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Our previous study revealed PAHs' wide occurrence in corals from multiple coral reef regions (CRRs) in the South China Sea. However, little is known about their occurrence, distribution, fate, and sources in the ambient environment of these CRRs. This study aimed to resolve these research gaps. The results showed ∑ 15 PAHs (total concentrations of 15 US EPA priority controlled PAHs exclude naphthalene) in the atmosphere (gas-phase: 0.31–49.6 ng m−3; particle-phase: 2.6–649 pg m−3) were mainly influenced by air mass origins. Southwesterly wind caused higher ∑ 15 PAHs than the southeasterly wind. The ∑ 15 PAHs in seawater from the nearshore (462 ± 244 ng L−1) was higher than that from offshore Zhongsha Islands (80.5 ± 72.1 ng L−1) because of the effect of terrigenous pollution and ocean current. Source apportionment indicated that the mixed sources of spilled oil and combustion from neighboring countries were the main contributors to PAHs in these CRRs. The total deposition fluxes showed that PAHs tended to migrate from the atmosphere to seawater. Global warming may inhibit this process, but PAHs still have a migration pattern of atmosphere-ocean-corals, which will further increase the environmental pressure on coral reef ecology. [Display omitted] • PAHs' level and sources were studied in air and water of coral reef regions (CRR). • Ocean current and wind fields were key factors affecting the distribution of PAHs. • Net atmospheric deposition of PAHs occurred in CRRs, South China Sea (SCS). • Global warming may retard atmospheric deposition of PAHs in coral reef regions. • PAHs may have a migration pattern of atmosphere-ocean-corals in SCS. [ABSTRACT FROM AUTHOR]

The seasonal and interannual variabilities of sea surface wind (SSW) in the South China Sea (SCS), especially in coral reef regions such as Nansha Islands, Xisha Islands, Zhongsha Islands and Dongsha Islands were investigated in detail using the Blended Sea Winds dataset (1988–2017). Annual and monthly variations of SSW and sea surface temperature (SST) in the four zones were investigated. Empirical Orthogonal Function (EOF) analysis of wind field was performed to aid in better understanding the different spatial patterns. The results indicate that, as observed in the spatial distribution of the first mode of monthly mean wind speed anomaly, the magnitudes in the four island zones are all negative and are similar to each other, showing that the variations of SSW in the four island zones are consistent. In the second mode, the magnitudes in Nansha Islands are opposite to those in the other three zones. The spatial distribution of the third mode reflects regional differences. The maximum annual SSW appears in Dongsha Islands, and the minimum appears in Nansha Islands. The interannual variations of SSW in all island zones are basically concurrent. The island zones with high SSW mostly have low SST, and vice versa. There may be an inverse relationship between SSW and SST in coral reef regions in the SCS. The multi-year monthly variations of SSW in the island zones present a 'W'-shaped structural variation. Each island undergoes two months of minimum SSW every year, one during March–May (MAM) and the other during September–November (SON). Both months are in monsoon transition periods. During the months with low SSW, high SST appears. The SST peaks almost correspond to the SSW troughs. This further indicates that SSW and SST may have opposite changes in coral reef regions. Coral bleaching events often correspond to years of high SST and low SSW. [ABSTRACT FROM AUTHOR]

β-Glucosidase is a microbial cellulose multienzyme that plays an important role in the regulation of the entire cellulose hydrolysis process, which is the rate-limiting step in bacterial carbon cycling in marine environments. Despite its importance in coral reefs, the diversity of β-glucosidase-producing bacteria, their genes, and enzymatic characteristics are poorly understood. In this study, 87 β-glucosidase-producing cultivable bacteria were screened from 6 genera of corals. The isolates were assigned to 21 genera, distributed among three groups: Proteobacteria, Firmicutes, and Actinobacteria. In addition, metagenomics was used to explore the genetic diversity of bacterial β-glucosidase enzymes associated with scleractinian corals, which revealed that these enzymes mainly belong to the glycosidase hydrolase family 3 (GH3). Finally, a novel recombinant β-glucosidase, referred to as Mg9373, encompassing 670 amino acids and a molecular mass of 75.2 kDa, was classified as a member of the GH3 family and successfully expressed and characterized. Mg9373 exhibited excellent tolerance to ethanol, NaCl, and glucose. Collectively, these results suggest that the diversity of β-glucosidase-producing bacteria and genes associated with scleractinian corals is high and novel, indicating great potential for applications in the food industry and agriculture. [ABSTRACT FROM AUTHOR]

Seven popular fluoroquinolone antibiotics (FQs) in synthetic marine aquaculture water were subject to sodium hypochlorite (NaClO) disinfection scenario to investigate their reaction kinetics and transformation during chlorination. Reactivity of each FQ to NaClO was following the order of ofloxacin (OFL) > enrofloxacin (ENR) > lomefloxacin (LOM) > ciprofloxacin (CIP) ~ norfloxacin (NOR) >> pipemedic acid (PIP), while flumequine did not exhibit reactivity. The coexisting chlorine ions and sulfate ions in the water slightly facilitated the oxidation of FQs by NaClO, while humic acid was inhibitable to their degradation. The bromide ions promoted degradation of CIP and LOM, but restrained oxidation of OFL and ENR. By analysis of liquid chromatography with tandem mass spectrometry (LC-MS/MS), eight kinds of emerging brominated disinfection byproducts (Br-DBPs) caused by FQ S were primarily identified in the chlorinated synthetic marine culture water. Through density functional theory calculation, the highest-occupied molecular orbital (HOMO) and the lowest-unoccupied molecular orbital (LUMO) characteristic as well as the charge distribution of the FQs were obtained to clarify transformation mechanisms. Their formation involved decarboxylation, ring-opening/closure, dealkylation and halogenation. Chlorine substitution occurred on the ortho-position of FQs's N4 and bromine substitution occurred on C8 position. The piperazine ring containing tertiary amine was comparatively stable, while this moiety with a secondary amine structure would break down during chlorination. Additionally, log K ow and logBAF of transformation products were calculated by EPI-SuiteTM to analyze their bioaccumulation. The values indicated that Br-DBPs are easier to accumulate in the aquatic organism relative to their chloro-analogues and parent compounds. Image, graphical abstract [ABSTRACT FROM AUTHOR]

Coral probiotics can improve the tolerance of corals to heat stress, thus mitigating the process of coral thermal bleaching. Sensitive and specific detection of coral probiotics at low abundances is highly desirable but remains challenging, especially for rapid and on-site detection of coral probiotics. Since the electrochemical biosensor has been recently used in the field of environmental DNA (eDNA) detection, herein, an efficient electrochemical biosensor was developed based on CoS 2 /CoSe 2 -NC HNCs electrode material with a specific DNA probe for the C. marina detection. After optimization, the lower limit of detection (LOD) values of such biosensors for the target DNA and genomic DNA were 1.58 fM and 6.5 pM, respectively. On this basis, a portable device was constructed for the practical detection of C. marina eDNA, and its reliability and accuracy were verified by comparison with the ddPCR method (P > 0.05). For each analysis, the average cost was only ∼ $1.08 and could be completed within 100 min with reliable sensitivity and specificity. Overall, the biosensor could reflect the protective effect of probiotics on coral heat stress, and the proposed technique will put new insights into the rapid and on-site detection of coral probiotics to assist corals against global warming. [ABSTRACT FROM AUTHOR]

• Occurrence and trophic transfer of 6 parabens and their metabolite were investigated. • MeP and 4-HB were the dominant target pollutants in marine organisms. • The values of log BAF were in the order of 4-HB > MeP > PrP. • The values of BSAF were in the order of MeP > 4-HB > PrP. • MeP was biomagnified, while 4-HB was biodiluted in the Beibu gulf. Parabens are of particular concern due to their ubiquity in aquatic environments and endocrine-disrupting effects. However, information on their bioaccumulation and trophic magnification is limited. In the present study, we performed a comprehensive survey to investigate the occurrence, bioaccumulation and trophic magnification of parabens and their metabolite 4-hydroxybenzoic acid (4-HB) in a marine food web from the Beibu Gulf, South China Sea. Results showed that methylparaben (MeP) and 4-HB were the predominant target pollutants in marine organisms, with their concentrations being in the range of 0.18–13.77 and 13.48–222.24 ng/g wet weight, respectively. The bioaccumulation factors (BAFs) for target analytes were all lower than 5000, suggesting negligible bioaccumulation. However, the biota-sediment accumulation factors (BSAFs) for MeP and 4-HB were 4.51 and 3.21, respectively, which indicates significant bioaccumulation from the sediment. Furthermore, the estimated trophic magnification factor (TMF) was 2.88 for MeP, suggesting its biomagnification along the food web. In contrast, a lower TMF of 0.45 was found for 4-HB, suggesting trophic dilution along the food web. The hazard quotients (HQs) for parabens were far less than 1 in all organisms, suggesting low risks for humans through consuming marine organisms from the Beibu Gulf. This study provides substantial data on the fate and trophic transfer of parabens in a subtropical marine ecosystem. [Display omitted] [ABSTRACT FROM AUTHOR]

