Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 767
Filter
1.
J Fungi (Basel) ; 10(7)2024 Jun 21.
Article in English | MEDLINE | ID: mdl-39057325

ABSTRACT

Species of the basidiomycetous genus Tomentella are widely distributed throughout temperate forests. Numerous studies on the taxonomy and phylogeny of Tomentella have been conducted from the temperate zone in the Northern hemisphere, but few have been from subtropical forests. In this study, four new species, T. casiae, T. guiyangensis, T. olivaceomarginata and T. rotundata from the subtropical mixed forests of Southwestern China, are described and illustrated based on morphological characteristics and phylogenetic analyses of the internal transcribed spacer regions (ITS) and the large subunit of the nuclear ribosomal RNA gene (LSU). Molecular analyses using Maximum Likelihood and Bayesian analysis confirmed the phylogenetic positions of these four new species. Anatomical comparisons among the closely related species in phylogenetic and morphological features are discussed. Four new species could be distinguished by the characteristics of basidiocarps, the color of the hymenophoral surface, the size of the basidia, the shape of the basidiospores and some other features.

2.
Front Vet Sci ; 11: 1398961, 2024.
Article in English | MEDLINE | ID: mdl-38978631

ABSTRACT

The present study evaluated the effects of omega-3 (ω-3) fatty acid-rich linseed supplementation on the reproductive performance, endocrine profile, and biochemical profile of ewes reared in subtropical climates. Forty-eight acyclic and clinically healthy Marwari sheep, aged 1.5-2.5 years with no parity, were divided into four groups (n = n = 12 in each). Ewes in the control group (group I) were fed only a basal feed, whereas ewes in the treatment groups II, III, and IV were fed the basal diet along with 10%, 15%, and 20% linseed, respectively, daily on a dry matter basis. The experiment was conducted during the typical breeding season (October-November) of the sheep. The estrus induction rate was significantly higher (p < 0.05) in all treatment groups than in the control group. The estrus induction interval was significantly lower (p < 0.05) in group III. The conception rate in group I was significantly lower (p < 0.05). In addition, ewes in the control group had a significantly lower (p < 0.05) lambing rate than all treatment groups. Serum progesterone concentrations differed significantly (p < 0.05) between the control and the treatment groups on days 15, 30, 45, and 60 of supplementation. On treatment days 15 and 30, the serum estrogen concentrations were significantly higher (p < 0.05) in all treatment groups compared to that in group I. In all treatment groups, monounsaturated fatty acid (MUFA) decreased significantly (p < 0.05), whereas polyunsaturated fatty acid (PUFA) increased significantly (p < 0.05) from day 15 onward. In conclusion, by providing 15% dietary linseed supplementation to ewes, their reproductive performance can be improved in subtropical climates. Future studies are recommended to further elucidate the role of linseed supplementation in sheep reproduction in subtropical climates.

3.
J Environ Manage ; 366: 121656, 2024 Jul 08.
Article in English | MEDLINE | ID: mdl-38981276

ABSTRACT

The accumulation of soil legacy phosphorus (P) due to past fertilization practices poses a persistent challenge for agroecosystem management and water quality conservation. This study investigates the spatial distribution and risk assessment of soil legacy P in subtropical grasslands managed for cow-calf operations in Florida, with two pasture types along the intensity gradient: improved vs semi-native pastures. Soil samples from 1438 locations revealed substantial spatial variation in soil legacy P, with total P concentrations ranging from 11.46 to 619.54 mg/kg and Mehlich-1 P concentrations spanning 0.2-187.27 mg/kg. Our analyses revealed that most of the sites in semi-native pastures may function as P sinks by exhibiting positive Soil P Storage Capacity (SPSC) values, despite having high levels of soil total P. These locales of higher SPSC values were associated with high levels of aluminum, iron, and organic matter that can adsorb P. In addition, our results from spatial random forest modelling demonstrated that factors including elevation, soil organic matter, available water storage, pasture type, soil pH, and soil order are important to explain and predict spatial variations in SPSC. Incorporating SPSC into the Phosphorus Index (PI) spatial assessment, we further determined that only 3% of the study area was considered as high or very high PI categories indicative of a significant risk for P loss. Our evaluation of SPSC and PI underscores the complexity inherent in P dynamics, emphasizing the need for a holistic approach to assessing P loss risk. Insights from this work not only help optimize agronomic practices but also promote sustainable land management, thus ensuring the long-term health and sustainability of grass-dominated agroecosystems.

