Research News
SUSTech researchers publish study on typhoon redistributed microplastics in coastal areas and uniformed plastisphere community
The increasing microplastic pollution, together with the plastisphere-associated ecological threats in coastal areas, have aroused global concern. Tropical cyclones have increased in both frequency and intensity under global warming, causing an intense impact on the microplastics distribution and the structure of coastal ecosystems. However, until most currently, the extent to which typhoon impacts the microplastics and plastisphere community remains poorly known.Recently, researchers from the Southern University of Science and Technology (SUSTech) published a paper on the subject. Their study, entitled “Typhoon-induced turbulence redistributed microplastics in coastal areas and reformed plastisphere community,” was published in the journal Water Research.The emergence of plastic has provided huge social benefits but also brought serious environmental problems. Due to the long half-life and the hydrophobic surface of plastics, it is generally believed that microplastics can be served as vehicles to promote microbial colonization and biofilm formation, the so-called “plastisphere”, and eventually become a pelagic habitat for microorganisms. At the same time, microplastics provide more ways for the long-distance transmission of potentially pathogenic microorganisms, posting ecological impacts on the original ecosystem.Extreme storm events, such as tropical cyclones (i.e., tropical storms and typhoons), can significantly affect coastal ecosystems. However, limited studies have been conducted to investigate the effect of typhoons on microplastic abundance, composition, and distribution to date. Given the growing ecological concerns aroused by increasingly frequent and severe tropical cyclones, such effort is of no doubt inadequate to clarify the impacts of typhoons on the coastal microplastic distribution.Furthermore, even though plastisphere has been recognized to modify the environmental fate of microplastic particles, no study has demonstrated the influence of typhoons on plastisphere to date. Therefore, more research is urgently needed to better understand how typhoons impact the microplastic distribution in the environment and ultimately impact ecosystem function by regulating plastisphere composition.Figure 1. Mean (±SD) abundance of microplastics in surface water (a) and sediments (b) collected in Shenzhen coastal areas before and after a typhoon (B: before the typhoon; A: after the typhoon). The bar plot at the upright corner shows differences in microplastic abundance before and after typhoon (paired-sample t-test). Correlation analysis of microplastic abundance in surface water (c) and sediment (d) before and after the typhoon.Figure 2. The microplastic characteristics before and after the typhoon (B: before the typhoon; A: after the typhoon). (a) Distribution of size, color, and shape of microplastics in surface water and sediment. (b) PCoA biplot shows the differences in microplastic characteristics before and after the typhoon for water and sediment samples.The study found a significant typhoon-induced increase in microplastic abundance in surface water, whereas an opposite trend was observed in sediment. Despite the evident transportation of microplastics from sediment to surface water by agitation, a possible microplastics influx was introduced by typhoons, as evidenced by the prominent attribution of unknown force in source tracking analysis.Additionally, typhoons have adeptly uniformed the plastisphere community in the sediment along the 190km coastal line overnight. A significant increase of nitrogen fixer, Bradyrhizobiaceae, was observed ubiquitously after a typhoon, which might alter the nitrogen cycling and increase the eutrophic condition of the coastal ecological system. Together, this study expanded the knowledge about the impact of a typhoon-induced influx of microplastics on coastal biogeochemical cycling.Figure 3. Bacterial community diversity of plastisphere and their shaping factors (B: before the typhoon; A: after the typhoon). (a) Bacterial community composition of plastisphere displayed at the phylum level. (b) Alpha diversity profiles of plastisphere community. Shannon and Pielou’s Evenness indices comprehensively denote the richness and homogeneity of the bacterial community. (c) Principal coordinate analysis of the plastisphere communities. (d) Bray–Curtis db-RDA plots displaying the relationships between plastisphere communities and microplastic characteristics.Figure 4. Spearman correlation between the relative abundance of each OTU and microplastic characteristics. OTU_1 was the most abundant taxon and affiliated with Bradyrhizobiaceae. The bar plot shows differences in the relative abundance of OTU_1 between before and after the typhoon.Liming Chen, a postdoctoral fellow, and Jiangpeng Li, a Ph.D. student, are the co-first authors of this paper. Associate Professor Yuanyuan Tang and Assistant Professor Yu Xia from the School of Environmental Science and Engineering at SUSTech are the co-corresponding authors.The study was supported by the National Natural Science Foundation of China (NSFC), Natural Science Foundation of Guangdong Province, State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, and the Center for Computational Science and Engineering at SUSTech.Paper link:https://doi.org/10.1016/j.watres.2021.117580Additional contact information:Associate Professor Yuanyuan Tang: tangyy@sustech.edu.cnAssistant Professor Yu Xia: xiay@sustech.edu.cn
