The ratio of methanogens to methanotrophs and water-level dynamics drive methane transfer velocity in a temperate kettle-hole peat bog

Abstract. Peatlands are a large source of methane (CH4) to the atmosphere, yet the uncertainty around the estimates of CH4 flux from peatlands is large. To better understand the spatial heterogeneity in temperate peatland CH4 emissions and their response to physical and biological drivers, we studied CH4 dynamics throughout the growing seasons of 2017 and 2018 in Flatiron Lake Bog, a kettle-hole peat bog in Ohio. The site is composed of six different hydro-biological zones: an open water zone, four concentric vegetation zones surrounding the open water, and a restored zone connected to the main bog by a narrow channel. At each of these locations, we monitored water level (WL), CH4 pore-water concentration at different peat depths, CH4 fluxes from the ground and from representative plant species using chambers, and microbial community composition with a focus here on known methanogens and methanotrophs. Integrated CH4 emissions for the growing season were estimated as 315.4±166 mgCH4m-2d-1 in 2017 and 362.3±687 mgCH4m-2d-1 in 2018. Median CH4 emission was highest in the open water, then it decreased and became more variable through the concentric vegetation zones as the WL dropped, with extreme emission hotspots observed in the tamarack mixed woodlands (Tamarack) and low emissions in the restored zone (18.8–30.3 mgCH4m-2d-1). Generally, CH4 flux from above-ground vegetation was negligible compared to ground flux (<0.4 %), although blueberry plants were a small CH4 sink. Pore-water CH4 concentrations varied significantly among zones, with the highest values in the Tamarack zone, close to saturation, and the lowest values in the restored zone. While the CH4 fluxes and pore-water concentrations were not correlated with methanogen relative abundance, the ratio of methanogens to methanotrophs in the upper portion of the peat was significantly correlated to CH4 transfer velocity (the CH4 flux divided by the difference in CH4 pore-water concentration between the top of the peat profile and the concentration in equilibrium with the atmosphere). Since ebullition and plant-mediated transport were not important sources of CH4 and the peat structure and porosity were similar across the different zones in the bog, we conclude that the differences in CH4 transfer velocities, and thus the flux, are driven by the ratio of methanogen to methanotroph relative abundance close to the surface. This study illustrates the importance of the interactions between water-level and microbial composition to better understand CH4 fluxes from bogs and wetlands in general.

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The ratio of methanogens to methanotrophs and water-level dynamics drive methane exchange velocity in a temperate kettle-hole peat bog

10.5194/bg-2019-116 ◽

2019 ◽

Cited By ~ 1

Author(s):

Camilo Rey-Sanchez ◽

Gil Bohrer ◽

Julie Slater ◽

Yueh-Fen Li ◽

Roger Grau-Andrés ◽

...

Keyword(s):

Water Level ◽

Microbial Community Composition ◽

Water Concentration ◽

Open Water ◽

Ground Vegetation ◽

Peat Bog ◽

Ch4 Flux ◽

Ch4 Emissions ◽

Kettle Hole ◽

Vegetation Zones

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Insights from year-long measurements of air–water CH<sub>4</sub> and CO<sub>2</sub> exchange in a coastal environment

Biogeosciences ◽

10.5194/bg-16-961-2019 ◽

2019 ◽

Vol 16 (5) ◽

pp. 961-978 ◽

Cited By ~ 4

Author(s):

Mingxi Yang ◽

Thomas G. Bell ◽

Ian J. Brown ◽

James R. Fishwick ◽

Vassilis Kitidis ◽

...

Keyword(s):

Wind Speed ◽

Co2 Flux ◽

Open Water ◽

Gas Transfer ◽

Co2 Efflux ◽

Water Sector ◽

Transfer Velocity ◽

Ch4 Flux ◽

Gas Transfer Velocity

Abstract. Air–water CH4 and CO2 fluxes were directly measured using the eddy covariance technique at the Penlee Point Atmospheric Observatory on the southwest coast of the United Kingdom from September 2015 to August 2016. The high-frequency, year-long measurements provide unprecedented detail on the variability of these greenhouse gas fluxes from seasonal to diurnal and to semi-diurnal (tidal) timescales. Depending on the wind sector, fluxes measured at this site are indicative of air–water exchange in coastal seas as well as in an outer estuary. For the open-water sector when winds were off the Atlantic Ocean, CH4 flux was almost always positive (annual mean of ∼0.05 mmol m−2 d−1) except in December and January, when CH4 flux was near zero. At times of high rainfall and river flow rate, CH4 emission from the estuarine-influenced Plymouth Sound sector was several times higher than emission from the open-water sector. The implied CH4 saturation (derived from the measured fluxes and a wind-speed-dependent gas transfer velocity parameterization) of over 1000 % in the Plymouth Sound is within range of in situ dissolved CH4 measurements near the mouth of the river Tamar. CO2 flux from the open-water sector was generally from sea to air in autumn and winter and from air to sea in late spring and summer, with an annual mean flux of near zero. A diurnal signal in CO2 flux and implied partial pressure of CO2 in water (pCO2) are clearly observed for the Plymouth Sound sector and also evident for the open-water sector during biologically productive periods. These observations suggest that coastal CO2 efflux may be underestimated if sampling strategies are limited to daytime only. Combining the flux data with seawater pCO2 measurements made in situ within the flux footprint allows us to estimate the CO2 transfer velocity. The gas transfer velocity and wind speed relationship at this coastal location agrees reasonably well with previous open-water parameterizations in the mean but demonstrates considerable variability. We discuss the influences of biological productivity, bottom-driven turbulence and rainfall on coastal air–water gas exchange.