Understanding the variation of tropical cyclones (TCs) and climate in the Western North Pacific (WNP) over the past two millennia can help us understand how TCs might change with the global warming scenario. Instrumental observations and model projections have revealed that the characteristics of TCs in the WNP are related to climate forcing. However, the limited availability of short instrumental records impedes our comprehension of the interactions between TCs and climate on historical time scales. Reconstructing the TC activity on geological time requires reliable alternative proxies, including sediments, tree rings, stalagmites, corals, Tridacna shells, and historical documents. This review mainly summarizes the reconstructions of paleo-TCs over the past two millennia and discusses the characteristics of TCs during typical climatic periods. Reconstructions of TC activity have indicated significant spatial and temporal asynchrony across the low to mid-latitudes in the WNP during the past two millennia. Our compilation includes 10 different sites in the WNP and further ascertains the range of the transition zone (24.74° ∼ 25.87°N). The TC frequency north (south) of the transition zone and SST were positively (negatively) correlated over the past two millennia. This pattern suggests that SST dominates the variation of TCs north of the transition zone and other pieces of evidence indicate that TCs south of the transition zone are controlled by Intertropical Convergence Zone. Notedly, El Niño-Southern Oscillation, aerosol, and the latitudinal shift of TCs also contribute to this pattern. Future research on paleo-TC and paleoclimate over the past two millennia should focus on improving the accuracy of proxies, increasing the resolution of proxy-based records, and expanding the representative areas to reconstruct comprehensive paleo-TC archives. This can provide powerful support for the study of TC variation patterns and climatic forcing mechanisms on decadal to centennial timescales, and contribute to the prediction of TC activity during the current warm period. [Display omitted] • Paleo-TC reconstructions in the WNP over the past two millennia were reviewed. • TC activities were asynchronous in a transition zone of WNP on century timescale. • The current northward shift of TCs in the WNP is a response to climate warming. [ABSTRACT FROM AUTHOR]

Heterosigma akashiwo (H. akashiwo) is recognized as a harmful algal bloom (HABs) species with a global distribution, capable of posing significant threats to marine ecosystems, particularly when spread through ship ballast water. This investigation focused on elucidating the inactivation kinetics and underlying mechanism of H. akashiwo through a combined ultraviolet irradiation and peroxydisulfate (UV/PDS) process. The results demonstrated a strong synergistic effect within the UV/PDS system, resulting in an inactivation of 0.78-ln and 2.67-ln within 40 min of UV and UV/PDS processes. The principal agents accountable for inactivation were identified as sulfate radicals (•SO 4 −) and hydroxyl radical (•OH), which exhibited a synergistic effect in the UV/PDS process. Furthermore, the study observed a negatively impact of seawater pH and salinity on the efficiency of inactivation. UV/PDS caused oxidative stress on algal cells, initially involving the participation of antioxidant enzymes in counteracting cellular damage, but this protective mechanism diminished as the reaction duration extended. The UV/PDS treatment not only inflicted damage upon H. akashiwo 's photosynthetic system but also caused the extracellular release of DNA and algal organic matter (AOM) due to damaged cell membranes. Transcriptome analysis provided a molecular biology perspective on the cellular inactivation process. Upregulation of genes linked to photosynthesis and oxidative phosphorylation suggested a potential elevation in energy metabolism. In contrast, genes associated with cellular and metabolic processes, including glycolysis and the tricarboxylic acid cycle (TCA cycle), exhibited downregulation. Moreover, this treatment exerted an inhibitory influence on RNA polymerase and protein synthesis, resulting in the reduced expression of genetic information. [Display omitted] • Cell membrane of H. akashiwo was damaged by both •SO 4 − and •OH in UV/PDS. • DNA and AMO of H. akashiwo were released. • Disorder cellular metabolic processes such as TCA cycle of H. akashiwo were suppressed. • Gene expressions (RNA polymerase and protein synthesis) of H. akashiwo were disrupted. • The energy metabolism of H. akashiwo was enhanced to resist oxidative stress. [ABSTRACT FROM AUTHOR]

[Display omitted] • Blue light increases the thermal bleaching tolerance of coral holobiont. • Blue light decreases photosynthesis, respiration and ROS release of Symbiodiniaceae under heat stress. • Blue light reduces respiration and lipid peroxidation of host under heat stress. • The up-regulation of the DAO gene indicates a coral bleaching model that dependents on the host. Given the high degree of heterogeneity of coral bleaching, there is potential for abiotic approaches to improve the thermal tolerance of coral. However, there is limited knowledge about such factors and causes that regulating acclimation of coral to warming. Here, a study was conducted on the reef building coral Acropora tenuis to investigate the impact of light qualities on the physiological, cellular, and molecular biochemical responses of the coral holobiont to heat stress. The results showed that after subjecting the samples to heat stress at 32 ℃ for 9 days, over 90% corals exposed to compound light experienced bleaching on the fifth day, while corals exposed to blue light showed no significant signs of bleaching even on the ninth day. This indicates that blue light may enhanced the coral's thermal bleaching tolerance. Further analysis revealed blue light primarily increased coral's resistance to thermal bleaching by remodeling the interactions between Symbiodiniaceae (i.e. decreased photosynthesis, respiration and ROS release) and coral (i.e. decreased respiration and lipid peroxidation). The study also found that the host's of reactive oxygen species (ROS) played a role in causing coral bleaching besides the ROS released by Symbiodiniaceae. The up-regulation of the DAO gene (encoding D-amino-acid oxidase, up-regulated nearly 1000 times under warming conditions) in the host highlights the mechanism of coral bleaching, whereby the catalysis of amino acids by the D-amino-acid oxidase produces ROS. In summary, the present study reveals novelty insights into the molecular processes related to thermal bleaching of coral, identifies blue light as a positive environmental factor that enhances coral's tolerance to global warming. [ABSTRACT FROM AUTHOR]

As global warming threatens their existence, there are widespread concerns regarding the persistence of lime-sand islands and the future of mid-ocean atoll nations. To investigate how climate change has affected lime-sand islands, changes in vegetation and other characteristics of such islands in the South China Sea (SCS) were investigated from 1989 to 2019 using 67 satellite images. First, boundaries of the lime-sand islands and their vegetation were extracted using an active contour extraction procedure called the gradient vector flow snake model. Afterwards, the spatial extents were estimated by enclosing the extracted boundaries, and the digital shoreline analysis system was used to calculate beach widths. Finally, area growth rates and speeds were used to evaluate areal changes in the lime-sand islands and their respective vegetation. Based on the estimated area growth rates, area growth speeds, and beach widths, the lime-sand islands in SCS eroded over the past three decades whereas their vegetation expanded. Further analysis suggested that direct inundation caused by sea-level rise might not be clearly identified from the satellite images. However, other climate change-related factors were most likely responsible for the observed island erosions. These factors included higher wave energy, stronger typhoon intensity and destructiveness, and accelerated coral reef degradation. In addition, the observed expansion of vegetation on the lime-sand islands was likely due to the increase in precipitation in a warming world. The results show that 1) the lime-sand islands will continue to erode whereas vegetation will continue to expand; 2) As vegetation growth is significantly inhibited by salt water when it is adjacent to the ocean, vegetation areas on lime-sand islands may start to continuously decline. Overall, this study is the first to quantitatively examine changes in SCS lime-sand islands due to global warming. [ABSTRACT FROM AUTHOR]

Understanding the marine radiocarbon reservoir effect (i.e., marine radiocarbon reservoir age (R) and/or correction (ΔR)) is important for the construction of robust radiocarbon chronologies for marine archives for various research areas including archaeology, palaeoecology, paleoceanography, Quaternary research and climate change studies. In this study, we examined temporal ΔR variability for the South China Sea (SCS) and the Great Barrier Reef (GBR) during the past ∼8.1 ka based on 14C analysis of 230Th-dated corals. Results show large ΔR variations of ∼410 yr and ∼490 yr for the SCS and the northern GBR for ∼5.5–8.1 ka and ∼5.5–7 ka, respectively, and a smaller ΔR variability of ∼200 yr for the SCS for ∼2–3.5 ka. Our data, together with those previously published for the Tropical and South Pacific, indicate that variability in ocean upwelling bringing old subsurface waters to the surface and/or changes in the sources (or 14C level) of the upwelled waters are responsible for seeing large ΔR variations in coastal areas along the eastern Pacific and the Tropical East Pacific (TEP) of several hundred to a thousand years mostly during the Early to Middle Holocene. ΔR variations in the central and western Pacific of several and a couple of hundred years during the Middle and Late Holocene, respectively, might be due to variability in Pacific-wide ocean circulation associated with climatic changes controlling the spread of upwelled waters from the TEP to the west. This mechanism together with local/regional effects, such as changes in ocean upwelling in the SCS resulting from East Asian monsoon variability and changes in upwelling and/or horizontal advection in the northern GBR associated with variability in the El Niño Southern Oscillation, might be responsible for the observed ΔR variations in these areas. The results of our study also indicate the need for regional marine radiocarbon calibration curves for improved radiocarbon dating of marine samples as the observed Holocene ΔR values for the Tropical and South Pacific are not fully reproduced by a recent modelling work using a 3D ocean model, which takes into account climate change effects. Ocean circulation changes were included in the model for the period of 11.5–50 cal kyr BP but possibly not considered or not well represented for the Holocene, which might explain the differences between the observed and modelled ΔR values. • New ΔR for Western Pacific for ∼0–8 ka based on 14C analysis of 230Th-dated corals. • ΔR variability of ∼200–490 yr for Western Pacific during the last ∼8 ka. • ΔR variability of ∼300–1000 yr for coastal Eastern Pacific during the last ∼12 ka. • ΔR variations are mainly due to large scale climate and ocean circulation changes. • Urgent need for local/regional marine calibration curves for improved 14C dating. [ABSTRACT FROM AUTHOR]

