The dissolved organic iodine species of the isotopic ratio of129I/127I: A novel tool for tracing terrestrial organic carbon in the estuarine surface waters of Galveston Bay, Texas

2005 ◽  
Vol 3 (8) ◽  
pp. 326-337 ◽  
Author(s):  
Kathleen A. Schwehr ◽  
Peter H. Santschi ◽  
David Elmore
Keyword(s):  
Organic Carbon ◽  
Surface Waters ◽  
Isotopic Ratio ◽  
Galveston Bay ◽  
Iodine Species ◽  
Organic Iodine

Particulate organic carbon in Atlantic surface waters

Nature ◽  
1977 ◽  
Vol 266 (5604) ◽  
pp. 713-716 ◽  
Author(s):  
S. KRISHNASWAMI ◽  
D. LAL
Keyword(s):  
Organic Carbon ◽  
Particulate Organic Carbon ◽  
Surface Waters

scholarly journals Prominent bacterial heterotrophy and sources of <sup>13</sup>C-depleted fatty acids to the interior Canada Basin

2013 ◽  
Vol 10 (11) ◽  
pp. 7065-7080 ◽  
Author(s):  
S. R. Shah ◽  
D. R. Griffith ◽  
V. Galy ◽  
A. P. McNichol ◽  
T. I. Eglinton
Keyword(s):  
Fatty Acids ◽  
Particulate Matter ◽  
Organic Carbon ◽  
Suspended Particulate Matter ◽  
Surface Waters ◽  
Canada Basin ◽  
The Arctic ◽  
Deep Basin ◽  
Suspended Particulate ◽  
Chemoautotrophic Bacteria

Abstract. In recent decades, the Canada Basin of the Arctic Ocean has experienced rapidly decreasing summer sea ice coverage and freshening of surface waters. It is unclear how these changes translate to deeper waters, particularly as our baseline understanding of organic carbon cycling in the deep basin is quite limited. In this study, we describe full-depth profiles of the abundance, distribution and carbon isotopic composition of fatty acids from suspended particulate matter at a seasonally ice-free station and a semi-permanently ice-covered station. Fatty acids, along with suspended particulate organic carbon (POC), are more concentrated and 13C-enriched under ice cover than in ice-free waters. But this influence, apparent at 50 m depth, does not propagate downward below 150 m depth, likely due to the weak biological pump in the central Canada Basin. Branched fatty acids have δ13C values that are similar to suspended POC at all depths and are more 13C-enriched than even-numbered saturated fatty acids at depths above 3000 m. These are likely to be produced in situ by heterotrophic bacteria incorporating organic carbon that is isotopically similar to total suspended POC. Below surface waters, there is also the suggestion of a source of saturated even-numbered fatty acids which could represent contributions from laterally advected organic carbon and/or from chemoautotrophic bacteria. At 3000 m depth and below, a greater relative abundance of long-chain (C20–24), branched and unsaturated fatty acids is consistent with a stronger influence of re-suspended sedimentary organic carbon. At these deep depths, two individual fatty acids (C12 and iso-C17) are significantly depleted in 13C, allowing for the possibility that methane oxidizing bacteria contribute fatty acids, either directly to suspended particulate matter or to shallow sediments that are subsequently mobilized and incorporated into suspended particulate matter within the deep basin.

scholarly journals Treatment of Combined Acid Black 48 and Coffee Wastewater by Low-Cost Adsorbents

2020 ◽  
Vol 76 (3) ◽  
pp. 47-61
Author(s):  
Yung-Tse Hung ◽  
Abhiram Pamula ◽  
Howard Paul
Keyword(s):  
Activated Carbon ◽  
Organic Carbon ◽  
Binary Mixture ◽  
Surface Waters ◽  
Low Cost ◽  
Combined Treatment ◽  
Synthetic Dyes ◽  
Treatment Methods ◽  
Onion Peel ◽  
Peanut Hull

