Notable increases in nutrient concentrations in a shallow lake during seasonal ice growth

Nutrients may be eliminated from ice when liquid water is freezing, resulting in enhanced concentrations in the unfrozen water. The nutrients diluted from the ice may contribute to accumulated concentrations in sediment during winter and an increased risk of algae blooms during the following spring and summer. The objective of this study was to evaluate the influence of ice cover on nitrogen (N) and phosphorus (P) concentrations in the water and sediment of a shallow lake, through an examination of Ulansuhai Lake, northern China, from the period of open water to ice season in 2011–2013. The N and P concentrations were between two and five times higher, and between two and eight times higher, than in unfrozen lakes, respectively. As the ice thickness grew, contents of total N and total P showed C-shaped profiles in the ice, and were lower in the middle layer and higher in the bottom and surface layers. Most of the nutrients were released from the ice to liquid water. The results confirm that ice can cause the nutrient concentrations in water and sediment during winter to increase dramatically, thereby significantly impacting on processes in the water environment of shallow lakes.

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Comparison of decay rates of faecal indicator organisms in recreational coastal water and sediment

Water Science & Technology Water Supply ◽

10.2166/ws.2002.0095 ◽

2002 ◽

Vol 2 (3) ◽

pp. 131-138 ◽

Cited By ~ 6

Author(s):

D.L. Craig ◽

H.J. Fallowfield ◽

N.J. Cromar

Keyword(s):

Water Column ◽

Coastal Water ◽

Decay Rates ◽

Organic Carbon Content ◽

Indicator Organisms ◽

Filtration Method ◽

E Coli ◽

Water And Sediment ◽

Increased Risk ◽

High Organic Carbon Content

A laboratory based microcosm study utilising intact non-sterile sediment cores was undertaken to determine the survival of the faecal indicator organisms Escherichia coli, Enterococcus faecium and somatic coliphage in both recreational coastal water and sediment. Overlying water was inoculated with the test organisms and incubated at 10°C, 20°C or 30°C. E. coli, enterococcus and coliphage were enumerated from the water column and sediment by the membrane filtration method, Enterolert (IDEXX Laboratories) and the double-agar overlay methods respectively on days 0, 1, 2, 7, 14 and 28 following inoculation. It was demonstrated that for all organisms, greater decay (k; d-1) occurred in the water column compared to sediment. Sediment characteristics were found to influence decay, with lowest decay rates observed in sediment consisting of high organic carbon content and small particle size. Decay of E. coli was significantly greater in both the water column and sediment compared with enterococcus and coliphage under all conditions. Decay of enterococcus was found to closely resemble that of coliphage decay. Survival of all organisms was inversely related to temperature, with greatest decay at 30°C. However, increased temperature had a less significant impact on survival of enterococcus and coliphage compared with E. coli. The importance of this study for estimating risk from recreational exposure is great if some pathogenic microorganisms behave similarly to the organisms tested in this study. In particular if survival rates of pathogens are similar to enterococcus and coliphage, then their ability to accumulate in coastal sediment may lead to an increased risk of exposure if these organisms are resuspended into the water column due to natural turbulence or human recreational activity.

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Prevalence and Risk of Mild Cognitive Impairment in Low and Middle-Income Countries: A Systematic Review

Journal of Alzheimer s Disease ◽

10.3233/jad-201043 ◽

2020 ◽

pp. 1-20

Author(s):

Andrea M. McGrattan ◽

Yueping Zhu ◽

Connor D. Richardson ◽

Devi Mohan ◽

Yee Chang Soh ◽

...

Keyword(s):

Systematic Review ◽

Cognitive Impairment ◽

Mild Cognitive Impairment ◽

Resource Planning ◽

Cognitive State ◽

Middle Income ◽

Total N ◽

Middle Income Countries ◽

Increased Risk ◽

Low And Middle Income

Background: Mild cognitive impairment (MCI) is a cognitive state associated with increased risk of dementia. Little research on MCI exists from low-and middle-income countries (LMICs), despite high prevalence of dementia in these settings. Objective: This systematic review aimed to review epidemiological reports to determine the prevalence of MCI and its associated risk factors in LMICs. Methods: Medline, Embase, and PsycINFO were searched from inception until November 2019. Eligible articles reported on MCI in population or community-based studies from LMICs. No restrictions on the definition of MCI used as long as it was clearly defined. Results: 4,621 articles were screened, and 78 retained. In total, n = 23 different LMICs were represented; mostly from China (n = 55 studies). Few studies from countries defined as lower-middle income (n = 14), low income (n = 4), or from population representative samples (n = 4). There was large heterogeneity in how MCI was diagnosed; with Petersen criteria the most commonly applied (n = 26). Prevalence of aMCI (Petersen criteria) ranged from 0.6%to 22.3%. Similar variability existed across studies using the International Working Group Criteria for aMCI (range 4.5%to 18.3%) and all-MCI (range 6.1%to 30.4%). Risk of MCI was associated with demographic (e.g., age), health (e.g., cardio-metabolic disease), and lifestyle (e.g., social isolation, smoking, diet and physical activity) factors. Conclusion: Outside of China, few MCI studies have been conducted in LMIC settings. There is an urgent need for population representative epidemiological studies to determine MCI prevalence in LMICs. MCI diagnostic methodology also needs to be standardized. This will allow for cross-study comparison and future resource planning.