Li, J.; Lu, J.; Wang, J.; Wang, Y.; Lai, J., and Yu, K., 2021. Do diploid and haploid solitary cells of Phaeocystis globosa support the same copepod grazing, survival, egg production, and hatching success? Journal of Coastal Research, 37(1), 113–121. Coconut Creek (Florida), ISSN 0749-0208. The food quality of phytoplankton affects the reproductive success of predators. Phaeocystis globosa blooms have negative effects on marine environments. However, the quality of P. globosa cells for predators is still under debate. The hypothesis that the nutritional value of diploid and haploid solitary cells would be different for the calanoid copepod predator Parvocalanus crassirostris was tested. The fatty acid compositions of diploid and haploid solitary cells and the effects of these cells on copepod grazing, survival, egg production, and hatching success were evaluated. In contrast to haploid solitary cells, diploid solitary cells did not contain C20:5ω3 (EPA) and C22:6ω3 (DHA) and were deficient in polyunsaturated fatty acids. Parvocalanus crassirostris individuals ingested more diploid than haploid cells. Egg hatching success was similar between the diets with diploid and haploid cells. Copepod survival and egg production were strongly inhibited by feeding on diploid cells. In contrast, they were high when copepods fed on haploid cells, reaching levels as high as those observed when the copepods fed on optimal diets of Isochrysis galbana and the diatom Thalassiosira weissflogii. The results suggest that diploid solitary cells of P. globosa are a poor food, whereas haploid solitary cells of this species are a nutrient-rich food for copepods. [ABSTRACT FROM AUTHOR]

Great efforts have been made to understand the impacts of the 1997 Indonesian wildfires on land ecology and human health, yet its influences on marine environments are poorly understood owing to sparse observations. Here we present weekly to monthly resolution coral δ13C records across the South China Sea in conjunction with a regional ocean general circulation model to study the effects of these cataclysmic wildfires on nearby oceans. Large and persistent negative δ13C excursions were found in corals from the interior South China Sea several months after the wildfires. This delay indicates that the 13C‐depleted ash fallout was distributed by ocean currents rather than direct atmospheric transport, which is supported by the results of our numerical model. Thus, the impacts of tropical wildfires on marine ecology may last for 1 year and extend thousands of kilometers from the burning center. Plain Language Summary: Tropical wildfires, intensified by extreme weather events and land use change, have continued to increase during this century, causing serious damage to the rainforests and local economies as well as human suffering and death. The threats of tropical wildfires to nearby oceans have been given little attention and are largely unknown because of limited observations. Here we use multiple coral records with weekly to monthly resolution from five sites near and around the South China Sea and a computer model to study the influences of the 1997 Indonesian wildfires on the ocean. We find a previously unrecognized ash fallout signal recorded in the corals in the interior of the South China Sea. Our model results indicate that the penetration of ash fallout into the South China Sea occurred through ocean currents rather than direct atmospheric transport. This study shows that the impacts of tropical wildfires on oceans may last for 1 year and can extend for thousands of kilometers from the source. We also show the potential for using coral records with computer modeling to identify and study the frequency and extent of past megafires. Key Points: A large negative excursion in δ13C values during summer–winter 1998 was detected in corals from the interior of the South China SeaModel shows that ash fallout from the 1997 Indonesian wildfires distributed by currents was responsible for the negative δ13C excursionNetworks of coral δ13C have great potential to record past pantropical wildfires [ABSTRACT FROM AUTHOR]

The source and transport process of sediments are of great concern in marine sedimentology. In this study, naturally occurring radionuclides (238U, 226Ra, 228Ra, and 40K) in surface sediments and sediment cores were comprehensively analysed using high-purity germanium (HPGe) γ spectrometry in order to explore radionuclide fingerprints as novel proxies for tracking the source and transport pathway of sediments in the Beibu Gulf. We found that the radioactivity level of sediments in the Beibu Gulf was lower than that in other Chinese seas, following a comprehensive compilation and comparison of radioactivity in the region, indicating the Beibu Gulf is a high-quality marine environment. An interesting "butterfly pattern" was exhibited in the horizontal distribution of radionuclides in surface sediments from the Beibu Gulf, mainly attributable to the controlling factors of the non-linear negative regulation of sediment grain size and positive role of total organic carbon in sediment. Furthermore, the vertical distribution of radionuclides in sediment cores was affected by the redox state and a physical/biological disturbance, which were demonstrated by the simultaneous analysis of redox-sensitive element Mn and 210Pb, respectively. Additionally, the 226Ra 238U endmember model and 232Th 238U endmember model were proposed for quantifying local input (85%) and trans-region input (15%) of marine sediments in the Beibu Gulf in the context of the Guangdong-Qiongzhou Strait-Guangxi framework. We inferred that the Beibu Gulf was at risk of contamination by artificial radionuclides derived from nearby Guangdong Province, which has the highest number of nuclear power plants in China, through a trans-region input by ocean currents. Our study not only provided spatiotemporal distributions of radionuclides in the Beibu Gulf and their controlling factors (sediment grain size, total organic carbon, redox state, physical/biological disturbance, and ocean currents) but also indicated the radionuclide fingerprints (226Ra/238U and 232Th/238U) as potential geochemical proxies for quantifying the distinct sources of radionuclides and other associated chemicals (e.g., heavy metals, organic pollutants) in sediments. Unlabelled Image • Radioactivity level in the Beibu Gulf was lower than that in other Chinese seas. • Controlling factors included sediment grain size, TOC, redox state, and disturbance. • 226Ra 238U and 232Th 238U as novel proxies for quantifying sediment source • Marine sediments originated from local input (85%) and trans-region input (15%) [ABSTRACT FROM AUTHOR]

• The study first studied PAHs contamination in coral mucus besides coral tissues. • 15 PAHs widely occurred in the coastal and offshore corals, the South China Sea. • The ∑ 15 PAHs was much higher in coastal coral tissues than in offshore tissues. • The PAHs widely occurred in the mucus at a much higher level than in the tissues. • Mucus played an essential role in the bioaccumulation of PAHs by corals. Coral reefs have suffered degradation from climate change and water quality deterioration. Studies have shown that PAHs are present widely in some coastal seawater and coral tissues. However, no studies have focused on the PAHs in coastal coral mucus and offshore coral tissues. Targeting the South China Sea, this study for the first time investigated the occurrence, tissue-mucus partitioning, and bioaccumulation of PAHs in coastal and offshore corals. The tissue and mucus of the corals were processed separately. The results indicated that the total concentration of 15 of the 16 PAHs that are prioritized by U.S. EPA (excluding naphthalene) (∑ 15 PAHs) was significantly higher in the coastal tissues (173 ± 314 ng g−1 dw) than in the offshore tissues (71 ± 109 ng g−1 dw), as well as in coastal seawater (196 ± 96 ng L−1) than in the offshore water (54 ± 9 ng L−1). ∑ 15 PAHs is two orders of magnitude higher in the mucus (3200 ± 6470 ng g−1 dw) than in the tissues (128 ± 43 ng g−1 dw). By average, 29% of ∑ 15 PAHs were accumulated in the mucus. The results suggest that mucus plays an important role in the bioaccumulation of PAHs by corals from ambient seawater. [ABSTRACT FROM AUTHOR]

Coral reefs are important as they can help to maintain ecological balance, biological resources, and species diversity on earth. However, they are globally threatened by human activities and climate change. As live coral cover (LCC) is regarded as an important measure of the health of coral reefs, analysis on LCC change associated with environmental parameters, such as chlorophyll-a concentration (Chl-a), sea surface temperature (SST), and photosynthetically active radiation (PAR), is of great value. Research on this front would help us comprehend the changes in coral reefs induced by human activities and global changes. Instead of using spasmodically in-field-measured environmental parameters, in this study, we chose to combine the successive Chl-a, SST, and PAR products of the Moderate Resolution Imaging Spectroradiometer (MODIS) with historic LCC records to establish an empirical relationship using nonlinear optimization. Thereafter, the established relationship was further used to discuss some possible developments of LCCs. According to the experiments, we concluded that the degradation of the LCC around Weizhou Island may be mainly caused by human-activity-caused eutrophication. Besides, we also showed that even if the Chl-a and the PAR can keep constant with current average levels, the corals around Weizhou Island may still be in a risk of disappearing between 2120–2140 as the SST continues to rise. [ABSTRACT FROM AUTHOR]

