Emerging investigator series: spatial distribution of dissolved organic matter in ice and at air–ice interfaces

2019 ◽  
Vol 21 (7) ◽  
pp. 1076-1084 ◽  
Author(s):  
Subha Chakraborty ◽  
Tara F. Kahan
Keyword(s):  
Organic Matter ◽  
Spatial Distribution ◽  
Dissolved Organic Matter ◽  
Surface Interactions ◽  
Heterogeneous Reactions ◽  
Organic Solutes ◽  
Ice Surface ◽  
Snow And Ice

Organic solutes in snow and ice can be distributed heterogeneously throughout the ice bulk and across the ice surface. This may affect air-surface interactions and heterogeneous reactions in snow-covered regions.

scholarly journals Temporal and Spatial Distribution and Fluorescence Spectra of Dissolved Organic Matter in Plateau Lakes: A Case Study of Qinghai Lake

Water ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 3481
Author(s):  
Zheng Li ◽  
Zhenghui Fu ◽  
Yang Zhang ◽  
Yunyan Guo ◽  
Feifei Che ◽  
...  
Keyword(s):  
Organic Matter ◽  
Spatial Distribution ◽  
Dissolved Organic Matter ◽  
Fluorescence Intensity ◽  
Rapid Development ◽  
Water Environment ◽  
Anthropogenic Sources ◽  
Qinghai Lake ◽  
Total Fluorescence ◽  
Temporal And Spatial

Dissolved organic matter (DOM) has a great impact on the main pollution indicators of lakes (such as chemical oxygen demand, COD). Therefore, DOM is the research basis for understanding the meaning of the water environment and the laws of the migration and transformation of pollutants. Qinghai Lake is one of the world’s typical inland plateau lake wetlands. It plays important roles in improving and regulating the climate and in promoting a virtuous regional ecological cycle. In recent years, with the acceleration of urbanization and the rapid development of tourism, under the background of climate change, and with grassland degradation and precipitation change, the whole basin of Qinghai Lake has been facing great ecological pressure. In order to comprehensively explore the water environment of Qinghai Lake and to protect the sustainable development of the basin, a systematic study was carried out on the whole basin of Qinghai Lake. The results show the following: (1) from 2010 to 2020, the annual average value of CODCr in Qinghai Lake fluctuated in the range from class III to class V according to the surface water environmental quality standard, showing first a downward trend and then an upward trend. (2) The concentration of CDOM in Qinghai Lake had obvious temporal and spatial changes. (3) The spatial distribution of the total fluorescence intensity of FDOM in water was also different in different seasons. However, in the three surveys, the area with the highest total fluorescence intensity of FDOM in the water body appeared near Erlangjian in the south of Qinghai Province, indicating that anthropogenic sources are the main controlling factors of dissolved organic matter in the lake.

Molecular fractionation and sub-nanoscale distribution of dissolved organic matter on allophane

2019 ◽  
Vol 6 (7) ◽  
pp. 2037-2048 ◽  
Author(s):  
Yang Ding ◽  
Yang Lu ◽  
Peng Liao ◽  
Shimeng Peng ◽  
Yuzhen Liang ◽  
...  
Keyword(s):  
Organic Matter ◽  
Spatial Distribution ◽  
Dissolved Organic Matter ◽  
Molecular Fractionation

We elucidated the spatial distribution of DOM on allophane and the mechanisms controlling the adsorptive fractionation of DOM molecules.

