scholarly journals Fine scale variability in methanol uptake and oxidation in the micro-layer and near-surface waters of the Atlantic

2012 ◽  
Vol 9 (4) ◽  
pp. 4513-4542
Author(s):  
J. L. Dixon ◽  
P. D. Nightingale
Keyword(s):  
Methanol Oxidation ◽  
Surface Waters ◽  
Significant Relationship ◽  
Heterotrophic Bacteria ◽  
Energy Generation ◽  
Cellular Growth ◽  
Leucine Incorporation ◽  
Marine Microbes ◽  
Near Surface ◽  
Uptake Rates

Abstract. The aim of this research was to make the first depth profiles of the microbial assimilation of methanol carbon, and its oxidation to carbon dioxide and use as an energy source from the micro-layer to 1000 m. Some of the highest reported methanol oxidation rate constants of 0.5–0.6 d−1 were occasionally found in the micro-layer, and immediately underlying waters (10 cm depth), albeit these samples also showed the greatest heterogeneity compared to other depths down to 1000 m. Methanol uptake into the particulate phase was exceptionally low in micro-layer samples, suggesting that any methanol utilised by microbes in this environment is for energy generation. The sea surface micro-layer and 10 cm depth also showed a higher proportion of bacteria with a low DNA content, and bacterial leucine uptake rates in surface micro-layer samples were either less than, or the same as those in the underlying 10 cm layer. The average methanol oxidation and particulate rates were however statistically the same throughout the depths sampled, although the later were highly variable in the near surface 0.25–2 m compared to deeper depths. The statistically significant relationship demonstrated between uptake of methanol into particles and bacterial leucine incorporation suggests that heterotrophic bacteria use methanol carbon for cellular growth, but the lack of relationships observed with methanol oxidation, perhaps suggest that a wider group of marine microbes use methanol for energy generation. Whilst the statistically significant relationship observed between the uptake of methanol into cell particles and the numbers of Prochlorococcus during diel experiments could also suggest that this abundant group of marine cyanobacteria are capable of mixotrophy, using methanol as a carbon source for growth. We conclude that microbial methanol uptake rates, i.e., loss from seawater are highly variable, particularly close to the seawater surface, which could significantly impact upon seawater concentrations and hence the air-sea flux.

scholarly journals Fine-scale variability in methanol uptake and oxidation: from the microlayer to 1000 m

2012 ◽  
Vol 9 (8) ◽  
pp. 2961-2972 ◽  
Author(s):  
J. L. Dixon ◽  
P. D. Nightingale
Keyword(s):  
Methanol Oxidation ◽  
Heterotrophic Bacteria ◽  
Growth Efficiency ◽  
Cellular Growth ◽  
Bacterial Growth Efficiency ◽  
Leucine Incorporation ◽  
Surface Microlayer ◽  
Near Surface ◽  
Sea Surface Microlayer ◽  
Uptake Rates

Abstract. The aim of this research was to make the first depth profiles of the microbial assimilation of methanol carbon and its oxidation to carbon dioxide and use as an energy source from the microlayer to 1000 m. Some of the highest reported methanol oxidation rate constants of 0.5–0.6 d−1 were occasionally found in the microlayer and immediately underlying waters (10 cm depth), albeit these samples also showed the greatest heterogeneity compared to other depths down to 1000 m. Methanol uptake into the particulate phase was exceptionally low in microlayer samples, suggesting that any methanol utilised by microbes in this environment is for energy generation. The sea surface microlayer and 10 cm depth also showed a higher proportion of bacteria with a low DNA content, and bacterial leucine uptake rates in surface microlayer samples were either less than or the same as those in the underlying 10 cm layer. The average methanol oxidation and particulate rates were however statistically the same throughout the depths sampled, although the latter were highly variable in the near-surface 0.25–2 m compared to deeper depths. The statistically significant relationship demonstrated between uptake of methanol into particles and bacterial leucine incorporation suggests that many heterotrophic bacteria could be using methanol carbon for cellular growth. On average, methanol bacterial growth efficiency (BGEm) in the top 25 m of the water column is 6% and decreases with depth. Although, for microlayer and 10 cm-depth samples, BGEm is less than the near-surface 25–217 cm, possibly reflecting increased environmental UV stress resulting in increased maintenance costs, i.e. energy required for survival. We conclude that microbial methanol uptake rates, i.e. loss from seawater, are highly variable, particularly close to the seawater surface, which could significantly impact upon seawater concentrations and hence the air–sea flux.

