scholarly journals Particulate and Dissolved Black Carbon in Bohai and Laizhou Bays, China: Distributions, Sources, and Contrasts Under Two Distinct Fluvial Hydrological Regimes

2021 ◽  
Vol 9 ◽  
Author(s):  
Yin Fang ◽  
Guopei Huang ◽  
Yingjun Chen ◽  
Limin Hu ◽  
Jun Lin ◽  
...  

Coastal seas, including coastal bays, are the geographically critical transitional zone that links terrestrial and open oceanic ecosystems. Organic carbon cycling in this area is a dynamic and disproportionally key component in the global carbon cycle and budget. As the thermally-transformed organic carbon produced exclusively from the incomplete combustion of biomass and fossil fuels, the recalcitrance and resultant longer environmental residence times result in important implications of black carbon (BC) in the global carbon budget. However, the environmental dynamics of BC in coastal seas have not well been constrained. In this study, we conducted one seawater sampling campaign in the high-intensity BC emission influenced Bohai Bay (BHB) and Laizhou Bay (LZB) in 2013, and quantified both particulate and dissolved BC (PBC and DBC). We elaborated the distributions, sources, and associated influencing factors of PBC and DBC in BHB and LZB in 2013, and simultaneously contrasted the PBC and DBC quantity and quality under two distinct fluvial hydrological regimes of 2013 and 2014 [discussed in Fang et al. (Environ. Sci. Technol., 2021, 55, 788–796)]. Except for the overwhelmingly high PBC in northern BHB caused by anthropogenic point-source emission, horizontally, both PBC and DBC showed a seaward decreasing trend, suggesting that riverine discharge was the major source for PBC and DBC. Vertically, in contrast to the uniform concentrations of DBC between surface and bottom waters, the PBC levels in bottom waters was significantly higher than that in surface waters, which was primarily resulted from the intense sediment re-suspension process during this sampling period. The nearly simultaneous investigations in 2013 and 2014 revealed consistent spatial patterns of PBC and DBC quantity and quality. But significantly lower PBC and DBC quantity and quality were found in 2014 than in 2013, which were largely due to the significantly different climatic conditions (including the watershed hydrology and sunlit radiation) between these 2 years.

2021 ◽  
Author(s):  
Marta Crispo ◽  
Duncan D. Cameron ◽  
Will Meredith ◽  
Aaron Eveleigh ◽  
Nicos Ladommatos ◽  
...  

<p>Black carbon (BC), the product of the incomplete combustion of fossil fuels and biomass, is ubiquitous in soils globally. Although BC is a major soil carbon pool, its effects on the global carbon cycle have not yet been resolved. It is deemed to represent a large stable pool in soils turning over on geological timescales, but research suggests it can alter soil biogeochemical cycling including that of ecosystem-derived organic carbon. Here, we established two soil microcosm chamber experiments: experiment one added <sup>13</sup>C organic carbon to soil with and without added BC (soot and biochar) to investigate whether it suppressed organic carbon mineralisation; experiment two added <sup>13</sup>C BC (soot) to soil to establish whether it is mineralised in soil over a short timescale. Gases were sampled over six-months and analysed using isotope ratio mass spectrometry. In experiment one we found that the efflux of <sup>13</sup>C organic carbon from the soil decreased over time, but the addition of soot to soil significantly reduced the mineralisation of organic carbon from 32% of the total supplied without soot to 14% of the total supplied with soot. In contrast, there was not a significant difference after the addition of biochar in the flux of δ <sup>13</sup>CO<sub>2 </sub>from the organic carbon added to the soil. In experiment two, we found that the efflux <sup>13</sup>C from soil with added <sup>13</sup>C labelled soot significantly differed from the control, but this efflux declined over time. There was a cumulative loss of 0.17% <sup>13</sup>C from soot over the experiment.These experimental results represent a step-change in understanding the influence of BC continuum on carbon dynamics, which has major consequences for the way we measure, monitor and manage soils for carbon storage and sequestration in the future.</p>


SOIL ◽  
2015 ◽  
Vol 1 (1) ◽  
pp. 147-171 ◽  
Author(s):  
C. L. Ping ◽  
J. D. Jastrow ◽  
M. T. Jorgenson ◽  
G. J. Michaelson ◽  
Y. L. Shur

Abstract. Knowledge of soils in the permafrost region has advanced immensely in recent decades, despite the remoteness and inaccessibility of most of the region and the sampling limitations posed by the severe environment. These efforts significantly increased estimates of the amount of organic carbon stored in permafrost-region soils and improved understanding of how pedogenic processes unique to permafrost environments built enormous organic carbon stocks during the Quaternary. This knowledge has also called attention to the importance of permafrost-affected soils to the global carbon cycle and the potential vulnerability of the region's soil organic carbon (SOC) stocks to changing climatic conditions. In this review, we briefly introduce the permafrost characteristics, ice structures, and cryopedogenic processes that shape the development of permafrost-affected soils, and discuss their effects on soil structures and on organic matter distributions within the soil profile. We then examine the quantity of organic carbon stored in permafrost-region soils, as well as the characteristics, intrinsic decomposability, and potential vulnerability of this organic carbon to permafrost thaw under a warming climate. Overall, frozen conditions and cryopedogenic processes, such as cryoturbation, have slowed decomposition and enhanced the sequestration of organic carbon in permafrost-affected soils over millennial timescales. Due to the low temperatures, the organic matter in permafrost soils is often less humified than in more temperate soils, making some portion of this stored organic carbon relatively vulnerable to mineralization upon thawing of permafrost.