4.
J Med Virol ; 96(7): e29797, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38988215

ABSTRACT

Temperature and humidity are studied in the context of seasonal infections in temperate and tropical zones, but the relationship between viral trends and climate variables in temperate subtropical zones remains underexplored. Our retrospective study analyzes respiratory pathogen incidence and its correlation with climate data in a subtropical zone. Retrospective observational study at Moinhos de Vento Hospital, South Brazil, aiming to assess seasonal trends in respiratory pathogens, correlating them with climate data. The study included patients of all ages from various healthcare settings, with data collected between April 2022 and July 2023. Biological samples were analyzed for 24 pathogens using polymerase chain reaction and hybridization techniques; demographic variables were also collected. The data was analyzed descriptively and graphically. Spearman tests and Poisson regression were used as correlation tests. Tests were clustered according to all pathogens, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), influenza viruses, rhinovirus, and respiratory syncytial virus (RSV). Between April 2022 and July 2023, 3329 tests showed a 71.6% positivity rate. Rhinovirus and RSV predominated, exhibiting seasonal patterns. Temperature was inversely correlated with the viruses, notably rhinovirus, but SARS-CoV-2 was positively correlated. Air humidity was positively correlated with all pathogens, RSV, rhinovirus, and atmospheric pressure with all pathogens and rhinovirus. Our results showed statistically significant correlations, with modest effect sizes. Our study did not evaluate causation effects. Despite the correlation between climate and respiratory pathogens, our work suggests additional factors influencing transmission dynamics. Our findings underscore the complex interplay between climate and respiratory infections in subtropical climates.


Subject(s)
COVID-19 , Humidity , Seasons , Temperature , Humans , Retrospective Studies , COVID-19/epidemiology , COVID-19/transmission , COVID-19/virology , Brazil/epidemiology , Female , Male , Adult , Middle Aged , Child , Adolescent , Child, Preschool , Aged , Young Adult , Infant , SARS-CoV-2/genetics , SARS-CoV-2/isolation & purification , Climate , Respiratory Tract Infections/virology , Respiratory Tract Infections/epidemiology , Tropical Climate , Infant, Newborn , Rhinovirus/genetics , Rhinovirus/isolation & purification , Incidence , Respiratory Syncytial Virus Infections/epidemiology , Respiratory Syncytial Virus Infections/virology , Aged, 80 and over
5.
FEMS Microbiol Ecol ; 100(8)2024 Jul 12.
Article in English | MEDLINE | ID: mdl-38992179

ABSTRACT

Dinitrogen (N2) fixation represents a key source of reactive nitrogen in marine ecosystems. While the process has been rather well-explored in low latitudes of the Atlantic and Pacific Oceans, other higher latitude regions and particularly the Indian Ocean have been chronically overlooked. Here, we characterize N2 fixation and diazotroph community composition across nutrient and trace metals gradients spanning the multifrontal system separating the oligotrophic waters of the Indian Ocean subtropical gyre from the high nutrient low chlorophyll waters of the Southern Ocean. We found a sharp contrasting distribution of diazotroph groups across the frontal system. Notably, cyanobacterial diazotrophs dominated north of fronts, driving high N2 fixation rates (up to 13.96 nmol N l-1 d-1) with notable peaks near the South African coast. South of the fronts non-cyanobacterial diazotrophs prevailed without significant N2 fixation activity being detected. Our results provide new crucial insights into high latitude diazotrophy in the Indian Ocean, which should contribute to improved climate model parameterization and enhanced constraints on global net primary productivity projections.