Molecular composition and spatial distribution of dissolved organic matter (DOM) in the Pearl River Estuary, China

2020 ◽  
Vol 17 (3) ◽  
pp. 240 ◽  
Author(s):  
Chen He ◽  
Qiong Pan ◽  
Penghui Li ◽  
Wei Xie ◽  
Ding He ◽  
...  
Keyword(s):  
Organic Matter ◽  
Spatial Distribution ◽  
Dissolved Organic Matter ◽  
River Estuary ◽  
Pearl River Estuary ◽  
Molecular Composition ◽  
Pearl River ◽  
Terrestrial Organic Matter ◽  
The Pearl River Estuary ◽  
The Pearl River

Environmental contextEstuaries play an important role in global carbon cycling in terms of transforming dissolved organic matter (DOM). We describe the molecular composition and spatial distribution of DOM in the Pearl River Estuary, an area severely impacted by anthropogenic activities, and show how DOM composition gradually changes with salinity. The results will help our understanding of the sources and transformations of anthropogenic DOM discharged to the coastal seas. AbstractThe Pearl River is the second-largest river in China in terms of water discharge and brings enormous amounts of nutrients and terrestrial organic matter to the South China Sea, which makes the Pearl River Estuary (PRE) highly eutrophic. However, the molecular composition and distribution of dissolved organic matter (DOM) in the PRE have scarcely been investigated. In this study, solid-phase extraction (SPE) was performed to collect DOM samples from PRE along a salinity gradient. The samples were characterised by negative-ion electrospray ionisation (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) to analyse their molecular composition and spatial distribution. The FT-ICR MS results showed that the terrestrial organic matter was gradually diluted and/or degraded during the migration from the river to the coastal ocean. Furthermore, both sulfur containing and unsaturated molecules were highly abundant in the upper stream samples, which indicated that anthropogenic input might be another important source of the assigned DOM in PRE. A group of bio-refractory molecules, characterised as carboxylic-rich alicyclic-like molecules, was found to accumulate with the increase of salinity. The composition of the SPE-DOM showed a gradual variation with the salinity and spatial changes; however, the variation was slightly different from those in pristine estuaries. This study demonstrates that the molecular composition of DOM is crucial for elucidating its source and transformation in an estuary.

scholarly journals Temporal and Spatial Distribution and Fluorescence Spectra of Dissolved Organic Matter in Plateau Lakes -- A Case Study of Qinghai Lake

2021 ◽  
Author(s):  
Zheng Li ◽  
Zhenghui Fu ◽  
Yang Zhang ◽  
Yunyan Guo ◽  
Feifei Che ◽  
...  
Keyword(s):  
Organic Matter ◽  
Spatial Distribution ◽  
Dissolved Organic Matter ◽  
Lake Water ◽  
Water Body ◽  
Mean Value ◽  
Qinghai Lake ◽  
Temporal And Spatial Distribution ◽  
The Mean ◽  
Temporal And Spatial

Abstract Dissolved organic matter (DOM) has a great influence on the main pollution indexes of lakes (such as COD). Therefore, DOM research is the basis for understanding the water environmental quality and the law of pollutant migration and transformation in the basin. In this study, the water quality monitoring data of Qinghai Lake water body and 8 rivers around the lake from 2010 to 2020 were collected, and the dissolved organic matter (DOM) was synchronously sampled in May, September and October 2020. The optical characteristics of DOM, the temporal and spatial distribution of CDOM and the fluorescence spectrum and fluorescence component characteristics of FDOM were analyzed and studied. The results show that: (1) From 2010 to 2020, the annual mean value of CODCr of Qinghai Lake water body fluctuates in the range of Class III to Class V according to the environmental quality standard of the surface water, and shows a downward trend first and then an upward one. In general, the mean value of CODCr concentration in Qinghai Lake water body is at a high level and varies slightly among different months. (2) The mean value of CODCr concentration of the eight main rivers entering Qinghai Lake from 2010 to 2020 can be sorted from lowest to highest as follows: Ganzi River, Buha River, Jilmeng River, Hargai River, Shaliu River, Quanji River, HeMa River, and DaoTang River. (3) The concentration of CDOM in Qinghai Lake shows not only obvious seasonal variation (October, September and May, in the descending order) but also spatial variation. (4) The three-dimensional fluorescence spectrum matrix data of DOM in Qinghai Lake were analyzed by PARAFAC model, and four DOM fluorescence components with single maximum emission wavelength were analyzed.

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