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Review of The ratio of methanogens to methanotrophs and water-level dynamics drive methane exchange velocity in a temperate kettle-hole peat bog

10.5194/bg-2019-116-rc2 ◽

2019 ◽

Author(s):

Anonymous

Keyword(s):

Water Level ◽

Peat Bog ◽

Kettle Hole

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Effects of Plant and Water Level on Nitrogen Variation in Overlying and Pore Water of Agricultural Drainage Ditches in Sanjiang Plain, Northeast China

CLEAN - Soil Air Water ◽

10.1002/clen.201200529 ◽

2013 ◽

Vol 42 (4) ◽

pp. 386-392 ◽

Cited By ~ 5

Author(s):

Yan Zhang ◽

Hui Zhu ◽

Baixing Yan ◽

Xuhui Li ◽

Yang Ou

Keyword(s):

Water Level ◽

Pore Water ◽

Northeast China ◽

Sanjiang Plain ◽

Agricultural Drainage ◽

Drainage Ditches ◽

Agricultural Drainage Ditches

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Unraveling the Gut Microbiome of the Invasive Small Indian Mongoose (Urva auropunctata) in the Caribbean

Microorganisms ◽

10.3390/microorganisms9030465 ◽

2021 ◽

Vol 9 (3) ◽

pp. 465

Author(s):

Anne A. M. J. Becker ◽

KC Hill ◽

Patrick Butaye

Keyword(s):

Relative Abundance ◽

Gut Microbiome ◽

Taxonomic Diversity ◽

Caribbean Islands ◽

Microbial Profile ◽

Vegetation Zones ◽

Males And Females ◽

The Caribbean ◽

Metabolic Properties ◽

Small Indian Mongoose

Small Indian mongooses (Urva auropunctata) are among the most pervasive predators to disrupt the native ecology on Caribbean islands and are strongly entrenched in their areas of introduction. Few studies, however, have considered the microbial ecology of such biological invasions. In this study, we investigated the gut microbiota of invasive small Indian mongooses in terms of taxonomic diversity and functional potential. To this end, we collected fecal samples from 60 free-roaming mongooses trapped in different vegetation zones on the island Saint Kitts. The core gut microbiome, assessed by 16S rRNA amplicon gene sequencing on the Ion S5TM XL platform, reflects a carnivore-like signature with a dominant abundance of Firmicutes (54.96%), followed by Proteobacteria (13.98%) and Fusobacteria (12.39%), and a relatively minor contribution of Actinobacteria (10.4%) and Bacteroidetes (6.40%). Mongooses trapped at coastal sites exhibited a higher relative abundance of Fusobacterium spp. whereas those trapped in scrubland areas were enriched in Bacteroidetes, but there was no site-specific difference in predicted metabolic properties. Between males and females, beta-diversity was not significantly different and no sex-specific strategies for energy production were observed. However, the relative abundance of Gammaproteobacteria, and more specifically, Enterobacteriaceae, was significantly higher in males. This first description of the microbial profile of small Indian mongooses provides new insights into their bioecology and can serve as a springboard to further elucidating this invasive predator’s impact throughout the Caribbean.

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Analysis of Pore Water Pressure and Piping of Hydraulic Well

Water ◽

10.3390/w13040502 ◽

2021 ◽

Vol 13 (4) ◽

pp. 502

Author(s):

Jinman Kim ◽

Heuisoo Han ◽

Yoonhwa Jin

Keyword(s):

