Aerobic and anaerobic respiration in profiles of Polesie Lubelskie peatlands

Soil respiration is a very important factor influencing carbon deposition in peat and reflecting the intensity of soil organic matter decomposition, root respiration, and the ease of transporting gases to the surface. Carbon dioxide release from three different peat soil profiles (0-80 cm) of the Polesie Lubelskie Region (Eastern Poland) was analyzed under laboratory conditions. Peat samples were incubated at 5, 10, and 20°C in aerobic and anaerobic environments, and their CO2-evolution was analyzed up to 14 days. The respiration activity was found to be in the range of 0.013-0.497 g CO2 kg-1 DW d-1. The respiratory quotient was estimated to be in the range of 0.51-1.51, and the difference in respiration rates over 10°C ranged between 4.15 and 8.72 in aerobic and from 1.15 to 6.53 in anaerobic conditions. A strong influence of temperature, depth, the degree of peat decomposition, pH, and nitrate content on respiration activity was found. Lack of oxygen at low temperature caused higher respiration activity than under aerobic conditions. These results should be taken into account when the management of Polish peatlands is considered in the context of climate and carbon storage, and physicochemical properties of soil in relation to soil respiration activity are considered

Metanotrofy odpowiedzialne za utlenianie metanu w naturalnych torfowiskach Polesia Lubelskiego

The potential of methanotrophic activity (MTA) has been investigated under labo-ratory conditions in three types of peatland profiles: high (H), transition (T) and low (L) originating from Polesie Lubelskie Region. Selected peat samples differed in respect of pH, TOC, von Post index and moisture. The experiment was conducted at natural moisture (198-719 %w/w) with dif-ferent ranges of both, temperature (5, 10 and 20°C) and CH4 enrichment (1 and 5%v/v). The highest MTA (19.69-155.79 mg CH4kg D.W.-1 d-1) was observed at 20°C. Regardless of temperature, MTA was lower (1.38-51.16 mg CH4 kg D.W.-1 d-1) when peat samples were incubated in atmosphere enriched in 1% than in 5% CH4 v/v (4.75-191.26 mg CH4kg D.W.-1 d-1). Strong influence of tem-perature and sampling sites on MTA was also noted. Total DNA was isolated from the most active (20°C, 5% CH4 v/v) peat samples from each site and the PCR (polimerase chain reaction) amplify-ing of genes pmoA (primers A189f/mb661r) and sequence 16S rRNA (primers Type If /Type Ir and Type IIf/Type IIr) specific for methanotrophic bacteria were carried out. Positive results of PCR with primers of pmoA gene after sequencing confirmed that methanotrophs from L point belong to family Methylococcaceae, while 16S rRNA gene sequences from microorganisms inhabiting H peat demonstrated the highest similarity to genus Methylocystis and Methylosinus.Potencjalna aktywność metanotroficzna (MTA) została wyznaczona w warunkach laboratoryjnych, w torfach pochodzących z torfowisk reprezentujących typy: wysokie (H), przejściowe (T) i niskie (L), zlokalizowanych na obszarze Polesia Lubelskiego. Badane torfowiska różniły się między sobą pod względem: pH, zawartości TOC, indeksem von Posta oraz wilgotności. Inkubacje przeprowadzono wnastępujących warunkach: wilgotność w stanie naturalnym (198-719 %w/w), temperatury: 5, 10 i 20oC, oraz atmosfera wzbogacona w 1 oraz 5% CH4 (v/v). Niezależnie od temperatury, niższe wartosci MTA (1,38-51,16 mg CH4 kg D.W.-1 d-1) wyznaczono dla torfu inkubowanego w atmosferze wzbogaconej o 1% CH4(v/v). Na MTA istotny wpływ wykazywała również temperatura oraz lokalizacja punktu poboru prób. Z najaktywniejszych metanotroficznie torfów (20oC, 5% CH4 v/v) izolowano całkowite DNA , na którym przeprowadzano reakcje PCR powielające fragment genu pmoA (startery A189f/mb661r) oraz sekwencję 16S rRNA (startery Typ If /Typ Ir oraz Typ IIf /Typ IIr), specyficzne dla bakterii metanotroficznych. Pozytywny wynik reakcji PCR ze starterami genu pmoA otrzymano dla materiału pochodzącego ze stanowiska L, sekwencjonowanie wskazało na obecność w tym materiale metanotrofów w największym stopniu podobnych do gatunków z rodziny Methylococcaceae, natomiast na podstawie sekwencji genu 16S rRNA pochodzącego z mikroorganizmów zasiedlających stanowisko H stwierdzono ich duże podobieństwo do przedstawicieli rodzaju Methylocystis i Methylosinus