scholarly journals Cytochrome P450 Monooxygenase-Mediated Metabolic Utilization of Benzo[a]Pyrene by Aspergillus Species

mBio ◽  
2019 ◽  
Vol 10 (3) ◽  
Author(s):  
Erin M. Ostrem Loss ◽  
Mi-Kyung Lee ◽  
Ming-Yueh Wu ◽  
Julia Martien ◽  
Wanping Chen ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Environmental Pollutants ◽  
Energy Generation ◽  
Fungal Species ◽  
Metabolic Changes ◽  
Cytochrome P450 Monooxygenase ◽  
Cellular Growth ◽  
P450 Monooxygenase ◽  
Content Type ◽  
Fundamental Knowledge

ABSTRACT Soil-dwelling fungal species possess the versatile metabolic capability to degrade complex organic compounds that are toxic to humans, yet the mechanisms they employ remain largely unknown. Benzo[a]pyrene (BaP) is a pervasive carcinogenic contaminant, posing a significant concern for human health. Here, we report that several Aspergillus species are capable of degrading BaP. Exposing Aspergillus nidulans cells to BaP results in transcriptomic and metabolic changes associated with cellular growth and energy generation, implying that the fungus utilizes BaP as a growth substrate. Importantly, we identify and characterize the conserved bapA gene encoding a cytochrome P450 monooxygenase that is necessary for the metabolic utilization of BaP in Aspergillus. We further demonstrate that the fungal NF-κB-type velvet regulators VeA and VelB are required for proper expression of bapA in response to nutrient limitation and BaP degradation in A. nidulans. Our study illuminates fundamental knowledge of fungal BaP metabolism and provides novel insights into enhancing bioremediation potential. IMPORTANCE We are increasingly exposed to environmental pollutants, including the carcinogen benzo[a]pyrene (BaP), which has prompted extensive research into human metabolism of toxicants. However, little is known about metabolic mechanisms employed by fungi that are able to use some toxic pollutants as the substrates for growth, leaving innocuous by-products. This study systemically demonstrates that a common soil-dwelling fungus is able to use benzo[a]pyrene as food, which results in expression and metabolic changes associated with growth and energy generation. Importantly, this study reveals key components of the metabolic utilization of BaP, notably a cytochrome P450 monooxygenase and the fungal NF-κB-type transcriptional regulators. Our study advances fundamental knowledge of fungal BaP metabolism and provides novel insight into designing and implementing enhanced bioremediation strategies.

scholarly journals Comparison of dry and wet deposition of particulate matter in near-surface waters during summer

PLoS ONE ◽  
2018 ◽  
Vol 13 (6) ◽  
pp. e0199241 ◽  
Author(s):  
Yanan Wu ◽  
Jiakai Liu ◽  
Jiexiu Zhai ◽  
Ling Cong ◽  
Yu Wang ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Surface Waters ◽  
Wet Deposition ◽  
Near Surface ◽  
Dry And Wet Deposition

Near-Surface Gas-Phase Methoxymethanol Is Generated by Methanol Oxidation over Pd-Based Catalysts

2021 ◽  
pp. 11252-11258
Author(s):  
Sadi M. Gurses ◽  
Trevor Price ◽  
Angie Zhang ◽  
Jonathan H. Frank ◽  
Nils Hansen ◽  
...  
Keyword(s):  
Gas Phase ◽  
Methanol Oxidation ◽  
Near Surface

The distribution and abundance of viruses in the Southern Ocean during spring

2000 ◽  
Vol 12 (4) ◽  
pp. 414-417 ◽  
Author(s):  
Harvey Marchant ◽  
Andrew Davidson ◽  
Simon Wright ◽  
John Glazebrook
Keyword(s):  
Southern Ocean ◽  
Sea Ice ◽  
Surface Waters ◽  
Significant Relationship ◽  
Polar Front ◽  
Open Ocean ◽  
Bacterial Concentration ◽  
Viral Abundance ◽  
Chroococcoid Cyanobacteria ◽  
Bacterial Concentrations