SUSTech's Junguo Liu co-authors paper on food waste and its environmental impact
Recently, Chair Professor Junguo Liu from the School of Environmental Science and Engineering at the Southern University of Science and Technology (SUSTech) co-authored a paper in Nature Food, an online journal publishing top-tier food-related research in the natural, applied, and social sciences. The paper was entitled “China's food loss and waste embodies increasing environmental impacts.”In recent years, food loss and waste have become a global problem, which has attracted widespread attention from academia, government, and the public. Food loss and waste are closely related to food security, food safety, nutrition and health, resources, environment, economy, and society. They are considered to be major environmental issues for the sustainable development of the global food system. However, monitoring and benchmarking food loss and waste reduction is often constrained by the lack of reliable and consistent data, especially for emerging economies. This research is based on the large-scale field investigations conducted by the Ministry of Agriculture and Rural Affairs and the Chinese Academy of Sciences (CAS) from 2013 to 2018 on food losses in the supply chain, food waste in households, and catering industries. It quantifies the food loss and waste of major agrifood products along the entire farm-to-fork chain in China.Figure 1. Food flow and waste in China’s supply chain from the farm to the tableThe result shows that 27% of food annually produced for human consumption in the country (349 ± 4 Mt) is lost or wasted. 45% of this is associated with postharvest handling and storage and 17% with consumption activities. The paper also shows that the land, water, carbon, nitrogen, and phosphorus footprints associated with total food loss and waste are similar to those of a medium-sized country, such as the United Kingdoms, in the case of carbon footprint.Figure 2. Land footprint, water footprint, carbon footprint, nitrogen footprint, and phosphorus footprint of food waste in ChinaThese results highlight that food loss and waste in China have a greater impact on resources and the environment. Reducing food waste at the consumption stage has a significant effect on reducing various environmental footprints.This paper is the work of a collaborative effort between researchers from the Chinese Academy of Sciences (CAS), the University of Southern Denmark, Ministry of Agriculture (MOA) of the People’s Republic of China, Wuhan University, the University of Pennsylvania, and SUSTech.It is worth mentioning that Junguo Liu was one of the earliest scholars in China who paid attention to food waste and its environmental impact. In 2013, as the first corresponding author, he published an article entitled “Food Loss and Waste in China and their Implication for Water and Land” in Environmental Science and Technology (ES&T). The results showed that food waste and food loss have a huge environmental impact on water and land resources. The food waste rate in China is 19% (+5%), which is far lower than the waste rate in the United States and European countries. The study found that the food waste rate in Chinese canteens and households is only 5-7%, but the food waste rate in restaurants is as high as 19%. This shows that Chinese food culture and habits play an important role in influencing the rate of food waste.Paper links:https://www.nature.com/articles/s43016-021-00317-6https://pubs.acs.org/doi/10.1021/es401426b 
Southeast Asia's forest clearance is climbing to higher elevations at an accelerating rate, resulting in unprecedented forest carbon stock loss
Recently, a joint research team led by the Southern University of Science and Technology (SUSTech) shows that forest clearance in Southeast Asia is accelerating during the 21st century, with clearance frontier climbing to higher elevations and steeper slopes with high forest carbon stocks. Forest losses have resulted in a tremendous biomass carbon loss (424 Tg C yr−1), potentially nudging Southeast Asian forests to be a net carbon source in the global carbon budget.Most tropical deforestation is believed to occur in lowlands where forests are easy to access and deforested lands are feasible to plantations. However, recent studies have reported new croplands and plantations converted from mountain forests in Southeast Asia, generating a deeply divided debate on forest dynamics in the region. The study, entitled “Upward expansion and acceleration of forest clearance in the mountains of Southeast Asia,” was published on June 28 in Nature Sustainability. It uncovered forest loss dynamics and associated topographical patterns using multiple high-resolution satellite products of forest change and topography.The authors found that forest clearance in the mountains of Southeast Asia has accelerated during the 21st century, accounting for a third of total forest loss in the region. New plantations primarily drove deforestation at high elevations. Zhenzhong Zeng, who led the research and works as an associate professor at SUSTech, visually interpreted high-resolution satellite imagery in Southeast Asia three years previously. He found substantial mountain forests converted to croplands, although mechanical and intensive plantations in the mountains are not technically possible and economically feasible.