Biological Indices Research Articles

Spatiotemporal smoothing of water quality in a complex riverine system with physical barriers

Freshwater ecosystems offer a variety of ecosystem services, and water quality is essential information for understanding their environment, biodiversity, and functioning. Interpolation by smoothing methods is a widely used approach to obtain temporal and/or spatial patterns of water quality from sampled data. However, when these methods are applied to freshwater systems, ignoring terrestrial areas that act as physical barriers may affect the structure of spatial autocorrelation and introduce bias into the estimates. In this study, we applied stochastic partial differential equation (SPDE) smoothing methods with barriers to spatial interpolation and spatiotemporal interpolation on water quality indices (chemical oxygen demand, phosphate phosphorus, and nitrite nitrogen) in a freshwater system in Japan. Then, we compared the estimation bias and accuracy with those of conventional non-barrier models. The results showed that the estimation bias of spatial interpolations of snapshot data was improved by considering physical barriers (5.8 % for (chemical oxygen demand, 22.5 % for phosphate phosphorus, and 21.6 % for nitrite nitrogen). The prediction accuracy was comparable to that of the non-barrier model. These were consistent with the expectation that accounting for physical barriers would capture realistic spatial correlations and reduce estimation bias, but would increase the variance of the estimates due to the limited information that can be gained from the neighbourhood. On the other hand, for spatiotemporal smoothing, the barrier model was comparable to the non-barrier model in terms of both estimation bias and prediction accuracy. This may be due to the availability of information in the time direction for interpolation. These results demonstrate the advantage of considering barriers when the available data are limited, such as snapshot data. SPDE smoothing methods can be widely applied to interpolation of various environmental and biological indices in river systems and are expected to be powerful tools for studying freshwater systems spatially and temporally.

Evaluating the response of current biotic indices and functional metrics to natural and anthropogenic predictors in disconnected pools of temporary rivers

Temporary rivers, forming the majority of river networks worldwide, are key biodiversity hotspots. Despite their great value for maintaining biodiversity and ecosystem functioning, they are often neglected in biomonitoring programs due to several challenges, such as their variable hydromorphology and the difficulty of establishing reference conditions given their dynamic nature, resulting in highly variable communities. Disconnected pools often form in temporary rivers when flow ceases, providing refuge for aquatic taxa. Given their importance for biodiversity conservation, revising and adapting biotic indices are needed. Here, we evaluate the performance of current biological indices designed for perennial rivers (macroinvertebrates, diatoms) and functional metrics (macroinvertebrates) in assessing biological quality of disconnected pools. We sampled 55 disconnected pools in Catalonia, NE Spain, covering local (e.g., physico-chemical variables, water chemistry) and regional (e.g., human influence, hydrological variables at the water body level) natural and anthropogenic gradients. Only a few macroinvertebrate biotic indices (e.g., family richness, EPT/EPT + OCH and OCH) showed strong responses to anthropogenic predictors and were unaffected by natural predictors at both local and regional scales, making them suitable for biomonitoring. Of the newly adopted functional metrics of macroinvertebrate communities tested, only two (i.e., functional redundancy of predators and response diversity based on the total community) responded strongly to anthropogenic predictors. The rest showed varying responses to the interactive effect of anthropogenic and natural predictors, requiring calibration efforts. Models assessing these metrics explained <40 % of the total variation, likely due to the interplay of colonization/extinction dynamics and density-dependent trophic interactions governing community assemblages in disconnected pools. Although some existing biological metrics could potentially be used to monitor the ecological status of disconnected pools, we call for further development of biomonitoring tools specifically designed for these habitats since they will become more widespread with global change.

