Direct Aquatic Application of Crushed Dolomite Reduces CO2 Evasion in an Acidified River

Acidified rivers may have increased CO2 emissions because their low pH transforms inorganic carbon in the form of bicarbonate anions to CO2, which can evade to the atmosphere, thus interrupting the delivery inorganic carbon to the oceans, a key flux in the long-term carbonate silicate cycle. Enhanced weathering (EW) is a carbon dioxide removal (CDR) strategy aiming to increase drawdown of atmospheric CO2 through accelerated carbonation weathering of crushed minerals with targeted carbonate sequestration in oceanic stores. To date, EW research has been focused on terrestrial application of crushed minerals, and the CDR capability of enhancing weathering via addition of crushed minerals to rivers from lime dosers is essentially unexplored. Lime dosers have been used for decades to directly deposit crushed carbonate rock to rivers as a function of river flow in Norway and Nova Scotia, Canada, yet their potential as a CDR tool has yet to be verified in the field. In this study, we adapt CO2 flux sensors (eosFD) designed for soils to be deployed in rivers. We conducted field trials on the Killag River, Nova Scotia, upstream and downstream of a lime doser over a period of six weeks in the autumn of 2020. Preliminary analysis shows elevated CO2 evasion rates upstream of the lime doser and decreased evasion rates downstream. Aside from flood waves, CO2 evasion at the downstream (treated) site is reduced to almost zero for extended periods of time. Next steps are to identify whether the reduced CO2 evasion is due to CO2 drawdown via increased carbonation weathering of the crushed dolomite or through reduced CO2 evasion due to increased pH, or from a combination of the two processes. The results of this study may have implications for carbon credit programs for acidification mitigation and may encourage more widespread use of enhanced weathering as a CDR tool in rivers.

Download Full-text

Temporal Patterns of Acidification of Rivers in Nova Scotia and Newfoundland and their Relationship to Sulphate Emissions

Water Quality Research Journal ◽

10.2166/wqrj.1988.041 ◽

1988 ◽

Vol 23 (4) ◽

pp. 532-541

Author(s):

G. D. Howell ◽

P.E.J. Green ◽

C.A. Field ◽

B. Freedman

Keyword(s):

Statistical Analysis ◽

Nova Scotia ◽

Water Chemistry ◽

Sulphur Dioxide ◽

Low Ph ◽

Hydrogen Ion ◽

Atlantic Canada ◽

Atmospheric Loading ◽

Mineral Acids ◽

Sulphur Dioxide Emission

Abstract Twenty-eight rivers in Atlantic Canada are sampled monthly, and have periods of record dating back as far as 1965. Statistical analysis of water chemistry for rivers in areas of Nova Scotia and Newfoundland that are believed to be sensitive to acidification has revealed that pH was significantly lower during the late 1960’s and early 1970’s. Annual hydrogen ion export for selected rivers was also greater during this period. This period of relatively low pH and large hydrogen ion export corresponds to a peak of North American sulphur dioxide emission, suggesting that these rivers may be responding to atmospheric loading of anthropogenic mineral acids.

Download Full-text

Cariogenic Biofilm: Pathology-Related Phenotypes and Targeted Therapy

Microorganisms ◽

10.3390/microorganisms9061311 ◽

2021 ◽

Vol 9 (6) ◽

pp. 1311

Author(s):

Xiuqin Chen ◽

Eric Banan-Mwine Daliri ◽

Akanksha Tyagi ◽

Deog-Hwan Oh

Keyword(s):

