ORCID Profile
0000-0001-9261-1287
Current Organisations
University of Rochester Medical Center
,
University of Rochester
,
The Chinese University of Hong Kong
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Publisher: Elsevier BV
Date: 04-2021
Publisher: Frontiers Media SA
Date: 27-01-2023
Publisher: Frontiers Media SA
Date: 12-2022
DOI: 10.3389/FMARS.2022.1031714
Abstract: The amounts of marine debris and plastic pollution have been growing dramatically in the environment. Floating marine debris can be transported between the sea and coastal zone by various processes. However, it remains unknown if marine debris in the sea and coastal zone are quantitatively related. This study collected time-series data on marine debris (including plastics) from China’s beaches and adjoining seas over a 10-year period (2012–2021). It aims to investigate (1) the characteristics of debris distribution in the beach-sea continuum, (2) the relationships among the density and accumulation density of marine debris on beaches, sea surfaces and seafloors. Our results show that the density of marine debris and plastics on beaches and seafloors in the pandemic period were 3–5 folds of those in the pre-pandemic period. The density (104682.4 ± 27793.0 items km –2 ) and accumulation density (1787.4 ± 220.0 kg km –2 ) of marine debris on beaches were significantly higher than those on both sea surfaces (3320.8 ± 446.0 items km –2 and 21.6 ± 5.7 kg km –2 ) and seafloors (2453.7 ± 868.4 items km –2 and 117.5 ± 70.4 kg km –2 ). The density of plastics on beaches (85373.0 ± 21633.8 items km –2 ) was significantly higher than that on sea surfaces (2915.4 ± 365.8 items km –2 ) and seafloors (2254.2 ± 717.1 items km –2 ). The density of small-to-medium (0–10cm) floating debris (3419.5 ± 418.2 items km –2 ) was more than 100 times higher than the density of large (& 10cm) floating debris (29.6 ± 3.1 items km –2 ). The proportion of plastics in marine debris on sea surfaces (83.3 ± 1.3%) was significantly higher than that on beaches (74.1 ± 2.5%) but not significantly different from that on seafloors (81.1 ± 3.0%). There are significant relationships between the density of debris on seafloors and that on beaches, between the density or accumulation density of debris on seafloors and that on sea surfaces. This study suggests that the density and accumulation density of marine debris on seafloors were closely associated with those on sea surfaces and beaches. The results can help to estimate the transportation, deposition and aggregation of marine debris from beaches and sea surfaces to seafloors.
Publisher: Wiley
Date: 06-05-2018
DOI: 10.1002/LNO.10818
Publisher: Elsevier BV
Date: 07-2021
Publisher: Elsevier BV
Date: 02-2023
DOI: 10.1016/J.SCITOTENV.2022.160220
Abstract: Coastal sediments are considered as hotspots of microplastics (MPs), with substantial MPs stocks found in blue carbon habitats such as mangroves and tidal marshes, where wave-d ing vegetation reduces sediment erosion and enhances accretion. Here, we examined the effects of such bio-geomorphic feedbacks in shaping MPs burial, through a year-round field study in a mangrove habitat along the coast of South China. The results revealed that MPs abundance decreased significantly with the increase of cumulative sediment erosion as the strength of bio-geomorphic feedbacks declined. More shapes and colors of MPs were found at locations with weaker waves and less sediment erosion, where the average particle size was also higher. Our findings highlight the importance of bio-geomorphic feedbacks in affecting both the abundance and characteristics of the buried MPs. Such knowledge extends our understanding of MPs transport and burial from the perspective of bio-geomorphology, which is essential to assess and predict MPs accumulation patterns as well as its impacts on ecosystem functioning of the blue carbon habitats.