Comparative Assessment of Physicochemical and Biological Indicies of Otamiri and Nworie River Using a Piper Diagram Model

The Surface Water Resources of Otamiri-Nworie Watershed within the Owerri Metropolis were studied with the prime aim of developing a Non-Point Source Event-Based Model to Contamination of the water bodies. Clean, safe, and sufficient water is essential for both human existence and the health of ecosystems, communities, and economies (Fubara and Kpormon, 2023). As human populations increase, industrial and agricultural production increases, and climate change pose a threat of significant disruption of the hydrologic cycle, and as such, declining water quality has emerged as a major global problem (Ogbonna and Orinya, 2023). Human-drinking water must be free of organisms and chemical substances, as high amounts might be harmful to one’s health (Adeyi et al., 2021). This study aimed at comparatively assessing the physicochemical and biological indices of Otamiri and Nworie Rivers, and the Piper diagram model was employed for the analysis. Fifteen water samples were collected along the course of the two rivers and analyzed for physical, chemical and microbial parameters. Physical, chemical, and biological parameters were analyzed. The analytical results of the samples were compared with notable standards like the World Health Organization [WHO], etc. It was observed that all the parameters analyzed for the rivers fall below the acceptable standards except for pH (6.5-8.5) indicating the acidic nature of these water bodies. Similarly, the colour value of the two rivers ranges between 21.5 to 229 PCU and observed to be decreasing downstream within Nworie and Otamiri rivers. Within the river Nworie axis, both the total dissolved solids (TDS) and the total suspended solids (TSS) were observed to be increasing downstream. Along Otamiri river before confluence, total dissolved solids increased downstream whereas the reverse was the case for the total suspended solids, just after the confluence. There is a noticeable increase in dissolved oxygen (DO) downstream within the Nworie axis. The biological oxygen demand (BOD) values for the rivers were below the WHO standard. Finally, the major sources of contamination within the study area revealed that they are mainly from agricultural practices, dumpsites, and human defecation. The quality can be improved by applying appropriate treatment to the water before its use for various purposes.

Study of biological quality of lake waters based on phycocyanin using tree‐based methodologies

AbstractThe provision of drinking water, agricultural, and industrial applications by reservoirs has made lake exploration and monitoring unavoidable. The features of the ecosystem, particularly physical and chemical elements, influence the evaluation of the quality of water resources. Lakes undergo extensive qualitative changes due to their vast amount of water. In general, these bodies of water represent geological conditions as well as water contamination produced by natural and human activities. In the present research, the prediction of the amount of phycocyanin (fPC) in the water of Lake Michigan has been implemented employing four tree‐based machine learning techniques based on seasonality factors. Phycocyanin has significant effects on quality parameters such as turbidity, chlorophyll concentration, algal bloom, and dissolved oxygen in water by affecting the photosynthesis process of algae. Therefore, in this study, the prediction of the amount of phycocyanin dissolved in the lake water using the mentioned variables, along with the temperature of the water, specific conductance, and pH, has been able to interpret the quality of the water and the occurrence of phenomena such as algal blooms. The results of the models in predicting fPCs equal to 0.44 and 0.55 μg/L were consistent with the natural conditions of the lake, and it seems that ensemble tree–based models, along with the biological index of fPC, formed the right combination of input and output parameters in modeling and obtained the lowest prediction error (root‐mean‐square error [RMSE] boosted trees = 0.0140 and RMSE random forests = 0.0141 μg/L).

Soil biological fertility evolution in a chronosequence under long‐term rice cultivation after land reclamation in China