“I was shocked by the tremendous deforestation in the mountains and think we should contribute to the sustainable development of forests. My Ph.D. student, Yu Feng, and I worked with Zhenzhong to figure out how Southeast Asia’s forests change. We combined multiple satellite data to quantify forest dynamics and associated topography, and surprisingly found accelerating mountain forest loss in the region,” said Professor Chunmiao Zheng of SUSTech.Figure 1. Example of massive forests that have been lost for cultivations in the mountains of Southeast AsiaThe researchers discovered that the frontier of forest clearance climbed to higher elevations and steeper slopes where forests have high carbon stocks. This means that forest loss shifted to regions with high carbon stocks, resulting in more forest carbon loss than expected. Combining forest loss data with a forest biomass carbon map, they discovered that carbon loss resulting from forest clearance was mainly in the lowlands in the 2000s, e.g., Indonesia. In the 2010s, however, lowland forest carbon loss decreased while mountain forest carbon loss in regions like Myanmar and Laos increased significantly. As mountain forests hold more biomass carbon than lowland forests, accelerating mountain forest clearance exacerbated carbon stock loss in the region.“I have spent three years doing a deforestation project in Nan Province, sponsored by the Kasikornbank and Princeton University, and took many pictures of mountain deforestation there as shown above. I’m glad to see the situation is becoming much better in Nan Province according to our new findings. Unfortunately, the situation of mountain deforestation is becoming worse in many other mountain regions of Southeast Asia,” said Professor Zeng.“Forest loss in the lowlands of Southeast Asia has rightly received a lot of attention, but that has shifted focus from an emerging pattern of extensive loss in the mountains that is increasing rapidly and threatens many species found nowhere else,” said Paul Elsen, Climate Adaptation Scientist for the Wildlife Conservation Society (WCS) and one of the co-authors of the study.Although multiple lines of evidence reveal that tropical forests likely act as a neutral contributor to the global carbon cycle, the accelerating clearance of mountain forests with high carbon density portends forest carbon loss in the near future. Consequently, this could potentially nudge Southeast Asia’s forests to be a net carbon source in the global carbon budget. Most deforested lands in the mountains have been turned into croplands, which may further intensify climate warming in the region through biochemical and biophysical feedbacks. The study provides important implications for regional land-use management and climate change adaption and mitigation.Figure 2. Corn and dasheen fields converted from forests in Southeast AsiaIn addition to Associate Professor Zhenzhong Zeng, Yu Feng, Professor Chunmiao Zheng, and Dr. Paul Elsen are also co-authors of this study. Other researchers included Yang Liu, Xinyue He, and Xin Jiang of SUSTech, Professor Alan D. Ziegler of MaeJo University (MJU), and Professors Dominick V. Spracklen and Joseph Holden, both of the University of Leeds.This project was supported in part by the National Natural Science Foundation of China (NSFC) and the start-up fund provided by SUSTech.Paper link: https://www.nature.com/articles/s41893-021-00738-y
SUSTech Xingxing Kuang's team publishes findings on relative air permeability for multiphase flow in porous media
Recently, Associate Professor Xingxing Kuang’s group from the School of Environmental Science and Engineering at the Southern University of Science and Technology (SUSTech) published a research article, entitled “Effects of water retention curves and permeability equations on the prediction of relative air permeability” in Geophysical Research Letters, a top journal in Geoscience category. Through model derivation and measured data validation, this research revealed the predominant role of the permeability equation in determining the relative air permeability in disturbed soils.Relative air permeability, a key parameter in multiphase flow numerical simulators like TOUGH2 and STOMP, is indispensable when investigating several geophysical issues such as soil aeration and evapotranspiration, the simulation of reservoir CO2 injection, and the study of hydraulic fracturing fluid migration in the subsurface. Currently, a lot of effort has been dedicated to studying the relative water permeability, whereas research upon relative air permeability is comparatively less. In addition, measured data on relative air permeability that is used for model validation is not plentiful in literature.Combining two traditional and two fractal water retention curves, respectively, with six permeability equations, they obtained twelve statistical and twelve fractal relative air permeability models (six statistical and nine fractal models were derived for the first time). These models were subsequently tested with thirty-one experimental datasets of disturbed soils to examine their predictive ability for relative air permeability. Results showed that compared to the selection of traditional or fractal water retention curves, the choice of permeability equations is more critical for the appropriate prediction of relative air permeability, indicating the dominant role of the pore tortuosity-connectivity in determining air permeability in disturbed soils. This research sheds light on the appropriate selection of relative air permeability, which will be used in the multiphase flow numerical simulators for the accurate modeling of airflow in porous/fractured media.Figure 1. Comparison of measured data for Poudre river sand with predicted