scholarly journals In Situ Hydrogen and Nitrous Oxide as Indicators of Concomitant Fermentation and Denitrification in the Alimentary Canal of the Earthworm Lumbricus terrestris

2009 ◽  
Vol 75 (7) ◽  
pp. 1852-1859 ◽  
Author(s):  
Pia K. Wüst ◽  
Marcus A. Horn ◽  
Harold L. Drake
Keyword(s):  
Organic Compounds ◽  
Alimentary Canal ◽  
Lumbricus Terrestris ◽  
High Water ◽  
Total Carbon ◽  
High Water Content ◽  
Microbial Activities ◽  
Mobile Source ◽  
In Situ Conditions

ABSTRACT The earthworm gut is a unique microzone in aerated soils that has been proposed to selectively stimulate ingested soil microorganisms by its in situ conditions, which include anoxia, high water content, a near-neutral pH, and high concentrations of organic compounds. The central objective of this study was to resolve potential links between in situ conditions and anaerobic microbial activities during the gut passage of Lumbricus terrestris. Both H2 and N2O were emitted by living earthworms, and in situ microsensor analyses revealed both H2 and N2O in the O2-free gut center. The highest H2 concentrations occurred in foregut and midgut regions, whereas the highest N2O concentrations occurred in crop/gizzard and hindgut regions. Thus, H2-producing fermentations were more localized in the foregut and midgut, whereas denitrification was more localized in the crop/gizzard and hindgut. Moisture content, total carbon, and total nitrogen were highest in the foregut and decreased from the anterior to posterior end of the gut. Nitrite, ammonium, and iron(II) concentrations were highest in the crop/gizzard and decreased from the anterior to posterior end of the alimentary canal. Concentrations of soluble organic compounds were indicative of distinct fermentation processes along the alimentary canal, with maximal concentrations of organic acids (e.g., acetate and butyrate) occurring in the midgut. These findings suggest that earthworms (i) contribute to the terrestrial cycling of carbon and nitrogen via anaerobic microbial activities in the alimentary canal and (ii) constitute a mobile source of reductant (i.e., emitted H2) for microbiota in aerated soils.

scholarly journals Longevity of seeds and soil seed bank of the Cerrado tree Miconia chartacea (Melastomataceae)

2015 ◽  
Vol 25 (4) ◽  
pp. 386-394 ◽  
Author(s):  
Diego F. Escobar E. ◽  
Victor J. M. Cardoso
Keyword(s):  
Seed Bank ◽  
Low Temperatures ◽  
Rainy Season ◽  
Storage Time ◽  
Soil Seed Bank ◽  
High Water ◽  
Ex Situ ◽  
High Water Content ◽  
Storage Test

AbstractMiconia chartacea is a widely distributed tree in Brazil, occurring at altitudes ranging from 300 m to 1900 m in the Caatinga, Cerrado and Atlantic Forest biomes. In this work we attempted to classify M. chartacea seeds regarding their behaviour during storage and their germination syndrome and to determine, from a storage test in Cerrado soil and laboratory conditions in situ and ex situ, the longevity of seeds, as well as the capacity of the species to form a soil seed bank. The results suggested that M. chartacea seeds form a transient soil seed bank in the Cerrado and can be classified as orthodox in terms of storage behaviour, although the seeds are dispersed with a relatively high water content. The life span of seeds was favoured in soil-stored seeds in comparison with dry storage at 25°C, whereas storage at low temperatures prevented a decrease of the seed's germinability with storage time (330 d). M. chartacea seeds are dispersed during the dry season and germinate during the next rainy season, which can be classified as an intermediate–dry germination syndrome. Seeds of this species are dispersed in the Cerrado when temperatures and soil moisture are relatively low, which favours the formation of a soil seed bank, considering that the seeds tolerate desiccation and their longevity is favoured by low temperatures. A transient seed bank type is favoured by the loss of viability in storage at warm temperatures linked to the rainy season, and the predictable seasonal variations in climate in the region, with germination being restricted to the beginning of the rainy season.

scholarly journals An Improved Cambridge Filter Pad Extraction Methodology to Obtain More Accurate Water and “Tar” Values: In Situ Cambridge Filter Pad Extraction Methodology

2014 ◽  
Vol 26 (2) ◽  
Author(s):  
David Ghosh ◽  
Cyril Jeannet
Keyword(s):  
Particulate Matter ◽  
Water Content ◽  
Extraction Procedure ◽  
High Water ◽  
Limited Range ◽  
High Water Content ◽  
Water Recovery ◽  
Water Losses ◽  
In Situ Extraction