AbstractLand use significantly affects soil biological fertility through impacts on carbon (C) and nitrogen (N) cycling. The present study investigated the effects of long‐term rice cultivation after tidal flat reclamation on soil C and N metabolism, microbial biomass and biological fertility. Eighteen composite topsoil (0–20 cm) samples were identified in a chronosequence of coastal reclamation areas (0–700 years old) in subtropical monsoon climate zone, namely tidal flat (T0), salt marsh soil (S10) and paddy soil (P50, P100, P300 and P700). Using ANOVA analysis, mono‐exponential regression model, and multiple linear regressions, soil organic matter (SOM), total nitrogen (TN), cumulative C mineralization content (Ct) and N mineralization content (Nt), basal soil respiration (BSR) and microbial biomass C and N (MBC and MBN) in the P50‐P700 samples were significantly higher than those in the T0 and S10 samples, whereas C metabolic quotients (qCO2) in the P50‐P700 were significantly lower than those in the T0 and S10 samples. The time to steady state for SOM and TN are 357 years and 80 years, respectively; 133 and 221 years for Ct and Nt, respectively; and 318 and 183 years for MBC and MBN, respectively. Also, a soil biological fertility index (SBFI) was calculated on the basis of SOM, BSR, Ct, MBC, qCO2 and qCM. P100‐P300 samples had the highest SBFI score (28.7) and ranked in the class V (very high) of biological fertility, achieving steady‐state conditions after 146 years. SBFI was significantly positively correlated with SOM, TN, MBC, MBN, BSR, Ct and Nt, whereas it was significantly negatively correlated with pH, qCO2 and C mineralization quotient (qCM). MBC and qCM were two independent variables with considerable positive effects on SBFI. Long‐term rice cultivation could facilitate C and N accumulation and enhance biological fertility in soils via microbial activity, especially within 300 years. Our findings demonstrate that rice cultivation has the potential to enhance soil C and N accumulation. Carbon‐related SBFI is suitable for assessing soils under long‐term rice cultivation, mainly because the rice paddy field is an intensive and conservative system.

How does geology influence the effect of land use on stream macroinvertebrate communities?

Abstract Both catchment geology and land use surrounding a stream will affect the degree of fine sediment deposition from erosion and its consequent impacts on stream macroinvertebrate communities. While geology and land use have been shown to impact stream communities individually, their interaction has received less attention. We investigated the interaction between geology and land use on stream macroinvertebrate communities in the Tairāwhiti Region, New Zealand. The region has streams that drain harder sandstones and softer shales and mudstones, the latter having some of the highest erosion rates in the world. Macroinvertebrates were sampled each year between 2016 and 2018 at 80 sites in exotic forest, indigenous forest and pasture streams that drained hard or soft geology catchments. Conductivity in pasture and exotic forest streams was nearly twice as high as in indigenous forest streams and higher in soft than hard sediment streams. Deposited sediment cover was greater in soft than hard sediment streams, and greater in pasture and exotic forest streams than in indigenous forest streams. Periphyton cover did not differ between land uses but was higher in soft sediment streams. Ecological health was higher in the indigenous forest sites, intermediate in exotic forest sites and lowest in pasture streams. Biological indices were also higher within each land use in streams draining hard than soft sediment streams. Invertebrate communities appear to be determined primarily by the amount of deposited fine sediment and conductivity, both of which are higher in soft than in hard bottom streams, and in exotic forest and pasture streams. Synthesis and applications: Our results illustrate a complex and strong interaction between geology and land use and the consequent impact on stream macroinvertebrate communities. The combination of soft bottom streams with pasture or exotic forest land use is more detrimental than in similar hard bottom streams. Therefore, regulations for the management of any given land use need to be much stricter in catchments dominated by soft sediment geology.

Phragmites australis straw and biochar additives regulate soil organic carbon fractions in a degraded coastal salt marsh

Severely degraded coastal salt marshes with impaired ecological functions urgently need to be restored to improve blue carbon sequestration. Although plant residues and biochar have been used to restore degraded wetlands, the dose-effects of these plant additives on soil organic carbon fractions in degraded coastal wetlands are still unclear. Here, we investigated the dynamic changes in DOC components and mineral-associated organic carbon, such as calcium-bound organic carbon (Ca-OC) and iron/aluminum-bound organic carbon (Fe/Al-OC), in a degraded coastal salt marsh in a 60-day incubation experiment with low (0.1%), medium (1%), and high (3%) doses of Phragmites australis straw (PS) and Phragmites australis-derived biochar (PB) addition treatments. The results showed that the medium and high doses of PB additives increased humus-like substances, with the maximum proportion occurring on day 60 of the incubation. The fluorescence index (FI) and biological index (BIX) were >1.9 and 0.8, respectively, and the humification index (HIX) was < 4 in most treatment groups. The mineral-associated organic carbon (Ca-OC and Fe/Al-OC) contents were higher in the 1% PS and 3% PS treatments (p < 0.05). The PS additives increased the soil Ca-OC/SOC and Fe/Al-OC/SOC ratios, whereas the PB additives decreased them. This study demonstrated that PS and PB are potential carbon-rich additives for enhancing soil organic carbon stability and carbon sequestration in coastal wetland restoration projects, contributing to regional carbon neutrality.

