scholarly journals Air–water fluxes and sources of carbon dioxide in the Delaware Estuary: spatial and seasonal variability

2015 ◽  
Vol 12 (20) ◽  
pp. 6085-6101 ◽  
Author(s):  
A. Joesoef ◽  
W.-J. Huang ◽  
Y. Gao ◽  
W.-J. Cai
Keyword(s):  
Carbon Dioxide ◽  
Late Summer ◽  
Tidal River ◽  
Salinity Range ◽  
Co2 Fluxes ◽  
Delaware Estuary ◽  
Delaware River ◽  
Great Contrast ◽  
Positive Correlations ◽  
Co2 Degassing

Abstract. Distributions of surface water partial pressure of carbon dioxide (pCO2) were measured on nine cruises in the Delaware Estuary (USA). The Delaware River was highly supersaturated in pCO2 with respect to the atmosphere during all seasons, while the Delaware Bay was undersaturated in pCO2 during spring and late summer and moderately supersaturated during mid-summer, fall, and winter. While the smaller upper tidal river was a strong CO2 source (27.1 ± 6.4 mol-C m−2 yr−1), the much larger bay was a weak source (1.2 ± 1.4 mol-C m−2 yr−1), the latter of which had a much greater area than the former. In turn, the Delaware Estuary acted as a relatively weak CO2 source (2.4 ± 4.8 mol-C m−2 yr−1), which is in great contrast to many other estuarine systems. Seasonally, pCO2 changes were greatest at low salinities (0 ≤ S < 5), with pCO2 values in the summer nearly 3-fold greater than those observed in the spring and fall. Undersaturated pCO2 was observed over the widest salinity range (7.5 ≤ S < 30) during spring. Near to supersaturated pCO2 was generally observed in mid- to high-salinity waters (20 ≤ S < 30) except during spring and late summer. Strong seasonal trends in internal estuarine production and consumption of CO2 were observed throughout both the upper tidal river and lower bay. Positive correlations between river-borne and air–water CO2 fluxes in the upper estuary emphasize the significance of river-borne CO2 degassing to overall CO2 fluxes. While river-borne CO2 degassing heavily influenced CO2 dynamics in the upper tidal river, these forces were largely compensated for by internal biological processes within the extensive bay system of the lower estuary.

scholarly journals Air–water fluxes and sources of carbon dioxide in the Delaware Estuary: spatial and seasonal variability

2015 ◽  
Vol 12 (13) ◽  
pp. 10899-10938
Author(s):  
A. Joesoef ◽  
W.-J. Huang ◽  
Y. Gao ◽  
W.-J. Cai
Keyword(s):  
Carbon Dioxide ◽  
Late Summer ◽  
Tidal River ◽  
Salinity Range ◽  
Co2 Fluxes ◽  
Delaware Estuary ◽  
Delaware River ◽  
Great Contrast ◽  
Positive Correlations ◽  
Co2 Degassing

Abstract. Distributions of surface water partial pressure of carbon dioxide (pCO2) were measured on nine cruises in the Delaware Estuary (USA). The Delaware River was highly supersaturated in pCO2 with respect to the atmosphere during all seasons while the Delaware Bay was undersaturated in pCO2 during spring and late summer and moderately supersaturated during midsummer, fall, and winter. While the upper tidal river was a strong CO2 source (24.6 ± 2.2 mol C m−2 year−1), the bay was a weak source (1.8 ± 0.2 mol C m−2 year−1), the latter of which had a much greater area than the former. In turn, the Delaware Estuary acted as a relatively weak CO2 source (2.4 ± 0.3 mol C m−2 year−1), which is in great contrast to many other estuarine systems. Seasonally, pCO2 changes were greatest at low salinities (0 ≤ S< 5) with pCO2 values in the summer nearly three-fold greater than those observed in the spring and fall. Undersaturated pCO2 was observed over the widest salinity range (7.5 ≤ S< 30) during spring. Near to supersaturated pCO2 was generally observed in mid- to high salinity waters (20 ≤ S< 30) except during spring and late summer. Strong seasonal trends in internal estuarine production and consumption of CO2 were observed throughout both the upper tidal river and lower bay. Comparably, positive correlations between river-borne and air–water CO2 fluxes in the upper estuary emphasize the significance of river-borne CO2 degassing to overall CO2 fluxes. While river-borne CO2 degassing heavily influenced CO2 dynamics in the upper tidal river, these forces were largely compensated by internal biological processes within the extensive bay system of the lower estuary.

