season CH4 concentrations in swamp and forest rivers suggest that CH4 can be derived from floating macrophytes during flooding and/or enhanced methanogenesis in adjacent flooded soils. Swamp rivers also exhibited both low (47 %) and high (205 %) N2O saturation but wet season values were overall significantly lower than in either tropical forest or savannah rivers, which were always supersaturated (103–266 %) and for which the overall means and ranges of N2O were not significantly different. In swamp and forest rivers O2 saturation co-varied inversely with CH4 saturation (log %) and positively with % N2O. A significant positive correlation between N2O and O2 saturation in swamp rivers was coincident with strong N2O and O2 undersaturation, indicating N2O consumption during denitrification in the sediments. In savannah rivers persistent N2O supersaturation and a negative correlation between N2O and O2 suggest N2O production mainly by nitrification. This is consistent with a stronger correlation between N2O and NH4+ than between N2O and NO3−. Our ranges of values for CH4 and N2O emission fluxes (33–48 705 µmol CH4 m−2 d−1; 1–67 µmol N2O m−2 d−1) are within the ranges previously estimated for sub-Saharan African rivers but they include uncertainties deriving from our use of basin-wide values for CH4 and N2O gas transfer velocities. Even so, because we did not account for any contribution from ebullition, which is quite likely for CH4 (at least 20 %), we consider our emission fluxes for CH4 to be conservative.

scholarly journals The riverine source of tropospheric CH<sub>4</sub> and N<sub>2</sub>O from the Republic of Congo, Western Congo Basin

2016 ◽  
Author(s):  
Robert C. Upstill-Goddard ◽  
Matthew E. Salter ◽  
Paul J. Mann ◽  
Jonathan Barnes ◽  
John Poulsen ◽  
...  
Keyword(s):  
Tropical Forest ◽  
Dry Season ◽  
Congo Basin ◽  
N2o Emissions ◽  
Wet Season ◽  
Swamp Forest ◽  
N2o Production ◽  
Republic Of Congo ◽  
Sub Saharan ◽  
Ch4 And N2o

Abstract. Abstract. We report concentrations of dissolved CH4, N2O, O2, NO3− and NH4+, and corresponding CH4 and N2O emissions for river sites in savanna, swamp forest and tropical forest, along the Congo main stem and in several of its tributary systems of the Western Congo Basin, Republic of Congo, during November 2010 (41 samples; ''wet season'') and August 2011 (25 samples; ''dry season''; CH4 and N2O only). Dissolved inorganic nitrogen (DIN: wet season; NH4&amp;plus; &amp;plus;  NO3−) was dominated by NO3− (63 ± 19 % of DIN), total DIN concentrations (1.5–45.3 nmol L−1) being consistent with small agricultural, domestic and industrial sources. Dissolved O2 (wet season) was mostly under-saturated in swamp forest (36 ± 29 %) and tropical forest (77 ± 36 %) rivers but predominantly super-saturated in savannah rivers (100 ± 17 %). Dissolved CH4 and N2O were within previously reported ranges for sub-Saharan African rivers. While CH4 was always super-saturated (11.2–9553 nmol L−1; 440–354 400 %), N2O ranged from strong under-saturation to strong super-saturation (3.2–20.6 nmol L−1; 47–205 %). Evidently, rivers of the ROC are persistent local sources of tropospheric CH4 but can be small sources or sinks for N2O. Dry season concentration means and ranges of CH4 and N2O were indistinguishable for all three land types and seasonal differences in means and ranges were not significant for N2O for any land type or for CH4 in savannah rivers; the latter is consistent with seasonal buffering of river discharge by an underlying sandy-sandstone aquifer. By contrast, swamp and forest river CH4 was significantly higher in the wet season, possibly reflecting CH4 derived from floating macrophytes during flooding and/or enhanced methanogenesis in adjacent flooded soils. Swamp rivers exhibited both low (47 %) and high (205 %) N2O saturations but wet season values were overall significantly lower than in either tropical forest or savannah rivers, which were always super-saturated (103–266 %) and for which the overall means and ranges of N2O were not significantly different. In swamp and forest rivers % O2 co-varied negatively with log % CH4 and positively with % N2O. The strong positive N2O–O2 correlation in swamp rivers was coincident with strong N2O and O2 under-saturation, indicating N2O consumption by sediment denitrification. In savannah rivers persistent N2O super-saturation and a negative N2O–O2 correlation may indicate N2O production mainly by nitrification, consistent with a stronger correlation between N2O and NH4&amp;plus; than between N2O and NO3−. Our range in CH4 and N2O emissions fluxes (33–48 705  μmol CH4 m−2 d−1; 1–67 μmol N2O m−2 d−1), is wider than previously estimated for sub-Saharan African rivers but it includes uncertainties deriving from our use of ''basin-wide'' values for CH4 and N2O gas transfer velocities. Even so, because we did not account for any contribution from ebullition, which for CH4 is likely to be at least 20 %, our emissions estimates for CH4 are probably conservative.