Subject(s)
Cyanobacteria , Nitrogen Fixation , Seawater , Indian Ocean , Seawater/microbiology , Cyanobacteria/genetics , Cyanobacteria/metabolism , Ecosystem
6.
Comp Biochem Physiol B Biochem Mol Biol ; 274: 111006, 2024 Jul 06.
Article in English | MEDLINE | ID: mdl-38977177

ABSTRACT

Psalidodon bifasciatus is a fish species sensitive to physical and chemical changes in water. It serves as a good bioindicator of temperature variations and is utilized in environmental monitoring studies in Brazilian rivers. The objective of this study was to evaluate antioxidant defense biomarkers in the heart, brain, and muscle of P. bifasciatus exposed to a 10 °C thermal increase. P. bifasciatus were collected and divided into a control group (21 °C) and groups subjected to thermal shock (31 °C) for periods of 2, 6, 12, 24, and 48h. Two-way ANOVA indicated that a 10 °C temperature increase caused oxidative stress in P. bifasciatus. This was evidenced by altered levels of lipid peroxidation (LPO), carbonylated proteins (PCO), and glutathione peroxidase (GPx) in the heart, catalase (CAT) and LPO in the brain, and LPO in the muscle. Principal component analysis (PCA) and integrated biomarker response (IBR) analysis indicated that, compared to the heart and muscle, the brain exhibited a greater activation of the antioxidant response. Sensitivity analysis indicated that the muscle was the most sensitive organ, followed by the brain and heart. Our results indicate that the stress response is tissue-specific through the activation of distinct mechanisms. These responses may be associated with the tissue's function as well as its energy demand. As expected, P. bifasciatus showed changes in response to thermal stress, with the brain showing the greatest alteration in antioxidant defenses and the muscle being the most sensitive tissue.

7.
Sci Total Environ ; 948: 174815, 2024 Jul 15.
Article in English | MEDLINE | ID: mdl-39019286

ABSTRACT

Plants are generally limited by soil phosphorus (P) deficiency in forest ecosystems. Soil available P is influenced by lithology, temperature, and soil microbes. However, the interactive effects of these factors on soil P availability in subtropical forests remain unclear. To assess their impacts, we measured soil inorganic and available P fractions and the diversity, composition, and co-occurrence network of phoD-harboring bacteria in two contrasting forest soils (lithosols in karst forests and ferralsols in non-karst forests) in the subtropical regions of southwestern China across six temperature gradients. The present results showed that the complexities in composition and network and the diversity indices of phoD-harboring bacteria were higher in the karst forest soils than those in the non-karst forest soils, with marked differences in composition. In both types of forest soils, the complexities of composition and networks and the diversity indices were higher in the high-temperature regions (mean annual temperature (MAT) > 16 °C) compared to the low-temperature regions (MAT <16 °C). Soil total inorganic and available P contents were lower in the karst forest soils compared to the non-karst forest soils. Soil total available P contents were lower in the high temperature regions than those in the low temperature regions in both forest soils, whereas soil total inorganic P contents were contrary. Variance partitioning analysis showed that soil inorganic and available P fractions were predominantly explained by lithology and its interaction with soil microbes and climate. The present findings demonstrate that soil P availability in subtropical forests of southwestern China is influenced by lithology and temperature, which regulate the diversity, composition, and network connectivity of phoD-harboring bacteria. Furthermore, this study highlights the significance of controlling the composition of phoD-harboring bacteria for mitigating plant P deficiency in karst ecosystems.