Soil functional indicators in a semi-arid environment change patchy under the influence of shrub species

The presence of mountain shrublands within semi-arid regions is of great importance due to their function in the preservation of water and soil resources and their contribution to the conservation of biodiversity. The study of the effects of semi-arid highland shrubs on soil functional indicators has not yet received sufficient attention. To fill this knowledge gap, we conducted a study to investigate the effects of different shrub species specifically Carpinus orientalis Miller, Berberis integerrima Bunge, Crataegus microphylla C. Koch, Prunus spinosa L., and Rhamnus pallasii Fisch. and C. A. Mey) on soil physical, chemical, and biological properties. For this study, 15 individuals of each of the above-mentioned shrub species were selected. Soil samples were collected at a depth of 10 cm and an area of 30 cm × 30 cm beneath the canopy of these particular species. The examination of the influence of various independent factors on the variability of soil microclimate and biological characteristics indicates that the presence of shrub covers is the primary determinant of changes in water content, fauna and microflora population, microbial respiration and biomass, whereas soil temperature, MBN/MBP and qCO2 are more affected by season factor. Based on the biological fertility index, all the studied shrub covers are in the medium class with the maximum score under Carpinus shrub. Results indicate that soil biological characteristics play a more significant role in distinguishing in terms of soil functional indicators. Based on hot spots output, the soil functional indicators decreased in order of Carpinus > Crataegus > Berberis > Prunus > Rhamnus. As a conclsuion, Carpinus create hot spots (areas) of soil functional indicators in the mountainous ecosystems that claimed the potentially role of nutrient-rich soil cycles.

Variability in excitation–emission spectra among wastewater treatment units and applications of fluorescence-based water quality monitoring

ABSTRACT The study assessed the feasibility of fluorescence spectroscopy for characterizing the wastewater of functional wastewater treatment plants (WWTPs) as a real-time monitoring aspect. Peak picking and fluorescence regional integration (FRI) techniques are employed on 3D excitation–emission matrix (EEM) contours in understanding the variations of dissolved organic matter (DOM) of wastewater. Results demonstrate significant reductions in treated wastewater traits, including 94.38% of total suspended solids (TSS), 83.27% of dissolved organic carbon (DOC), and 85.38% of chemical oxygen demand (COD). The microbial analysis detected fecal and total coliforms in the effluent, highlighting the need for continuous monitoring and treatment. However, the biodegradable organic components decrease significantly, with protein-like peaks T1 and B1 intensities declining by 62.17 and 71.7%, respectively, during secondary treatment and further diminishing during tertiary treatment. Conversely, peaks associated with refractory humic and protein-bound components increased after tertiary treatment due to the formation of secondary products. The humification index (HIX) rises from influent to effluent, indicating a reduced carbon-to-nitrogen ratio. At the same time, the biological index (BIX) remained consistent, indicating microbial activity as a significant DOM contributor. The study establishes fluorescence spectroscopy as a promising and rapid monitoring tool for understanding DOM in WWTPs and optimizing treatment effectiveness.

Effect of aromatic massage on brain waves and physiological indices of older adults.