Atmosphere ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 923
Author(s):  
Outi Meinander ◽  
Enna Heikkinen ◽  
Minna Aurela ◽  
Antti Hyvärinen

Black carbon (BC), organic carbon (OC), and total carbon (TC) in snow are important for their climatic and cryospheric effects. They are also part of the global carbon cycle. Atmospheric black and organic carbon (including brown carbon) may deposit and darken snow surfaces. Currently, there are no standardized methods for sampling, filtering, and analysis protocols to detect carbon in snow. Here, we describe our current methods and protocols to detect carbon in seasonal snow using the OCEC thermal optical method, a European standard for atmospheric elemental carbon (EC). We analyzed snow collected within and around the urban background SMEARIII (Station for Measuring Ecosystem-Atmosphere Relations) at Kumpula (60° N) and the Arctic GAW (Global Atmospheric Watch) station at Sodankylä (67° N). The median BC, OC, and TC in snow samples (ntot = 30) in Kumpula were 1118, 5279, and 6396 ppb, and in Sodankylä, they were 19, 1751, and 629 ppb. Laboratory experiments showed that error due to carbon attached to a sampling bag (n = 11) was <0.01%. Sonication slightly increased the measured EC, while wetting the filter or filtering the wrong side up indicated a possible sample loss. Finally, we discuss the benefits and drawbacks of OCEC to detect carbon in snow.


Water ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1509
Author(s):  
Yuanyi Li ◽  
Huan Feng ◽  
Guillaume Vigouroux ◽  
Dekui Yuan ◽  
Guangyu Zhang ◽  
...  

A storm surge is a complex phenomenon in which waves, tide and current interact. Even though wind is the predominant force driving the surge, waves and tidal phase are also important factors that influence the mass and momentum transport during the surge. Devastating storm surges often occur in the Bohai Sea, a semi-enclosed shallow sea in North China, due to extreme storms. However, the effects of waves on storm surges in the Bohai Sea have not been quantified and the mechanisms responsible for the higher surges that affect part of the Bohai Sea have not been thoroughly studied. In this study, we set up a storm surge model, considering coupled effects of tides and waves on the surges. Validation against measured data shows that the coupled model is capable of simulating storm surges in the Bohai Sea. The simulation results indicate that the longshore currents, which are induced by the large gradient of radiation stress due to wave deformation, are one of the main contributors to the higher surges occurring in some coastal regions. The gently varying bathymetry is another factor contributing to these surges. With such bathymetry, the wave force direction is nearly uniform, and pushes a large amount of water in that direction. Under these conditions, the water accumulates in some parts of the coast, leading to higher surges in nearby coastal regions such as the south coast of the Bohai Bay and the west and south coasts of the Laizhou Bay. Results analysis also shows that the tidal phase at which the surge occurs influences the wave–current interactions, and these interactions are more evident in shallow waters. Neglecting these interactions can lead to inaccurate predictions of the storm surges due to overestimation or underestimation of wave-induced set-up.


2011 ◽  
Vol 116 (D15) ◽  
Author(s):  
L. K. Sahu ◽  
Y. Kondo ◽  
Y. Miyazaki ◽  
Prapat Pongkiatkul ◽  
N. T. Kim Oanh

2013 ◽  
Vol 54 (62) ◽  
pp. 97-104 ◽  
Author(s):  
Chengyu Liu ◽  
Wei Gu ◽  
Jinlong Chao ◽  
Lantao Li ◽  
Shuai Yuan ◽  
...  

AbstractTo investigate the spatio-temporal characteristics of sea-ice resource, we used sea-ice volume to measure the amount of sea-ice resource in the Bohai Sea, China. The sea-ice area was extracted from Advanced Very High Resolution Radiometer (AVHRR) remote-sensing images using the zonal threshold method. The sea-ice thickness was estimated using a sea-ice model based on shortwave radiation theory and field measurements. The spatio-temporal characteristics of sea-ice volume were then analysed using GIS technology. The results indicate that the Bohai Sea experienced two sea-ice volume peaks in winter 2009/10. The largest sea-ice volume was in Liaodong Bay (∼80.26% of the entire sea-ice volume of the Bohai Sea). Bohai Bay had the second largest ice volume, and Laizhou Bay the smallest. The relationship between sea-ice volume and distance from shore is essentially exponential. The proportion of total sea-ice volume that is 0–10 km from shore is ∼42.43%, whereas the proportion that is 100–110 km from shore is only 0.002%.