Microplastic pollution of coral reef ecosystems has received increasing attention since the discovery that several typical coral types have the ability to ingest (micro-) plastics. However, data on the distribution of microplastics in coral reef ecosystems are still very limited. The study reported here selected sands/sediments from coral reef islands located in the South China Sea as a representative study site. The abundance of microplastics was found to reach 90 ± 5 items/kg and 530 ± 7 items/kg at the Weizhou Island and Sanya Lu Hui Tou (LHT) sites (fringing reef), respectively. Each of these qualities are lower than the quantity of microplastics collected from the Xisha Islands (atoll) (60 ± 3 to 610 ± 11 items/kg), which experiences less human activity and pollution. Moreover, further investigation demonstrated that the differences in the microplastics in the sands of these atolls and fringing reefs were determined not only by their sources, but were also dependent on their water exchange rates. The primary type and color of the microplastics found in these four sampling zones was red polypropylene and there was a greater proportion of smaller size particles (<1 mm) in the remote atolls of the Nansha and Xisha islands than in the other fringing reef sites. Additionally, there were no obvious differences found in the abundance of microplastics and the compositions/structures of coral sand in the Weizhou Island and Sanya LHT sites. Unlabelled Image • Firstly determination of microplastic in the sand of coral island at South China Sea • Higher content of microplastic was detected in the Xisha Islands than coastal sites. • Human activities were not the only source for microplastic in the sand of coral island. • Mineral type was one of the dominant factor affect the distribution of microplastics. • No obviously differences were found between the sand in reef flat and ragoon zones. [ABSTRACT FROM AUTHOR]

Eight fish species were sampled from a coastal coral reef ecosystem near Weizhou Island, South China Sea, to investigate the composition profiles and bioaccumulation of organochlorines (OCs). The total concentrations of 18 organochlorine pesticides (OCPs) and 22 polychlorinated biphenyls (PCBs) were found to be 26.5–452 ng/g lw and 0.87–19.8 ng/g lw, respectively. The contaminant distribution pattern indicated that agrochemical sources were more important than industrial sources, and that historical residues remain the primary source of OCs in Weizhou Island. Bioaccumulation factors (BAFs) indicated that dichlorodiphenyltrichloroethanes was bioaccumulating with log BAFs ranging from 3.53 to 5.21. Some congeners diverged from the general trend predicted by the logarithm octanol-water partition coefficient (log K ow); this was mainly attributable to differences in the bioaccumulation potentials of these congeners in the studied samples. Trophic magnification factors demonstrated that aldrin, endrin, and dieldrin undergo significant trophic dilution, while the other six OC compounds undergo trophic magnification in the food chain. The presence of OCP congeners was also probably affected by their metabolism in fish tissues. The estimated daily intakes of OCPs via fish consumption by residents ranged from 0.05 to 5.45 ng/kg body weight/day, which is below the acceptable daily intake recommended by the FAO/WHO. Image 1 • We studied OCs in the coastal coral reef ecosystems of the South China Sea.. • Organochlorines from historical agricultural sources persisted in the fish muscle. • The TMFs for organochlorines were lower than those from high latitude regions. • Consumption of the coral reef fish may not pose health risk to human at present. [ABSTRACT FROM AUTHOR]

• Novel wet chemical route was proposed for efficiently obtaining porous SnO 2 NTs. • A strong interaction between the Au NPs and hierarchical SnO 2 NTs was witnessed. • The Au-SnO 2 NTs composite demonstrated high sensing properties for acetone at 200 °C. • Such strategy essentially paves the way to prepare other high performance sensing materials. SnO 2 -based materials are helpful to detect low concentration of volatile organic compounds (VOCs), whereas high operating temperatures (≥ 350 °C), poor selectivity and inadequate detection limit of the pristine SnO 2 hinder their broader applications. An alternative strategy to address these challenge issues is to adopt porous SnO 2 nanotubes (NTs) constructed with ultrathin walls to monitor VOCs. However, inconvenient synthetic routes and low-yield rate of NTs with satisfactory wall thickness restrained the application of SnO 2 NTs. Herein, we directly turned SnS 2 nanosheets to the porous SnO 2 NTs by thermal oxidizing the SnS 2 precursor in air. After thermal treatment, high crystallinity and porous hierarchical SnO 2 NTs with ultrathin walls were successfully synthesized without any impurities. After decorated with Au nanoparticles (NPs), a strong interaction between the Au NPs and hierarchical SnO 2 NTs was witnessed. Compared with those reported SnO 2 -based materials, hierarchical SnO 2 NTs indeed improved the gas sensing properties; particularly, the sensor using Au-SnO 2 NTs composite gave the largest sensing magnitude, satisfactory detection limit and high selectivity to acetone at operating temperature of 200 °C. Conclusively, the innovation of transforming SnS 2 to the hierarchical SnO 2 NTs paves the way to building SnO 2 NTs from 2 dimensions ultrathin bricks, and for high performance sensing VOCs. [ABSTRACT FROM AUTHOR]

Oil pollution can release trace metals (TMs) with cumulative toxicity into seawater, harming marine ecosystems in the long term. However, the lack of studies has inhibited our understanding of the effects and mechanisms of oil pollution on TMs in seawater. Hence, we investigated the 10-year monthly variation of TMs in Porites coral skeletons from the northern South China Sea (SCS), complemented by spatial distribution of TMs in seawater, sediments and characterization of TMs in fuel oil. The results of principal component-multivariate linear regression showed that the total contribution of oil pollution as a source to TMs in surface seawater was 77.2%, where the residence time of TMs (Ni, V, Cr, Co, Cu, Mn, Fe, and Mo) released from oil spills in surface seawater was approximately 1.4 months. Due to the geochemical nature of the metals, their seasonal variations are controlled by tropical cyclones (Ni, V, Cr, Co, Cu, Mn, Fe, and Mo), winter monsoons (Pb, Cd, Ba, and Zn) and sea surface temperature (Sr). This study shows that coral skeletons can be used as a new tool to study marine oil pollution. This provides valuable reference data for accurately identifying and quantifying the effects of oil pollution on TMs in seawater from a spatial and temporal perspective. [Display omitted] • High-resolution coral skeletons can be used as a novel tool for marine pollution. • Contribution of oil pollution to each trace metal in surface seawater was estimated. • Effects of oil spills on trace metal in surface seawater can last for ∼1.4 months. [ABSTRACT FROM AUTHOR]

P-Chlorophenols (4-CP) are known as persistent toxic compounds for their acute toxicity and poor biodegradability. When the concentration of phenolic substances in water reaches 0.1005 mg/L, it becomes undrinkable. As a result, the detection of this human-toxic compound was indispensable. Hence, the high sensitivity and absorption ability of MOFs@MOFs composites (HP-UIO66@Ni-BDC) was applied to detect the 4-CP, which was constructed by using the ligand defect NH 2 -UIO-66 and Ni-BDC via a ligand linking approach. The improved performance of the materials compared to bare MOFs was attributable to the enhanced catalytic ability by the interaction of the MOFs and the high affinity between the 4-CP and the MOFs@MOFs composites (the electron donor-acceptor interaction and π-π stacking interaction). The electrochemical results illustrated the satisfactory electrochemical performances of modified GCEs toward 4-CP, such as the low limit of detection (LOD = 0.328 μM), wider linear detection range from 10 to 160 μM, and good stability and selectivity. Besides, the recovery experiments' results have shown that the electrochemical sensor could be used in the actual sample detecting. All the results suggested that the prepared HP-UIO66@Ni-BDC composites could serve as a prospective sensor for the real-time detection of 4-CP. [Display omitted] • The double MOF composite of HP-UIO66@Ni-BDC electrode was successfully synthesized. • Ligand connecting mode can promote electron transfer and electrochemical sensing. • Low LOD and wide detection range for detecting P-Chlorophenol were realized. • The reliability, veracity, and practicality of the electrochemical sensor was verified. [ABSTRACT FROM AUTHOR]

Most studies on coral bleaching alerts use common Degree Heating Week (DHW) thresholds; however, these may underestimate historical patterns of heat stress for coral reef ecosystems. Taking an optimized DHW threshold for coral bleaching alerts for Coral Reef Watch (CRW) and Coral Reef Temperature Anomaly Database (CoRTAD) products, we analyzed the precise spatial and temporal pattern of heat stress on China's coral reefs from 2010 to 2021 in the South China Sea (SCS) and the Beibu Gulf (BG). We compared acute heat stress using common and optimized thresholds. Results indicated that the ocean warming rate in 2010–2021 was approximately 0.43 ± 0.22 °C/10a, showing a significant increase in the northern SCS and the BG. More severe bleaching events were predicted by the optimized thresholds and the high-frequency areas were mainly in the northern SCS. The number and intensity of years with severe heat stress anomalies was in the order 2020 > 2014 > 2010 > 2015. Heat stress duration was the longest in the Xisha Islands among offshore archipelagos, and longest in 2020–2021 in Weizhou Island in BG in the relative high-latitude inshore reefs. These abnormal events were mainly caused by El Niño, but La Niña was also involved in 2020. • The most intense severe heat stress anomaly years were 2010 > 2014>2020 > 2015. • The anomaly duration of offshore islands was Xisha > Dongsha > Zhongsha > Nansha Islands. • High-latitude reefs were predicted not to be future thermal refuges for SCS reefs. • The optimized DHW threshold more accurately predicted spatiotemporal heat stress. [ABSTRACT FROM AUTHOR]