Publisher: Wiley
Date: 07-09-2017
DOI: 10.1002/LNO.10663
Publisher: Elsevier BV
Date: 02-2020
Publisher: eLife Sciences Publications, Ltd
Date: 02-11-2021
DOI: 10.7554/ELIFE.70554
Abstract: Antibody production following vaccination can provide protective immunity to subsequent infection by pathogens such as influenza viruses. However, circumstances where antibody formation is impaired after vaccination, such as in older people, require us to better understand the cellular and molecular mechanisms that underpin successful vaccination in order to improve vaccine design for at-risk groups. Here, by studying the breadth of anti-haemagglutinin (HA) IgG, serum cytokines, and B and T cell responses by flow cytometry before and after influenza vaccination, we show that formation of circulating T follicular helper (cTfh) cells was associated with high-titre antibody responses. Using Major Histocompatability Complex (MHC) class II tetramers, we demonstrate that HA-specific cTfh cells can derive from pre-existing memory CD4 + T cells and have a erse T cell receptor (TCR) repertoire. In older people, the differentiation of HA-specific cells into cTfh cells was impaired. This age-dependent defect in cTfh cell formation was not due to a contraction of the TCR repertoire, but rather was linked with an increased inflammatory gene signature in cTfh cells. Together, this suggests that strategies that temporarily d en inflammation at the time of vaccination may be a viable strategy to boost optimal antibody generation upon immunisation of older people.
Publisher: Elsevier BV
Date: 11-2021
Publisher: Copernicus GmbH
Date: 19-09-2014
Abstract: Abstract. Studies on carbon stock in salt marsh sediments have increased since the review by Chmura et al. (2003). However, uncertainties exist in estimating global carbon storage in these vulnerable coastal habitats, thus hindering the assessment of their importance. Combining direct data and indirect estimation, this study compiled studies involving 143 sites across the Southern and Northern hemispheres, and provides an updated estimate of the global average carbon accumulation rate (CAR) at 244.7 g C m−2 yr−1 in salt marsh sediments. Based on region-specific CAR and estimates of salt marsh area in various geographic regions between 40° S to 69.7° N, total CAR in global salt marsh sediments is estimated at ~10.2 Tg C yr−1. Latitude, tidal range and elevation appear to be important drivers for CAR of salt marsh sediments, with considerable variation among different biogeographic regions. The data indicate that while the capacity for carbon sequestration by salt marsh sediments ranked the first amongst coastal wetland and forested terrestrial ecosystems, their carbon budget was the smallest due to their limited and declining global areal extent. However, some uncertainties remain for our global estimate owing to limited data availability.
Publisher: Copernicus GmbH
Date: 06-12-2013
DOI: 10.5194/BGD-10-19155-2013
Abstract: Abstract. Studies on carbon stock in salt marsh sediments are increasing. However, uncertainties exist in estimating global carbon storage in these vulnerable coastal habitats, thus hindering the assessment of their importance. Combining direct data and indirect estimation, this study compiled studies involving 158 sites across the southern and Northern Hemispheres, and estimated the global average carbon accumulation rate (CAR) at 242.2 g C m−2 yr−1 in saltmarsh sediments. Based on region-specific CAR and estimates of salt marsh area in various geographic regions between 40° S to 78.3° N, total CAR in global salt marsh sediments is ~ 10.1 Tg C yr−1. The data indicate that while the capacity for carbon sequestration by salt marsh sediments ranked the first amongst coastal wetland and forested terrestrial ecosystems, their carbon budget was the smallest due to their limited and declining global areal extent. However, there may be uncertainties for our global estimate owing to limited and patchy data availability. CAR of salt marsh sediments changes with latitude, tidal range, halophyte genera and elevation, with considerable variation among different biogeographic regions.
Publisher: Elsevier BV
Date: 09-2015
Publisher: Springer Science and Business Media LLC
Date: 14-02-2018
DOI: 10.1038/S41598-018-21217-Z
Abstract: Coastal wetlands are increasingly recognised for their pivotal role in mitigating the growing threats from cyclones (including hurricanes) in a changing climate. There is, however, insufficient information about the economic value of coastal wetlands for cyclone mitigation, particularly at regional scales. Analysis of data from 1990–2012 shows that the variation of cyclone frequencies is related to EI Niño strength in the Pacific Ocean adjacent to Australia, but not China. Among the cyclones hitting the two countries, there are significant relationships between the ratio of total economic damage to gross domestic production (TD/GDP) and wetland area within cyclone swaths in Australia, and wetland area plus minimum cyclone pressure despite a weak relationship in China. The TD/GDP ratio is significantly higher in China than in Australia. Despite their extensive and growing occurrence, seawalls in China appear not to play a critical role in cyclone mitigation, and cannot replace coastal wetlands, which provide other efficient ecosystem services. The economic values of coastal wetlands in Australia and China are respectively estimated at US$52.88 billion and 198.67 billion yr −1 for cyclone mitigation, albeit with large within-country geographic variation. This study highlights the urgency to integrate this value into existing valuations of coastal wetlands.