AbstractPrevious investigations by others and internal investigations at Philip Morris International (PMI) have shown that the standard trapping and extraction procedure used for conventional cigarettes, defined in the International Standard ISO 4387 (Cigarettes -- Determination of total and nicotine-free dry particulate matter using a routine analytical smoking machine), is not suitable for high-water content aerosols. Errors occur because of water losses during the opening of the Cambridge filter pad holder to remove the filter pad as well as during the manual handling of the filter pad, and because the commercially available filter pad holder, which is constructed out of plastic, may adsorb water. This results in inaccurate values for the water content, and erroneous and overestimated values for Nicotine Free Dry Particulate Matter (NFDPM). A modified 44 mm Cambridge filter pad holder and extraction equipment which supports in situ extraction methodology has been developed and tested. The principle of the in situ extraction methodology is to avoid any of the above mentioned water losses by extracting the loaded filter pad while kept in the Cambridge filter pad holder which is hermetically sealed by two caps. This is achieved by flushing the extraction solvent numerous times through the hermetically sealed Cambridge filter pad holder by means of an in situ extractor. The in situ methodology showed a significantly more complete water recovery, resulting in more accurate NFDPM values for high-water content aerosols compared to the standard ISO methodology. The work presented in this publication demonstrates that the in situ extraction methodology applies to a wider range of smoking products and smoking regimens, whereas the standard ISO methodology only applies to a limited range of smoking products and smoking regimens, e.g., conventional cigarettes smoked under ISO smoking regimen. In cases where a comparison of yields between the PMI HTP and conventional cigarettes is required the in situ extraction methodology must be used for the aerosol of the PMI HTP to obtain accurate NFDPM/”tar” values. This would be for example the case if there were a need to print “tar” yields on packs or compare yields to ceilings. Failure to use the in situ extraction methodology will result in erroneous and overestimated NFDPM/”tar” values.

scholarly journals IN-SITU BEHAVIOR OF SUPER-HIGH WATER CONTENT CLAY IMPROVED BY PLASTIC BOARD DRAIN

2012 ◽  
Vol 68 (4) ◽  
pp. 583-596 ◽  
Author(s):  
Takao YAMAMOTO ◽  
Satoru SHIBUYA ◽  
Akihiko OHSHIMA ◽  
Tsuneharu ORIHASHI ◽  
Mitsuhiro NAMBU ◽  
...  
Keyword(s):  
Water Content ◽  
High Water ◽  
High Water Content

scholarly journals In Vivo Emission of Dinitrogen by Earthworms via Denitrifying Bacteria in the Gut

2006 ◽  
Vol 72 (2) ◽  
pp. 1013-1018 ◽  
Author(s):  
Marcus A. Horn ◽  
Ralph Mertel ◽  
Matthias Gehre ◽  
Matthias Kästner ◽  
Harold L. Drake
Keyword(s):  
Lumbricus Terrestris ◽  
Denitrifying Bacteria ◽  
Gut Contents ◽  
Emission Rates ◽  
Aporrectodea Caliginosa ◽  
Fresh Weight ◽  
In Situ Conditions ◽  
Incubation Periods

ABSTRACT Earthworms emit the greenhouse gas nitrous oxide (N2O), and ingested denitrifiers in the gut appear to be the main source of this N2O. The primary goal of this study was to determine if earthworms also emit dinitrogen (N2), the end product of complete denitrification. When [15N]nitrate was injected into the gut, the earthworms Aporrectodea caliginosa and Lumbricus terrestris emitted labeled N2 (and also labeled N2O) under in vivo conditions; emission of N2 by these two earthworms was relatively linear and approximated 1.2 and 6.6 nmol N2 per h per g (fresh weight), respectively. Isolated gut contents also produced [15N]nitrate-derived N2 and N2O under anoxic conditions. N2 is formed by N2O reductase, and acetylene, an inhibitor of this enzyme, inhibited the emission of [15N]nitrate-derived N2 by living earthworms. Standard gas chromatographic analysis demonstrated that the amount of N2O emitted was relatively linear during initial incubation periods and increased in response to acetylene. The calculated rates for the native emissions of N2 (i.e., without added nitrate) by A. caliginosa and L. terrestris were 1.1 and 1.5 nmol N2 per h per g (fresh weight), respectively; these emission rates approximated that of N2O. These collective observations indicate that (i) earthworms emit N2 concomitant with the emission of N2O via the in situ activity of denitrifying bacteria in the gut and (ii) N2O is quantitatively an important denitrification-derived end product under in situ conditions.

scholarly journals The Earthworm Gut: an Ideal Habitat for Ingested N2O-Producing Microorganisms

2003 ◽  
Vol 69 (3) ◽  
pp. 1662-1669 ◽  
Author(s):  
Marcus A. Horn ◽  
Andreas Schramm ◽  
Harold L. Drake
Keyword(s):  
Organic Carbon ◽  
Water Content ◽  
Soil Bacteria ◽  
Synergistic Effects ◽  
Posterior Part ◽  
Total Carbon ◽  
Gut Contents ◽  
In Situ Conditions ◽  
Earthworm Gut