results. (a) BCB, VGB, ASVB, and LB models and (b) BCMB, VGMB, ASVMB, and LMB models.Figure 2. Comparison of measured data for Columbia sandy loam with predicted results. (a) BCM, VGM, ASVM, and LM models and (b) BCMM, VGMM, ASVMM, and LMM models.Figure 3. Scatter charts of measured versus predicted relative air permeability values by (a) VGM, (b) VGMM, (c) LM, and (d) LMM models.Associate Professor Xingxing Kuang at SUSTech is the corresponding author for this paper. Westlake University’s research scientist Zhenlei Yang and Chair Professor Ling Li are the first and co-author, respectively. Assistant Professor Xin Tong at Inner Mongolia Agricultural University (IMAU) and Regent Professor Binayak P. Mohanty at Texas A&M University also participated in this study. This work was funded by the National Natural Science Foundation of China (NSFC).Paper link: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2021GL092459
SUSTech's Hailong Li joins international team to reveal effects of submarine groundwater discharge on coastal ecosystems
Recently, Professor Hailong Li from the School of Environmental Sciences and Engineering at the Southern University of Science and Technology (SUSTech), in collaboration with an international research team including scientists from the University of Gothenburg, Leibniz Centre for Tropical Marine Research (ZMT), and Westlake University, published a paper in Nature Reviews Earth & Environment, entitled “Submarine groundwater discharge impacts on coastal nutrient biogeochemistry”. This paper evaluates the results of numerous studies, quantifies nutrient fluxes from groundwater inputs, and explains their effects on marine ecosystems.Water quality management in the ocean often targets visible pollution sources such as rivers, atmospheric deposition, and sewage. But nutrients also enter the oceans through groundwater. The importance of Submarine Groundwater Discharge (SGD) has often been overlooked in comparison to other sources mainly because the discharge occurs below the water surface and cannot be easily observed and measured. Quantifying SGD-derived nutrient fluxes is therefore challenging and involves nuanced assumptions and interpretations, and a wide range of skills in oceanography, hydrology, and biogeochemistry.This paper evaluates the results of numerous studies. They were conducted at more than 200 sites in coastal areas worldwide, ranging from polar to tropical seas (Figure 1). Of the locations investigated, around 60% of the studies showed that nutrients such as nitrogen, phosphorus, and silicon enter the sea in greater quantities via groundwater than via rivers, the largest sources of nutrients in the oceans (Figure 2). This makes groundwater the most important nutrient supplier to coastal ecosystems at many coastal locations. Projections show that groundwater worldwide releases around 140 million tons of silicon, 40 million tons of nitrogen, and 9 million tons of phosphorus into the sea each year.Figure 1. Submarine Groundwater Discharge (SGD) rates from study cases reviewed. (a) SGD fluxes globally, color-coded by ecosystem type, where the size of the circle represents the reported SGD rate. Similar maps for each nutrient are shown in the supplementary material. Investigations where SGD rates are reported without any nutrient fluxes were not included in the compilation. (b) SGD in Hawaii, USA, with ecosystems colored and rates scaled as above. (c) SGD in the Mediterranean. (d) SGD on the east coast of the USA. (e) SGD in East Asia. (f) SGD on the eastern coast of Australia.Figure 2. River and SGD-derived nutrient inputs to the ocean. (a) Summary of global-scale fluxes compiled from the river, Fresh Submarine Groundwater Discharge (Fresh SGD) and total (mostly saline) SGD estimates. (b) Histogram of ratios between SGD and river-derived dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus (DIP), and dissolved silicate (DSi) fluxes summarized from the global study cases reviewed.SGD consists of a mixture of continental fresh water and saltwater that permeates from the coastal aquifer. It is an invisible hydrological link between coastal aquifers and the sea. In addition to supplying fresh water to the sea or other coastal systems (lagoons, wetlands), SGD can represent an important source of nutrients for these ecosystems. Therefore, SGD plays a critical role in their sustainment and, consequently, on the goods and services provided by these ecosystems. Due to this underground connectivity, any anthropogenic impact on coastal groundwater, such as pumping water, the use of fertilizers, or the infiltration of urban water into aquifers, can affect the transfer of nutrients to the ocean.SGD-substance inputs can be a blessing or a curse for coastal ecosystems. For example, coral reefs can benefit from the fact that carbonate dissolved in groundwater promotes coral calcification. An example of this would be the nutrient-rich groundwater sources of Australia’s “Wonky Holes”, which are hotspots for fish such as giant bass and, highlighting the importance for fishing and tourism. However, there are also negative impacts of groundwater flows on coastal ecosystems. In many places, excess nutrients lead to overfertilization of water bodies and to algal blooms (Figure 3). Such negative effects of nutrients are seen off the coast of Hawaii where the U.S. Supreme Court also recently ruled that groundwater must be better protected to guard the coastal ocean.Figure 3. The biological impacts of SGDUnderstanding the delivery of anthropogenically-derived nutrients to the coastal ocean