Massage and aromatherapy are frequently used by older adults as alternative interventions to enhance immunity and induce relaxation. This pilot study evaluated the effect of massage therapy with oil and aromatherapy alone and in combination using objective biological indices. Twenty-eight participants recruited by convenience sampling included adults aged between 25 and 65 years (Group 1), elderly individuals over 65 years without nursing care (Group 2), and older adults over 65 needing long-term nursing support (Group 3). A multiple-group pretest-post-test design was employed, and the effect among the three groups was compared. Interventions included: (i) oil massage therapy; (ii) aromatherapy; and (iii) aroma oil massage therapy. Each therapy session lasted 5 min, with 3 min of observation before and after the session and 10 min interval between sessions. Group 3 omitted one therapy (2: aromatherapy) to reduce their physical burden. An electroencephalogram (EEG) was recorded for α, β, and θ activities of brain waves. EEG data were collected at three points: before, during, and after each treatment. Salivary secretory immunoglobulin A (s-IgA) concentration, oxygen saturation (SPO2), and pulse rate were measured before and after each session. Across all therapy modalities, there was a noticeable increase in the α wave, indicative of relaxation, during the treatment. Significant differences were observed before and during the oil massage in both Group 1 and Group 2. Aromatherapy demonstrated a significant difference before and during treatment in Group 1. Among the biological parameters, s-IgA levels indicated no significant changes. The pulse rate decreased with oil massage. Significant differences were noted before and after therapy in all cases for SPO2 and in Group 2 for pulse rate. Three therapies induced EEG and physiological changes in the adult group and older adults without nursing care. However, these effects are limited in older adults requiring nursing care.

Untangling the interplay of dissolved organic matters variation with microbial symbiotic network in sludge anaerobic fermentation triggered by various pretreatments

Various pretreatments are commonly adopted to facilitate dissolved organic matter (DOM) release from waste activated sludge (WAS) for high-valued volatile fatty acids (VFAs) promotion, while the interplay impact of DOM dynamics transformation on microbial population and metabolic function traits is poorly understood. This work constructed “DOM-microorganisms-metabolism-VFAs” symbiotic ecologic networks to disclose how DOM dynamics variation intricately interacts with bacterial community networks, assembly processes, and microbial traits during WAS fermentation. The distribution of DOM was altered by different pretreatments, triggering the release of easily biodegradable compounds (O/C ratio > 0.3) and protein-like substance. This alteration greatly improved the substrates biodegradability (higher biological index) and upregulated microbial metabolism capacity (e.g., hydrolysis and fatty acid synthesis). In turn, microbial activity modifications augment substance metabolism level and expedite the conversion of highly reactive compounds (proteins-like DOM) to VFAs, leading to 1.6–4.2 fold rise in VFAs generation. Strong correlations were found between proteins-like DOM and topological properties of DOM-bacteria associations, suggesting that high DOM availability leads to more intricate ecological networks. A change in the way communities assemble, shifting from stronger uniform selection in pH10 and USp reactors to increased randomness in heat reactor, was linked to DOM composition alterations. The ecologic networks further revealed metabolic synergy between hydrolytic-acidogenic bacteria (e.g., Bacteroidota and Firmicutes) and biodegradable DOM (e.g., proteins and amino sugars) leading to higher VFAs generation. This study provides a deeper knowledge of the inherent connections between DOM and microbial traits for efficient VFAs biosynthesis during WAS anaerobic fermentation, offering valuable insights for effective WAS pretreatment strategies.

Comparative Performance Evaluation of Double-Stranded RNA High-Throughput Sequencing for the Detection of Viral Infection in Temperate Fruit Crops.

There is limited information on the compared performances of biological, serological. and molecular assays with high-throughput sequencing (HTS) for viral indexing in temperate fruit crops. Here, using a range of samples of predetermined virological status, we compared two performance criteria (inclusivity and analytical sensitivity) of enzyme-linked immunosorbent assay (ELISA), molecular hybridization, reverse transcription (RT)-PCR, and double-stranded RNA (dsRNA) HTS for the detection of a total of 14 viruses (10 genera) and four viroids (three genera). When undiluted samples from individual plants were used, ELISA had the lowest performance, with an overall detection rate of 68.7%, followed by RT-PCR (82.5%) and HTS (90.7%; 100% if considering only viruses). The lower performance of RT-PCR reflected the inability to amplify some isolates as a consequence of point mutations affecting primer-binding sites. In addition, HTS identified viruses that had not been identified by other assays in nearly two-thirds of the samples. Analysis of serial dilutions of fruit tree samples allowed comparison of analytical sensitivities for various viruses. ELISA showed the lowest analytical sensitivity, but RT-PCR showed higher analytical sensitivity than HTS for most of the samples. Overall, these results confirm the superiority of HTS over biological indexing in terms of speed and inclusivity and show that while the absolute analytical sensitivity of RT-PCR tends to be higher than that of HTS, PCR inclusivity is affected by viral genetic diversity. Taken together, these results make a strong case for the implementation of HTS-based approaches in fruit tree viral testing protocols supporting quarantine and certification programs.