ABSTRACT The in vivo production of nitrous oxide (N2O) by earthworms is due to their gut microbiota, and it is hypothesized that the microenvironment of the gut activates ingested N2O-producing soil bacteria. In situ measurement of N2O and O2 with microsensors demonstrated that the earthworm gut is anoxic and the site of N2O production. The gut had a pH of 6.9 and an average water content of approximately 50%. The water content within the gut decreased from the anterior end to the posterior end. In contrast, the concentration of N2O increased from the anterior end to the mid-gut region and then decreased along the posterior part of the gut. Compared to the soil in which worms lived and fed, the gut of the earthworm was highly enriched in total carbon, organic carbon, and total nitrogen and had a C/N ratio of 7 (compared to a C/N ratio of 12 in soil). The aqueous phase of gut contents contained up to 80 mM glucose and numerous compounds that were indicative of anaerobic metabolism, including up to 9 mM formate, 8 mM acetate, 3 mM lactate, and 2 mM succinate. Compared to the soil contents, nitrite and ammonium were enriched in the gut up to 10- and 100-fold, respectively. The production of N2O by soil was induced when the gut environment was simulated in anoxic microcosms for 24 h (the approximate time for passage of soil through the earthworm). Anoxia, high osmolarity, nitrite, and nitrate were the dominant factors that stimulated the production of N2O. Supplemental organic carbon had a very minimal stimulatory effect on the production of N2O, and addition of buffer or ammonium had essentially no effect on the initial N2O production rates. However, a combination of supplements yielded rates greater than that obtained mathematically for single supplements, suggesting that the maximum rates observed were due to synergistic effects of supplements. Collectively, these results indicate that the special microenvironment of the earthworm gut is ideally suited for N2O-producing bacteria and support the hypothesis that the in situ conditions of the earthworm gut activate ingested N2O-producing soil bacteria during gut passage.

Vertical distribution and abundance of pelagic cnidarians in the eastern Weddell Sea, Antarctica

1997 ◽  
Vol 77 (2) ◽  
pp. 341-360 ◽  
Author(s):  
P.R. Pugh ◽  
F. Pages ◽  
B. Boorman
Keyword(s):  
Species Composition ◽  
Vertical Distribution ◽  
Water Content ◽  
High Water ◽  
Weddell Sea ◽  
Total Carbon ◽  
High Water Content ◽  
Eastern Weddell Sea

The species composition, abundance and vertical distribution of micronektonic cnidarians has been investigated in the upper 2800 m at Discovery Station 9969, located in the cold regime in the eastern Weddell Sea, Antarctica. In total 22 siphonophore and 20 medusan species were identified. Overall siphonophores were more abundant than medusae, but the latter usually contributed much more to the biovolume. On average, cnidarians contributed more than 50% to the total biovolume of each catch; and they contributed >70% to the combined total of all the samples. Despite the high water content of these animals, these large biovolumes meant that the cnidarians formed ∼25% of the total carbon in each catch. The possible impact of these gelatinous cnidarian populations on the ecosystem is discussed.

scholarly journals Improving carbon product yields in biocarbon production by combining pyrolysis and anaerobic digestion

BioResources ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. 3964-3977
Author(s):  
Cornelis van der Wijst ◽  
Nirmal Ghimire ◽  
Wenche Hennie Bergland ◽  
Kai Toven ◽  
Rune Bakke ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Energy Content ◽  
High Water ◽  
Raw Material ◽  
Total Carbon ◽  
High Water Content ◽  
Promising Tool ◽  
Carbon Recovery ◽  
Intermediate Pyrolysis ◽  
Carbon Losses

Solid carbon is an important raw material in industrial processes. Most of the charcoal produced today is via conventional carbonization, which suffers from huge carbon losses due to system inefficiency. Intermediate pyrolysis is principally similar to conventional carbonization and produces biocarbon while capturing the off gasses; among these off gasses is aqueous condensate, which is difficult to utilize due to the high water content and low energy content. This fraction can contain up to 25% of the carbon from feedstock, so utilization of this fraction is important for good overall carbon balance. Anaerobic digestion can be a promising tool for utilizing the carbon in the aqueous condensate by converting it into biomethane. Here, birch and spruce wood were pyrolyzed and the biomethane potential for the aqueous condensates was tested. The mass and carbon balances of the pyrolysis products of birch and spruce at two pyrolysis temperatures were performed, and biocarbon carbon yields ranging from 42% to 54% were obtained. Anaerobic digestion of the aqueous phases collected from the pyrolysis process was performed, with carbon recovery yields between 44% and 59%. A total carbon recovery of 77.8% to 85.7% was obtained, and the primary carbon losses were identified.

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