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Chemical and Microbial Characterization of Washed Rice Water Waste to Assess Its Potential as Plant Fertilizer and for Increasing Soil Health

Agronomy ◽

10.3390/agronomy11122391 ◽

2021 ◽

Vol 11 (12) ◽

pp. 2391

Author(s):

Abba Nabayi ◽

Christopher Teh Boon Sung ◽

Ali Tan Kee Zuan ◽

Tan Ngai Paing ◽

Nurul Izzati Mat Akhir

Keyword(s):

Bacterial Species ◽

Soil Health ◽

Nutrient Content ◽

Nutrient Concentrations ◽

Total N ◽

Available N ◽

Microbial Characterization ◽

Rice Water ◽

Water Waste

The wastewater from washed rice water (WRW) is often recommended as a source of plant nutrients in most Asian countries, even though most current research on WRW lack scientific rigor, particularly on the effects of rice washing intensity, volumetric water-to-rice ratio (W:R), and condition of the WRW before plant application. This research was thus carried out: (1) to determine how various rice washing intensities, fermentation periods (FP), and W:R would affect the nutrient content in WRW, and (2) to isolate, identify, and characterize the bacterial community from fermented WRW. The WRW was prepared at several rice washing intensities (50, 80, and 100 rpm), FP (0, 3, 6, and 9 days), and W:R (1:1, 3:1, and 6:1). The concentrations of all elements (except P, Mg, and Zn) and available N forms increased with increasing FP and W:R. Beneficial N-fixing and P- and K-solubilizing bacteria were additionally detected in WRW, which helped to increase the concentrations of these elements. Monovalent nutrients -N, , and K are soluble in water. Thus, they were easily leached out of the rice grains and why their concentrations increased with W:R. The bacteria population in WRW increased until 3 days of fermentation, then declined, possibly because there was an insufficient C content in WRW to be a source of energy for bacteria to support their prolonged growth. While C levels in WRW declined over time, total N levels increased then decreased after 3 days, where the latter was most possibly due to the denitrification and ammonification process, which had led to the increase in -N and . The optimum FP and W:R for high nutrient concentrations and bacterial population were found to be 3 to 9 days and 3:1 to 6:1, respectively. WRW contained nutrients and beneficial bacterial species to support plant growth.

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Makro- és mikroelem-tartalom összehasonlítása almaültetvények talajában

Agrokémia és Talajtan ◽

10.1556/agrokem.54.2005.3-4.10 ◽

2005 ◽

Vol 54 (3-4) ◽

pp. 389-402 ◽

Cited By ~ 1

Author(s):

Péter Tamás Nagy

Keyword(s):

Humus Content ◽

Active Agent ◽

Apple Orchard ◽

Organic Manure ◽

Organic N ◽

Nutrient Concentrations ◽

Apple Orchards ◽

Total N ◽

Significant Difference ◽

Organic Orchards

In a three-year study carried out at the Debrecen-Pallagi nursery of the University of Debrecen, the nutrient contents, humus content and pH of the soil were determined in integrated and organic apple orchards established on brown forest soil with thin interstratified layers of colloid and sesquioxide accumulation. The organic orchard was only given organic manure (50 t/ha) in spring 2000 and 2002, while the integrated orchard was treated with 250 kg/ha complex NPK fertilizer (16.5-16.5-16.5) every year between 1997 and 2003 after the leaves had fallen. An additional 50 kg/ha N active agent as NH 4 NO 3 was applied every year, while 4 t/ha lime fertilizer (carbonation mud) was provided in autumn 2002 and 25 t/ha organic manure in November 2003. In 2004 no fertilizer was given to either orchard. The available forms of N (NO 3- , NH 4+ , organic N and total N) and P (ortho-, organic and total-PO 43- ) were determined after extraction with 0.01 M CaCl 2 , while the Ca, Mg and microelement (Mn, Cu, Zn) content of the soil was extracted with NH 4 -acetate +EDTA (Lakanen-Erviö extractant). Potassium was measured in both extractants. The results showed that the inorganic, organic and total soluble nitrogen in the soil were significantly higher (P = 0.05) in the integrated orchard than in the organic one. It was found that the quantity and ratio of the organic N fraction was comparable with that of the inorganic N forms. The ortho- phosphate and total P fractions were significantly higher (P = 0.05) in the integrated apple orchard than in the organic orchard, while there was no significant difference in the organic P quantity. The potassium data showed that both the integrated and organic orchards contained a satisfactory amount of adsorbed K in spite of the poor colloid content and high soil acidity. The Ca, Mg, Co and Zn contents of the integrated soils were significantly higher (P = 0.05) than in the organic orchard. For Mn, however, no substantial difference was found between the integrated and organic orchards. With the exception of Mn, the nutrient concentrations reflected the differences in the nutrient management of the integrated and organic apple orchards.