Association between single and mixed exposure to polycyclic aromatic hydrocarbons and biological aging.

Aging is one of the most important public health issues. Previous studies on the factors affecting aging focused on genetics and lifestyle, but the association between polycyclic aromatic hydrocarbons (PAHs) and aging is still unclear. This study utilized data from the National Health and Nutrition Examination Survey (NHANES) 2003-2010. A total of 8,100 participants was used to construct the biological age predictors by using recent advanced algorithms Klemera-Doubal method (KDM) and Mahalanobis distance. Two biological aging indexes, recorded as KDM-BA acceleration and PhenoAge acceleration, were used to investigate the relationship between single PAHs and biological age using a multiple linear regression analysis, and a weighted quantile sum (WQS) model was constructed to explore the mixed effects of PAHs on biological age. Finally, we constructed the restricted cubic spline (RCS) model to assess the non-linear relationship between PAHs and biological age. Exposure to PAHs was associated with PhenoAge acceleration. Each unit increase in the log10-transformed level of 1-naphthol, 2-naphthol, and 2-fluorene was associated with a 0.173 (95% CI: 0.085, 0.261), 0.310 (95% CI: 0.182, 0.438), and 0.454 (95% CI: 0.309, 0.598) -year increase in PhenoAge acceleration, respectively (all corrected P < 0.05). The urinary PAH mixture was relevant to KDM-BA acceleration (β = 0.13, 95% CI: 0, 0.26, P = 0.048) and PhenoAge acceleration (β = 0.59, 95% CI: 0.47, 0.70, P < 0.001), and 2-naphthol had the highest weight in the weighted quantile sum (WQS) regression. The RCS analyses showed a non-linear association between 2-naphthol and 2-fluorene with KDM-BA acceleration (all P < 0.05) in addition to a non-linear association between 1-naphthol, 2-naphthol, 3-fluorene, 2-fluorene, and 1-pyrene with PhenoAge acceleration (all P < 0.05). Exposure to mixed PAHs is associated with increased aging, with 2-naphthol being a key component of PAHs associated with aging. This study has identified risk factors in terms of PAH components for aging.

Decadal growth pattern of an indicator species Sebastes koreanus in the Yellow Sea and its response to environmental changes at differing scales

Climate change and human activities are significantly impacting coastal ecosystems and the species that inhabit them. Understanding how individual growth of key species varies and responds to environmental changes is essential for a better understanding of population dynamics and prediction of ecological responses to environmental changes. Here, a 20-year growth history of Sebastes koreanus was reconstructed based on otolith chronology analysis. Then the relationships between environmental factors (local and basin scales) and the growth variability were analyzed using a mixed effect model. The reconstructed growth chronology showed distinct inter-annual variability that alternatively increased and decreased, and a rapid increasing trend was observed during 2011–2014. The growth pattern significantly correlated with summer Chlorophyll-a concentration, indicating bottom-up control in the coastal ecosystem of the Yellow Sea. Significant relationships were also detected between otolith growth and winter bottom temperature and summer Southern Oscillation index, the two significant factors that also represent intensity of the Yellow Sea Cold Water Mass (YSCWM), which is the most important hydrographic feature influencing the Yellow Sea. The study result contributes to better understand fish growth plasticity under environmental changes. This result also reveals the relationship between fish dynamics and the YSCWM intensity in the Yellow Sea. The growth condition of S. koreanus could be used as a biological index for the YSCWM intensity and contribute to better understand the influence of the YSCWM on fish populations.