Numerical Analysis ◽

Water Level ◽

Pore Water ◽

Large Scale ◽

Pore Water Pressure ◽

Water Pressure ◽

Hydraulic Gradient ◽

Water Levels ◽

Seepage Velocity ◽

Seepage Analysis

This paper shows the results of a field appliance study of the hydraulic well method to prevent embankment piping, which is proposed by the Japanese Matsuyama River National Highway Office. The large-scale embankment experiment and seepage analysis were conducted to examine the hydraulic well. The experimental procedure is focused on the pore water pressure. The water levels of the hydraulic well were compared with pore water pressure data, which were used to look over the seepage variations. Two different types of large-scale experiments were conducted according to the installation points of hydraulic wells. The seepage velocity results by the experiment were almost similar to those of the analyses. Further, the pore water pressure oriented from the water level variations in the hydraulic well showed similar patterns between the experiment and numerical analysis; however, deeper from the surface, the larger pore water pressure of the numerical analysis was calculated compared to the experimental values. In addition, the piping effect according to the water level and location of the hydraulic well was quantitatively examined for an embankment having a piping guide part. As a result of applying the hydraulic well to the point where piping occurred, the hydraulic well with a 1.0 m water level reduced the seepage velocity by up to 86%. This is because the difference in the water level between the riverside and the protected side is reduced, and it resulted in reducing the seepage pressure. As a result of the theoretical and numerical hydraulic gradient analysis according to the change in the water level of the hydraulic well, the hydraulic gradient decreased linearly according to the water level of the hydraulic well. From the results according to the location of the hydraulic well, installation of it at the point where piping occurred was found to be the most effective. A hydraulic well is a good device for preventing the piping of an embankment if it is installed at the piping point and the proper water level of the hydraulic well is applied.

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Geochemistry of intertidal sediment pore waters from the industrialized Santos-Cubatão Estuarine System, SE Brazil

Anais da Academia Brasileira de Ciências ◽

10.1590/s0001-37652012005000021 ◽

2012 ◽

Vol 84 (2) ◽

pp. 427-442 ◽

Cited By ~ 6

Author(s):

Winston F.O. Gonçalves ◽

Wanilson Luiz-Silva ◽

Wilson Machado ◽

Erico C. Nizoli ◽

Ricardo E. Santelli

Keyword(s):

Surface Water ◽

Pore Water ◽

Surface Waters ◽

Water Concentration ◽

Point Sources ◽

Intertidal Sediment ◽

Estuarine System ◽

Pore Waters ◽

Geochemical Composition ◽

Se Brazil

The geochemical composition of sediment pore water was investigated in comparison with the composition of sediment particles and surface water in an estuary within one of the most industrialized areas in Latin America (Santos-Cubatão estuarine system, SE Brazil). Pore and surface waters presented anomalously high levels of F-, NH4+, Fe, Mn and P due to two industrial point sources. In the summer, when SO4(2-)/Cl- ratios suggested an enhanced sulfate reduction, the higher dissolved levels observed in pore waters for some metals (e.g., Cu and Ni) were attributed to reductive dissolution of oxidized phases. Results evidenced that the risks of surface water concentration increase due to diffusion or advection from pore water are probably dependent on coupled influences of tidal pumping and groundwater inputs.

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Regulation of Vegetation and Evapotranspiration by Water Level Fluctuation in Shallow Lakes

Water ◽

10.3390/w13192651 ◽

2021 ◽

Vol 13 (19) ◽

pp. 2651

Author(s):

Qiang Liu ◽

Liqiao Liang ◽

Xiaomin Yuan ◽

Sirui Yan ◽

Miao Li ◽

...

Keyword(s):

Water Level ◽

Open Water ◽

Water Area ◽

Water Level Fluctuation ◽

Water Levels ◽

Water Level Fluctuations ◽

Water Evaporation ◽

Level Fluctuation ◽

Open Water Area ◽

Annual Scale

Water level fluctuations play a critical role in regulating vegetation distribution, composition, cover and richness, which ultimately affect evapotranspiration. In this study, we first explore water level fluctuations and associated impacts on vegetation, after which we assess evapotranspiration (ET) under different water levels. The normalized difference vegetation index (NDVI) was used to estimate the fractional vegetation cover (Fv), while topography- and vegetation-based surface-energy partitioning algorithms (TVET model) and potential evaporation (Ev) were used to calculate ET and water evaporation (Ep). Results show that: (1) water levels were dramatically affected by the combined effect of ecological water transfer and climate change and exhibited significant decreasing trends with a slope of −0.011 m a−2; and (2) as predicted, there was a correlation between water level fluctuation at an annual scale with Phragmites australis (P. australis) cover and open-water area. Water levels also had a controlling effect on Fv values, an increase in annual water levels first increasing and then decreasing Fv. However, a negative correlation was found between Fv values and water levels during initial plant growth stages. (iii) ET, which varied under different water levels at an annual scale, showed different partition into transpiration from P. australis and evaporation from open-water area and soil with alterations between vegetation and open water. All findings indicated that water level fluctuations controlled biological and ecological processes, and their structural and functional characteristics. This study consequently recommends that specifically-focused ecological water regulations (e.g., duration, timing, frequency) should be enacted to maintain the integrity of wetland ecosystems for wetland restoration.