Publisher: Elsevier BV
Date: 2015
Publisher: Elsevier BV
Date: 12-2016
Publisher: Springer Science and Business Media LLC
Date: 16-01-2020
DOI: 10.1038/S41467-019-14120-2
Abstract: Tidal wetlands are global hotspots of carbon storage but errors exist with current estimates on their carbon density due to the use of factors estimated from other habitats for converting loss-on-ignition (LOI) to organic carbon (OC) and the omission of certain significant carbon pools. Here we show that the widely used conversion factor (LOI/OC = 1.724) is significantly lower than our measurements for saltmarsh sediments (1.92 ± 0.01) and oversimplifies the polynomial relationship between sediment OC and LOI for mangrove forests. Global mangrove OC stock in the top-meter sediment reaches 1.93 Pg when corrected for this bias, and is 20% lower than the previous estimates. Ecosystem carbon stock (living and dead biomass, sediment OC and inorganic carbon) is estimated at 3.7–6.2 Pg. Mangrove deforestation leads to carbon emission rates at 23.5–38.7 Tg yr −1 after 2000. Mangrove sediment OC stock has previously been over-estimated while ecosystem carbon stock underestimated.
Publisher: Elsevier BV
Date: 04-2018
DOI: 10.1016/J.CHEMOSPHERE.2017.12.102
Abstract: Municipal wastewater discharge is widespread and one of the sources of coastal eutrophication, and is especially uncontrolled in developing and undeveloped coastal regions. Mangrove forests are natural filters of pollutants in wastewater. There are three paradigms of mangroves for municipal wastewater treatment and the selection of the optimal one is a multi-criteria decision-making problem. Combining intuitionistic fuzzy theory, the Fuzzy Delphi Method and the fuzzy analytical hierarchical process (AHP), this study develops an intuitionistic fuzzy AHP (IFAHP) method. For the Fuzzy Delphi Method, the judgments of experts and representatives on criterion weights are made by linguistic variables and quantified by intuitionistic fuzzy theory, which is also used to weight the importance of experts and representatives. This process generates the entropy weights of criteria, which are combined with indices values and weights to rank the alternatives by the fuzzy AHP method. The IFAHP method was used to select the optimal paradigm of mangroves for treating municipal wastewater. The entropy weights were entrained by the valid evaluation of 64 experts and representatives via online survey. Natural mangroves were found to be the optimal paradigm for municipal wastewater treatment. By assigning different weights to the criteria, sensitivity analysis shows that natural mangroves remain to be the optimal paradigm under most scenarios. This study stresses the importance of mangroves for wastewater treatment. Decision-makers need to contemplate mangrove reforestation projects, especially where mangroves are highly deforested but wastewater discharge is uncontrolled. The IFAHP method is expected to be applied in other multi-criteria decision-making cases.
Publisher: Elsevier BV
Date: 03-2017
Publisher: MDPI AG
Date: 27-11-2021
DOI: 10.3390/SU132313163
Abstract: Aquaculture, particularly shellfish ponds, has expanded dramatically and become a major cause of mangrove deforestation and “blue carbon” loss in China. We present the first study to examine CO2 efflux from marine aquaculture/shellfish ponds and in relation to land-use change from mangrove forests in China. Light and dark sediment CO2 efflux from shellfish ponds averaged at 0.61 ± 0.07 and 0.90 ± 0.12 kg CO2 m−2 yr−1 (= 37.67 ± 4.89 and 56.0 ± 6.13 mmol m−2 d−1), respectively. The corresponding rates (−4.21 ± 4.54 and 41.01 ± 4.15 mmol m−2 d−1) from the adjacent mangrove forests that were devoid of aquaculture wastewater were lower, while those from the adjacent mangrove forests (3.48 ± 7.83 and 73.02 ± 5.76 mmol m−2 d−1)) receiving aquaculture wastewater markedly increased. These effluxes are significantly higher than those reported for mangrove forests to date, which is attributable to the high nutrient levels and the physical disturbance of the substrate associated with the aquaculture operation. A rise of 1 °C in the sediment temperature resulted in a 6.56% rise in CO2 released from the shellfish ponds. Combined with pond area data, the total CO2 released from shellfish ponds in 2019 was estimated to be ~12 times that in 1983. The total annual CO2 emission from shellfish ponds associated with mangrove conversion reached 2–5 Tg, offsetting the C storage by mangrove forests in China. These are significant environmental consequences rather than just a simple shift of land use. Around 30% higher CO2 emissions are expected from aquaculture ponds (including shellfish ponds) compared to shellfish ponds alone. Total annual CO2 emission from shellfish ponds will likely decrease to the level reported in early 1980 under the pond area-shrinking scenario, but it will be more than doubled under the business-as-usual scenario projected for 2050. This study highlights the necessity of curbing the expansion of aquaculture ponds in valuable coastal wetlands and increasing mangrove restoration to abandoned ponds.