Flora of the riverside-water side of the lower section of the Nistru river and its tributaries on the territory of the Republic of Moldova

The studied section of the river. The Dniester and its tributaries are represented by 113 species, 103 genera from 55 families of higher plants (Magnoliophyta). The greatest diversity is found in the Asteraceae (21 species) and Poaceae (8 species) families. About 1/3 of the total number of species are represented by the Eurasian element. The spontaneous element of the studied flora is represented by 54 species, and the ruderal element by 36 species. Invasive elements are represented by the species Ailanthus altissima (Mill.) Swingle, Acer negundo L. Amorpha fruticosa L., Ambrosia artemisiifolia L., Grindelia squarrosa Willd.. It was also carried out for all species: determination of the percentage ratio of life forms, biological indices, ecological groups in relation to humidity, the ratio of plant species by origin, the distribution of indicator species by nitrogen (N) in percentage terms and the ratio of plant species in relation to the category trophicity.

Application of Fish-Integrity Biological Index and Water Quality Index to Assess the Ecological Health of the Pahang River, Malaysia

Application of Fish-Integrity Biological Index and Water Quality Index to Assess the Ecological Health of the Pahang River, Malaysia

Measurement report: Optical characterization, seasonality, and sources of brown carbon in fine aerosols from Tianjin, North China: year-round observations

Abstract. To investigate the optical characteristics and sources of brown carbon (BrC) in North China, where the atmospheric aerosol loadings are high and have severe impacts on Earth's climate system, we collected fine aerosols (PM2.5) at an urban site in Tianjin over a 1-year period. We measured the ultraviolet (UV) light absorption and excitation emission matrix (EEM) fluorescence of the water-soluble BrC (WSBrC) and the water-insoluble but methanol-soluble BrC (WI-MSBrC) in the PM2.5 using a three-dimensional fluorescence spectrometer. The average light absorption efficiency of both WSBrC (Abs365, WSBrC) and WI-MSBrC (Abs365, WI-MSBrC) at 365 nm was found to be highest in winter (10.4 ± 6.76 and 10.0 ± 5.13 Mm−1, respectively) and distinct from season to season. The averages of the fluorescence index (FI) and the biological index (BIX) of WSBrC were lower in summer than in the other seasons and opposite to that of the humification index (HIX), which implied that the secondary formation and further chemical processing of aerosols were more intensive during the summer period than in the other seasons. However, in winter, the higher HIX together with the higher FI and BIX of WI-MSBrC suggested that the BrC loading was mainly influenced by primary emissions from biomass burning and coal combustion. Based on the EEM, the types of fluorophores in WSBrC were divided into humic-like substances (HULIS), including low-oxygenated and high-oxygenated species and protein-like compounds (PLOM), though mostly PLOM in the WI-MSBrC. The direct radiation absorption by both WSBrC and WI-MSBrC in the range of 300–400 nm accounted for ∼ 40 % of that (SFEAbs, 4.97 ± 2.71 and 7.58 ± 5.75 W g−1, respectively) in the range 300–700 nm.

Response of selected nutrient elements in leaf tissues of sweet potato cv. 'Bophelo' to Nemafric-BL phytonematicide

Nemafric-BL phytonematicide is a potent plant-based nematicide which consistently suppress nematode population densities of root-knot (Meloidogyne species) nematodes on various crops, but with limited information on its effects on foliar nutrient elements in sweet potato. The objective of this study, therefore, was to investigate the effects of Nemafric-BL phytonematicide on accumulation of nutrient elements in leaf tissues of sweet potato cv. 'Bophelo' under greenhouse conditions in Limpopo Province, South Africa, during autumn (February-April) in 2021 and validated in 2022. The product was applied weekly at geometric concentrations, with mature leaves collected and prepared for analysis of nutrient elements at eight weeks. Seasonal interactions were not significant and therefore data were pooled (n = 70) and then subjected to the Curve-fitting Allelochemical Response Dose (CARD) algorithm computer model. Iron (R2 = 0.86), K (0.91) and Na (0.82) versus Nemafric-BL phytonematicide each exhibited negative quadratic relations, whereas Zn (0.83) versus the product exhibited positive quadratic relations. In all test elements, the CARD-generated biological indices illustrated that the accumulation of elements was highly sensitive to the concentration of Nemafric-BL phytonematicide. In conclusion, in sweet potato production, the application of Nemafric-BL phytonematicide can inhibit (Fe, K) and stimulate (Zn) the accumulation of certain elements in leaf tissues of sweet potato cv. ′Bophelo‵.