8.
Environ Sci Technol ; 58(28): 12420-12429, 2024 Jul 16.
Article in English | MEDLINE | ID: mdl-38965050

ABSTRACT

Dissolved organic carbon (DOC) dynamics are critical to carbon cycling in forest ecosystems and sensitive to global change. Our study, spanning from 2001 to 2020 in a headwater catchment in subtropical China, analyzed DOC and water chemistry of throughfall, litter leachate, soil waters at various depths, and streamwater. We focused on DOC transport through hydrological pathways and assessed the long-term trends in DOC dynamics amidst environmental and climatic changes. Our results showed that the annual DOC deposition via throughfall and stream outflow was 14.2 ± 2.2 and 1.87 ± 0.83 g C m-2 year-1, respectively. Notably, there was a long-term declining trend in DOC deposition via throughfall (-0.195 mg C L-1 year-1), attributed to reduced organic carbon emissions from clean air actions. Conversely, DOC concentrations in soil waters and stream waters showed increasing trends, primarily due to mitigated acid deposition. Moreover, elevated temperature and precipitation could partly explain the long-term rise in DOC leaching. These trends in DOC dynamics have significant implications for the stability of carbon sink in terrestrial, aquatic, and even oceanic ecosystems at regional scales.


Subject(s)
Carbon , Forests , Ecosystem , China , Soil/chemistry , Carbon Cycle
9.
Polymers (Basel) ; 16(13)2024 Jul 05.
Article in English | MEDLINE | ID: mdl-39000774

ABSTRACT

Steel structures located in subtropical marine climates face harsh conditions such as strong sunlight and heavy rain, and they are extremely corroded. In this study, a waterborne coating with excellent corrosion resistance, hydrophobic ability, high-temperature resistance and high density was successfully prepared by using modified nanoscale titania powders and grafted polymers. The effects of three modifiers on titania nanoparticles and waterborne coatings' properties were studied independently. The experimental results showed that the activation index of the modification employing methacryloxy silane reached 97.5%, which achieved the best modification effect at 64.4 °C for 43.3 min. The waterborne coating with nanoscale titania modified by methacryloxy silane exhibited the best hydrophobic effect, with a drop contact angle of 115.4° and excellent heat resistance of up to 317.2 °C. The application of the waterborne modified coating in steel structures under subtropical maritime climates showed that the waterborne titania coatings demonstrated excellent resistance to corrosion, high temperatures and harsh sunlight, with a maximum service life of up to five years. Economic analysis indicated that, considering a conservative three-year effective lifespan, this coating could save more than 50% in cost compared with conventional industrial coatings. Finally, the strengthening mechanism of the polymer coatings with modified nanoscale titania was analyzed.

10.
PeerJ ; 12: e17471, 2024.
Article in English | MEDLINE | ID: mdl-38952986

ABSTRACT

The restoration of succulent thicket (the semi-arid components of the Albany Subtropical Thicket biome endemic to South Africa) has largely focused on the reintroduction of Portulacaria afra L. Jacq-a leaf- and stem-succulent shrub-through the planting of unrooted cuttings directly into field sites. However, there has been inconsistent establishment and survival rates, with low rates potentially due to a range of factors (e.g., post-planting drought, frost or herbivory), including the poor condition of source material used. Here we test the effect of parent-plant and harvesting site on the root development of P. afra cuttings in a common garden experiment. Ten sites were selected along a ∼110 km transect, with cuttings harvested from five parent-plants per site. Leaf moisture content was determined for each parent-plant at the time of harvesting as a proxy for plant condition. Root development-percentage of rooted cuttings and mean root dry weight-was recorded for a subset of cuttings from each parent-plant after 35, 42, 48, 56, and 103 days after planting in a common garden setting. We found evidence for cutting root development (rooting percentage and root dry mass) to be strongly associated with harvesting site across all sampling days (p < 0.005 for all tests). These differences are likely a consequence of underlying physiological factors; this was supported by the significant but weak correlation (r 2 = 0.10-0.26) between the leaf moisture content of the parent-plant (at the time of harvesting) and dry root mass of the cuttings (at each of the sampling days). Our findings demonstrate that varying plant condition across sites can significantly influence root development during dry phases (i.e., intra- and inter-annual droughts) and that this may be a critical component that needs to be understood as part of any restoration programme. Further work is required to identify the environmental conditions that promote or impede root development in P. afra cuttings.