scholarly journals The economics of phosphorus supplementation of beef cattle grazing northern Australian rangelands

2020 ◽  
Vol 60 (5) ◽  
pp. 683
Author(s):  
M. K. Bowen ◽  
F. Chudleigh ◽  
R. M. Dixon ◽  
M. T. Sullivan ◽  
T. Schatz ◽  
...  
Keyword(s):  
Economic Benefits ◽  
Dry Season ◽  
Cattle Herd ◽  
Annual Business ◽  
Northern Australia ◽  
Wet Season ◽  
P Deficiency ◽  
Business Profit ◽  
Dry Seasons ◽  
Land Types

Context Phosphorus (P) deficiency occurs in beef cattle grazing many rangeland regions with low-P soils, including in northern Australia, and may severely reduce cattle productivity in terms of growth, reproductive efficiency and mortality. However, adoption of effective P supplementation by cattle producers in northern Australia is low. This is likely to be due to lack of information and understanding of the profitability of P supplementation where cattle are P-deficient. Aims The profitability of P supplementation was evaluated for two dissimilar regions of northern Australia, namely (1) the Katherine region of the Northern Territory, and (2) the Fitzroy Natural Resource Management (NRM) region of central Queensland. Methods Property-level, regionally relevant herd models were used to determine whole-of-business productivity and profitability over 30 years. The estimated costs and benefits of P supplementation were obtained from collation of experimental data and expert opinion of persons with extensive experience of the industry. The economic consequences of P supplementation at the property level were assessed by comparison of base production without P supplementation with the expected production of P-supplemented herds, and included the implementation phase and changes over time in herd structure. In the Katherine region, it was assumed that the entire cattle herd (breeders and growing cattle) grazed acutely P-deficient land types and the consequences of (1) no P supplementation, or P supplementation during (2) the dry season, or (3) both the wet and dry seasons (i.e. 3 scenarios) were evaluated. In the Fitzroy NRM region, it was assumed that only the breeders grazed P-deficient land types with three categories of P deficiency (marginal, deficient and acutely deficient), each with either (1) no P supplementation, or P supplementation during (2) the wet season, (3) the dry season, or (4) both the wet and dry seasons (i.e. 12 scenarios). Key results In the Katherine region, year-round P supplementation of the entire cattle herd (7400 adult equivalents) grazing acutely P-deficient pasture resulted in a large increase in annual business profit (+AU$500000). Supplementing with P (and N) only in the dry season increased annual business profit by +AU$200000. In the Fitzroy NRM region, P supplementation during any season of the breeder herd grazing deficient or acutely P-deficient pastures increased profit by +AU$2400–AU$45000/annum (total cattle herd 1500 adult equivalents). Importantly, P supplementation during the wet season-only resulted in the greatest increases in profit within each category of P deficiency, comprising +AU$5600, AU$6300 and AU$45000 additional profit per annum for marginal, deficient and acutely P-deficient herds respectively. Conclusions The large economic benefits of P supplementation for northern beef enterprises estimated in the present study substantiate the current industry recommendation that effective P supplementation is highly profitable when cattle are grazing P-deficient land types. Implications The contradiction of large economic benefits of P supplementation and the generally low adoption rates by the cattle industry in northern Australia suggests a need for targeted research and extension to identify the specific constraints to adoption, including potential high initial capital costs.