2021 ◽  
Vol 1 ◽  
Author(s):  
Sebastian Preusser ◽  
Patrick Liebmann ◽  
Andres Stucke ◽  
Johannes Wirsching ◽  
Karolin Müller ◽  
...  

Litter-derived dissolved organic carbon (DOC) is considered to be a major source of stabilised C in soil. Here we investigated the microbial utilisation of litter-derived DOC within an entire soil profile using a stable isotope labelling experiment in a temperate beech forest. The natural litter layer of a Dystric Cambisol was replaced by 13C enriched litter within three areas of each 6.57 m−2 for 22 months and then replaced again by natural litter (switching-off the 13C input). Samples were taken continuously from 0 to 180 cm depths directly after the replacement of the labelled litter, and 6 and 18 months thereafter. We followed the pulse of 13C derived from aboveground litter into soil microorganisms through depth and over time by analysing 13C incorporation into microbial biomass and phospholipid fatty acids. Throughout the sampling period, most of the litter-derived microbial C was found in the top cm of the profile and only minor quantities were translocated to deeper soil. The microbial 13C stocks below 30 cm soil depth at the different samplings accounted constantly for only 6–12% of the respective microbial 13C stocks of the entire profile. The peak in proportional enrichment of 13C in subsoil microorganisms moved from upper (≤ 80 cm soil depth) to lower subsoil (80–160 cm soil depth) within a period of 6 months after switch-off, and nearly disappeared in microbial biomass after 18 months (&lt; 1%), indicating little long-term utilisation of litter-derived C by subsoil microorganisms. Among the different microbial groups, a higher maximum proportion of litter-derived C was found in fungi (up to 6%) than in bacteria (2%), indicating greater fungal than bacterial dependency on litter-derived C in subsoil. However, in contrast to topsoil, fungi in subsoil had only a temporarily restricted increase in litter C incorporation, while in the Gram-positive bacteria, the C incorporation in subsoil raised moderately over time increasingly contributing to the group-specific C stock of the entire profile (up to 9%). Overall, this study demonstrated that microorganisms in topsoil of a Dystric Cambisol process most of the recently deposited aboveground litter C, while microbial litter-derived C assimilation in subsoil is low.


Author(s):  
Robert Hall ◽  
Jennifer Tank ◽  
Michelle Baker ◽  
Emma Rosi-Marshall ◽  
Michael Grace ◽  
...  

Primary production and respiration are core functions of river ecosystems that in part determine the carbon balance. Gross primary production (GPP) is the total rate of carbon fixation by autotrophs such as algae and higher plants and is equivalent to photosynthesis. Ecosystem respiration (ER) measures rate at which organic carbon is mineralized to CO2 by all organisms in an ecosystem. Together these fluxes can indicate the base of the food web to support animal production (Marcarelli et al. 2011), can predict the cycling of other elements (Hall and Tank 2003), and can link ecosystems to global carbon cycling (Cole et al. 2007).


2019 ◽  
Vol 29 (2) ◽  
Author(s):  
Miroslav Josipovic ◽  
Catherine Leal-Liousse ◽  
Belinda Crobeddu ◽  
Armelle Baeza-Squiban ◽  
C. Keitumetse Segakweng ◽  
...  

This study aimed to characterise aerosols sampled in the vicinity of a major industrialised area, i.e. the Vaal Triangle. It included thedetermination of oxidative potential as a predictive indicator of particle toxicity. Aerosol samples were collated through the cascadefiltering during an eight-month period (12 h over three days in one week). Three size fractions were analysed for organic carbon(OC), black carbon (BC) and oxidative potential (OP), while ionic content was presented as monthly and seasonal concentrations. Thecontinuous measurement of black carbon by an optical attenuation instrument was collated concurrently with cascade filtering. Thecarbonaceous content was low compared to the ionic one. Within the carbonaceous concentrations, the organic carbon was higherthan concentrations of black carbon in both seasons in the ultra-fine fraction; the opposite was the case for the fine fraction, whilethe coarse fraction concentrations of organic carbon in the dry season had higher concentrations than black carbon in the wet seasonand organic carbon in the wet season. The OP tended to increase as the size was decreasing for wet season aerosols, whereas, forthe dry season, the highest OP was exerted by the fine fraction. The ultrafine fraction was the one showing the most contrasting OPbetween the two seasons. Continuous monitoring indicated that the higher BC concentrations were recorded in the dry/winter partof the year, with the daily pattern of concentrations being typically bimodal, having both the morning and evening peaks in bothseasons. Within the ionic content, the dominance of sulphate, nitrate and ammonium was evident. Multiple linear correlations wereperformed between all determined compounds. Strong correlations of carboxylic acids with other organic compounds were revealed.These acids point to emissions of VOC, both anthropogenic and biogenic. Since they were equally present in both seasons, a mixtureof sources was responsible, both present in the wider area and throughout the year.


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