Subject(s)
Droughts , Plant Roots , South Africa , Plant Roots/growth & development , Conservation of Natural Resources/methods , Caryophyllales , Plant Leaves/growth & development
11.
Sci Total Environ ; 949: 174692, 2024 Jul 11.
Article in English | MEDLINE | ID: mdl-39002597

ABSTRACT

Global warming may reshape seasonal changes in microbial community diversity and co-occurrence network patterns, with significant implications for terrestrial ecosystem function. We conducted a 2-year in situ field simulation of the effects of warming on the seasonal dynamics of soil microbial communities in a northern subtropical Quercus acutissima forest. Our study revealed that warming had no significant effect on the richness or diversity of soil bacteria or fungi in the growing season, whereas different warming gradients had different effects on their diversity in the nongrowing season. Warming also changed the microbial community structure, increasing the abundance of some thermophilic microbial species and decreasing the abundance of some symbiotrophic microorganisms. The co-occurrence network analysis of the microbial community showed that warming decreased the complexity of the intradomain network in the soil bacterial community in the growing and nongrowing seasons but increased it in the fungal community. Moreover, increasing warming temperatures increased the complexity of the interdomain network between bacteria and fungi in the growing season but decreased it in the nongrowing season, and the keystone species in the interdomain network changed with warming. Warming also reduced the proportion of positive microbial community interactions, indicating that warming reduced the mutualism, commensalism, and neutralism of microorganisms as they adapted to soil environmental stress. The factors affecting the fungal community varied considerably across warming gradients, with the bacterial community being significantly affected by soil temperature, MBC, NO3--N and NH4+-N, moreover, SOC and TN significantly affected fungal communities in the 4 °C warming treatment. These results suggest that warming increases seasonal differences in the diversity and complexity of soil microbial communities in the northern subtropical region, significantly influencing soil dynamic processes regulating forest ecosystems under global warming.

12.
J Hazard Mater ; 477: 135324, 2024 Jul 25.
Article in English | MEDLINE | ID: mdl-39068890

ABSTRACT

Plastic pollution poses a significant threat to marine ecosystems. Microfibres from fabrics have become the most prevalent shape of microplastic found in the marine environment. The northern krill (Meganyctiphanes norvegica) is the most abundant euphausiid species in the northern hemisphere, playing a crucial role in various pelagic ecosystems. Anthropogenic microparticles in northern krill was assessed for the first time in samples collected in the Azores on two occasions - April 2019 (n = 480) and April 2023 (n = 480). Analysis of all individuals revealed 533 anthropogenic particles, with an average abundance of 0.56 ± 0.14 items per individual and, no significant differences between years. Microfibres were the most common shape (94.8 %), with the remaining items being fragments (5.2 %), and blue and black were the predominant colours. MicroFourier transform infrared spectroscopy analysis (µFTIR) of 22.1 % of the total number of particles, showed that they were mainly cellulosic (65.3 %) - either natural or semisynthetic - followed by polyester (7.6 %). Our finding of microplastics in the northern krill raises important questions due to its crucial role in marine food webs. The intake of anthropogenic particles, particularly those that are 100 % synthetic, suggests that the northern krill may act as a transfer vector of these pollutants to higher trophic levels.

