Fulvic acid: A key factor governing mercury bioavailability in a polluted plateau wetland

Abstract The timing and length of the dry season is a key factor governing ecosystem productivity and the carbon cycle of the tropics. Mounting evidence has suggested a lengthening of the dry season with ongoing climate change. However, this conclusion is largely based on changes in precipitation (P) compared to its long-term average (P ̅) and lacks consideration of the simultaneous changes in ecosystem water demand (measured by potential evapotranspiration, Ep, or actual evapotranspiration, E). Using several long-term (1979-2018) observational datasets, we compared changes in tropical dry season length (DSL) and timing (dry season arrival, DSA, and dry season end, DSE) among three common metrics used to define the dry season: P < P ̅, P < Ep, and P < E. We found that all three definitions show that dry seasons have lengthened in much of the tropics since 1979. Among the three definitions, P < E estimates the largest fraction (49.0%) of tropical land area likely experiencing longer dry seasons, followed by P < Ep (41.4%) and P < P ̅ (34.4%). The largest differences in multi-year mean DSL (> 120 days) among the three definitions occurred in the most arid and the most humid regions of the tropics. All definitions and datasets consistently showed longer dry seasons in southern Amazon (due to delayed DSE) and central Africa (due to both earlier DSA and delayed DSE). However, definitions that account for changing water demand estimated longer DSL extension over those two regions. These results indicate that warming-enhanced evapotranspiration exacerbates dry season lengthening and ecosystem water deficit. Thus, it is necessity to account for the evolving water demand of tropical ecosystems when characterizing changes in seasonal dry periods and ecosystem water deficits in an increasingly warmer and drier climate.

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Temperate carbonate cycling and water mass properties from intertidal to bathyal depths (Azores, N-Atlantic)

Biogeosciences Discussions ◽

10.5194/bgd-7-3297-2010 ◽

2010 ◽

Vol 7 (3) ◽

pp. 3297-3333 ◽

Cited By ~ 1

Author(s):

M. Wisshak ◽

A. Form ◽

J. Jakobsen ◽

A. Freiwald

Keyword(s):

Cold Water ◽

Light Availability ◽

Euphotic Zone ◽

Carbonate Production ◽

Carbonate Budget ◽

Mass Properties ◽

Accretion Rates ◽

Key Factor ◽

Temperate Carbonate ◽

Factor Governing

Abstract. The rugged submarine topography of the Azores supports a diverse heterozoan association resulting in intense biotically-controlled carbonate production and accumulation. In order to characterise this cold-water (C) factory a 2-year experiment was carried out to study the biodiversity of hardground communities and for budgeting carbonate production and degradation along a bathymetrical transect from the intertidal to bathyal 500 m depth. Seasonal temperatures peak in September (above a thermocline) and bottom in March (stratification diminishes) with a decrease in amplitude and absolute values with depth, and with tidal-driven short-term fluctuations. Measured seawater stable isotope ratios and levels of dissolved nutrients decrease with depth, as do the calcium carbonate saturation states. The photosynthetic active radiation shows a base of the euphotic zone in ~70 m and a dysphotic limit in ~150 m depth. Bioerosion, being primarily a function of light availability for phototrophic endoliths and grazers feeding upon them, is ~10 times stronger on the illuminated upside versus the shaded underside of substrates in the photic zone, with maximum rates in the intertidal (−631 g/m2/yr). Rates rapidly decline towards deeper waters where bioerosion and carbonate accretion are slow and epibenthic/endolithic communities take years to mature. Accretion rates are highest in the lower euphotic zone (955 g/m2/yr), where the substrate is less prone to hydrodynamic force. Highest rates are found – inversely to bioerosion – on downward facing substrates, suggesting that bioerosion may be a key factor governing the preferential settlement and growth of calcareous epilithobionts on downward facing substrates. In context of a latitudinal gradient, the Azores carbonate cycling rates plot between known values from the cold-temperate Swedish Kosterfjord and the tropical Bahamas, with a total range of two orders in magnitude. Carbonate budget calculations for the bathymetrical transect yield a mean 266.9 kg of epilithic carbonate production, −54.6 kg of bioerosion, and 212.3 kg of annual net carbonate production per metre of coastline in the Azores C factory.

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Key factor governing the physicochemical properties and extent of proton transfer in protic ionic liquids: ΔpKa or chemical structure?