scholarly journals Seasonal source variability of carbonaceous aerosols at the Rwanda Climate Observatory

2020 ◽  
Vol 20 (8) ◽  
pp. 4561-4573
Author(s):  
August Andersson ◽  
Elena N. Kirillova ◽  
Stefano Decesari ◽  
Langley DeWitt ◽  
Jimmy Gasore ◽  
...  
Keyword(s):  
Hot Spot ◽  
Regional Climate ◽  
Fine Fraction ◽  
Dry Season ◽  
Sub Saharan Africa ◽  
Carbonaceous Aerosol ◽  
Carbonaceous Aerosols ◽  
Wet Season ◽  
Aerosol Composition ◽  
Sub Saharan

Abstract. Sub-Saharan Africa (SSA) is a global hot spot for aerosol emissions, which affect the regional climate and air quality. In this paper, we use ground-based observations to address the large uncertainties in the source-resolved emission estimation of carbonaceous aerosols. Ambient fine fraction aerosol was collected on filters at the high-altitude (2590 m a.s.l.) Rwanda Climate Observatory (RCO), a SSA background site, during the dry and wet seasons in 2014 and 2015. The concentrations of both the carbonaceous and inorganic ion components show a strong seasonal cycle, with highly elevated concentrations during the dry season. Source marker ratios, including carbon isotopes, show that the wet and dry seasons have distinct aerosol compositions. The dry season is characterized by elevated amounts of biomass burning products, which approach ∼95 % for carbonaceous aerosols. An isotopic mass-balance estimate shows that the amount of the carbonaceous aerosol stemming from savanna fires may increase from 0.2 µg m−3 in the wet season up to 10 µg m−3 during the dry season. Based on these results, we quantitatively show that savanna fire is the key modulator of the seasonal aerosol composition variability at the RCO.

scholarly journals On the Role of Aerosol Radiative Effect in the Wet Season Onset Timing over the Congo Rainforest during Boreal Autumn

2021 ◽  
Author(s):  
Sudip Chakraborty ◽  
Jonathon H. Jiang ◽  
Hui Su ◽  
Rong Fu
Keyword(s):  
Dry Season ◽  
Congo Basin ◽  
Shortwave Radiation ◽  
Boreal Summer ◽  
Onset Date ◽  
Strongly Correlated ◽  
Wet Season ◽  
African Easterly Jet ◽  
Kalahari Desert ◽  
Onset Timing

Abstract. The boreal summer dry season length is reported to have been increasing in the last three decades over the Congo rainforest, which is the second-largest rainforest in the world. In some years, the wet season in boreal autumn starts early while in others it arrives late. The mechanism behind such a change in wet season onset date has not been investigated yet. Using multi-satellite datasets, we discover that the variation of aerosols in dry season plays a major role in determining the subsequent wet season onset. Dry season aerosol optical depth (AOD) influences the strength of the southern African easterly jet (AEJ-S) and thus the onset of the wet season. Higher AOD associated with a higher dust mass flux reduces the net downward shortwave radiation and decreases the surface temperature over the Congo rainforest region, leading to a stronger meridional temperature gradient between the rainforest and the Kalahari Desert as early as in June. The latter, in turn, strengthens the AEJ-S, sets in an early and a stronger easterly flow, leads to a stronger equatorward convergence and an early onset of the wet season in late August to early September. The mean AOD in the dry season over the region is strongly correlated (r =0.7) with the timing of the subsequent wet season onset. Conversely, in low AOD years, the onset of the wet season over the Congo basin is delayed to mid-October.