13.
Front Microbiol ; 15: 1419645, 2024.
Article in English | MEDLINE | ID: mdl-39077738

ABSTRACT

Background: Transforming coniferous plantation into broadleaved or mixed broadleaved-coniferous plantations is the tendency of forest management strategies in subtropical China. However, the effects of this conversion on soil phosphorus (P) cycling microbial functional genes are still unknown. Methods: Soil samples were collected from 0-20, 20-40, and 40-60 cm (topsoil, middle layer, and subsoil, respectively) under coniferous Pinus massoniana (PM), broadleaved Erythrophleum fordii (EF), and their mixed (PM/EF) plantation in subtropical China. Used metagenomic sequencing to examine the alterations of relative abundances and molecular ecological network structure of soil P-cycling functional genes after the conversion of plantations. Results: The composition of P-cycling genes in the topsoil of PM stand was significantly different from that of PM/EF and EF stands (p < 0.05), and total phosphorus (TP) was the main factor causing this difference. After transforming PM plantation into EF plantation, the relative abundances of P solubilization and mineralization genes significantly increased in the topsoil and middle layer with the decrease of soil TP content. The abundances of P-starvation response regulation genes also significantly increased in the subsoil (p < 0.05), which may have been influenced by soil organic carbon (SOC). The dominant genes in all soil layers under three plantations were phoR, glpP, gcd, ppk, and ppx. Transforming PM into EF plantation apparently increased gcd abundance in the topsoil (p < 0.05), with TP and NO3 --N being the main influencing factors. After transforming PM into PM/EF plantations, the molecular ecological network structure of P-cycling genes was more complex; moreover, the key genes in the network were modified with the transformation of PM plantation. Conclusion: Transforming PM into EF plantation mainly improved the phosphate solubilizing potential of microorganisms at topsoil, while transforming PM into PM/EF plantation may have enhanced structural stability of microbial P-cycling genes react to environmental changes.

14.
Ecol Evol ; 14(6): e11530, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38895566

ABSTRACT

The capacity of forests to sequester carbon in both above- and belowground compartments is a crucial tool to mitigate rising atmospheric carbon concentrations. Belowground carbon storage in forests is strongly linked to soil microbial communities that are the key drivers of soil heterotrophic respiration, organic matter decomposition and thus nutrient cycling. However, the relationships between tree diversity and soil microbial properties such as biomass and respiration remain unclear with inconsistent findings among studies. It is unknown so far how the spatial configuration and soil depth affect the relationship between tree richness and microbial properties. Here, we studied the spatial distribution of soil microbial properties in the context of a tree diversity experiment by measuring soil microbial biomass and respiration in subtropical forests (BEF-China experiment). We sampled soil cores at two depths at five locations along a spatial transect between the trees in mono- and hetero-specific tree pairs of the native deciduous species Liquidambar formosana and Sapindus saponaria. Our analyses showed decreasing soil microbial biomass and respiration with increasing soil depth and distance from the tree in mono-specific tree pairs. We calculated belowground overyielding of soil microbial biomass and respiration - which is higher microbial biomass or respiration than expected from the monocultures - and analysed the distribution patterns along the transect. We found no general overyielding across all sampling positions and depths. Yet, we encountered a spatial pattern of microbial overyielding with a significant microbial overyielding close to L. formosana trees and microbial underyielding close to S. saponaria trees. We found similar spatial patterns across microbial properties and depths that only differed in the strength of their effects. Our results highlight the importance of small-scale variations of tree-tree interaction effects on soil microbial communities and functions and are calling for better integration of within-plot variability to understand biodiversity-ecosystem functioning relationships.

15.
Animals (Basel) ; 14(11)2024 May 24.
Article in English | MEDLINE | ID: mdl-38891607

ABSTRACT

This review aims to provide an insight into the application and efficiency of CIDR-based protocols for ES in goats raised under tropical and subtropical environments. In temperate regions, short-term CIDR treatments are replacing long-term treatments and sponges used in earlier decades. In addition, the use of co-treatments for the induction of ovulation is gradually changing from hormonal to non-hormonal methods, given the drive towards clean, green, and ethical techniques for reproductive management. Whereas the subtropical region registers ongoing research in the development of new ES protocols, there are few reports from the tropics, particularly Africa, one of the regions with the highest population of goats. Therefore, this calls for research to develop the most appropriate protocols for these regions, since the protocols currently used are largely hormonal based, as they were developed for goats at higher latitudes. Management and environmental factors determine the breeding pattern of goats at tropical latitudes rather than photoperiods, and they are the main causes of reproductive seasonality. The use of ES methods, particularly short-term CIDR-based protocols, along with artificial insemination, may have a significant impact on the productivity of goats in these regions when these factors are controlled.