Physical Chemistry Chemical Physics ◽

10.1039/c8cp06973e ◽

2019 ◽

Vol 21 (1) ◽

pp. 418-426 ◽

Cited By ~ 11

Author(s):

Muhammed Shah Miran ◽

Mahfuzul Hoque ◽

Tomohiro Yasuda ◽

Seiji Tsuzuki ◽

Kazuhide Ueno ◽

...

Keyword(s):

Thermal Stability ◽

Ionic Liquids ◽

Proton Transfer ◽

Physicochemical Properties ◽

Chemical Structure ◽

Protic Ionic Liquids ◽

Key Factor ◽

Factor Governing

A series of protic ionic liquids (PILs) are prepared by neutralisation of bis(trifluoromethanesulfonyl)amide acid (H[NTf2]) with various amines, and the properties (especially thermal stability and ionicity) are compared with those of PILs from 1,8-diazabicyclo[5.4.0]-7-undecene (DBU) and various acids.

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Aggressive flushing for discolouration event mitigation in water distribution networks

Water Science & Technology Water Supply ◽

10.2166/ws.2003.0101 ◽

2003 ◽

Vol 3 (1-2) ◽

pp. 179-186 ◽

Cited By ~ 14

Author(s):

J.B. Boxall ◽

P.J. Skipworth ◽

A.J. Saul

Keyword(s):

Exponential Decay ◽

Distribution Systems ◽

Water Distribution ◽

Potable Water ◽

Distribution Networks ◽

Customer Complaint ◽

Key Factor ◽

The Uk ◽

Factor Governing ◽

Pipe Materials

Discolouration is one of the biggest causes of customer complaint associated with potable water. The flushing of systems has been widely identified as an appropriate pro-active means of removing material from distribution networks and hence controlling discolouration. Such flushing involves creating aggressive hydraulic forces within the network such that the materials that contribute to discolouration are mobilised and removed. Understanding of the causes and mechanisms leading to discolouration are poor. Previous work has been presented on the characterisation of material and particles collected at hydrants during flushing trials in the UK. From this data it was hypothesised that the materials causing discolouration originated from cohesive layers on pipe walls, and that once disturbed the material is maintained as a permanent suspension even under the most quiescent of networks conditions. The work presented in this paper attempts to validate the hypothesis that the discolouration materials originate from cohesive layers, and investigate the nature and variability of such layers within live distribution systems. The study involved the aggressive flushing of a long discrete length of cast iron pipe with known discolouration problems. The results showed a progressive generation of material over the length of the pipe, confirming that the material originated from a uniformly distributed cohesive source. This was followed by a sequence of flushing operations for the systematic cleaning of a complex network area, encompassing a mixture of pipe materials and ages. All measured turbidity traces showed exponential decay with time. Such exponential decay may be predicted by a model based on a change in layer strength with degree of erosion. Hydraulic forces appear to be a key factor governing the availability and mobilisation of material. Iron is the dominant material mobilised from all the pipes. There is no direct trend between the amount or the composition of the material mobilised from the different pipes.

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Charge-transfer-energy-dependent oxygen evolution reaction mechanisms for perovskite oxides

Energy & Environmental Science ◽

10.1039/c7ee02052j ◽

2017 ◽

Vol 10 (10) ◽

pp. 2190-2200 ◽

Cited By ~ 137

Author(s):

Wesley T. Hong ◽

Kelsey A. Stoerzinger ◽

Yueh-Lin Lee ◽

Livia Giordano ◽

Alexis Grimaud ◽

...

Keyword(s):

Charge Transfer ◽

Oxygen Evolution ◽

Oxygen Evolution Reaction ◽

Reaction Mechanisms ◽

Transfer Energy ◽

Charge Transfer Energy ◽

Wide Range ◽

Key Factor ◽

Energy Dependent ◽

Factor Governing

This work experimentally identifies the charge-transfer energy as a key factor governing the catalytic oxygen evolution reaction (OER) activity and mechanism across a wide range of perovskite chemistries.

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Characterization of suspended particles and deposits in drinking water reservoirs

Water Science & Technology Water Supply ◽

10.2166/ws.2001.0071 ◽

2001 ◽

Vol 1 (4) ◽

pp. 89-94 ◽

Cited By ~ 1

Author(s):

V. Gauthier ◽

J.M. Portal ◽

J. Yvon ◽

C. Rosin ◽

J.C. Block ◽

...