Effects of light availability and rainfall on leaf production in a moist tropical forest in central Panama

1998 ◽  
Vol 14 (3) ◽  
pp. 309-321 ◽  
Author(s):  
JOHN A. BARONE
Keyword(s):  
Tropical Forest ◽  
Tropical Forests ◽  
Light Availability ◽  
Dry Season ◽  
Wet Season ◽  
Leaf Production ◽  
Active Radiation ◽  
One Year ◽  
The Relationship ◽  
Central Panama

New leaf production in seasonal tropical forests may result from changes in water or light availability. In this study, the relationship between leaf flushing, photosynthetically active radiation (PAR) and rainfall was examined for understorey saplings in a moist tropical forest over one year. During the wet season, weeks with greater PAR were correlated with a greater proportion of saplings flushing new leaves during subsequent weeks in nine out of ten species. Rainfall was negatively correlated with subsequent leafing during the wet season for six of ten species. However, during the dry season, rainfall was positively correlated with leafing during the following weeks for six species, but the relationship was much weaker. PAR in the dry season was negatively correlated with flushing in eight species. These results support the hypothesis that under well-watered conditions, light limits leaf production, and peaks in insolation result in greater leaf production.

scholarly journals Woody encroachment and forest degradation in sub-Saharan Africa's woodlands and savannas 1982–2006

2013 ◽  
Vol 368 (1625) ◽  
pp. 20120406 ◽  
Author(s):  
Edward T. A. Mitchard ◽  
Clara M. Flintrop
Keyword(s):  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Forest Degradation ◽  
Dry Season ◽  
Congo Basin ◽  
Sub Saharan Africa ◽  
Woody Encroachment ◽  
Small Scale ◽  
The North ◽  
Sub Saharan

We review the literature and find 16 studies from across Africa's savannas and woodlands where woody encroachment dominates. These small-scale studies are supplemented by an analysis of long-term continent-wide satellite data, specifically the Normalized Difference Vegetation Index (NDVI) time series from the Global Inventory Modeling and Mapping Studies (GIMMS) dataset. Using dry-season data to separate the tree and grass signals, we find 4.0% of non-rainforest woody vegetation in sub-Saharan Africa (excluding West Africa) significantly increased in NDVI from 1982 to 2006, whereas 3.52% decreased. The increases in NDVI were found predominantly to the north of the Congo Basin, with decreases concentrated in the Miombo woodland belt. We hypothesize that areas of increasing dry-season NDVI are undergoing woody encroachment, but the coarse resolution of the study and uncertain relationship between NDVI and woody cover mean that the results should be interpreted with caution; certainly, these results do not contradict studies finding widespread deforestation throughout the continent. However, woody encroachment could be widespread, and warrants further investigation as it has important consequences for the global carbon cycle and land–climate interactions.

scholarly journals Monitoring of Nutrient Status at Ratargul Swamp Forest in Sylhet, Bangladesh

2020 ◽  
Vol 3 (1) ◽  
pp. 36-49
Author(s):  
Sabiha Akter ◽  
Md. Sirajul Islam ◽  
Shamim Al Mamun
Keyword(s):  
Nutrient Concentration ◽  
Significant Positive Correlation ◽  
Nutrient Status ◽  
Dry Season ◽  
Available Phosphorus ◽  
Plant Leaves ◽  
Wet Season ◽  
Swamp Forest ◽  
Nutrient Contents ◽  
Photosynthetic Activities

Nutrient concentration is an important parameter to recognize critical processes of an ecosystem and environmental quality. This paper is based on a study carried out to evaluate the nutrient status in sediments, water and plant leaves from Ratargul swamp forest of Bangladesh during the period from September 2016 to August 2017. The samples were collected from twelve sampling stations of four different canals during dry (September 2016 to April 2017) and wet (May to August, 2017) seasons, respectively. The nutrient contents such as total nitrogen (TN), available phosphorus (AP) and total organic carbon (TOC) were analysed in the laboratory of the Bangladesh Institute of Nuclear Agriculture (BINA), Mymensingh, Bangladesh. The TN, AP and TOC in sediments were ranged from 2.22 to 5.23, 0.032 to 0.035 and 2.6 to 4.52%, respectively, whereas TN and AP in water were found 5.34 to 22.54% and 0.002 to 0.366%, respectively. Result showed that the TOC in plant leaves was higher in wet season than in dry season, where the TN and AP were higher in dry season than in wet season due to high temperature which increases the rate of photosynthetic activities in the dry season. In both Korochand Hijal plants, the TOC and AP were higher in green leaves than brown leaves, while TN was higher in brown leaves than green ones. Moreover, a statistically significant positive correlation was found among the samples. The study concluded that the nutrient status in sediments, water and leaves were perfectly natural during both the dry and wet season.