Publisher: Elsevier BV
Date: 02-2016
DOI: 10.1016/J.SCITOTENV.2015.12.013
Abstract: Mangroves have been increasingly recognized for treating wastewater from aquaculture, sewage and other sources with the overwhelming urbanization trend. This study clarified the three paradigms of mangroves in disposing wastewater contaminants: natural mangroves, constructed wetlands (including free water surface and subsurface flow) and mangrove-aquaculture coupling systems. Plant uptake is the common major mechanism for nutrient removal in all the paradigms as mangroves are generally nitrogen and phosphorus limited. Besides, sediments accrete and provide substrates for microbial activities, thereby removing organic matter and nutrients from wastewater in natural mangroves and constructed wetlands. Among the paradigms, the mangrove-aquaculture coupling system was determined to be the optimal alternative for aquaculture wastewater treatment by multi-criterion decision making. Sensitivity analysis shows variability of alternative ranking but underpins the coupling system as the most environment-friendly and cost-efficient option. Mangrove restoration is expected to be achievable if aquaculture ponds are planted with mangrove seedlings, creating the coupling system.
Publisher: Elsevier BV
Date: 2014
DOI: 10.1016/J.JENVMAN.2013.10.020
Abstract: Reductive dechlorination is a crucial pathway for anaerobic biodegradation of highly chlorinated organic contaminants. Under an anoxic environment, reductive dechlorination of organic contaminants can be affected by many redox processes such as nitrate reduction and iron reduction. In the present study, batch incubation experiments were conducted to investigate the effect of nitrate addition on reductive dechlorination of PCP in paddy soil with consideration of iron transformation. Study results demonstrate that low concentrations (0, 0.5 and 1 mM) of nitrate addition can enhance the reductive dechlorination of PCP and Fe(III) reduction, while high concentrations (5, 10, 20 and 30 mM) of nitrate addition caused the contrary. Significant positive correlations between PCP degradation rates and the formation rates of dissolved Fe(II) (pearson correlation coefficients r = 0.965) and HCl-extractable Fe(II) (r = 0.921) suggested that Fe(III) reduction may enhance PCP dechlorination. Furthermore, consistent variation trends of PCP degradation and the abundances of the genus Comamonas, capable of Fe(III) reduction coupled to reductive dechlorination, and of the genus Dehalobacter indicated the occurrence of microbial community variation induced by nitrate addition as a response to PCP dechlorination.
Publisher: Elsevier BV
Date: 02-2017
DOI: 10.1016/J.SCITOTENV.2016.10.218
Abstract: Mangroves are blue carbon ecosystems that sequester significant carbon but release CO
Publisher: Wiley
Date: 13-02-2019
DOI: 10.1002/LNO.11146
Publisher: American Chemical Society (ACS)
Date: 28-01-2022
Abstract: Coastal wetlands trap plastics from terrestrial and marine sources, but the stocks of plastics and their impacts on coastal wetlands are poorly known. We evaluated the stocks, fate, and biological and biogeochemical effects of plastics in coastal wetlands with plastic abundance data from 112 studies. The representative abundance of plastics that occurs in coastal wetland sediments and is ingested by marine animals reaches 156.7 and 98.3 items kg
Publisher: Elsevier BV
Date: 03-2022
Publisher: Springer Science and Business Media LLC
Date: 21-04-2009
Location: United States of America
Location: China
Location: China
Location: China
No related grants have been discovered for Xiaoguang Ouyang.