Treatment Strategies ◽

High Specificity ◽

Low Ph ◽

Oral Microbiota ◽

Extracellular Polymers ◽

Dental Biofilm ◽

Health And Disease ◽

Promising Treatment ◽

Cariogenic Biofilm

The initiation and development of cariogenic (that is, caries-related) biofilms are the result of the disruption of homeostasis in the oral microenvironment. There is a daily accumulation of dental biofilm on the surface of teeth and its matrix of extracellular polymers supports the host in its defense against invading microbes, thus helping to achieve oral microbial homeostasis. However, the homeostasis can be broken down under certain circumstances such as during long-term exposure to a low pH environment which results in the dominance of acidogenic and acid-tolerating species in the dental biofilm and, thus, triggers the shift of harmless biofilm to an acidic one. This work aims to explore microbial diversity and the quorum sensing of dental biofilm and their important contributions to oral health and disease. The complex and multispecies ecosystems of the cariogenic biofilm pose significant challenges for the modulation of the oral microenvironment. Promising treatment strategies are those that target cariogenic niches with high specificity without disrupting the balance of the surrounding oral microbiota. Here, we summarized the recent advances in modulating cariogenic biofilm and/or controlling its pathogenic traits.

Download Full-text

High Mountain Asian glacier response to climate revealed by multi-temporal satellite observations since the 1960s

Nature Communications ◽

10.1038/s41467-021-24180-y ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Atanu Bhattacharya ◽

Tobias Bolch ◽

Kriti Mukherjee ◽

Owen King ◽

Brian Menounos ◽

...

Keyword(s):

Mass Loss ◽

River Flow ◽

Tien Shan ◽

High Mountain ◽

Glacier Mass Balance ◽

Temperature And Precipitation ◽

Multi Temporal ◽

The 1960S ◽

Northern Tien Shan

AbstractKnowledge about the long-term response of High Mountain Asian glaciers to climatic variations is paramount because of their important role in sustaining Asian river flow. Here, a satellite-based time series of glacier mass balance for seven climatically different regions across High Mountain Asia since the 1960s shows that glacier mass loss rates have persistently increased at most sites. Regional glacier mass budgets ranged from −0.40 ± 0.07 m w.e.a−1 in Central and Northern Tien Shan to −0.06 ± 0.07 m w.e.a−1 in Eastern Pamir, with considerable temporal and spatial variability. Highest rates of mass loss occurred in Central Himalaya and Northern Tien Shan after 2015 and even in regions where glaciers were previously in balance with climate, such as Eastern Pamir, mass losses prevailed in recent years. An increase in summer temperature explains the long-term trend in mass loss and now appears to drive mass loss even in regions formerly sensitive to both temperature and precipitation.

Download Full-text

Tracking Changes on Soil Structure and Organic Carbon Sequestration after 30 Years of Different Tillage and Management Practices

Agronomy ◽

10.3390/agronomy11020291 ◽

2021 ◽

Vol 11 (2) ◽

pp. 291

Author(s):

Ramón Bienes ◽

Maria Jose Marques ◽

Blanca Sastre ◽

Andrés García-Díaz ◽

Iris Esparza ◽

...

Keyword(s):

Triticum Aestivum ◽

Organic Carbon ◽

Management Practices ◽

Management Strategies ◽

Triticum Aestivum L ◽

Field Trials ◽

Conventional Tillage ◽

Soil Parameters ◽

Wilting Point

Long-term field trials are essential for monitoring the effects of sustainable land management strategies for adaptation and mitigation to climate change. The influence of more than thirty years of different management is analyzed on extensive crops under three tillage systems, conventional tillage (CT), minimum tillage (MT), and no-tillage (NT), and with two crop rotations, monoculture winter-wheat (Triticum aestivum L.) and wheat-vetch (Triticum aestivum L.-Vicia sativa L.), widely present in the center of Spain. The soil under NT experienced the largest change in organic carbon (SOC) sequestration, macroaggregate stability, and bulk density. In the MT and NT treatments, SOC content was still increasing after 32 years, being 26.5 and 32.2 Mg ha−1, respectively, compared to 20.8 Mg ha−1 in CT. The SOC stratification (ratio of SOC at the topsoil/SOC at the layer underneath), an indicator of soil conservation, increased with decreasing tillage intensity (2.32, 1.36, and 1.01 for NT, MT, and CT respectively). Tillage intensity affected the majority of soil parameters, except the water stable aggregates, infiltration, and porosity. The NT treatment increased available water, but only in monocropping. More water was retained at the permanent wilting point in NT treatments, which can be a disadvantage in dry periods of these edaphoclimatic conditions.