Keyword(s):

Drinking Water ◽

Bacterial Colonization ◽

Suspended Particles ◽

Amorphous Iron ◽

Reservoir Sediments ◽

Biological Matter ◽

Key Factor ◽

Bacterial Accumulation ◽

Factor Governing

Suspended particles transported by drinking water were examined to understand their role in deposit accumulation and colonization in pilot and full-scale reservoirs. No pesticides were detected in the deposits but several PAH were identified. Deposits accumulated at a rate of 8 μg/cm2/day (29 g/m2/year) over a five month period. Quartz, feldspar, and amorphous iron were characterized in reservoir sediments. Sedimentation of suspended particles, mainly those composed of organic (biological) matter, was incomplete, and was not a key factor governing bacterial accumulation in the deposits (104 to 105 CFU/ cm2). Thus, limiting bacterial nutrients - dissolved organic matter - in treated water should be the only way to control the extent of bacterial colonization of deposits.

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THE ANALYSIS OF INTRAGENERATION CHANGE IN EASTERN ONTARIO POPULATIONS OF THE ALFALFA WEEVIL, HYPERA POSTICA (COLEOPTERA: CURCULIONIDAE)

The Canadian Entomologist ◽

10.4039/ent1091521-12 ◽

1977 ◽

Vol 109 (12) ◽

pp. 1521-1534 ◽

Cited By ~ 11

Author(s):

D. G. Harcourt ◽

J. C. Guppy ◽

M. R. Binns

Keyword(s):

Population Decline ◽

Mortality Data ◽

Mortality Factors ◽

Independent Manner ◽

Alfalfa Weevil ◽

Hypera Postica ◽

Key Factor ◽

Components Analysis ◽

Eastern Ontario ◽

Factor Governing

AbstractFifteen life tables were compiled from population and mortality data collected in the Quinte area of eastern Ontario during the 5-year period, 1972–76, that spanned the rise and fall of an outbreak of the alfalfa weevil, Hypera postica (Gyll.).Components analysis of the data showed that a disease of the feeding larvae caused by Entomophthora phytonomi Arthur, a fungus new to the insect in North America, was the principal determinant of intrageneration survival. Multivariate analysis of the separate mortalities, expressed as k-values, confirmed that this agent was the key factor governing population trends of the weevil and was mainly responsible for its population decline.Examination of the properties of the various mortality factors showed that E. phytonomi was density dependent but overcompensating. Other agents, including the parasitoids Bathyplectes curculionis (Thom.) and Tetrastichus incertus (Ratz.) acted in a density independent manner and contributed little to population trend.

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INTERNAL FRICTION AS POSSIBLE KEY FACTOR GOVERNING THE THERMOSENSITIVITY OF TRP CHANNELS

Письма в Журнал экспериментальной и теоретической физики ◽

10.1134/s0370274x1915013x ◽

2019 ◽

Vol 110 (3-4(8)) ◽

pp. 213-214

Author(s):

A. O. OKENOV ◽

B. I. IAPAROV ◽

A. S. MOSKVIN

Keyword(s):

Internal Friction ◽

Trp Channels ◽

Key Factor ◽

Factor Governing

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Basal melt of the southern Filchner Ice Shelf, Antarctica

10.5194/tc-2021-230 ◽

2021 ◽

Author(s):

Ole Zeising ◽

Daniel Steinhage ◽

Keith W. Nicholls ◽

Hugh F. J. Corr ◽

Craig L. Stewart ◽

...

Keyword(s):

Remote Sensing ◽

Velocity Fields ◽

Ice Shelf ◽

Ice Shelves ◽

Grounding Line ◽

Key Factor ◽

Radio Echo Sounding ◽

Support Force ◽

The Antarctic ◽

Factor Governing

Abstract. Basal melt of ice shelves is a key factor governing discharge of ice from the Antarctic Ice Sheet as a result of its effects on buttressing. Here, we use radio echo sounding to determine the spatial variability of the basal melt rate of the southern Filchner Ice Shelf, Antarctica along the inflow of Support Force Glacier. We find moderate melt rates with a maximum of 1.13 m a−1 about 50 km downstream of the grounding line. The variability of the melt rates over distances of a few kilometres is low (all but one < 0.15 m a−1 at < 2 km distance), indicating that measurements on coarse observational grids are able to yield a representative melt rate distribution. A comparison with remote sensing based melt rates revealed that, for the study area, large differences were due to inaccuracies in the estimation of vertical strain rates from remote sensing velocity fields. These inaccuracies can be overcome by using modern velocity fields.

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