through groundwater discharge is, therefore, crucial to ensure appropriate management of coastal waters. Researchers consider that, unfortunately, since SGD is essentially invisible and highly variable along different coastlines, decision-makers face two opposing risks; ignoring a potentially important pollution source or wasting resources on a potentially small source. In addition, since the role of SGD in ecological, economic, and societal context is not appropriately constrained, management strategies and policies cannot become effective.Climate and land-use change are expected to modify patterns of global water use, drive sea levels to rise, force seawater infiltration into coastal aquifers, and modify the chemical composition and volume of groundwater. These changes are expected to modify fluxes of nutrients from SGD, but little is known on how increased anthropogenic pressures will modify the quality and quantity of groundwater fluxes to the ocean. In addition, the slow movement of SGD relative to rivers implies that current contaminant and nutrient flows reflect past inputs, and management approaches must prepare for increasing loads in the decades to come. A proper understanding of their role in the ecological and economic context is needed to develop effective coastal management strategies.The joint study was led by Professor Isaac R. Santos at the University of Gothenburg, Sweden. Professor Isaac R. Santos is the first and corresponding author of the paper. Professor Hailong Li from the School of Environmental Sciences and Engineering at SUSTech is a member of the international team that authored this paper. His research was supported by the National Natural Science Foundations of China (NSFC) (41972260, 41430641).Paper link: https://doi.org/10.1038/s43017-021-00152-0
SUSTech Chunmiao Zheng's team unveils role of groundwater flow in "Asian water tower"areas
The Himalayas are the greatest mountain range on Earth, but these peaks are not just a magnificent spectacle. They are also regarded as “Water towers of Asia”. The Himalayas are critical for supplying water for around two billion people who live downstream, and available water is highly sensitive to climate change. The role of the groundwater system in sustaining the northern Himalayan rivers remains unknown, and this compromises Asia's future water sustainability.Recently, Professor Chunmiao Zheng’s research team from the Southern University of Science and Technology (SUSTech), discovered the role of groundwater flow in “Asian water tower” areas. They published their results in collaboration with top research institutions in China and internationally, including Xi’an Jiaotong University (XJTU), The University of Texas at Austin (UT Austin), Seoul National University (SNU), and the Institute of Tibetan Plateau Research (ITP), Chinese Academy of Science (CAS). Their research, entitled “Role of Groundwater in Sustaining Northern Himalayan Rivers”, was published in the high-impact journal Geophysical Research Letters. Their study models the spatial groundwater flow and discharge volume to the Yarlung Zangbo, the largest river of the Himalayas in China, based on long-term climate and streamflow observations.The research group of Professor Zheng quantifies the spatiotemporal contribution of groundwater to river flows in the Yarlung Zangbo Basin (upper reaches of Brahmaputra). Their results show that the groundwater recharge represents around 23% of mean annual precipitation, translating into around 30 km3/yr of baseflow, which contributes to around 55% of the total river discharge in the upstream reaches and 27% in the downstream reaches. The percentage of groundwater contribution is inversely related to topographic steepness and total precipitation, with the steepest topography and highest precipitation in the eastern Himalayas. This study fills a knowledge gap on subsurface flow processes in the northern Himalayas and provides a baseline for comparing changes in the stream flow under climatic warming over vulnerable water tower regions.Figure 1. Spatial distribution of groundwater flow. (a) Simulated groundwater flow paths and heads; the color of the lines represents the distance of the flow path from source to sink area, and the frequency histograms of the distance of flow path and head are showed on the left side. (b) Simulated average annual groundwater discharge volume (Qg) in the form of baseflow along streams per kilometer and groundwater recharge (R) per unit basin area, and the frequency histograms of Qg and R are shown on the left side.The groundwater flow patterns and recharge-discharge mechanisms within the aquifers of the northern Himalayans are poorly known, which limits understanding of the hydrological cycle and predictions of future changes in the sensitive “water tower” mountainous regions. A three-dimensional, physically-based regional-scale groundwater model was developed for the Yarlung Zangbo basin in the northern Himalayan mountainous region. Major study findings include that the short (<5 km) and intermediate (10–50 km) distance flow paths account for over 75% and dominate spatial flow patterns for the groundwater system of the northern Himalayans in China. It’s estimated that 124 mm/yr, around 23% of mean precipitation, recharges to groundwater, and this translates into about 30 km3/yr of baseflow.The Northern Himalayan groundwater system contributes 27%-55% of annual river discharge from west upstream to east downstream. The percentage of groundwater contribution to river discharge is inversely related to the steepness of