Effect of vegetation on limestone solution in a small High Arctic basin

1977 ◽  
Vol 14 (4) ◽  
pp. 571-581 ◽  
Author(s):  
Ming-Ko Woo ◽  
Philip Marsh
Keyword(s):  
Carbon Dioxide ◽  
Partial Pressure ◽  
Soil Water ◽  
Water Hardness ◽  
Late Summer ◽  
Arctic Basin ◽  
The Arctic ◽  
Total Hardness ◽  
Equilibrium Partial Pressure ◽  
Biogenic Carbon

To evaluate the effect of tundra vegetation on limestone solution processes, the present study was carried out in a small basin in southwestern Ellesmere Island, N.W.T. A test reach was selected along the stream, and water samples were collected at regular intervals from a seepage point entering the reach, a soil water pit at the bottom of a vegetated slope along the test reach, and from the stream at the outlet of the reach. Hydrochemical characteristics of the samples were described by several measured and calculated variables including water temperature, pH, calcium and total hardness, bicarbonate concentration, equilibrium partial pressure of carbon dioxide, and indices of saturation with respect to calcite and dolomite. Throughout the growing season of 1975, all samples indicated higher concentrations in water hardness and in bicarbonate than those reported in nonvegetated areas of the Arctic. A rising trend was apparent in these data, with the concentrations reaching a seasonal maximum in late summer. These phenomena are attributed to the production of biogenic carbon dioxide, which increased the aggressiveness of the water. The partial pressure of carbon dioxide in soil water was directly increased by this process, while the addition of soil water to the stream caused noticeable downstream increase in partial pressure of carbon dioxide and a corresponding reduction in saturation with respect to calcite and to dolomite. The influence of vegetation was therefore very marked in both surface and in subsurface flows.

Ammonia and other microclimatic conditions at an Australian pre-export sheep assembly depot

2013 ◽  
Vol 53 (6) ◽  
pp. 580
Author(s):  
Mathew K. Pines ◽  
Tracy Muller ◽  
Clive J. C. Phillips
Keyword(s):  
Carbon Dioxide ◽  
Hydrogen Sulfide ◽  
Moisture Content ◽  
Gaseous Emissions ◽  
Housing Systems ◽  
Health And Wellbeing ◽  
Ammonia Accumulation ◽  
Animal Excreta ◽  
Microclimatic Conditions ◽  
Positive Correlations

Noxious gases produced at hazardous concentrations in animal housing systems may affect the health and wellbeing of both animals and workers. In order to determine if the gaseous emissions from a pre-export assembly depot for sheep constituted a risk, atmospheric ammonia was measured in eight sheep buildings at an Australian assembly depot. Additionally, meteorological variables and distance from excreta were measured to determine their influence on ammonia, carbon dioxide and hydrogen sulfide concentrations. Repeat measurements were made at 12 sites in each building on 4 separate days, and four buildings were mapped using longitudinal and latitudinal transects. Concentrations of ammonia, carbon dioxide and hydrogen sulfide were all below the recommended safety thresholds for humans and livestock. There were positive correlations between ammonia and the following variables: ambient temperature and moisture content, and negative correlations with distance from animal excreta. Understanding these relationships will help to understand the reasons for ammonia accumulation in such buildings.

scholarly journals Environmental influences on carbon dioxide fluxes over three grassland ecosystems in China

2009 ◽  
Vol 6 (12) ◽  
pp. 2879-2893 ◽  
Author(s):  
Y. Fu ◽  
Z. Zheng ◽  
G. Yu ◽  
Z. Hu ◽  
X. Sun ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Soil Moisture ◽  
Alpine Meadow ◽  
Growing Season ◽  
Co2 Fluxes ◽  
Meadow Steppe ◽  
Temperate Steppe ◽  
Area Index ◽  
Grassland Ecosystems ◽  
Alpine Shrub