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Modelling marine emissions and atmospheric distributions of halocarbons and DMS: the influence of prescribed water concentration vs. prescribed emissions

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-15-17553-2015 ◽

2015 ◽

Vol 15 (12) ◽

pp. 17553-17598

Author(s):

S. T. Lennartz ◽

G. Krysztofiak-Tong ◽

C. A. Marandino ◽

B.-M. Sinnhuber ◽

S. Tegtmeier ◽

...

Keyword(s):

Wind Speed ◽

Atmospheric Chemistry ◽

Climate Model ◽

Trace Gases ◽

Surface Wind ◽

Water Concentration ◽

Absolute Magnitude ◽

Actual State ◽

Transfer Velocity ◽

Mixing Ratios

Abstract. Marine produced short-lived trace gases such as dibromomethane (CH2Br2), bromoform (CHBr3), methyliodide (CH3I) and dimethylsulfide (DMS) significantly impact tropospheric and stratospheric chemistry. Describing their marine emissions in atmospheric chemistry models as accurately as possible is necessary to quantify their impact on ozone depletion and the Earth's radiative budget. So far, marine emissions of trace gases have mainly been prescribed from emission climatologies, thus lacking the interaction between the actual state of the atmosphere and the ocean. Here we present simulations with the chemistry climate model EMAC with online calculation of emissions based on surface water concentrations, in contrast to directly prescribed emissions. Considering the actual state of the model atmosphere results in a concentration gradient consistent with model real-time conditions at ocean surface and atmosphere, which determine the direction and magnitude of the computed flux. This method has a number of conceptual and practical benefits, as the modelled emission can respond consistently to changes in sea surface temperature, surface wind speed, sea ice cover and especially atmospheric mixing ratio. This online calculation could enhance, dampen or even invert the fluxes (i.e. deposition instead of emissions) of VSLS. We show that differences between prescribing emissions and prescribing concentrations (−28 % for CH2Br2 to +11 % for CHBr3) result mainly from consideration of the actual, time-varying state of the atmosphere. The absolute magnitude of the differences depends mainly on the surface ocean saturation of each particular gas. Comparison to observations from aircraft, ships and ground stations reveals that computing the air–sea flux interactively leads in most of the cases to more accurate atmospheric mixing ratios in the model compared to the computation from prescribed emissions. Calculating emissions online also enables effective testing of different air–sea transfer velocity parameterizations k, which was performed here for eight different parameterizations. The testing of these different k values is of special interest for DMS, as recently published parameterizations derived by direct flux measurements using eddy covariance measurements suggest decreasing k values at high wind speeds or a linear relationship with wind speed. Implementing these parameterizations reduces discrepancies in modelled DMS atmospheric mixing ratios and observations by a factor of 1.5 compared to parameterizations with a quadratic or cubic relationship to wind speed.

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The spatial variation of oxygen condition in carp pond located in nature reserve „Stawy Milickie” / Przestrzenne zróżnicowanie warunków tlenowych w stawie karpiowym położonym w rezerwacie przyrody „Stawy Milickie”

Journal of Water and Land Development ◽

10.2478/jwld-2013-0015 ◽

2013 ◽

Vol 19 (1) ◽

pp. 47-52 ◽

Cited By ~ 1

Author(s):

Bartosz Jawecki ◽

Tomasz Jaroszewicz-Smyk ◽

Andrzej Drabiński

Keyword(s):

Dissolved Oxygen ◽

Spatial Variation ◽

Oxygen Concentration ◽

Water Concentration ◽

Open Water ◽

Average Concentration ◽

Optimum Level ◽

Emergent Plants ◽

Oxygen Conditions ◽

Oxygen Condition

Abstract The paper presents the results of research on the spatial variation of oxygen condition in a carp pond. The analysis of dissolved oxygen was carried out in the summer in 29 measuring points. In the analysed months the differences were determined between dissolved oxygen concentration in the strip of rushes and the part of the pond free from macrophytes. In the strip of rushes, the average concentration of dissolved oxygen was between 4.69-6.49 mg O2·dm-3. In the part of pond located near the strip of rushes the oxygen concentration was between 6.23-7.91 mg O2·dm-3 and in open water concentration of dissolved oxygen was in range 7.60-9.09 mg O2·dm-3. It was found that the biggest differences in oxygen concentration occur between the strip of rushes and the open water column: 40% in June, 26% in July, 28% in August, 38% in September, respectively. In the south-western part of the pond, covered with macrophytes and shaded by trees, the worst oxygen conditions were observed - below the optimum level for carps, sometimes reaching lethal values. The best oxygen conditions, noted in July and August, were in the central and northern part of the pond including the fishery and feeding point. In order to improve the oxygen conditions in macrophytes zone it is recommended to remove the rushes periodically and to remember to leave the part of emergent plants that are necessary for breeding and living avifauna. The scope and timing of the removal of plants has to be consulted and co-ordinated with the Regional Conservator of Nature.

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