Removal of synthetic dyes from wastewater is essential both from the environmental and human health point of view. A small concentration of synthetic dyes can reduce water transparency and consequently influence photosynthesis and alter aquatic ecosystems. Acid black 48 is an Azo dye that falls under the category of synthetic dyes used in the textile industry. With dyes, coffee wastewater has high chemical oxygen demand (COD) that can affect dissolved oxygen (DO) in surface waters. A mixture of wastes in surface waters creates a need to investigate the efficiency of existing treatment methods and optimize them. Adsorption using activated carbon is a conventional method used to remove dyes and heavy metals from wastewater. Industries prefer efficient and economical treatment methods to meet challenging effluent standards regarding COD, BOD, and intensity of color. The adsorption process was optimized using low-cost adsorbents in the current study, including peanut hull and onion peel, to treat a binary mixture of acid black 48 and coffee wastewater. After adsorption, microfiltration was used to remove any suspended solids from the wastewater solution. The performance of combined treatment processes for the color removal of the binary mixture was analyzed and compared using transmittance and absorbance. Treatment efficiency of adsorption using low-cost adsorbents was compared with powdered activated carbon. Apart from absorbance and transmittance, non-purgeable organic carbon (NPOC) values were analyzed to determine organic carbon removal in the combined binary wastewater. Experimental results indicated that Langmuir isotherm was the best fit for a binary mixture with an optimum dosage of 1.2 g using onion peel. The regression coefficient value was 0.82, and the uptake was 58.13 mg of binary mixture per 1 g of onion peel. The effective pH for maximum uptake of acid black 48 using onion peel for adsorption was 5.7. The increasing dosage of low-cost adsorbents adsorption improved in removing binary waste of dyes and coffee waste from wastewater. Adsorption using onion peel improved adsorbent performance up to 1.2 g dosage and steadily decreased beyond that. The adsorption capacity of onion peel was comparatively higher than the peanut hull based on the linear fit.

scholarly journals Characterizing the origin of excess dissolved organic carbon in coastal seawater using stable carbon isotope and light absorption characteristics

2020 ◽  
Author(s):  
Heejun Han ◽  
Jeomshik Hwang ◽  
Guebuem Kim
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Isotopic Ratio ◽  
Stable Carbon Isotope ◽  
Bacterial Degradation ◽  
Salinity Range ◽  
Stable Carbon ◽  
Reclaimed Land ◽  
Δ13c Values ◽  
Coastal Seawater

Abstract. In order to determine the origins of dissolved organic matter (DOM) occurring in coastal seawater of the Sihwa Lake, South Korea, which is semi-enclosed by a dyke, we measured the stable carbon isotopic ratio of dissolved organic carbon (DOC-δ13C) and optical properties (absorbance and fluorescence) of the DOM in two different seasons (March 2017 and September 2018). The concentrations of DOC were generally higher in lower-salinity waters in both periods, while a significant excess of DOC was observed in 2017 in the same salinity range. The main source of DOC, dependent on salinity, was found to be from marine sediments in the freshwater-seawater mixing zone rather than from terrestrial sources based on the DOC-δ13C values (−20.7±1.2 ‰) and good correlations among DOC, humic-like fluorescent DOM (FDOMH), and NH4+ concentrations. However, the excess DOC observed in 2017 seems to originate from terrestrial sources by direct land-seawater interactions rather than from in-situ biological production, considering the lower DOC-δ13C values (−27.8 ‰ to −22.6 ‰) and higher spectral slope ratio (SR) of light absorbance, without increases in FDOMH and NH4+ concentrations. This terrestrial DOM source could have been exposed to light and bacterial degradation for a long time, resulting in nonfluorescent and low-molecular-weight DOM, as this study area is surrounded by the reclaimed land. Our results suggest that the combination of these biogeochemical tools can be a powerful tracer of coastal DOM sources.

scholarly journals Origin and fate of particulate and dissolved organic matter in a naturally iron-fertilized region of the Southern Ocean

2014 ◽  
Vol 11 (10) ◽  
pp. 14097-14132 ◽  
Author(s):  
L. Tremblay ◽  
J. Caparros ◽  
K. Leblanc ◽  
I. Obernosterer
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Dissolved Organic Matter ◽  
Southern Ocean ◽  
Surface Waters ◽  
Bacterial Degradation ◽  
Natural Iron ◽  
Average Proportion ◽  
Carbon Pump ◽  
Microbial Carbon