The highly sensitive electrochemical DNA biosensor and portable detection device were fabricated for quantitatively detecting the influenza A virus in animal tissue. [Display omitted] • A dual probe strategy guaranteed the performance of the biosensor. • The biosensor showed a wide detection range with a lower detection limit. • The reliability was determined by comparing it to the standard methods of ddPCR. • Portable detection devices could be utilized for influenza surveillance. Influenza A virus (IAV) can cause influenza, a highly infectious zoonotic respiratory disease, and early detection is essential to prevent and control its rapid spread in the population. Given the limitations of traditional detection methods in clinical laboratories, we report a large surface TPB-DVA COFs (TPB: 1,3,5-Tris(4-aminophenyl) benzene, DVA: 1,4-Benzenedicarboxaldehyd, COFs: Covalent organic frameworks) nanomaterial modified electrochemical DNA biosensor, which has dual-probe specific recognition and signal amplification. The biosensor enables quantitative detection of influenza A viruses' complementary DNA (cDNA) from 10 fM to 1 × 103 nM (LOD = 5.42 fM) with good specificity and high selectivity. The reliability of the biosensor and portable device was verified by comparing the virus concentrations in animal tissues with those measured by digital droplet PCR (ddPCR) (P > 0.05). Moreover, the potential for influenza surveillance in this work was demonstrated by detecting the tissue samples from mice at different stages of infection. In summary, the good performance of this electrochemical DNA biosensor we proposed suggested it has the potential to be a rapid detection device for the influenza A virus, which could assist doctors or other professionals in obtaining rapid and accurate results for outbreak investigation and disease diagnosis. [ABSTRACT FROM AUTHOR]

Per-and polyfluoroalkyl substances (PFASs) have received great attention due to their persistence, bioaccumulation and toxicity. Various activated carbons (ACs) exhibit wide variability in adsorptive performance towards PFASs. In order to gain a systematic understanding of adsorptive removal of legacy and emerging PFASs by ACs, the adsorption of ten PFASs on various ACs was comprehensively investigated. Results showed that granular activated carbon-1 (GAC-1) and powdered activated carbon-1 (PAC-1) removed more than 90% of all target PFASs. Particle size, surface charge, and micropores quantity of ACs were closely related to their performance for PFASs removal. Electrostatic interaction, hydrophobic interaction, surface complexation and hydrogen bonding were the adsorption mechanisms, with hydrophobic interaction being the predominant adsorptive force. Physical and chemical adsorption were both involved in PFAS adsorption. The removal rates of PFASs by GAC-1 decreased from 93%–100% to 15%–66% in the presence of 5 mg/L fulvic acid (FA). GAC was able to remove more PFASs under acidic medium, whereas PAC removed hydrophobic PFASs better under the neutral medium. The removal rates of PFASs by GAC-3 increased significantly from 0%–21% to 52%–97% after being impregnated with benzalkonium chlorides (BACs), demonstrating the superiority of this modification method. Overall, this study provided theoretical support for removing PFASs from water phase with ACs. • Particle size and surface properties of ACs affect their efficiency for PFAS removal. • Removal of PFASs by GAC was probably homogenous physical adsorption. • Neutral medium was favorable for the removal of long-chain PFASs by PAC. • Adsorption of PFASs by GAC was enhanced significantly by BACs impregnation. [ABSTRACT FROM AUTHOR]

Gestational diabetes mellitus (GDM) is a severe perinatal condition with serious consequences for the growth and development of the mother and baby. MicroRNA-29b (miR-29b) is essential to the pathogenesis of GDM and can be used as a molecular biomarker for diagnosis. Given the limitations of current GDM screening technologies, there is a pressing need for a sensitive detection approach to evaluate serum miR-29b in GDM patients, thus aiding in disease treatment. In this study, an electrochemical biosensor Co 7 Fe 3 –CN nanoparticles (NPs) was developed. Using a duplex-specific nuclease (DSN) signal amplification strategy with a linear range of 1–104 pM and a low detection limit of 0.79 pM, the ultra-sensitive detection and quantification of miR-29b were accomplished. The dependability and applicability of the developed biosensor were validated by the standard method of qRT-PCR, and the content of serum miR-29b in GDM patients was shown to be significantly lower than that in the control group (P = 0.03). Specifically, miR-29b concentrations could be detected from 2.0 to 7.5 and 2.4 to 7.3 pM using qRT-PCR and the biosensor, respectively. These similar results indicated that a biosensor based on miR-29b detection has the potential to be used in the point-of-care testing of GDM patients in clinical practice. [Display omitted] • Co 7 Fe 3 –CN nanomaterials and DSN as signal amplifiers constructed the biosensor. • The biosensor exhibited a high specificity and sensitivity in detecting miR-29b. • The qRT-PCR method validated the dependability and applicability of the biosensor. • POCT of GDM in future clinical practice will be of revolutionary potential. [ABSTRACT FROM AUTHOR]

Abstract Exploring high-performance sensing materials is ultra-important for safety control. Herein, 1D α-MoO 3 /0D ZnO nanocomposites are prepared via a facile hydrothermal method and its microstructure is characterized through X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), energy dispersive X-ray (EDX) and X-ray photoelectron spectroscopy (XPS). It is confirmed that the as-prepared nanocomposites are constituted by 1D α-MoO 3 nanobelts (200–300 nm in width), with the surface loaded with fine ZnO nanoparticles. Sensing properties of the α-MoO 3 and 1D α-MoO 3 /0D ZnO nanocomposites to ethanol are measured and compared. Interestingly, the ZnO-decorated α-MoO 3 nanobelts exhibited excellent sensitivity and selectivity to ethanol at relatively low operating temperature (250 °C) when compared with that of the raw α-MoO 3 nanobelts, indicating a good candidate of 1D α-MoO 3 /0D ZnO nanocomposites for future ethanol detection. Graphical abstract Image 1 Highlights • 1D α-MoO 3 /0D ZnO was successfully synthesized by a two-step hydrothermal method. • 1D α-MoO 3 /0D ZnO nanocomposite showed enhanced sensing properties to ethanol vapor at relatively low operating temperature. • The significant enhancement can be attributed to the variation of the n-n junction barrier. [ABSTRACT FROM AUTHOR]

Highlights • Roxithromycin was oxidized during disinfection of marine culture water. • Bromide accelerates the reaction of roxithromycin with sodium hypochlorite. • The desosamine moiety was broken away from roxithromycin. • The Br-DBP were generally more toxic than the Cl-DBPs and roxithromycin. Abstract The effects of water matrices on the reaction kinetics and transformation products of roxithromycin (ROX) with sodium hypochlorite (NaClO) were investigated. It was found that the removal efficiency of ROX was dependent on the type of disinfected water. For simulated fresh water, marine culture water and seawater, the reaction rate constant was 0.0521 min−1, 0.0757 min−1 and 0.106 min−1, respectively. The bromide ions in seawater and marine culture water not only promoted the reaction of ROX with NaClO but also caused the generation of brominated DBPs (Br-DBPs). Four DBPs including one chlorinated DBP (Cl-DBP) and three Br-DBPs were identified. The cladinose moiety and C14 atom were the main reaction centers which were easily attacked by disinfectant in fresh water. The desosamine moiety was also broken away from the parent compound ROX in the simulated marine culture water and seawater. Adsorbable organic halogen (AOX) analysis demonstrated that the Br-DBPs in water samples containing bromide ions were generally more carcinogenic than the Cl-DBPs formed in fresh water. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Ultra-uniform 3D α-Fe 2 O 3 nanotubes were packaged by PANI through the two-stage solution processes. • PANI/α-Fe 2 O 3 -based sensor could detect low concentration of acetone (1 ppm) at lower temperature of 180 °C. • The unique structure of α-Fe 2 O 3 support and its synergetic effect with PANI layers improved the sensor performances. Abstract This paper reports the PANI (polyaniline)-packaged three-dimensional (3D) α-Fe 2 O 3 nanotubes P/N heterojunction, which was constructed successfully though a facile hydrothermal reaction without adding any surfactant followed by in-situ chemical polymerization in the liquid phase. The structure and morphology of the products were characterized by means of FESEM, XRD, TEM & HRTEM, TGA and FT-IR. Gas sensing test results found that, the PANI/α-Fe 2 O 3 nanocomposite sensor exhibited obviously higher response, lower working temperature (180 °C), fast response and recovery speeds, good selectivity and excellent stability to acetone gas, indicating its promising application for high-performance acetone sensors. The enhanced gas sensing performances can be attributed to the factors like ultra-uniform 3D nanotube-like structure for α-Fe 2 O 3 , the noticeable advantages of PANI, as well as the construction of heterojunction barrier at their interface. The as-prepared PANI/α-Fe 2 O 3 nanocomposite may be also applied in other areas like photocatalysis, water purification, ion batteries, optical devices, and so on. [ABSTRACT FROM AUTHOR]