Abstract. This study compared carbon dioxide (CO2) fluxes over three grassland ecosystems in China, including a temperate semiarid steppe in Inner Mongolia (NMG), an alpine shrub-meadow in Qinghai (HB), and an alpine meadow-steppe in Tibet (DX). Measurements were made in 2004 and 2005 using the eddy covariance technique. Objectives were to document the seasonality of the net ecosystem exchange of CO2 (NEE) and its components, gross ecosystem photosynthesis (GEP), and ecosystem respiration (Reco), and to examine how environmental factors affect the CO2 exchange in these grassland ecosystems. The 2005 growing season (from May to September) was warmer than that of 2004 across the three sites, and precipitation in 2005 was less than that in 2004 at NMG and DX. The magnitude of CO2 fluxes (daily and annual sums) was largest at HB, which also showed the highest temperature sensitivity of Reco among the three sites. A stepwise multiple regression analysis showed that the seasonal variation of GEP, Reco, and NEE of the alpine shrub-meadow was mainly controlled by air temperature, whereas leaf area index can likely explain the seasonal variation in GEP, Reco, and NEE of the temperate steppe. The CO2 fluxes of the alpine meadow-steppe were jointly affected by soil moisture and air temperature. The alpine shrub-meadow acted as a net carbon sink over the two study years, whereas the temperate steppe and alpine meadow-steppe acted as net carbon sources. Both GEP and Reco were reduced by the summer and spring drought in 2005 at NMG and DX, respectively. The accumulated leaf area index during the growing season (LAIsum) played a key role in the interannual and intersite variation of annual GEP and Reco across the study sites and years, whereas soil moisture contributed most significantly to the variation in annual NEE. Because LAIsum was significantly correlated with soil moisture at a depth of 20 cm, we concluded that the available soil moisture other than annual precipitation was the most important factor controlling the variation in the CO2 budgets of different grassland ecosystems in China.

scholarly journals Carbon Dioxide Fluxes and Carbon Stocks under Conservation Agricultural Practices in South Africa

Agriculture ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 374 ◽  
Author(s):  
Patrick Nyambo ◽  
Chiduza Cornelius ◽  
Tesfay Araya
Keyword(s):  
South Africa ◽  
Carbon Dioxide ◽  
Soil Moisture ◽  
Carbon Stock ◽  
Crop Residue ◽  
Agricultural Practices ◽  
Carbon Stocks ◽  
Residue Management ◽  
Co2 Fluxes ◽  
Carbon Dioxide Fluxes

Understanding the impacts of agricultural practices on carbon stocks and CO2 emission is imperative in order to recommend low emission strategies. The objective of this study was to investigate the effects of tillage, crop rotation, and residue management on soil CO2 fluxes, carbon stock, soil temperature, and moisture in the semi-arid conditions in the Eastern Cape of South Africa. The field trial was laid out as a split-split-plot design replicated three times. The main plots were tillage viz conventional tillage (CT) and no-till (NT). The sub-plots were allocated to crop rotations viz maize–fallow–maize (MFM), maize–oat–maize (MOM), and maize–vetch–maize (MVM). Crop residue management was in the sub-sub plots, viz retention (R+), removal (R−), and biochar (B). There were no significant interactions (p > 0.05) with respect to the cumulative CO2 fluxes, soil moisture, and soil temperature. Crop residue retention significantly increased the soil moisture content relative to residue removal, but was not different to biochar application. Soil tilling increased the CO2 fluxes by approximately 26.3% relative to the NT. The carbon dioxide fluxes were significantly lower in R− (2.04 µmoL m−2 s−1) relative to the R+ (2.32 µmoL m−2 s−1) and B treatments (2.36 µmoL m−2 s−1). The carbon dioxide fluxes were higher in the summer (October–February) months compared to the winter period (May–July), irrespective of treatment factors. No tillage had a significantly higher carbon stock at the 0-5 cm depth relative to CT. Amending the soils with biochar resulted in significantly lower total carbon stock relative to both R+ and R−. The results of the study show that NT can potentially reduce CO2 fluxes. In the short term, amending soils with biochar did not reduce the CO2 fluxes compared to R+, however the soil moisture increases were comparable.

scholarly journals Geochemical Modeling of Scale Formation due to Cooling and CO2-degassing in San Kamphaeng Geothermal Field, Northern Thailand