the topography and precipitation, with the steepest topography and highest annual precipitation in the downstream reaches. These results also indicate that the groundwater recharge and discharge would increase with the projected increasing ratio of recharge to precipitation, and thawing permafrost would increase groundwater recharge and discharge. Their evaluation fills a knowledge gap in one of the most complex alpine groundwater systems and provides a baseline for extending geoscience and socio-economic studies in high mountainous regions.Figure 2. Seasonal groundwater recharge and discharge. (a) Spatial distribution of annual average ratio between recharge and precipitation. (b to h) Seasonal changes of observed river discharge (Q), groundwater discharge (Qg), precipitation (P), and groundwater recharge (R) for each sub basin. In top subfigures, the monthly averaged Q and ranges of Q are shown in dotted blue lines and transparent blue areas, respectively, and the computed Qg by digital filter algorithms and the Qg simulated by three-dimensional numerical groundwater model are shown in dotted black lines and red lines, respectively. In the bottom subfigures, the monthly average P and R are shown in transparent blue areas and red areas, and the R/P is shown in dotted black lines.Yingying Yao, an Associate Professor at XJTU is the first author of this paper. Professor Chunmiao Zheng of the School of Environmental Science and Engineering at SUSTech is the corresponding author. This work was supported by the National Natural Science Foundation of China (NSFC) and the Shenzhen Municipal Science, Technology and Innovation Committee.Paper link: http://dx.doi.org/10.1029/2020GL092354
Researchers collaborate to pinpoint sources of ozone pollution in the Beijing−Tianjin−Hebei area using adjoint modeling
A group of researchers from the Southern University of Science and Technology (SUSTech) and Peking University (PKU) collaborated to pinpoint the sources of surface ozone pollution in the Beijing-Tianjin-Hebei area using adjoint modeling. Their research, entitled “Sensitivities of Ozone Air Pollution in the Beijing−Tianjin−Hebei Area to Local and Upwind Precursor Emissions Using Adjoint Modeling”, was published in Environmental Science & Technology, a top journal in the field of environmental science.The Beijing−Tianjin−Hebei area (BTH) of China has experienced severe summertime surface ozone pollution, which poses serious public health risks. The Chinese government has recently strengthened BTH ozone pollution prevention, emphasizing the emission reductions of highly active non-methane volatile organic compounds (NMVOCs). For such efforts to be effective, there must be quantitative understandings of the sources of ozone pollution, including the contributing precursors, their spatial origins, and their emitting activities. Adjoint modeling is an efficient method to quantify the source of ozone in the receptor area and can provide speciated, sector-resolved, and spatially-resolved information on the precursors contributing to ozone.Figure 1. Quantifying the sensitivity of surface ozone pollution in the Beijing-Tianjin-Hebei area to local and upwind precursor emissions.Researchers from SUSTech and PKU used the GEOS-Chem chemical transport model’s adjoint to analyze the sensitivity of population-weighted BTH ozone to regional precursor emissions in June 2019 under three different levels of ozone pollution severity: (1) heavily polluted (exceeding 20% or more), (2) slightly polluted (exceeding 0-10%), and (3) non-exceedance.Figure 2. Sensitivities of population-weighted BTH MDA8 surface ozone concentrations to a 10% increase of precursor emissions (unit, 10−3 ppb) over North China on BTH heavily polluted days in June 2019.The study showed that during heavily polluted days (Figure 2), BTH ozone was highly sensitive to emissions from BTH and south of BTH in the Shandong, Henan, and Jiangsu region (SHJ). To mitigate heavy BTH ozone pollution, the most effective measures entailed reducing NOx (from industrial process and transportation), ≥C3 alkenes (from on-road gasoline vehicles and industrial processes), and xylenes (from paint use) emitted from both BTH and SHJ, and CO (from industrial processes, transportation, and power generation) and ≥C4 alkanes (from industrial processes, paint and solvent use, and on-road gasoline vehicles) emissions from SHJ.Figure 3. Sensitivities of BTH ozone to four anthropogenic NMVOC species (≥C4 alkanes, ≥C3 alkenes, xylenes, and toluene) on heavily polluted days. Sensitivities are segregated for the emitting activities and the provinces/cities of emission.NMVOC species are emitted from a wide range of anthropogenic activities. As such, species-based emission reductions may be difficult to implement and manage. In comparison, sector- or subsector-based emission reduction actions target key emitting activities, where emissions can be controlled by improving or substituting processes and technologies. By further mapping the sensitivities to the subsector NMVOC emissions (Figure 3), this study pointed out the key NMVOC emission activities that should be targeted: paint use (for architecture, vehicles, wood products, and other products), on-road gasoline vehicles, and industrial processes (mainly including coking, oil refinement, distribution and storage of oil/gas, and chemical production).This research pinpointed the key areas and sectors that should be targeted in regionally-coordinated emission reduction efforts and provided a concrete and feasible way for improving the ground-level ozone air quality in Beijing-Tianjin-Hebei. The methodology can also be applied to address ozone pollution issues in other parts of the country.Xiaolin Wang, a Ph.D. student at PKU, is the first author of this study. Professor Tzung-May Fu of SUSTech and Professor Lin Zhang of PKU are the corresponding authors. This work was supported by the National Natural Science Foundation of China (NSFC) and the Basic and Applied Basic Research Foundation of Guangdong Province. Computational resources were provided by the Center for Computational Science and Engineering at SUSTech.Paper link: https://pubs.acs.org/doi/abs/10.1021/acs.est.1c00131