A novel sensor material of Au nanoparticles (NPs) functionalized 1D α -MoO3 nanobelts (NBs) was fabricated by a facile lysine-assisted approach. The obtained Au/ α -MoO3 product was characterized by means of X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and energy dispersive X-ray (EDX), and X-ray photoelectron spectra (XPS). Then, in order to investigate the gas sensing performances of our samples, a comparative gas sensing study was carried out on both the α -MoO3 NBs before and after Au NPs decoration by using ethanol vapor as the molecular probe. The results turned out that, after the functionalization of Au NPs, the sensor exhibited improved gas-sensing characteristics than the pure α -MoO3, such as response and recovery time, optimal operating temperature (OT) and excellent selectivity. Take for example 200 ppm of ethanol, the response/recovery times were 34 s/43 s and 5.7 s/10.5 s, respectively, while the optimal operating temperature (OT) was lower to 200 ∘ C rather than 250 ∘ C. Besides, the functionalized sensor showed a higher response to ethanol at 200 ∘ C, and response was 1.6 times higher than the pure MoO3. The mechanism of such improved sensing properties was interpreted, which might be attributed to the spillover effect of Au NPs and the electronic metal-support interaction. A novel sensor material based on 1D Au/α-MoO3 nanobelts was fabricated by a facile lysine-assisted approach. The comprehensive gas sensing study with ethanol molecular probe turned out that, after the functionalization of Au NPs, the sensor exhibited improved gas sensing characteristics than the pure α-MoO3, such as response and recovery times, optimal operating temperature and excellent selectivity. Such improved sensing properties might be attributed to the spillover effect of Au NPs and the electronic metal-support interaction. [ABSTRACT FROM AUTHOR]

The plasma concentrations of methotrexate (MTX) and its major metabolite 7-hydroxy methotrexate (7-OH-MTX) are highly correlated with the toxicities in patients with high-dose MTX therapy. Routine monitoring of MTX and 7-OH-MTX plasma levels is useful for dose adjustment of rescue drugs and toxicity prevention. A UHPLC-MS/MS method for simultaneous determination of plasma MTX and 7-OH-MTX was developed, validated, and applied in 181 plasma samples. The ion transition was m/z 455.2 → 308.2 for MTX and m/z 471.2 → 324.1 for 7-OH-MTX. The flow rate was 0.4 mL/min with a run time of 2.6 min. The calibration range was 0.002–2 μM for MTX, and 0.01–10 μM for 7-OH-MTX. The intra-day and inter-day inaccuracy and imprecision were –5.50% to 10.93% and less than 9.20% for both analytes. The internal standard (MTX-D 3 ) normalized recovery and matrix factor were consistent at four quality control levels. 14 h, 38 h, and 62 h after dosing, MTX and 7-OH-MTX plasma levels were significantly higher in patients with impaired renal function compared to those with normal renal function. 7-OH-MTX plasma levels were significantly higher in patients with impaired liver function compared to those with normal liver function. [ABSTRACT FROM AUTHOR]

The coral reef crisis has significantly intensified over the last decades, mainly due to severe outbreaks of crown-of-thorns starfish (COTS). Current ecological monitoring has failed to detect COTS densities at the pre-outbreak stage, thus preventing early intervention. In this work, we developed an effective electrochemical biosensor modified by a MoO 2 /C nanomaterial, as well as a specific DNA probe that could detect trace COTS environmental DNA (eDNA) at a lower detection limit (LOD = 0.147 ng/μL) with excellent specificity. The reliability and accuracy of the biosensor were validated against the standard methods by an ultramicro spectrophotometer and droplet digital PCR (p > 0.05). The biosensor was then utilized for the on-site analysis of seawater samples from SYM-LD and SY sites in the South China Sea. For the SYM-LD site suffering an outbreak, the COTS eDNA concentrations were 0.33 ng/μL (1 m, depth) and 0.26 ng/μL (10 m, depth), respectively. According to the ecological survey, the COTS density was 500 ind/hm2 at the SYM-LD site, verifying the accuracy of our measurements. At the SY site, COTS eDNA was also detected at 0.19 ng/μL, but COTS was not found by the traditional survey. Hence, larvae were possibly present in this region. Therefore, this electrochemical biosensor could be used to monitor COTS populations at the pre-outbreak stages, and potentially serve as a revolutionary early warning method. We will continue to improve this method for picomolar or even femtomolar detection of COTS eDNA. [ABSTRACT FROM AUTHOR]

Nutrient enrichment is a widely recognized threat to coastal coral reefs. Yet its impact on open ocean reefs is largely unknown due to the lack of long-term observations at remote sites and the entanglement of various environmental factors affecting coral growth. Here we determined growth rates and the carbonate chemistry of calcifying fluid (CF) of massive corals over the last 550 years at a remote South China Sea reef ecosystem. We show that large growth variations cannot be fully explained by changes in seawater pH or temperature due to the antiphase relationship between growth rate and pH cf as well as small sea surface temperature variations before the 1960s. Instead, coral growth rate decreases proportionally with past seabird populations over the past centuries. We suggest that excess nutrient loads through monsoon pumping and seabird migration played an important role in controlling coral growth at this remote reef ecosystem. Specifically, episodic eutrophication as indicated by a ∼ 3 per mil increase in coral δ13C has depressed coral growth by ∼30% during 15th to 18th centuries, which is comparable to the modern decline. Thus, accurate projections of future coral growth for remote reefs under ongoing human activities and climate change needs to take into account the history of past nutrient inputs into these ecosystems under pre-anthropogenic conditions, which has been overlooked previously due to a lack of historical observations. • Coral cores from an open ocean reef that grew from ∼1450 to present were analyzed. • Temperature affects multi-decadal variability in coral calcifying fluid DIC but not pH. • Reef-water pH modified by monsoon controls calcifying fluid pH and [CO 3 2−] • Eutrophication caused by monsoon and seabirds depressed coral growth during the Little Ice Age • An analog to the responses of corals to the projected rise in anthropogenic nutrient inputs. [ABSTRACT FROM AUTHOR]

[Display omitted] • Dual-anion incorporation reduces the band gap in layer titanium-based oxides. • The covalence of Ti-O bond is also improved through dual-anion incorporation. • Atom scale insights into the relations between electronic structure and performance. • S, N -NTO offers the lower detection limit for DA in artificial sweat and human serum. • The microdevice enables the rapid and efficient in-situ detection in applications. Flexible chemical sensors have attracted significant interest in real-time health monitoring, the internet of things, and robots. Titanium-based layered oxide (TLO) is a potential material for high-performance sensors, but the drawbacks of poor conductivity and low adsorption capacity limit its practical applications. Herein, we effectively optimize the electron structure of Na 2 Ti 3 O 7 (NTO) through S and N dual anions doping technology, which can reduce the electron density of interlayer sodium ions, enhance the hybridization of Ti 3d-O 2p bonds, and optimize the p-blocking center near the Fermi level. These changes decrease the band gap and favor the electron transfer and adsorption capacity for S, N-Na 2 Ti 3 O 7 (S, N -NTO). As a result, the S, N -NTO displays favorable neurotransmitter dopamine (DA) selectivity, wide detection range, low limit of detection, and ultrafast response for electrochemical sensing. Furthermore, the prepared flexible paper-based portable microsensors enable rapid and in-situ identification of DA in artificial sweat and human serum and show excellent mechanical stability and durability. This study provides an important perspective to develop practical wearable medical test devices as well as highlights the key role of anion doping in modulating the electronic structure of TLO. [ABSTRACT FROM AUTHOR]

The intra- and inter-individual variances of methotrexate (MTX) pharmacokinetics are extremely large, and the pharmacokinetic property of MTX in patients with primary central nervous system lymphoma (PCNSL) is unestablished. A total of 701 MTX plasma concentrations from 98 patients with PCNSL under high-dose MTX therapy were used to develop the population pharmacokinetic (popPK) model of MTX by using the nonlinear mixed-effects modeling method. A 2-compartment model was employed to describe the pharmacokinetic property of MTX. In the final popPK model, inclusion of serum creatinine and body surface area significantly reduced objective function value for clearance over the base model ( p <0.001), and inclusion of age significantly reduced objective function value for distribution volume of central compartment ( V c ) over the base model ( p <0.001). In the final popPK model, the inter-individual clearance = 6.67 × (SCR/68.1) −0.48 × (BSA/1.75) 1.17 ; V c = 24.46 × (age/57.16) 0.81 . The precision of all parameters was acceptable (relative standard error <28.61%). Bootstrap and visual predictive check results indicated that the final popPK model was stable with acceptable predictive ability. The popPK model may be useful for personalized medication in PCNSL patients under high-dose MTX therapy. Further studies are warranted to confirm the results. [ABSTRACT FROM AUTHOR]