Abstract. Natural iron fertilization of high-nutrient low-chlorophyll (HNLC) waters induces annually occurring spring phytoplankton blooms off Kerguelen Islands (Southern Ocean). To examine the origin and fate of particulate and dissolved organic matter (POM and DOM), D- and L-amino acids (AA) were quantified at bloom and HNLC stations. Total hydrolysable AA accounted for 21–25% of surface particulate organic carbon (%POCAA) at the bloom sites, but for 10% at the HNLC site. A marked decrease in %POCAA with depth was observed at the most productive stations leading to values between 3 and 5% below 300 m depth. AA contributed to only 0.9–4.4% of dissolved organic carbon (%DOCAA) at all stations. The only consistent vertical trend was observed at the most productive station (A3-2) where %DOCAA decreased from ∼2% in the surface waters to 0.9% near 300 m. These AA yields and other markers revealed that POM and DOM were more rapidly altered or mineralized at the bloom sites compared to the HNLC site. Different molecular markers indicated that POM mostly originated from diatoms and bacteria. The estimated average proportion of POM from intact phytoplankton cells in surface waters was 45% at the bloom station A3-2, but 14% at the HNLC site. Estimates based on D-AA yields indicated that ∼15% of POM and ∼30% of DOM was of bacterial origin (cells and cell fragments) at all stations. Surprisingly, the DOM in HNLC waters appeared less altered than the DOM from the bloom, had slightly higher dissolved AA concentrations, and showed no sign of alteration within the water column. Unfavorable conditions for bacterial degradation in HNLC regions can explain these findings. In contrast, large inputs of labile organic molecules and iron, likely stimulate the degradation of organic matter (priming effect) and the production of more recalcitrant DOM (microbial carbon pump) during iron-fertilized blooms.

Links between hydrological patterns and lateral carbon fluxes: a comparison between a wet and a drained site on a Siberian permafrost floodplain tundra

2021 ◽  
Author(s):  
Sandra Raab ◽  
Mathias Goeckede ◽  
Jorien Vonk ◽  
Anke Hildebrandt ◽  
Martin Heimann
Keyword(s):  
Organic Carbon ◽  
Water Table ◽  
Surface Waters ◽  
Carbon Fluxes ◽  
Flow Patterns ◽  
Control Site ◽  
Water Levels ◽  
Soil Conditions ◽  
Transport Patterns ◽  
Carbon Transport

&lt;p&gt;As a major reservoir for organic carbon, permafrost areas play a pivotal role in global climate change. Vertical carbon fluxes as well as lateral transport from land to groundwaters and surface waters towards the ocean are highly dependent on various abiotic and biotic factors. These include for example temperature, groundwater depth, or vegetation community. During summer months, when soils thaw and lateral carbon transport within suprapermafrost groundwater bodies and surface waters occurs, flow patterns and therefore carbon redistribution may differ significantly between dry and wet conditions. Since dry soil conditions are expected to become more frequent in the future, associated shifts in carbon transport patterns play an important role in quantifying the carbon input into the water body linked to permafrost degradation.&lt;/p&gt;&lt;p&gt;This study focuses on hydrological and carbon transport patterns within a floodplain tundra site near Chersky, Northeast Siberia. We compared a wet control site with a site affected by a drainage ring built in 2004 to study the effect of water availability on carbon production and transport. Water table depths at both sites were continuously monitored with a distributed sensor network over the summer seasons 2016-2020. At several locations, water samples were collected in 2016 and 2017 to determine organic carbon concentrations (DOC) as well as carbon isotopes (e.g. &amp;#8710;&lt;sup&gt;14&lt;/sup&gt;C-DOC). Suprapermafrost groundwater and surface water from the drainage ditch and the nearby Ambolikha river were included in the analysis.&lt;/p&gt;&lt;p&gt;Our results focus on the physical hydrological conditions as well as on DOC and &amp;#8710;&lt;sup&gt;14&lt;/sup&gt;C-DOC observations. The spatio-temporal dynamics of water table depth revealed systematic differences between control and drained sites. The drained area showed a stronger decrease in water tables towards peak summer season in July and stronger reactions to precipitation events. The control area responded less pronounced to short-term changes. At the drained site, the main groundwater flow direction was stable throughout the measurement period. The control site was characterized by a shift in water flow confluence depending on increasing and decreasing water levels. DOC and &amp;#8710;&lt;sup&gt;14&lt;/sup&gt;C-DOC data showed that the highest concentrations of organic carbon and oldest DOC can be found in late summer. DOC concentrations were higher at the drained site compared to the wet site. We will show that the distribution of dissolved carbon can be directly related to hydrological flow patterns, and that understanding of these redistribution processes is essential for interpreting the carbon budget in disturbed permafrost.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;

scholarly journals Iodine speciation and size distribution in ambient aerosols at a coastal new particle formation hotspot in China