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High net CO<sub>2</sub> and CH<sub>4</sub> release at a eutrophic shallow lake on a formerly drained fen

Biogeosciences ◽

10.5194/bg-13-3051-2016 ◽

2016 ◽

Vol 13 (10) ◽

pp. 3051-3070 ◽

Cited By ~ 28

Author(s):

Daniela Franz ◽

Franziska Koebsch ◽

Eric Larmanou ◽

Jürgen Augustin ◽

Torsten Sachs

Keyword(s):

Global Warming ◽

Shallow Lake ◽

Typha Latifolia ◽

Open Water ◽

Emergent Vegetation ◽

Lake Ecosystem ◽

Co2 Uptake ◽

Mild Winter ◽

Ch4 Emissions ◽

Northeastern Germany

Abstract. Drained peatlands often act as carbon dioxide (CO2) hotspots. Raising the groundwater table is expected to reduce their CO2 contribution to the atmosphere and revitalise their function as carbon (C) sink in the long term. Without strict water management rewetting often results in partial flooding and the formation of spatially heterogeneous, nutrient-rich shallow lakes. Uncertainties remain as to when the intended effect of rewetting is achieved, as this specific ecosystem type has hardly been investigated in terms of greenhouse gas (GHG) exchange. In most cases of rewetting, methane (CH4) emissions increase under anoxic conditions due to a higher water table and in terms of global warming potential (GWP) outperform the shift towards CO2 uptake, at least in the short term.Based on eddy covariance measurements we studied the ecosystem–atmosphere exchange of CH4 and CO2 at a shallow lake situated on a former fen grassland in northeastern Germany. The lake evolved shortly after flooding, 9 years previous to our investigation period. The ecosystem consists of two main surface types: open water (inhabited by submerged and floating vegetation) and emergent vegetation (particularly including the eulittoral zone of the lake, dominated by Typha latifolia). To determine the individual contribution of the two main surface types to the net CO2 and CH4 exchange of the whole lake ecosystem, we combined footprint analysis with CH4 modelling and net ecosystem exchange partitioning.The CH4 and CO2 dynamics were strikingly different between open water and emergent vegetation. Net CH4 emissions from the open water area were around 4-fold higher than from emergent vegetation stands, accounting for 53 and 13 g CH4 m−2 a−1 respectively. In addition, both surface types were net CO2 sources with 158 and 750 g CO2 m−2 a−1 respectively. Unusual meteorological conditions in terms of a warm and dry summer and a mild winter might have facilitated high respiration rates. In sum, even after 9 years of rewetting the lake ecosystem exhibited a considerable C loss and global warming impact, the latter mainly driven by high CH4 emissions. We assume the eutrophic conditions in combination with permanent high inundation as major reasons for the unfavourable GHG balance.

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Density-driven current between reed belts and open water in a shallow lake

Water Resources Research ◽

10.1029/2008wr006949 ◽

2008 ◽

Vol 44 (10) ◽

Cited By ~ 17

Author(s):

Charlotta Borell Lövstedt ◽

Lars Bengtsson

Keyword(s):

Shallow Lake ◽

Open Water

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Adverse childhood experiences and bullying behaviours at work among workers in Japan

Occupational and Environmental Medicine ◽

10.1136/oemed-2019-106009 ◽

2019 ◽

Vol 77 (1) ◽

pp. 9-14

Author(s):

Masashi Kizuki ◽

Takeo Fujiwara ◽

Tomohiro Shinozaki

Keyword(s):