As a kind of tropical agricultural solid waste, cassava dregs had become a thorny nonpoint source pollution problem. This study investigated the feasibility of applying cassava dregs as a substitute for sucrose in biofloc technology (BFT) systems. Three types of biofloc systems (using three different carbon sources sucrose (BFT1), cassava dregs (BFT2) and enzyme-hydrolyzed cassava dregs (BFT3) respectively), and the control were constructed in this experiment in 200 L tanks with a C/N ratio of 20/1. The comparison of the water quality indicators (The total ammonia nitrogen (TAN), nitrite (NO 2 − -N), nitrate (NO 3 − -N), chemical oxygen demand (COD)), biofloc for the above four groups was performed, and the results indicated that BFT3 showed greater potential to the formation of biofloc, which was beneficial for the water quality control. So the shrimp survival rate was the highest and the feed conversion rate was the lowest in BFT3. Besides, the high-throughput sequencing results showed that the relative abundance of heterotrophic bacteria in the top 30 dominant microbial communities in BFT3 was higher than those in BFT1 and BFT2 by 20.70% and 1.19%, respectively, which could decrease TAN to improve the water quality. Overall, the results had proved that the cassava dregs of enzymes hydrolysis could be used as an ideal and cheap carbon source in BFT. [ABSTRACT FROM AUTHOR]

Unexpected reduction of iminoquinone (IQ) and quinone derivatives was first reported during positive electrospray ionization mass spectrometry. Upon increasing spray voltage, the intensities of IQ and quinone derivatives decreased drastically, accompanying the increase of the intensities of the reduction products, amodiaquine (AQ) and phenol derivatives. To gain more insight into the mechanism of such reduction, we explored the experimental factors that are influential to corona discharge (CD). The results show that experimental parameters that favor severe CD, including metal spray emitter, using water as spray solvent, sheath gas with low dielectric strength (e.g., nitrogen), and shorter spray tip-to-mass spectrometer inlet distance, facilitated the reduction of IQ and quinone derivatives, implying that the reduction should be closely related to CD in the gas phase. [ABSTRACT FROM AUTHOR]

Chlorination disinfection and antibiotic addition are two universal processes of marine culture. The generation of disinfection byproducts (DBPs) is unavoidable. Antibiotic residue not only pollutes water but also acts as a precursor to the production of new DBPs. The fate of antibiotic norfloxacin (NOR) in chlorination disinfection was investigated. It was observed that NOR could be oxidized by disinfection agent sodium hypochlorite, but the oxidation rate varied considerably with the type of disinfected water. For fresh water, marine culture water and sea water, the reaction rate constant was 0.066 min −1 , 0.466 min −1 and 1.241 min −1 , respectively. The difference was primarily attributed to the promotion role of bromide ions in seawater and marine culture water. Moreover, the bromide ions could result in the generation of brominated DBPs (Br-DBPs). The kinetics, products, reaction centers and mechanisms were investigated. The active site of NOR was found to be the N4 atom on piperazinyl in fresh water. During marine culture water and sea water disinfection, the carboxyl on NOR was oxidized and two Br-DBPs were formed. This was attributed to the lowering of the reaction's required activation energy when performed in the presence of bromide ions. The Br-DBPs were also confirmed in real shrimp pond brackish water. Quantitative structure activity relationships and the total organic halogen analysis showed that the DBPs in marine culture water possessed stronger toxicological properties than the DBPs in fresh water. The toxicity increase was attributed to the production of Br-DBPs in the disinfection process of marine culture water. [ABSTRACT FROM AUTHOR]

• DNA barcode design by screening SNP is essential for accurate quantitation. • High-quality DNA extraction prevents qPCR inhibition. • Spiking H. pluvialis genomic DNA is suitable to quantify DNA recovery efficiency. • Plunge in solitary-cells abundance before bloom conflicts with lab-based findings. • Blooms can be forecasted earlier from the perspective of early-stage solitary cells. Phaeocystis globosa bloom develops from its early solitary cells, providing clues for early warning of its bloom and timely responding to possible consequences. However, the early prediction requires quantification of the solitary cells for a thorough understanding of bloom formation. Therefore, we developed an accurate, sensitive, and specific qPCR assay for this need. Results show that the accuracy of qPCR was significantly enhanced by ameliorating DNA barcode design, improving genomic DNA extraction, and introducing a strategy of internal amplification control (IAC). This approach reached a quantification limit of 1 cell/reaction, making low-abundance cells (101−103 cells/L) detection possible, and we also observed a plunge in the abundance of the solitary cells before the bloom outbreak in two winters in 2019 and 2020 for the first time, which is quite unique from laboratory results showing an increase instead. The plunge in solitary-cell abundance might be associated with the attachment of solitary cells to solid matrices to form non-solitary attached aggregate, the precursor of colonies, which gains supports from other studies and needs more investigations in the future. Therefore, as the plunge in solitary-cell abundance is a sign of colony formation, it can be used as an early warning indicator to P. globosa bloom. Improvement and application of qPCR assay revealed new insight on early warning of Phaeocystis globosa bloom [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Day-night cycle had notable effect on the photo-physiology and Symbiodiniaceae cell density of coral holobionts. • The Symbiosis, immune system and NH 4 + assimilation related genes were affected by day-night oscillation. • The A. pruinosa holobiont had larger day-night oscillations than the P. damicornis holobiont. • The cooperation strategies of coral holobionts were affected by day-night cycle. Interpreting the coral-Symbiodiniaceae symbiosis in light of the day-night cycle may provide missing links in understanding the function of endosymbiosis. In this study, we found the photo-physiology, Symbiodinaiceae cell density and gene transcription of two coral holobionts (Acropora pruinosa-Cladocopium sp. and Pocillopora damicorni s- Durusdinium sp.) have clear day-night oscillations. These two coral holobionts showed lower maximum quantum yield of photosystem II but higher Symbiodiniaceae cell density at day-time, as compared to at night-time. At day-time, the genes related to circadian rhythm and symbiosis in both hosts were up-regulated, while those related to immunity were down-regulated. Simultaneously, both symbionts had lower abundances of genes involved in the light reaction, Calvin cycle and glycolysis, but higher abundances of genes involved in the NH 4 + assimilation. These results indicated the high density of Symbiodiniaceae at day-time might be attributed to up-regulating of genes involved in symbiosis and nitrogen metabolism but down-regulating of genes involved in immunity. Moreover, the A. pruinosa - Cladocopium sp. holobiont had larger day-night oscillations than P. damicornis - Durusdinium sp. holobiont, in terms of photo-physiology, Symbiodinaiceae cell density and gene transcription, revealing species-specific day-night oscillation. This study provides valuable insights into the cooperation strategies of coral holobionts to adapt to the day-night environmental changes. [ABSTRACT FROM AUTHOR]

The Indo-Pacific Convergence Zone (IPCZ) has a complex ocean dynamical system. All scale processes are active and interplay from small-scale turbulent mixing to basin-scale circulation. The IPCZ acts as an "oceanic bridge" for the inter-basin mass transports and basin-scale planetary waves, closely linking basin-scale circulations in the Pacific and Indian Oceans. Numerous straits in the Indonesian Seas provide oceanic channels for planetary waves propagating between the tropical Pacific and the southeast Indian Ocean. On a large scale, the inter-basin mass transports and planetary waves change the ocean thermal structure, triggering strong air-sea interactions, and further regulating the variability of Walker and Hadley Circulations. The latter form an "atmospheric bridge", which significantly affects the Asian and Australian monsoon systems and a series of global climate events like El Niño-Southern Oscillation (ENSO), Indian Ocean Dipole, and Indian Ocean Basinwide warming. On meso- and small- scales, eddy, submesoscale processes, and turbulent motions mix the water mass from different sources, dramatically stirring the upper ocean in the IPCZ. Ocean dynamics have essential impacts on the ecological system in the IPCZ. On the one hand, these processes directly affect biodiversity by controlling the genetic exchanges and species dispersals between basins. On the other hand, the ocean dynamical processes influence biogeochemical cycling by controlling the trophic transfer, which further impacts primary productivity. With the intensified climate variations under global warming, e.g., marine heatwaves and extreme events, the ocean dynamical processes turn more active and enhance the influence on the ecosystem. This work overviews a series of studies focusing on the multi-scale ocean dynamical and environmental processes in the IPCZ, including the climatic signatures in coral records and the ecological response. [ABSTRACT FROM AUTHOR]

