Organic matter quality structures benthic fatty acid patterns and the abundance of fungi and bacteria in temperate lakes

Humping/hollowing and flipping are land development practices widely used on the West Coast to overcome waterlogging constraints to pasture production. However, there is very limited information about how the resulting "new" soils function and how their properties change over time following these extreme modifications. We hypothesised that soil quality will improve in response to organic matter inputs from plants and excreta, which will in turn increase nutrient availability. We tested this hypothesis by quantifying the soil organic matter and nutrient content of soils at different stages of development after modification. We observed improvements in soil quality with increasing time following soil modification under both land development practices. Total soil C and N values were very low following flipping, but over 8 years these values had increased nearly five-fold. Other indicators of organic matter quality such as hot water extractable C (HWC) and anaerobically mineralisable N (AMN) showed similar increases. With large capital applications of superphosphate fertiliser to flipped soils in the first year and regular applications of maintenance fertiliser, Olsen P levels also increased from values

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Impacts of long-term plant residue management on soil organic matter quality, Pseudomonas community structure and disease suppressiveness

Soil Biology and Biochemistry ◽

10.1016/j.soilbio.2019.05.020 ◽

2019 ◽

Vol 135 ◽

pp. 396-406 ◽

Cited By ~ 7

Author(s):

Bryony E.A. Dignam ◽

Maureen O'Callaghan ◽

Leo M. Condron ◽

Jos M. Raaijmakers ◽

George A. Kowalchuk ◽

...

Keyword(s):

Organic Matter ◽

Community Structure ◽

Soil Organic Matter ◽

Residue Management ◽

Plant Residue ◽

Organic Matter Quality ◽

Soil Organic Matter Quality

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Particle export fluxes to the oxygen minimum zone of the eastern tropical North Atlantic

Biogeosciences ◽

10.5194/bg-14-1825-2017 ◽

2017 ◽

Vol 14 (7) ◽

pp. 1825-1838 ◽

Cited By ~ 12

Author(s):

Anja Engel ◽

Hannes Wagner ◽

Frédéric A. C. Le Moigne ◽

Samuel T. Wilson

Keyword(s):

Organic Matter ◽

North Atlantic ◽

Organic Phosphorus ◽

Euphotic Zone ◽

Carbon Export ◽

Organic Matter Quality ◽

B Values ◽

Chl A ◽

Tropical North Atlantic ◽

Particle Export

Abstract. In the ocean, sinking of particulate organic matter (POM) drives carbon export from the euphotic zone and supplies nutrition to mesopelagic communities, the feeding and degradation activities of which in turn lead to export flux attenuation. Oxygen (O2) minimum zones (OMZs) with suboxic water layers (< 5 µmol O2 kg−1) show a lower carbon flux attenuation compared to well-oxygenated waters (> 100 µmol O2 kg−1), supposedly due to reduced heterotrophic activity. This study focuses on sinking particle fluxes through hypoxic mesopelagic waters (< 60 µmol O2 kg−1); these represent ∼  100 times more ocean volume globally compared to suboxic waters, but they have less been studied. Particle export fluxes and attenuation coefficients were determined in the eastern tropical North Atlantic (ETNA) using two surface-tethered drifting sediment trap arrays with seven trapping depths located between 100 and 600 m. Data on particulate matter fluxes were fitted to the normalized power function Fz =  F100 (z∕100)−b, with F100 being the flux at a depth (z) of 100 m and b being the attenuation coefficient. Higher b values suggest stronger flux attenuation and are influenced by factors such as faster degradation at higher temperatures. In this study, b values of organic carbon fluxes varied between 0.74 and 0.80 and were in the intermediate range of previous reports, but lower than expected from seawater temperatures within the upper 500 m. During this study, highest b values were determined for fluxes of particulate hydrolyzable amino acids (PHAA), followed by particulate organic phosphorus (POP), nitrogen (PN), carbon (POC), chlorophyll a (Chl a) and transparent exopolymer particles (TEP), pointing to a sequential degradation of organic matter components during sinking. Our study suggests that in addition to O2 concentration, organic matter composition co-determines transfer efficiency through the mesopelagic. The magnitude of future carbon export fluxes may therefore also depend on how organic matter quality in the surface ocean changes under influence of warming, acidification and enhanced stratification.