Download Full-text

Application of a 1 km2 resolution model for climate change effects upon Benin and Nigeria vegetable agriculture

GEOMATICA ◽

10.1139/geomat-2019-0014 ◽

2019 ◽

Vol 73 (4) ◽

pp. 93-106

Author(s):

Colin Minielly ◽

O. Clement Adebooye ◽

P.B. Irenikatche Akponikpe ◽

Durodoluwa J. Oyedele ◽

Dirk de Boer ◽

...

Keyword(s):

Climate Change ◽

Food Security ◽

Field Trials ◽

Development Planning ◽

Climate Modelling ◽

Intergovernmental Panel ◽

Amaranthus Cruentus ◽

Global Issues ◽

Climate Change Effects

Climate change and food security are complex global issues that require multidisciplinary approaches to resolve. A nexus exists between both issues, especially in developing countries, but little prior research has successfully bridged the divide. Existing resolutions to climate change and food security are expensive and resource demanding. Climate modelling is at the forefront of climate change literature and development planning, whereas agronomy research is leading food security plans. The Benin Republic and Nigeria have grown and developed in recent years but may not have all the tools required to implement and sustain long-term food security in the face of climate change. The objective of this paper is to describe the development and outputs of a new model that bridges climate change and food security. Data from the Intergovernmental Panel on Climate Change’s 5th Regional Assessment (IPCC AR5) were combined with a biodiversity database to develop the model to derive these outputs. The model was used to demonstrate what potential impacts climate change will have on the regional food security by incorporating agronomic data from four local underutilized indigenous vegetables (Amaranthus cruentus L., Solanum macrocarpon L., Telfairia occidentalis Hook f., and Ocimum gratissimum L.). The model shows that, by 2099, there is significant uncertainty within the optimal recommendations that originated from the MicroVeg project. This suggests that MicroVeg will not have long-term success for food security unless additional options (e.g., new field trials, shifts in vegetable grown) are considered, creating the need for need for more dissemination tools.

Download Full-text

Carrier-microencapsulation using Al-catecholate complex to suppress arsenopyrite oxidation: Evaluation of the coating stability under simulated weathering conditions

MATEC Web of Conferences ◽

10.1051/matecconf/201926806002 ◽

2019 ◽

Vol 268 ◽

pp. 06002 ◽

Cited By ~ 1

Author(s):

Kensuke Seno ◽

Ilhwan Park ◽

Carlito Tabelin ◽

Kagehiro Magaribuchi ◽

Mayumi Ito ◽

...

Keyword(s):

Protective Coating ◽

Sulfide Mineral ◽

Sulfide Minerals ◽

Low Ph ◽

Oxidation Products ◽

Arsenic Sulfide ◽

Catecholate Complex ◽

Coating Stability ◽

The Stability

Arsenopyrite (FeAsS) is the most common primary arsenic-sulfide mineral in nature, and its oxidation causes the release of toxic arsenic (As). To mitigate these problems, carrier-microencapsulation (CME), a technique that passivates sulfide minerals by covering their surfaces with a protective coating, has been developed. In the previous study of authors on CME, Al-catecholate complex significantly suppressed arsenopyrite oxidation via electron donating effects of the complex and the formation of an Al-oxyhydroxide coating. For the application of this technique to real tailings, however, further study should be carried out to elucidate long-term effectiveness of the coating to suppress arsenopyrite oxidation. This study investigates the stability of the coating formed on arsenopyrite by Al-based CME using weathering tests. The Al-oxyhydroxide coating suppressed arsenopyrite oxidation until about 50 days of the experiment, but after this, the amounts of oxidation products like dissolved S and As increased due to the gradual dissolution of the coating with time as a result of the low pH of leachate. This suggests that co-disposal of Al-based CME-treated arsenopyrite with minerals that have appropriate neutralization potentials, so that the pH is maintained at around 5 to 8 where Al-oxyhydroxide is stable.