2021 ◽  
Vol 20 (3) ◽  
Author(s):  
Sutthipong Taweelarp ◽  
Supanut Suntikoon ◽  
Thaned Rojsiraphisal ◽  
Nattapol Ploymaklam ◽  
Schradh Saenton
Keyword(s):  
Carbon Dioxide ◽  
Hot Springs ◽  
Hot Spring ◽  
Geochemical Modeling ◽  
Chemical Properties ◽  
Geothermal Field ◽  
Spring Water ◽  
Northern Thailand ◽  
Scaling Potential ◽  
Co2 Degassing

Scaling in a geothermal piping system can cause serious problems by reducing flow rates and energy efficiency. In this work, scaling potential of San Kamphaeng (SK) geothermal energy, Northern Thailand was assessed based on geochemical model simulation using physical and chemical properties of hot spring water. Water samples from surface seepage and groundwater wells, analyzed by ICP-OES and ion chromatograph methods for chemical constituents, were dominated by Ca-HCO3 facies having partial pressure of carbon dioxide of 10–2.67 to 10–1.75 atm which is higher than ambient atmospheric CO2 content. Surface seepage samples have lower temperature (60.9°C) than deep groundwater (83.1°C) and reservoir (127.1°C, based on silica geothermometry). Geochemical characteristics of the hot spring water indicated significant difference in chemical properties between surface seepage and deep, hot groundwater as a result of mineral precipitation along the flow paths and inside well casing. Scales were mainly composed of carbonates, silica, Fe-Mn oxides. Geochemical simulations based on multiple chemical reaction equilibria in PHREEQC were performed to confirm scale formation from cooling and CO2-degassing processes. Simulation results showed total cumulative scaling potential (maximum possible precipitation) from 267-m deep well was estimated as 582.2 mg/L, but only 50.4% of scaling potential actually took place at SK hot springs. In addition, maximum possible carbon dioxide outflux to atmosphere from degassing process in SK geothermal field, estimated from the degassing process, was 6,960 ton/year indicating a continuous source of greenhouse gas that may contribute to climate change. Keywords: Degassing, Geochemical modeling, PHREEQC, San Kamphaeng Hot Springs, Scaling

Optical Properties, Suspended Sediments, and Chemistry Associated with the Turbidity Maxima of the Delaware Estuary

1983 ◽  
Vol 40 (S1) ◽  
pp. s172-s179 ◽  
Author(s):  
Robert B. Biggs ◽  
Jonathan H. Sharp ◽  
Thomas M. Church ◽  
John M. Tramontano
Keyword(s):  
Optical Properties ◽  
Trace Metals ◽  
Attenuation Coefficient ◽  
Inorganic Nitrogen ◽  
Suspended Sediments ◽  
Inorganic Phosphorus ◽  
Turbidity Maximum ◽  
Salinity Range ◽  
Delaware Estuary ◽  
High Concentrations

Two turbidity maxima were found in the Delaware Estuary and were distinct both in terms of optical properties of the water and in quantity of suspended material. The upstream maximum occurred at about 1‰ salinity. Both the diffuse attenuation coefficient (KD) and the beam attenuation coefficient (α) responded to the double turbidity maxima. The upstream maximum contains a larger number of individual mineral grains with a mean diameter of about 3 μm; the downstream maximum, which occurred at salinities of 7.5–10‰, was dominated by composite particles with a mean size of 12 μm; at salinities > 10‰, the suspended sediment population was dominated by large (10–20 μm) individual particles with few composite particles.Nutrients, productivity, particulate organic matter, and dissolved and particulate metals all showed relationships to the turbidity maxima when viewed on salinity and on geographic axes. An excess of dissolved inorganic nitrogen in relation to dissolved inorganic phosphorus was mirrored by exceptionally low particulate C/P ratios in the region of the turbidity maxima. Primary productivity appeared to be greatly reduced in the region of the downstream turbidity maximum.The trace metals Fe, Mn, Cd, Cu, Co, and Ni showed a general association with particulate phases at lowest salinities, at the upstream turbidity maximum. The more particle reactive metals (Fe, Mn, and Co) reflected this as enrichment relative to particulate aluminum. At the downstream turbidity maximum, in the mid-salinity range, the trace metals showed a minimum relative to Al, probably due to dilution by resuspended bottom sediments. In the lower estuary, the trace metals exhibited the highest enrichment (relative to aluminum) and an association with high concentrations of particulate carbon.Key words: Delaware Estuary, turbidity maxima, optical properties, suspended sediments, chemistry

scholarly journals Seasonal variability of the inorganic carbon system in a large coastal plain estuary