Prevalence of insulin resistance and its associated factors in drug-naïve patients with bipolar disorder among Han Chinese population

BackgroundMetabolic syndrome (Mets) is commonly seen in bipolar disorder (BD). As the key component and early biological index of Mets, insulin resistance (IR) among BD has received more and more attention. However, little is known about the prevalence of IR and its associated factors in drug-naïve patients with (BD), especially among Han Chinese population.MethodsA cross-sectional study was conducted on 125 drug-naïve patients with bipolar disorder (BD) and 85 healthy controls (HC). The Homeostatic Model Assessment of insulin resistance (HOMA-IR) was calculated, and IR was defined as HOMA-IR greater than the 75th percentile value for health controls (2.35). Clinical characteristics of BD were collected through semi-structural interview performed by a trained interviewer with background of psychiatric education.ResultsAmong the measured anthropocentric variables including BMI, waist circumference, abdomen circumference, hipline, and hip-waist ratio, waist circumference was found to be the most closely related to IR (0R = 1.070, 95%CI = 1.031–1.110, P < 0.001). Male was another factor that was associated with IR (OR = 2.281, 95%CI = 1.107–4.702, P = 0.025). After adjusted for gender and waist circumference, the risk of IR was significantly higher in bipolar disorder than in healthy controls (OR = 2.66, 95%CI = 1.364–5.214, P = 0.004). No significant association was found between IR and any of the observed physical and mental comorbidities, any characteristic of illness course including age onset, number of mixed episodes, types of current state, duration of current episode, duration of illness course, rapid cycling, number of mood episodes, and subgroup of BD. Hypersomnia was the only symptomatic feature that was significantly associated with IR (OR = 0.316, 95%CI = 0.124–0.803, P = 0.016).ConclusionsBipolar disorder increases two-to-three-fold risk of IR, both circumference and male are the risk factors of IR but hypersomnia act as a protective factor.

Microplastic coupled with soil dissolved organic matter mediated changes in the soil chemical and microbial characteristics

The abundance of microplastics (MPs) in soil environments has attracted significant attentions, due to their impact on soil physico-chemical properties. However, limited information is available on the influences of MPs on soil carbon composition and microbial utilization characteristics. Therefore, a two-month incubation experiment was conducted to add polyethylene microplastics (PE-MPs) with different levels (1%, 10%) and sizes (150–300 μm and 75–150 μm) into different soils. After that, soil chemical properties including the dissolved organic carbon (DOC), spectral characteristics of dissolved organic matter (DOM) and soil microbial characteristics were analyzed. Results revealed that PE-MPs addition caused significant differences in soil chemical properties between farmland and woodland soils, particularly in soil pH, DOM composition, and soil phosphatase activity. Woodland soil always exhibited higher levels of DOC content, microbial diversity, and soil carbon source utilization compared to farmland soil, leading to increased humification in the DOM of woodland soil. PE-MPs with a larger particle size significantly increased both the soil DOC content and enzyme activity. Addition of PE-MPs altered the soil DOM composition, and the fluorescence parameters like the biological index (BIX) and humification degree. Moreover, the carbon source utilization intensity of microorganisms on PE MPs-contaminated soils is higher in woodland soils. Various analyses confirmed that compared to other soil properties, characteristics of soil DOM had a more significant impact on soil microbial community composition. Thus, PE-MPs in conjunction with soil DOM spectral characteristics regulated soil microbial diversity, which is crucial for understanding soil carbon sequestration.