2019 ◽  
Vol 19 (6) ◽  
pp. 4025-4039 ◽  
Author(s):  
Huan Yu ◽  
Lili Ren ◽  
Xiangpeng Huang ◽  
Mingjie Xie ◽  
Jun He ◽  
...  
Keyword(s):  
Particle Formation ◽  
Coastal Areas ◽  
Aerosol Sample ◽  
Size Distributions ◽  
New Particle Formation ◽  
Nucleation Mode ◽  
Iodine Species ◽  
Organic Iodine ◽  
Iodine Compounds ◽  
Iodine Speciation

Abstract. Intense new particle formation (NPF) events were observed in the coastal atmosphere during algae growth and farming season at Xiangshan gulf of the east China coast. High nucleation-mode iodine concentrations measured by ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF-MS) confirmed that the NPF events were induced by iodine species. Our study provides important information on iodine speciation, size distributions, and its role in NPF in the context of heavy air pollution in China's coastal areas. For the first time, we identified 5 inorganic iodine species, 45 organic iodine compounds (35 molecular formulas), and a group of iodide–organic adducts in aerosols. The concentrations and size distributions of iodine species down to 10 nm were measured during the iodine-induced NPF, continental NPF, and non-NPF days at the coastal site and compared to those at an inland site. The iodine in the above four aerosol sample types were characterized by iodate, aromatic iodine compounds, iodoacetic acid or iodopropenoic acid, and iodide–organic adducts, respectively. Iodide and organic iodine compounds were found in the nucleation-mode particles; however, it is still not clear whether they contributed to nucleation or just new particle growth. Wild algae, as well as farmed algae, could be an important NPF source in China's coastal areas.

Changes in surface water quality after inundation of acid sulfate soils of different vegetation cover

Soil Research ◽  
2005 ◽  
Vol 43 (1) ◽  
pp. 1 ◽  
Author(s):  
S. G. Johnston ◽  
P. G. Slavich ◽  
P. Hirst
Keyword(s):  
Surface Water ◽  
Organic Carbon ◽  
Surface Waters ◽  
Titratable Acidity ◽  
Grass Species ◽  
Melaleuca Quinquenervia ◽  
Vegetative Cover ◽  
Acid Sulfate ◽  
Surface Water Chemistry ◽  
Short Period

Surface soils from an acid sulfate soil (ASS) backswamp were inundated in a temperature controlled environment and surface-water chemistry changes monitored. The soils had contrasting in situ vegetative cover [i.e. 2 grass species, Cynodon dactylon and Pennisetum clandestinum (Poaceae), and litter from Melaleuca quinquenervia (Myrtaceae)]. The different vegetation types had similar biomass and carbon content; however, there were large differences in the quality and lability of that carbon, which strongly influenced decay/redox processes and the chemical composition of surface waters. The grass species had more labile carbon. Their surface waters displayed rapid sustained O2 depletion and sustained low Eh (~0 mV), high dissolved organic carbon (DOC), and moderate pH (5–6). Their soil acidity was partially neutralised, sulfides were re-formed, and reductive dissolution of Fe(III) led to the generation of stored acidity in the water column as Fe2+(aq). In contrast, M. quinquenervia litter was high in decay-resistant compounds. Its surface waters had lower DOC and low pH (<4) and only underwent a short period of low O2/Eh. Soluble Al caused M. quinquenervia surface waters to have higher titratable acidity and soil pH remained consistently low (~3.8–4.0). Concentrations of Cl– and Al in surface waters were strongly correlated to initial soil contents, whereas the behaviour of Fe and SO42– varied according to pH and redox status. This study demonstrates that changes in vegetation communities in ASS backswamps that substantially alter either (a) the pool of labile vegetative organic carbon or (b) the concentration of acidic solutes in surface soil can have profound implications for the chemical characteristics of backswamp surface waters.

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