scholarly journals Assessing evapotranspiration drivers and patterns at multiple scale in the Amazon basin

2020 ◽  
Author(s):  
Adriana Aparecida Moreira ◽  
Anderson Luis Ruhoff
Keyword(s):  
Remote Sensing ◽  
Tropical Forest ◽  
Amazon Basin ◽  
Vegetation Index ◽  
Dry Season ◽  
Limiting Factors ◽  
Net Radiation ◽  
Wet Season ◽  
Basin Scale ◽  
The Tropics

&lt;p&gt;Evapotranspiration (ET) is a key variable to terrestrial climate system, transferring water from the surface to the atmosphere, regulating air temperature and carbon exchanges, thus, linking the water, carbon and water cycles. Despite its great importance, ET patterns in tropical biomes are not fully understood yet. Studies with eddy covariance (EC) ET measurements and remote sensing models demonstrated a huge importance over ET drivers and limiting factors. In this context, this study aimed to assess the ET process in the tropics, from local to basin scale, using EC measurements (from the LBA project) and remote sensing models (MOD16 and GLEAM). At local scale, measurements and estimates were evaluated against net radiation, precipitation and vegetation index (EVI), in order to assess how these drivers control ET patterns. Then, a Budyko approach was applied at basin scale to calculate how water and energy constrain ET in large basins, including Amazon, Solim&amp;#245;es, Purus, Medeira, Tapaj&amp;#243;s, and Xingu rivers. Our results demonstrated disagreements between models to represent maximum and minimum ET rates at tropical forest vegetation (at K43, K67 and K83 sites), with ET measurements peaking during the dry season, in a pattern coincident with annual net radiation cycle. Moreover, deep rooting of well-established rainforests, available soil moisture and increased solar radiation allow ET processes to be maintained during the dry season. ET estimates from MOD16 algorithm agree with these patterns, however, estimates from GLEAM indicates maximum ET rates during the rainy season. At cropland/pasture vegetation (at K77 site), also located in central Amazon, EC measurements showed moderate negative agreement with net radiation (R&amp;#178; = -0.48) and positive with precipitation (R&amp;#178; = 0.53), with decreasing ET rates during the dry season. GLEAM showed ET rates reduction in dry months, but also showed a peak in during wet season, while increasing ET estimates are observed for MOD16, both presented similar behavior as in tropical forest sites. Furthermore, measurements in the southwest part (RJA and FNS sites) did not show clear seasonal patterns, and both MOD16 and GLEAM algorithms, agree with decreasing ET rates during the dry season, showing a significant relationship with precipitation and vegetation indices. Results based on the Budyko approach indicated agreement between the models, indicating a predominant energy-limited condition when evaluated whole basin (at &amp;#211;bidos station), or basins located in the northern and western parts of Amazon (in Amazon, Purus, and Negro basins), which corroborates with other studies, where ET has limited energy availability. However, our results also demonstrated disagreements in basins located in the southern and eastern parts (in Madeira, Tapaj&amp;#243;s and Xingu basins), where MOD16 showed some water-limited conditions, whilst it was not observed for GLEAM algorithm. Whether the models agree in terms of seasonality and water and energy limitations, they also disagree between them and ground measurements. This study highlighted the importance to understand limitations of multi-models and multi-scale ET processes for hydroclimatological studies in the tropics.&lt;/p&gt;

scholarly journals On the role of aerosol radiative effect in the wet season onset timing over the Congo rainforest during boreal autumn