The concentrations of viruses, bacteria, chroococcoid cyanobacteria and chlorophyll a were determined in surface waters of the Southern Ocean during spring. Viral concentrations declined southward from around 4 × 106 ml−1 near Tasmania to a minimum of around 1 × 106 ml−1 at the Polar Front. South of the Front, virus concentrations increased again, reaching around 4 × 106 ml−1 in the sea-ice zone south of 60°S. Bacterial concentration decreased southwards across the Southern Ocean from around 6.5 × 105 ml−1 near Tasmania to < 1.0 × 105 ml−1 in the sea-ice zone. Cyanobacteria accounted for < 8% of the prokaryotes. There was no significant relationship between viral abundance and eithercyanobacterial or chl a concentration. Viral and bacterial concentrations were not significantly correlated north (P {0.10 < r < 0.20}) or south (P {0.20 < r < 0.5}) of the Polar Front. The virus to bacteria ratio (VBR) was between 3 and 15 in the open ocean but varied between 15 and 40 in the sea-ice region. These virus concentrations and VBRs indicate that viruses are no less important in Southern Ocean ecosystems than elsewhere in the world's oceans.

scholarly journals Environmental control on the variability of DMS and DMSP in the Mauritanian upwelling region

2012 ◽  
Vol 9 (3) ◽  
pp. 1041-1051 ◽  
Author(s):  
C. Zindler ◽  
I. Peeken ◽  
C. A. Marandino ◽  
H. W. Bange
Keyword(s):  
Surface Waters ◽  
Coastal Upwelling ◽  
Environmental Control ◽  
Hot Spot ◽  
Local Source ◽  
Surface Seawater ◽  
Near Surface ◽  
Northwest Africa ◽  
N:P Ratios ◽  
A Minor

Abstract. Dimethylsulphide (DMS) and dissolved and particulate dimethylsulfoniopropionate (DMSPd, DMSPp) were measured in near-surface waters along the Mauritanian coast, Northwest Africa, during the upwelling season in February 2008. DMS, DMSPd and DMSPp surface concentrations of up to 10 nmol L−1, 15 nmol L−1 and 990 nmol L−1, respectively, were measured. However, the DMS concentrations measured are in the low range compared to other upwelling regions. The maximum DMSPp concentration is the highest reported from upwelling regions so far, which might indicate that the Mauritanian upwelling is a hot spot for DMSP. Within the phytoplankton groups, dinoflagellates were identified as important contributors to DMS concentrations, while other algae seemed to have only a minor or no influence on DMS and DMSP concentrations. A pronounced switch from high DMSP to high DMS concentrations was observed when the nitrogen to phosphorus ratio (N:P) was below 7. The high DMS/DMSP ratios at N:P ratios <7 indicate that nitrogen limitation presumably triggered a switch from DMSP to DMS independent of the species composition. Our results underline the importance of coastal upwelling regions as a local source for surface seawater sulphur.

scholarly journals Radiocesium in the Taiwan Strait and the Kuroshio east of Taiwan from 2018 to 2019

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Wei-Jen Huang ◽  
Ming-Ta Lee ◽  
Kuei-Chen Huang ◽  
Kai-Jung Kao ◽  
Ming-An Lee ◽  
...  
Keyword(s):  
Water Column ◽  
Surface Waters ◽  
Half Life ◽  
North Pacific Ocean ◽  
Taiwan Strait ◽  
Depth Range ◽  
Near Surface ◽  
Activity Concentrations ◽  
The Taiwan Strait ◽  
The Kuroshio

AbstractThe release of anthropogenic radiocesium to the North Pacific Ocean (NPO) has occurred in the past 60 years. Factors controlling 137Cs (half-life, 30.2 year) and 134Cs (half-life, 2.06 year) activity concentrations in the Kuroshio east of Taiwan and the Taiwan Strait (latitude 20° N–27° N, longitude 116° E–123° E) remain unclear. This study collected seawater samples throughout this region and analyzed 134Cs and 137Cs activity concentrations between 2018 and 2019. A principal component analysis (PCA) was performed to analyze the controlling factors of radiocesium. Results of all 134Cs activity concentrations were below the detection limit (0.5 Bq m−3). Analyses of water column 137Cs profiles revealed a primary concentration peak (2.1–2.2 Bq m−3) at a depth range of 200–400 m (potential density σθ: 25.3 to 26.1 kg m−3). The PCA result suggests that this primary peak was related to density layers in the water column. A secondary 137Cs peak (1.90 Bq m−3) was observed in the near-surface waters (σθ = 18.8 to 21.4 kg m−3) and was possibly related to upwelling and river-to-sea mixing on the shelf. In the Taiwan Strait, 137Cs activity concentrations in the near-surface waters were higher in the summer than in the winter. We suggest that upwelling facilitates the vertical transport of 137Cs at the shelf break of the western NPO.