Download Full-text

Limnetic Zooplankton Assemblages in Atlantic Canada with Special Reference to Acidification

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f86-055 ◽

1986 ◽

Vol 43 (2) ◽

pp. 444-456 ◽

Cited By ~ 34

Author(s):

J. C. H. Carter ◽

W. D. Taylor ◽

R. Chengalath ◽

D. A. Scruton

Keyword(s):

Nova Scotia ◽

New Brunswick ◽

Fish Predation ◽

Low Ph ◽

Buffering Capacity ◽

The Other ◽

Bay Of Fundy ◽

Factor Scores ◽

Multiple Discriminant Analysis ◽

Biological Factors

Crustacean and rotifer plankton assemblages of 93 lakes in Labrador, 107 in Newfoundland, and 142 in New Brunswick – Nova Scotia were investigated for evidence of correlations with lake morphometric, chemical, or biological factors. Labrador assemblages were almost completely lacking in identifiable structure. Newfoundland species clustered into two groups of different body size, suggesting the influence of fish predation. Only one species in Labrador and Newfoundland was significantly correlated with a derived factor related to lake water buffering capacity. New Brunswick – Nova Scotia species clustered into two groups, one featuring significant positive and the other significant negative correlations with the buffering factor. From this we conclude that acidification is having an impact on the limnetic zooplankton of these two provinces. Multiple discriminant analysis was used to demonstrate that New Brunswick – Nova Scotia lakes differing in their buffering capacity were also distinct in zooplankton composition. Lakes with low factor scores (low pH, alkalinity, and calcium) were mainly located in the Bay of Fundy region; this area has above average fog and precipitation, and lies within the summer air flow carrying pollutants from the south.

Download Full-text

Influences on the Hydrophobicity of Concrete Surfaces Treated with Alkyl Trialkoxysilanes

Restoration of Buildings and Monuments ◽

10.1515/rbm14.20.6-0039 ◽

2014 ◽

Vol 20 (6) ◽

pp. 405-412

Author(s):

U. Antons ◽

M. Raupach ◽

O. Weichold

Keyword(s):

Uv Radiation ◽

Cement Hydration ◽

Alkaline Media ◽

Water Repellent ◽

Portland Cement Concrete ◽

Accelerated Carbonation ◽

Surface Layers ◽

Hydrophobic Layer ◽

Furnace Slag

Abstract The paper focuses on how alkaline media, UV radiation, and carbonation as well as on-going cement hydration affects hydrophobic treatments of concrete and influences the properties of these water-repellent layers. Single-sided nuclear magnetic resonance measurements show that layers formed by impregnating samples with alkyl trialkoxysilanes are stable even under long-term exposure to alkaline solution and UV radiation, with the damage of the latter being limited to the topmost surface layers. Microstructural changes during accelerated carbonation of blast furnace slag cement based concrete have a major impact on the hydrophobic layer properties, while the carbonation of Portland cement concrete has no influence. On-going hydration additionally influences the hydrophobic layer properties.

Download Full-text

Nondestructive Sampling to Monitor Macrophomina phaseolina Root Colonization in Overwintering Stevia

Plant Health Progress ◽

10.1094/php-10-20-0092-br ◽

2021 ◽

Author(s):

Layne W. Rogers ◽

Alyssa M. Koehler

Keyword(s):