2017 ◽  
Vol 14 (21) ◽  
pp. 4949-4963 ◽  
Author(s):  
Andrew Joesoef ◽  
David L. Kirchman ◽  
Christopher K. Sommerfield ◽  
Wei-Jun Cai
Keyword(s):  
Inorganic Carbon ◽  
Drainage Basin ◽  
Dissolved Inorganic Carbon ◽  
Coastal Ocean ◽  
Total Alkalinity ◽  
Delaware Estuary ◽  
Terrestrial Organic Matter ◽  
Delaware River ◽  
Export Flux ◽  
Carbon System

Abstract. Carbonate geochemistry research in large estuarine systems is limited. More work is needed to understand how changes in land-use activity influence watershed export of organic and inorganic carbon, acids, and nutrients to the coastal ocean. To investigate the seasonal variation of the inorganic carbon system in the Delaware Estuary, one of the largest estuaries along the US east coast, dissolved inorganic carbon (DIC), total alkalinity (TA), and pH were measured along the estuary from June 2013 to April 2015. In addition, DIC, TA, and pH were periodically measured from March to October 2015 in the nontidal freshwater Delaware, Schuylkill, and Christina rivers over a range of discharge conditions. There were strong negative relationships between river TA and discharge, suggesting that changes in HCO3− concentrations reflect dilution of weathering products in the drainage basin. The ratio of DIC to TA, an understudied but important property, was high (1.11) during high discharge and low (0.94) during low discharge, reflecting additional DIC input in the form of carbon dioxide (CO2), most likely from terrestrial organic matter decomposition, rather than bicarbonate (HCO3−) inputs due to drainage basin weathering processes. This is also a result of CO2 loss to the atmosphere due to rapid water transit during the wet season. Our data further show that elevated DIC in the Schuylkill River is substantially different than that in the Delaware River. Thus, tributary contributions must be considered when attributing estuarine DIC sources to the internal carbon cycle versus external processes such as drainage basin mineralogy, weathering intensity, and discharge patterns. Long-term records in the Delaware and Schuylkill rivers indicate shifts toward higher alkalinity in estuarine waters over time, as has been found in other estuaries worldwide. Annual DIC input flux to the estuary and export flux to the coastal ocean are estimated to be 15.7 ± 8.2  ×  109 mol C yr−1 and 16.5 ± 10.6  ×  109 mol C yr−1, respectively, while net DIC production within the estuary including inputs from intertidal marshes is estimated to be 5.1  ×  109 mol C yr−1. The small difference between riverine input and export flux suggests that, in the case of the Delaware Estuary and perhaps other large coastal systems with long freshwater residence times, the majority of the DIC produced in the estuary by biological processes is exchanged with the atmosphere rather than exported to the sea.

scholarly journals Quantitative Fluxes of the Greenhouse Gases CH4 and CO2 from the Surfaces of Selected Polish Reservoirs

Atmosphere ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 286
Author(s):  
Renata Gruca-Rokosz
Keyword(s):  
Carbon Dioxide ◽  
Greenhouse Gases ◽  
Water Column ◽  
Co2 Fluxes ◽  
Ch4 Flux ◽  
Chamber Method ◽  
Tropical Reservoirs ◽  
Se Poland ◽  
Carbon Dioxide Co2 ◽  
Eutrophic Reservoirs

Research carried out in the years 2009–2011 and 2018–2019 sought to determine the magnitudes of fluxes of methane (CH4) and carbon dioxide (CO2) from the surfaces of three eutrophic reservoirs in SE Poland. The “static chamber” method was deployed at five or six stations located along the reservoirs, where the water column at its deepest slightly exceeds 2 m. Obtained values for the fluxes of CH4 varied across a wide (0–2513.48 mmol·m−2·d−1) range, with many of these values therefore exceeding those characteristics for large tropical reservoirs. The reservoirs studied were not found to differ significantly in terms of average CH4 flux, however. Where obtained values for CO2 fluxes in the range from −10.96 to 621.69 mmol·m−2·d−1 were concerned, most fell within the range given for temperate-zone reservoirs, while differences between reservoirs were noted for average values in this case.

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