scholarly journals A Method for Processing Acoustic Doppler Current Profiler Velocity Data from Towed, Undulating Vehicles

2008 ◽  
Vol 25 (9) ◽  
pp. 1710-1716 ◽  
Author(s):  
Jiayi Pan ◽  
David A. Jay
Keyword(s):  
Surface Waters ◽  
High Frequency ◽  
Acoustic Doppler Current Profiler ◽  
Small Time ◽  
Ocean Current ◽  
Near Surface ◽  
Vertical Range ◽  
External Reference ◽  
Current Profiler ◽  
Adcp Measurements

Abstract The utility of the acoustic Doppler current profiler (ADCP) for sampling small time and space scales of coastal environments can be enhanced by mounting a high-frequency (1200 kHz) ADCP on an oscillating towed body. This approach requires both an external reference to convert the measured shears to velocities in the earth coordinates and a method to determine the towed body velocities. During the River Influence on the Shelf Ecosystems (RISE) project cruise, a high-frequency (1200 kHz) and narrowbeam ADCP with mode 12 sampling was mounted on a TRIAXUS oscillating towfish, which steers a 3D path behind the ship. This deployment approach extended the vertical range of the ADCP and allowed it to sample near-surface waters outside the ship’s wake. The measurements from a ship-mounted 1200-kHz narrowbeam ADCP are used as references for TRIAXUS ADCP data, and a method of overlapping bins is employed to recover the entire vertical range of the TRIAXUS ADCP. The TRIAXUS vehicle horizontal velocities are obtained by removing the derived ocean current velocity from the TRIAXUS ADCP measurements. The results show that the method is practical.

scholarly journals The Weathering Microbiome of an Outcropping Granodiorite

2020 ◽  
Vol 11 ◽  
Author(s):  
Stephanie A. Napieralski ◽  
Eric E. Roden
Keyword(s):  
Essential Elements ◽  
Cellular Growth ◽  
Metabolic Energy ◽  
Microbial Consortia ◽  
Extracellular Electron Transfer ◽  
Silicate Mineral ◽  
Near Surface ◽  
Natural Systems ◽  
Luquillo Mountains ◽  
Metabolic Energy Generation

Microorganisms have long been recognized for their capacity to catalyze the weathering of silicate minerals. While the vast majority of studies on microbially mediated silicate weathering focus on organotrophic metabolism linked to nutrient acquisition, it has been recently demonstrated that chemolithotrophic ferrous iron [Fe(II)] oxidizing bacteria (FeOB) are capable of coupling the oxidation of silicate mineral Fe(II) to metabolic energy generation and cellular growth. In natural systems, complex microbial consortia with diverse metabolic capabilities can exist and interact to influence the biogeochemical cycling of essential elements, including iron. Here we combine microbiological and metagenomic analyses to investigate the potential interactions among metabolically diverse microorganisms in the near surface weathering of an outcrop of the Rio Blanco Quartz Diorite (DIO) in the Luquillo Mountains of Puerto Rico. Laboratory based incubations utilizing ground DIO as metabolic energy source for chemolithotrophic FeOB confirmed the ability of FeOB to grow via the oxidation of silicate-bound Fe(II). Dramatically accelerated rates of Fe(II)-oxidation were associated with an enrichment in microorganisms with the genetic capacity for iron oxidizing extracellular electron transfer (EET) pathways. Microbially oxidized DIO displayed an enhanced susceptibility to the weathering activity of organotrophic microorganisms compared to unoxidized mineral suspensions. Our results suggest that chemolithotrophic and organotrophic microorganisms are likely to coexist and contribute synergistically to the overall weathering of the in situ bedrock outcrop.

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