Handaxes, the characteristic tool of the Acheulean industrial complex, are predominantly made of stone. Handaxes made of bone are much less common. Only a few have been reported, from sites in Africa, Europe and western Asia. In this study we report a bone handaxe from Chongqing, southwest China, which represents the first bone handaxe ever discovered in China or any other part of East Asia. Typologically, it is somewhat inconsistent with the classic Acheulean handaxe morphology and is therefore classified as a proto-handaxe in this study. The bone from which the handaxe was made, which is now fossilized, has been dated to ∼170 ka based on a U-series technique. The handaxe was manufactured from the mandible of an individual of the stegodontid Stegodon orientalis , a typical member of the Middle Pleistocene Ailuropoda - Stegodon fauna ( sensu stricto ) of southern China. This artifact represents the earliest evidence for a tradition of bone handaxe manufacture in East Asia, and provides important evidence regarding the lifestyle, technology, and environmental surroundings of the humans that occupied the upstream region of the Yangtze River during the Middle Pleistocene. [ABSTRACT FROM AUTHOR]

Persistent organic pollutants (POPs) present in water may be bioconcentrated in phytoplankton and further transferred into higher trophic levels. In the present study, seawater, sediment, phytoplankton and macroalgae ( Ulva lactuca L.) samples were collected from two estuarine bays in South China and analyzed for 24 polybrominated diphenyl ethers (PBDEs) and 22 organochlorine pesticides (OCPs). The concentrations of PBDE congeners except BDE-209 were low in both phytoplankton and Ulva . BDE-209 was the predominant congener in phytoplankton and Ulva , accounting for 89.5% and 86.6% of the total average concentrations of PBDEs (48.5 and 4.1 ng g − 1 dw), respectively. The average concentrations of DDTs, HCHs and 1-chloro-2,2-bis(4-chlorophenyl)ethane ( p , p ′-DDMU) in phytoplankton were 398, 241 and 11.3 ng g − 1 dw, respectively, while those of DDTs and HCHs in Ulva were 8.4 and 33.1 ng g − 1 dw. The levels of both PBDEs and OCPs were an order of magnitude higher in phytoplankton than in Ulva , indicating that phytoplankton with larger surface areas have higher uptake efficiency for POPs than Ulva . Bioconcentration factors (BCFs) of DDT and PBDE in phytoplankton from the two bays were in the range of 10 5 – 10 6 , suggesting that bioconcentration may be one of the key sources of POPs and algae can be an important route for POPs to move toward higher trophic levels. [ABSTRACT FROM AUTHOR]

[Display omitted] • The first to investigate the Uronema marinum inactivation mechanism by omics. • The inactivation of Uronema marinum by UV/PDS in marine waters. • Contribution of reactive species on the inactivation of Uronema marinum. • Effect of reaction parameters on the inactivation of Uronema marinum. Protozoa in mariculture water will cause the outbreak of seafood diseases, and there are also discharge regulations about protozoa in the ballast water of ocean ships. However, the inactivation of protozoa has not attracted attention. This study investigated the inactivation of ciliate Uronema marinum (U. marinum) as surrogate for protozoa by ultraviolet (UV)/peroxydisulfate (PDS) system. Results showed that the addition of 1 mM PDS significantly enhanced the inactivation from 0.73 log to 1.47 log by UV exposure at 3.6 mJ·cm−2. Reactive species responsible for the inactivation were identified to be •SO 4 − and •OH. The anions in seawater inhibited the inactivation of U. marinum in UV/PDS system. UV/PDS inactivated U. marinum by damaging the cell membrane and releasing of intracellular materials. The activities change of the antioxidant enzymes showed that oxidative species destroyed the defense function. Moreover, omics analysis proved that the radicals affected the expression of genes, proteins and metabolites of U.marinum. In authentic marine water, the inactivation of U. marinum was 1.38 log in 120 s. There was no generation of chlorate (ClO 3 −), bromate (BrO 3 −) and adsorbable organic halogens (AOX). The economic cost of UV/PDS for inactivation of U. marinum was preliminarily calculated to be 0.062 $ m−3. The results suggest that it will be beneficial to upgrade UV disinfection to •SO 4 − based advanced oxidation technology for inactivation of protozoa in marine water. [ABSTRACT FROM AUTHOR]

[Display omitted] • Biphasic interfacial assembly method was addressed to optimize the hybrid electrodes. • The typical product of CC/MMPCA presented multistaged sizes from ca. 10 to 250 nm. • The CC/MMPCA-based sensor showed high selectivity and ultra-low LOD (0.27 µM) to DA. • Achieving successful extension to other substrates for rapid and in situ detection. Hybrid electrodes based on conductive inorganic substrates and organic porous structured polymer have attracted significantly scientific and technological interests in numerous areas including electrochemical sensors, catalysis, and energy storage due to their excellent functionality of good permeability to the inner host. The mesoscopic channels, however, pose a problem because their potential applications require mass transport within them, so they are limited by the undesirable and finite structure of mesoscopic channels due to the immense synthetic difficulties. In this study, we demonstrate a facile interfacial assembly strategy for fabricating hybrid electrodes with highly accessible nanochannels on carbon cloth (CC), called macroporous/mesoporous polymer carbon arrays (MMPCA), where the multistage pores size extremely wide from ca. 10 to 250 nm. Owing to these vertically irregular, permeable and multistage channels, electrochemical sensors based on the MMPCA exhibit a low limit of detection (LOD, 0.27 µM) and nice sensitivity (0.545 µA µM−1 cm−2) in dopamine (DA) detection. This strategy creates opportunities to controllably tailor the interfacial assembly of multistage mesoporous nanounits on diverse conductive substrate towards versatile applications and underscores the importance of structural alignments for advanced technologies, which could be applied to various fields related to mass transportation and electronic signal transmission. [ABSTRACT FROM AUTHOR]

• The source-sink variability of dissolved nutrients was studied in QZB and MWS. • Rivers and groundwater discharged contributed significantly to nutrient input. • N -limitation occurred before the 1980 s and thereafter P-limitation in QZB. • MWS is a sink of N- nutrients and a source of P-nutrients. • The relief of P-limitation in the dry season is crucial for frequent algal blooms. Maowei Sea is a typical semi-enclosed subtropical bay where eutrophication has been rising due to human activities in recent years. At present, the source and long-term variability properties of nutrients are not well understood. This study investigated the dissolved inorganic nutrients in the riverine sections to the sea and the coastal areas from 2011 to 2017 in Qinzhou Bay (QZB), Beibu Gulf. Results showed that harmful blooms were frequent in the dry season due to rapid urbanization in recent years. During dry season, the concentrations of dissolved inorganic nitrogen (DIN) and dissolved inorganic phosphorus (DIP) increased by 67% and 150%, respectively. Most of the nutrients input to the bay were supplied by the adjoining rivers, followed by groundwater discharge according to the classical box model devised by the Land-Ocean Interactions in the Coastal Zone. High DIN concentrations in rivers were mainly caused by intensified agriculture, including urban and rural effluents, due to inadequate sanitary sewer systems. Maowei Sea (the inner bay of QZB) is a sink system for DIN but a strong source system for DIP, which surpassed riverine input, probably due to the discharge of DIP-containing effluent from the industries around the Maoling River mouth. The discrepancy in DIN and DIP sources resulted in different DIN/DIP ratios between the wet and dry seasons. P-limitation generally occurs in the wet season and is relieved in the dry season. The relief of P-limitation in the dry season may be crucial for the frequent harmful algal blooms, which may be further aggravated in the future with the rapid increase in DIP concentrations in the bay. Therefore, the results of this study provide a basis for the effective improvement of the ecological environment in the Maowei Sea. [ABSTRACT FROM AUTHOR]

Multiple environmental pressures caused by global warming and human activities have aroused widespread concern about PAHs pollution in tropical marine coral reef regions (CRRs). However, the trophodynamics of PAHs in the food webs of the CRRs and the related influence factors have not been reported. This study investigated the occurrence, trophic amplification, and transmission of PAHs in various organisms selecting between at least representative species for each level in CRRs of the South China Sea (SCS); revealed their driving mechanisms; and explored the trophodynamics of PAHs in the food web of the coral reef ecosystem. Results showed that more PAHs can be accumulated in the mantle tissue of Tridacnidae, and the proportion of mantle tissue of Tridacnidae increases with the increase of latitude (y = 0.01x + 0.17, R2 = 0.49, p < 0.05). Latitude drives the differential occurrence level and bioaccumulation of PAHs in tropical marine organisms, and also affects the trophodynamics of PAHs in aquatic ecosystem food webs. PAHs undergo trophic amplification in the food webs of tropical marine ecosystems represented by coral reefs, thus further aggravating the negative environmental impact on coral reef ecosystems. The cancer risk caused by accidental ingestion of PAHs by humans through consumption of seafood in CRRs is very low, but we should be alert to the biomagnification effect of PAHs. [Display omitted] • Reported PAHs' occurrence in the coral reef food web for the first time. • Latitude affected PAHs' occurrence and bioaccumulation in the organisms. • Latitude drove the PAHs' trophodynamics in aquatic ecosystem food webs. • PAHs underwent trophic amplification in the food webs of coral reef ecosystems. [ABSTRACT FROM AUTHOR]