Selected chemical and physicochemical properties of sediments in Moszne Lake and mire (Polesie National Park)

Properties of peat reflect the peat-forming environment, peat development processes and the types of peat-forming plant. They also enable peat classification and quality evalution. Investigation of the physicochemical properties of organic matter is the key to understanding the history, evolution and geology of bogs. The purpose of this study was to determine some physicochemical properties, such as pH, Eh, electrolytic conductivity, carbon forms in water extracts and dry peat samples (TOC, IC, TC), degree of decomposition, macrofossil plant analysis and ash content, in a whole stratigraphic profile of bog sediment located near Lake Moszne. The research comprised a 17.5 ha lake, which was described in the 1990s as a dystrophic one, and the adjacent mires. The open water surface of the lake is surrounded by a 30–150 m wide belt of floating mat, composed of peatmosses and sedges with the dominant Sphagno-Caricetum rostratae association, all representing vegetation typical for transitional mires. These communities are most often found in the Polesie Lubelskie Region, in old lakes, and usually on their floating mat. The research material was collected from such a site. The analysis demonstrated acidic pH (4.17 in profile I and 4.08 in profile II, respectively) in the layer of 0-0.65 m, whilst from the 1.50 m depth to the mineral bottom the pH increased to nearly neutral (pH = 6.62 ± 0.18 in profile I and pH = 6.45 ± 0.12 in profile II). Redox potential in the surface layer corresponds to good oxygenation of mineral soils: 577 mV and 490 mV for profile I and II, respectively. A nearly linear decrease of Eh was observed to about 118 mV at the depth of 2.50 m. Lower than that, down to the depth of 3.50 m, the Eh value was stabilized. The graphical presentation of the Eh-pH relationship shows that in both cases (profiles I and II) aerobiosis prevails to the depth of 0.45-0.65 m, confirming that oxygen continues to be the final electron acceptor

Selected chemical and physicochemical properties of sediments in Moszne Lake and mire (Polesie National Park)

Properties of peat reflect the peat-forming environment, peat development processes and the types of peat-forming plant. They also enable peat classification and quality evalution. Investigation of the physicochemical properties of organic matter is the key to understanding the history, evolution and geology of bogs. The purpose of this study was to determine some physicochemical properties, such as pH, Eh, electrolytic conductivity, carbon forms in water extracts and dry peat samples (TOC, IC, TC), degree of decomposition, macrofossil plant analysis and ash content, in a whole stratigraphic profile of bog sediment located near Lake Moszne. The research comprised a 17.5 ha lake, which was described in the 1990s as a dystrophic one, and the adjacent mires. The open water surface of the lake is surrounded by a 30–150 m wide belt of floating mat, composed of peatmosses and sedges with the dominant Sphagno-Caricetum rostratae association, all representing vegetation typical for transitional mires. These communities are most often found in the Polesie Lubelskie Region, in old lakes, and usually on their floating mat. The research material was collected from such a site. The analysis demonstrated acidic pH (4.17 in profile I and 4.08 in profile II, respectively) in the layer of 0-0.65 m, whilst from the 1.50 m depth to the mineral bottom the pH increased to nearly neutral (pH = 6.62 ± 0.18 in profile I and pH = 6.45 ± 0.12 in profile II). Redox potential in the surface layer corresponds to good oxygenation of mineral soils: 577 mV and 490 mV for profile I and II, respectively. A nearly linear decrease of Eh was observed to about 118 mV at the depth of 2.50 m. Lower than that, down to the depth of 3.50 m, the Eh value was stabilized. The graphical presentation of the Eh-pH relationship shows that in both cases (profiles I and II) aerobiosis prevails to the depth of 0.45-0.65 m, confirming that oxygen continues to be the final electron acceptor

Methanotroph-derived bacteriohopanepolyol signatures in sediments covering Miocene brown coal deposits