SUSTech's Environment and Ecology discipline enters ESI's global top 1%
On May 13, 2021, Clarivate Analytics released the latest Essential Science Indicators (ESI) ranking data. For the first time, the Environment and Ecology discipline at the Southern University of Science and Technology (SUSTech) ranks among the top 1% of all institutes in the world. This makes Environment and Ecology the fifth discipline at SUSTech to rank within the top 1% of the world, following Chemistry, Materials Sciences, Engineering, and Clinical Medicine.The ESI ranking is based on citation statistics for the period from 2011 to 2021. During this time, a total of 544 ESI papers on environmental science and ecology were published, with a total of 4785 citations. These papers were mostly published by faculty and students from the School of Environmental Science and Engineering, the Department of Ocean Science and Engineering, and the Department of Materials Science and Engineering. The School of Environmental Science and Engineering was established in May 2015. The fact that the Environment/Ecology discipline is ranking top 1% in the world after only six years is a testament to its rapid development and the high quality of its research.The ESI is an analytical tool that helps identify top-performing research based on the Web of Science Core Collection. ESI surveys more than 12,000 journals worldwide to rank authors, institutions, countries, and journals in 22 broad fields based on publication and citation performance. The data covers a rolling 10-year period and includes bi-monthly updates to rankings and citation counts. It should be noted that ESI is only a partial reflection of scientific research performance, and it is not the sole indicator of academic excellence and innovation.
SUSTech Zuotai Zhang's team makes advanced progress in solid amine CO2 capture materials
China is an active participant in global climate governance and insists on promoting CO2 mitigation. General Secretary Xi Jinping put forward the ambitious goal of striving to achieve carbon neutrality by 2060 at the 75th United Nations General Assembly. The development of CO2 capture and storage (CCS) technology can avoid CO2 emissions from industrial emission point sources and reduce the CO2 already in the atmosphere. It is an important part of achieving the goal of “carbon neutrality”, and is of great significance for deep decarbonization, large-scale production of low-carbon hydrogen energy, low-carbon power supply, and realization of negative emissions.Recently, Professor Zuotai Zhang and Research Assistant Professor Feng Yan from the School of Environmental Science and Engineering (ESE) at the Southern University of Science and Technology (SUSTech), innovatively prepared a series of low-cost, green, and efficient porous nano-SiO2/Al2O3 supported solid amine CO2 adsorbents using solid waste as the main raw materials. These results have been published in the well-known journals of Environmental Science & Technology and Chemical Engineering Journal in the environmental and energy fields.Figure 1. Preparation and carbon neutralization application of solid waste-derived nano-Al2O3 supported solid amine CO2 adsorbentsThe porous nano-Al2O3 support was firstly synthesized from high-aluminum coal fly ash, and the active PEI was then impregnated on the nano-Al2O3 support to prepare the solid amine CO2 adsorbent, which possessed a superior CO2 adsorption capacity of 136 mg·g-1. Significantly, this solid amine CO2 adsorbent showed stable adsorption capacity even regenerated under the pure CO2 atmosphere, and its CO2 adsorption capacity still maintained as high as 111 mg·g-1 adsorbent after 10 cycles, which was 5.5 times higher than that of traditional nano-SiO2 supported solid amine adsorbents. Therefore, this technical route, which can realize the high-value utilization of coal fly ash and significantly improve the cyclic stability of solid amine adsorbent regenerated under the pure CO2 atmosphere, has broad application prospects in CO2 capture and separation processes such as industrial source CO2 capture and biogas upgrading. This research, entitled “Highly efficient and stable PEI@Al2O3 adsorbents derived from coal fly ash for biogas upgrading”, was published in the Chemical Engineering Journal.On this basis, the research group continued to study in-depth the interaction mechanism of support-organic amine and the anti-urea chain formation mechanism of nano-Al2O3 supported solid amine CO2 adsorbents. The results have shown that the unique cross-linking reaction between nano-Al2O3 support and organic amine molecules significantly inhibited the formation of urea chains in nano-Al2O3 supported solid amine CO2 adsorbents during the cyclic adsorption-regeneration process, thereby greatly improving the cyclic stability of CO2 adsorption capacity.The study further verified the long-term cyclic stability of nano-Al2O3 supported solid amine CO2 adsorbents, whose