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Characterization of Aeromonas genomic species by using quinone, polyamine, and fatty acid patterns

Canadian Journal of Microbiology ◽

10.1139/m94-134 ◽

1994 ◽

Vol 40 (10) ◽

pp. 844-850 ◽

Cited By ~ 11

Author(s):

Peter Kämpfer ◽

Klaus Blasczyk ◽

Georg Auling

Keyword(s):

Fatty Acids ◽

Fatty Acid ◽

Octadecenoic Acid ◽

Hexadecenoic Acid ◽

Genomic Species ◽

Great Homogeneity ◽

Hydroxylated Fatty Acids ◽

Fatty Acid Patterns ◽

Chemotaxonomic Study

A chemotaxonomic study was carried out on representative strains of 13 Aeromonas genomic species. Quinone, polyamine, and fatty acid patterns were found to be very useful for an improved characterization of the genus and an improved differentiation from members of the families Enterobacteriaceae and Vibrionaceae. The Q-8-benzoquinone was the predominant ubiquinone, and putrescine and diaminopropane were the major poly amines of the genus. The fatty acid patterns of 181 strains, all characterized by DNA–DNA hybridization, showed a great homogeneity within the genus, with major amounts of hexadecanoic acid (16:0), hexadecenoic acid (16:1), and octadecenoic acid (18:1), and minor amounts of the hydroxylated fatty acids (3-OH 13:0, 2-OH 14:0, 3-OH 14:0) in addition to some iso and anteiso branched fatty acids (i-13:0, i-17:1, i-17:0, and a-17:0). Although some differences in fatty acid profiles between the genomic species could be observed, a clearcut differentiation of all species was not possible.Key words: Aeromonas, polyamines, quinones, fatty acids, differentiation.

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Methyl mercury in zooplanktonthe role of size, habitat, and food quality

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f02-125 ◽

2002 ◽

Vol 59 (10) ◽

pp. 1606-1615 ◽

Cited By ~ 38

Author(s):

Martin Kainz ◽

Marc Lucotte ◽

Christopher C Parrish

Keyword(s):

Organic Matter ◽

Fatty Acid ◽

Body Size ◽

Methyl Mercury ◽

Size Fraction ◽

Food Sources ◽

Calanoid Copepods ◽

Bacterial Food

Pathways of methyl mercury (MeHg) accumulation in zooplankton include ingestion of organic matter (OM). We analyzed fatty acid (FA) biomarkers in zooplankton to (i) investigate the effect of allochthonous and autochthonous OM ingestion on MeHg concentrations ([MeHg]) in zooplankton and (ii) examine how algal and bacterial food sources affect MeHg bioaccumulation. We partitioned bulk zooplankton samples (i.e., >500, 202, 100, and 53 μm) from Lake Lusignan (Québec) and measured [MeHg] and [FA] in each fraction. [MeHg] increased with increasing body size and was significantly higher in pelagic than in littoral macrozooplankton (>500 μm). The amount of the ingested terrestrial FA biomarker 24:0 indicated that less than 1% of the total FA in zooplankton was derived from allochthonous sources. More than 60% of the ingested FA originated from algal biomarkers and <10% from bacterial biomarkers. Relative amounts of algal-derived essential FA and bacterial FA were not associated with [MeHg] in any size fraction. In pelagic zones, the amount of MeHg in zooplankton related positively to the number of large organisms such as Calanoid copepods and Daphnia. We propose that the accumulation of MeHg in lacustrine zooplankton depends on the zooplankton habitat rather than on the quality of ingested food.

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