Methanotrophic bacteria (MB) are an important group of microorganisms, involved in the greenhouse gas (GHG) cycles. They are responsible for the utilization of methane, one of the main GHGs, which is released in large amounts (via biogenic and abiogenic processes) during coal formation. This study aimed to determine the main factors affecting the distribution of the MB in two lignite-bearing series of the Turów and Bełchatów coal basins. Distribution of MB in the lignite profiles was studied using methanotroph-specific lipid biomarkers such as amino-bacteriohopanepolyols (NH-BHPs) and C-3 methylated BHPs. BHP results were combined with physical and chemical properties of the studied sediments. In general, lignites were richer in BHPs than the mineral samples, which points to the important role of the intrinsic methane cycling. NH-BHP speciation confirmed that the methanotrophic community of the studied sediments was a combination of both type I and, especially, type II methanotrophs. Based on geological data, it was suggested that elevated temperature during diagenesis intensifies decomposition of methanotroph-specific biomarkers (aminopentol and 3-Me BHT). It was found that the tested BHPs can derive from both fossil and living MB. The presence of metabolically active methanotrophs should therefore be accounted for during studies aimed at using lignite deposits as a source of methane

A survey of greenhouse gases production in central European lignites

Due to changes in the energy market, it is projected that lignite excavation will be reduced in the near future. Cessation of exploitation is associated with restitution of natural water conditions and flooding of the resources left in the mines. Flooded lignite mines are a potential source of greenhouse gases (GHG) (CH4, CO2 and N2O), which should be monitored due to growing environmental concerns. Here, we aim to recognize GHG release from the lignites collected from the main deposits of Poland, Slovenia and Serbia. GHG production was studied along with a range of physical and chemical parameters that are crucial for microbial growth and activity. The microcosm experiments showed that the main gas emitted from the lignites was carbon dioxide. Daily CO2 production was highly variable. The highest values were recorded for detroxylitic lignite collected from the Konin deposit (402.05 nmol CO2 g-1 day-1) while the lowest were for the Kolubara xylitic lignite (19.64 nmol CO2 g-1 day-1). Methane production was much lower and ranged from nearly zero to 66.75 nmol g dry mass-1 d-1. Nitrous oxide production was not detected. It was found that CO2 production, being a general measure of microbial activity, was positively affected by NO3- concentration and redox potential. With respect to methane formation, the lower atmospheric oxygen exposure of the sample from the Velenje underground mine compared to the samples from the opencast mines has been identified as a possible cause of the high methane production. The overall global warming potential (GWP) of the gases released by xylitic lignite was lowest among the samples. Preferential extraction of the detritic lignites is suggested as a means to reduce GHG emissions from the abandoned lignite mines

Microbial involvement in carbon transformation via ch<inf>4</inf> and co<inf>2</inf> in saline sedimentary pool

Methane and carbon dioxide are one of the most important greenhouse gases and significant components of the carbon cycle. Biogeochemical methane transformation may occur even in the extreme conditions of deep subsurface ecosystems. This study presents methane-related biological processes in saline sediments of the Miocene Wieliczka Formation, Poland. Rock samples (W2, W3, and W4) differed in lithology (clayey salt with veins of fibrous salt and lenses of gypsum and anhydrite; siltstone and sandstone; siltstone with veins of fibrous salt and lenses of anhydrite) and the accompanying salt type (spiza salts or green salt). Microbial communities present in the Miocene strata were studied using activity measurements and high throughput sequencing. Biological activity (i.e., carbon dioxide and methane production or methane oxidation) occurred in all of the studied clayey salt and siltstone samples but mainly under water-saturated conditions. Microcosm studies performed at elevated moisture created more convenient conditions for the activity of both methanogenic and methanotrophic microorganisms than the intact sediments. This points to the fact that water activity is an important factor regulating microbial activity in saline subsurface sediments. Generally, respiration was higher in anaerobic conditions and ranged from 36 ± 2 (W2200%t.w.c ) to 48 ± 4 (W3200%t.w.c ) nmol CO2 gdw−1 day−1 . Methanogenic activity was the highest in siltstone and sandstone (W3, 0.025 ± 0.018 nmol CH4 gdw−1 day−1 ), while aerobic methanotrophic activity was the highest in siltstone with salt and anhydrite (W4, 220 ± 66 nmol CH4 gdw−1 day−1 ). The relative abundance of CH4-utilizing microorganisms (Methylomicrobium, Methylomonas, Methylocystis) constituted 0.7–3.6% of all taxa. Methanogens were represented by Methanobacterium (0.01–0.5%). The methane-related microbes were accompanied by a significant number of unclassified microorganisms (3–64%) and those of the Bacillus genus (4.5–91%). The stable isotope composition of the CO2 and CH4 trapped in the sediments suggests that methane oxidation could have influenced δ13CCH4, especially in W3 and W4