Root Colonization ◽

Root Zone ◽

Macrophomina Phaseolina ◽

Field Trials ◽

Soil Core ◽

Climate Data ◽

Sample Weight ◽

The Family ◽

Soil Temperatures

Macrophomina phaseolina is a soilborne fungal pathogen in the family Botryosphaeriaceae. Microsclerotia of M. phaseolina were first observed at the base of overwintering stevia stems in North Carolina in spring 2016. Previous studies utilized destructive sampling methods to monitor M. phaseolina in stevia fields; however, these methods are not feasible for long-term monitoring of disease in a perennial system. In the current study, nondestructive root soil-core sampling was conducted during overwintering months, from October 2018 to January 2020, to monitor M. phaseolina root colonization in stevia in Rocky Mount, NC. Two-inch-diameter soil cores were collected through the root zone, and fresh weight of roots was recorded for each soil core. M. phaseolina recovery was evaluated by examining mycelial growth from roots plated onto potato dextrose agar. There was no significant effect of sample weight on M. phaseolina across all dates, but there was one date for which sample weight had a significant effect on recovery (P = 0.01; α = 0.05). For both recovery and sample weight, sampling date was a significant predictor (P = 1.68e-5 and P = 0.0389, respectively; α = 0.05). Weather and climate data revealed that dates with no M. phaseolina recovery had lowest mean air and soil temperatures and the greatest number of days below freezing in the month prior to sampling. In separate sampling years, October sampling dates had the highest recovery of M. phaseolina. Future field trials should determine if October samplings can predict survival and vigor of reemerging stevia plants.

Download Full-text

Solute transport dynamics in small, shallow groundwater-dominated agricultural catchments: insights from a high-frequency, multisolute 10 yr-long monitoring study

Hydrology and Earth System Sciences ◽

10.5194/hess-17-1379-2013 ◽

2013 ◽

Vol 17 (4) ◽

pp. 1379-1391 ◽

Cited By ~ 54

Author(s):

A. H. Aubert ◽

C. Gascuel-Odoux ◽

G. Gruau ◽

N. Akkal ◽

M. Faucheux ◽

...

Keyword(s):

High Frequency ◽

Inorganic Carbon ◽

Shallow Groundwater ◽

Data Series ◽

Wet Season ◽

Transport Dynamics ◽

Agricultural Catchments ◽

Organic And Inorganic Carbon ◽

The Impact

Abstract. High-frequency, long-term and multisolute measurements are required to assess the impact of human pressures on water quality due to (i) the high temporal and spatial variability of climate and human activity and (ii) the fact that chemical solutes combine short- and long-term dynamics. Such data series are scarce. This study, based on an original and unpublished time series from the Kervidy-Naizin headwater catchment (Brittany, France), aims to determine solute transfer processes and dynamics that characterise this strongly human-impacted catchment. The Kervidy-Naizin catchment is a temperate, intensive agricultural catchment, hydrologically controlled by shallow groundwater. Over 10 yr, five solutes (nitrate, sulphate, chloride, and dissolved organic and inorganic carbon) were monitored daily at the catchment outlet and roughly every four months in the shallow groundwater. The concentrations of all five solutes showed seasonal variations but the patterns of the variations differed from one solute to another. Nitrate and chloride exhibit rather smooth variations. In contrast, sulphate as well as organic and inorganic carbon is dominated by flood flushes. The observed nitrate and chloride patterns are typical of an intensive agricultural catchment hydrologically controlled by shallow groundwater. Nitrate and chloride originating mainly from organic fertilisers accumulated over several years in the shallow groundwater. They are seasonally exported when upland groundwater connects with the stream during the wet season. Conversely, sulphate as well as organic and inorganic carbon patterns are not specific to agricultural catchments. These solutes do not come from fertilisers and do not accumulate in soil or shallow groundwater; instead, they are biogeochemically produced in the catchment. The results allowed development of a generic classification system based on the specific temporal patterns and source locations of each solute. It also considers the stocking period and the dominant process that limits transport to the stream, i.e. the connectivity of the stocking compartment. This mechanistic classification can be applied to any chemical solute to help assess its origin, storage or production location and transfer mechanism in similar catchments.

Download Full-text