2021 ◽  
Vol 21 (17) ◽  
pp. 12855-12866
Author(s):  
Sudip Chakraborty ◽  
Jonathon H. Jiang ◽  
Hui Su ◽  
Rong Fu
Keyword(s):  
Dry Season ◽  
Congo Basin ◽  
Shortwave Radiation ◽  
Boreal Summer ◽  
Onset Date ◽  
Data Sets ◽  
Strongly Correlated ◽  
Wet Season ◽  
African Easterly Jet ◽  
Kalahari Desert

Abstract. The boreal summer dry season length is reported to have been increasing in the last 3 decades over the Congo rainforest, which is the second-largest rainforest in the world. In some years, the wet season in boreal autumn starts early, while in others it arrives late. The mechanism behind such a change in the wet season onset date has not been investigated yet. Using multi-satellite data sets, we discover that the variation in aerosols in the dry season plays a major role in determining the subsequent wet season onset. Dry season aerosol optical depth (AOD) influences the strength of the southern African easterly jet (AEJ-S) and, thus, the onset of the wet season. Higher AOD associated with a higher dust mass flux reduces the net downward shortwave radiation and decreases the surface temperature over the Congo rainforest region, leading to a stronger meridional temperature gradient between the rainforest and the Kalahari Desert as early as in June. The latter, in turn, strengthens the AEJ-S, sets in an early and a stronger easterly flow, and leads to a stronger equatorward convergence and an early onset of the wet season in late August to early September. The mean AOD in the dry season over the region is strongly correlated (r=0.7) with the timing of the subsequent wet season onset. Conversely, in low AOD years, the onset of the wet season over the Congo basin is delayed to mid-October.

scholarly journals The seasonal changes of the gut microbiome of the population living in traditional lifestyles are represented by characteristic species-level and functional-level SNP enrichment patterns

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Xue Zhu ◽  
Jiyue Qin ◽  
Chongyang Tan ◽  
Kang Ning
Keyword(s):  
Gut Microbiome ◽  
Seasonal Changes ◽  
Dry Season ◽  
Urban Setting ◽  
Snp Analysis ◽  
Wet Season ◽  
Human Gut ◽  
Human Gut Microbiome ◽  
Genome Level ◽  
Prevalent Species

Abstract Background Most studies investigating human gut microbiome dynamics are conducted on humans living in an urban setting. However, few studies have researched the gut microbiome of the populations living traditional lifestyles. These understudied populations are arguably better subjects in answering human-gut microbiome evolution because of their lower exposure to antibiotics and higher dependence on natural resources. Hadza hunter-gatherers in Tanzania have exhibited high biodiversity and seasonal patterns in their gut microbiome composition at the family level, where some taxa disappear in one season and reappear later. Such seasonal changes have been profiled, but the nucleotide changes remain unexplored at the genome level. Thus, it is still elusive how microbial communities change with seasonal changes at the genome level. Results In this study, we performed a strain-level single nucleotide polymorphism (SNP) analysis on 40 Hadza fecal metagenome samples spanning three seasons. With more SNP presented in the wet season, eight prevalent species have significant SNP enrichment with the increasing number of SNP calling by VarScan2, among which only three species have relatively high abundances. Eighty-three genes have the most SNP distributions between the wet season and dry season. Many of these genes are derived from Ruminococcus obeum, and mainly participated in metabolic pathways including carbon metabolism, pyruvate metabolism, and glycolysis. Conclusions Eight prevalent species have significant SNP enrichments with the increasing number of SNP, among which only Eubacterium biforme, Eubacterium hallii and Ruminococcus obeum have relatively high species abundances. Many genes in the microbiomes also presented characteristic SNP distributions between the wet season and the dry season. This implies that the seasonal changes might indirectly impact the mutation patterns for specific species and functions for the gut microbiome of the population that lives in traditional lifestyles through changing the diet in wet and dry seasons, indicating the role of these variants in these species’ adaptation to the changing environment and diets.

Sign in / Sign up

Export Citation Format

Share Document