Direct Effect ◽

Adverse Childhood Experiences ◽

Workplace Bullying ◽

Structural Model ◽

Marginal Structural Model ◽

Childhood Experiences ◽

Total N ◽

Adverse Childhood ◽

Increased Risk ◽

Bullying Victimisation

ObjectivesTo examine the relationship between adverse childhood experiences (ACEs), workplace bullying victimisation and bullying behaviours to subordinates among Japanese workers.MethodsWe conducted an internet-based cross-sectional survey among workers who had enacted 0, 1 and ≥2 types of bullying behaviours that had been directed towards subordinates in the past 3 years (n=309 for each group, total N=927). We assessed ACEs with questionnaires about adverse experiences at home and bullying victimisation at school. The total and controlled direct effects of ACEs on the number of bullying behaviours to subordinates were estimated from a baseline-adjusted and a direct-effect marginal structural ordinal logistic model, respectively.ResultsThere was a positive dose–response association between the level of ACEs and the frequency of workplace bullying victimisation, as well as the number of bullying behaviours enacted at work after adjustment for sex, age and childhood socioeconomic status (both p<0.001). Workers in the highest tertile of ACEs compared with the lowest tertile had 3.15 (95% CI 2.20 to 4.50) times higher odds of having perpetrated more bullying behaviours at work. The magnitude of the effect was 2.57 (95% CI 1.70 to 3.90) via pathways not mediated by workplace bullying victimisation in a direct-effect marginal structural model.ConclusionsPeople who had ACEs were at increased risk later in life of enacting bullying behaviours at work. Current findings may be useful to prevent bullying behaviours at work.

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Effect of Cover Crops on Yield and Leaf Nutrient Concentrations in an Organic Honeycrisp Apple (Malus domestica ‘Honeycrisp’) Orchard in Nova Scotia, Canada

HortScience ◽

10.21273/hortsci10615-16 ◽

2016 ◽

Vol 51 (11) ◽

pp. 1378-1383

Author(s):

Mehdi Sharifi ◽

Julia Reekie ◽

Andrew Hammermeister ◽

Mohammed Zahidul Alam ◽

Taylor MacKey

Keyword(s):

Nova Scotia ◽

Malus Domestica ◽

Cover Crops ◽

Cover Crop ◽

Red Clover ◽

Nutrient Concentrations ◽

Soil Productivity ◽

Total N ◽

Leaf Nutrient Concentrations ◽

K Concentration

There is an increasing interest for use of cover crops in orchards; however, the species that are most likely to be successfully implemented and their impact on yield and soil productivity have not been fully explored under Maritimes climate. This study investigated the effect of various cover crops treatments on organic apple (Malus domestica Borkh cv. Honeycrisp) yield and leaf nutrient concentrations in Nova Scotia over 3 years. Various cover crop mixtures including legumes, cereals, and grasses were planted using a modified Swiss Sandwich System (SSS). The cover crops treatments did not affect apple yield. In 2012, the input of biomass to the soil was 89% and 144% greater for alfalfa (ALF) and other cover crop treatments than unseeded (CON) treatment, respectively. The pea, oats, vetch mixture (POVM) contributed 24% higher biomass N to soil compared with average of other cover crops in 2012. Soil available K concentration in the tilled strip was increased in the 3rd year of the study compared with the initial values across cover crop treatments. The red clover oats mixture (RCOM), POVM, and Triple Mix (TM) treatments appeared to add the greatest amount of available K to the soil among treatments. The CON, TM, and ALF treatments resulted in higher leaf Mn concentration in only 2012 and CON, sweet clover and oats mixture (SCOM), and ALF resulted in higher leaf P concentration in 2014, compared with other treatments. Cover crops did not compete with apple trees and their most beneficial and consistent contribution was to total C, total N, and K input to the soil.

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Predicting Cyanobacteria dominance in lakes

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f01-143 ◽

2001 ◽

Vol 58 (10) ◽

pp. 1905-1908 ◽

Cited By ~ 403

Author(s):

John A Downing ◽

Susan B Watson ◽

Edward McCauley

Keyword(s):

Field Experiments ◽

Nutrient Concentrations ◽

Strongly Correlated ◽

Total N ◽

Algae Biomass ◽

Cyanobacteria Blooms ◽

Freshwater Resource ◽

Toxic Blooms ◽

Total P ◽

Controversial Concept

A controversial precept of aquatic ecology asserts that low ratios of nitrogen to phosphorus (N:P) lead to noxious and sometimes toxic blooms of Cyanobacteria. Cyanobacteria dominance is a major risk to human and ecosystem health. The stoichiometric control of Cyanobacteria therefore has become central to freshwater resource management. This controversial concept is based on observed Cyanobacteria dominance in lakes with low N:P and the results of lab and field experiments. Here we analyze data from 99 of the temperate zone's most studied lakes and show that this model is flawed. We show that the risk of water quality degradation by Cyanobacteria blooms is more strongly correlated with variation in total P, total N, or standing algae biomass than the ratio of N:P. Risks associated with Cyanobacteria are therefore less associated with N:P ratios than a simple increase in nutrient concentrations and algal biomass.

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