adsorption capacity decreased by only 29% after 100 cycles regenerated under the pure CO2 atmosphere. This work not only clarifies the CO2 adsorption cycle stabilization mechanism of nano-Al2O3 supported solid amine CO2 adsorbents, but also provides design ideas for the development of new high-stable solid amine CO2 adsorbents with anti-urea properties. This research, entitled “Biogas Upgrading via Cyclic CO2 Adsorption: Application of Highly Regenerable PEI@nano-Al2O3 Adsorbents with Anti-Urea Properties”, was published in Environmental Science & Technology.Figure 2. The cross-linking mechanism between nano-Al2O3 support and organic amine moleculeChunyan Li, a master’s student from the ESE at SUSTech, and Xuehua Shen, a doctoral student supported by the joint Ph.D. program between SUSTech and Harbin Institute of Technology (HIT), are the first authors of these two papers, respectively. Professor Zuotai Zhang and Research Assistant Professor Feng Yan from the ESE at SUSTech are the co-corresponding authors. SUSTech is also the first affiliation and communication affiliation of these papers.These studies were supported by the National Natural Science Foundation of China (NSFC), the National Key R&D Program of China, Shenzhen Science, Technology and Innovation Committee (SZSTI), and the Pearl River Scholars Funding Program for Higher Education Institutions in Guangdong Province.Paper links:Chemical Engineering Journal link: https://doi.org/10.1016/j.cej.2020.128117Environmental Science & Technology link: https://doi.org/10.1021/acs.est.0c07973
China is an active participant in global climate governance and insists on promoting CO2 mitigation. General Secretary Xi Jinping put forward the ambitious goal of striving to achieve carbon neutrality by 2060 at the 75th United Nations General Assembly.
Recently, Chair Professor Junguo Liu’s research group from the School of Environmental Sciences & Engineering at the Southern University of Science and Technology (SUSTech), in collaboration with scholars from the University of Hong Kong (HKU) and Michigan State University, published findings for a new method that is used to extract high-resolution drainage network. The paper, entitled “Basin-scale high-resolution extraction of drainage networks using 10-m Sentinel-2 imagery” was published in Remote Sensing of Environment, a renowned academic journal that focuses on remote sensing studies.Extraction of drainage networks is an important element of river flow routing in hydrology and large-scale estimates of river behaviors in Earth sciences. Emerging studies with a focus on greenhouse gases reveal that small rivers can contribute to more than half of the global carbon emissions from inland waters (including lakes and wetlands). However, large-scale extraction of drainage networks is constrained by the coarse resolution of observational data and models, which hinders assessments of terrestrial hydrological and biogeochemical cycles.Figure 1: (a) Lancang-Mekong River networks extracted in this study. (b) State-of-the-art Landsat-based river centerlines extraction (GRWL) in the study area with breakpoints (river centerline disconnections).Recognizing that the Sentinel-2 satellite can detect surface water up to a 10-m resolution over large scales, they proposed a new method named Remote Sensing Stream Burning (RSSB) to integrate high-resolution observational flow location with coarse topography to improve the extraction of the drainage network. In RSSB, satellite-derived input is integrated in a spatially continuous manner, producing a quasi-bathymetry map where relative relief is enforced, enabling a fine-grained, accurate, and multitemporal extraction of the drainage network. RSSB was applied to the Lancang-Mekong River basin to derive a 10-m resolution drainage network, with a significant reduction in location errors as validated by the river centerline measurements.Figure 2: Location errors of river networks generated by the RSSB method and conventional method (non-RSSB). The closer the CDF curve near the top left, the better.The high-resolution extraction resulted in a realistic representation of meanders and detailed network connections. Furthermore, RSSB enabled a multitemporal extraction of river networks during wet/dry seasons and before/after the formation of new channels. The proposed method is fully automated, meaning that the network extraction preserves basin-wide connectivity without requiring any postprocessing, hence facilitating the construction of drainage network data with openly accessible imagery.Figure 3: Comparisons of 90-m and 10-m drainage networks, including flow direction, flow accumulation, and extracted river vector.The RSSB method provides a basis for the accurate representation of drainage networks that maintains channel connectivity, allowing a more realistic inclusion of small rivers and streams. This enables a greater understanding of complex but active exchange between inland water and other related Earth system components.Zifeng Wang, a doctoral student supported by the joint Ph.D. program between SUSTech and HKU, and Junguo Liu, Chair Professor at SUSTech, are the first and corresponding authors, respectively, of this paper. Jinbao Li and Hongsheng Zhang from HKU, Ying Meng from SUSTech, and Yadu Pokhrel from Michigan State University are the co-authors.This study was supported by the Strategic Priority Research Program of the Chinese Academy of Sciences, the National Natural Science Foundation of China (NSFC), and SUSTech.Paper link: https://doi.org/10.1016/j.rse.2020.112281
^ TOP