16.
Biol Trace Elem Res ; 2024 Jun 14.
Article in English | MEDLINE | ID: mdl-38877165

ABSTRACT

In the presented study, 15 tropical and subtropical fruits were studied for their mineral composition ranging from trace to major elements by ICP-OES after microwave digestion. The moisture amounts were assigned to be between 21.90 (tamarind) and 95.66% (pepino). The differences between the macroelement quantities of the fruits were established to be statistically significant (p<0.01). P and K quantities of fruits were displayed to be between 53.40 (pepino) and 927.74 mg/kg (tamarind) to 720.27 (pepino) and 13441.12 mg/kg (tamarind), respectively. While Ca quantities of fruits vary between 123.71 (pineapple) and 1519.76 mg/kg (blood orange), Mg quantities of fruits were established to be between 78.66 (pepino) and 875.02 mg/kg (tamarind). In general, the lowest macroelement quantities were determined in pepino fruit, but the highest P and K contents were determined in Gooseberry and Tamarind fruits, respectively. The microelement amounts of the fruits were established to be at very low levels compared to the macroelement contents. In general, the most abundant element in fruits was Fe, followed by Zn, Cu, Mn and B in decreasing order. In general, heavy metal quantities of fruits were detected at very low levels (except As and Ba). As and Ba quantities of fruits were assigned to be between 0.972 µg/g (mandarin) and 5.86 (kiwi) to 0.103 (pineapple) and 4.08 (avocado), respectively. As with macro and microelements, results regarding heavy metal concentrations varied depending on fruit types.

17.
Mar Pollut Bull ; 205: 116571, 2024 Aug.
Article in English | MEDLINE | ID: mdl-38941805

ABSTRACT

This study assessed the ecological health of waters within the Saudi Arabian Exclusive Economic Zone, by utilizing benthic biotic indices with a marine monitoring dataset covering the years 2013 to 2018. This comprehensive evaluation covered a vast expanse, encompassing 67 distinctive sampling locations characterized by a wide range of depth and salinity gradients. The study examined spatial fluctuations in the benthic community and assessed potential correlations with environmental variables, including salinity, depth, sediment texture, total organic carbon, and other relevant factors. The macrobenthic density varied across the study sites, with an average density of 566 ± 120 ind.m-2. The Shannon diversity index ranged from 3.21 and 5.90, with an average of 4.70 ± 0.52. Based on the average AMBI values, all the locations were categorized as either slightly disturbed or undisturbed. Additionally, the M-AMBI analysis indicated that 95.5 % sites were in good or high ecological status.


Subject(s)
Biodiversity , Ecosystem , Environmental Monitoring , Saudi Arabia , Animals , Aquatic Organisms , Geologic Sediments , Salinity , Invertebrates
18.
BMC Plant Biol ; 24(1): 516, 2024 Jun 08.
Article in English | MEDLINE | ID: mdl-38851686

ABSTRACT

BACKGROUND: The influence of native secondary succession associated with anthropogenic disturbance on the biodiversity of the forests in subtropical China remains uncertain. In particular, the evolutionary response of small understory shrubs, particularly pioneer species inhabiting continuously disturbed habitats, to topographic heterogeneity and climate change is poorly understood. This study aimed to address this knowledge gap by focusing on the Gaultheria crenulata group, a clade of small pioneer shrubs in subtropical China. RESULTS: We examined the genetic structure and demographic history of all five species of the G. crenulata group with two maternally inherited chloroplast DNA (cpDNA) fragments and two biparentally inherited low-copy nuclear genes (LCG) over 89 natural populations. We found that the genetic differentiation of this group was influenced by the geomorphological boundary between different regions of China in association with Quaternary climatic events. Despite low overall genetic diversity, we observed an isolation-by-distance (IBD) pattern at a regional scale, rather than isolation-by-environment (IBE), which was attributed to ongoing human disturbance in the region. CONCLUSION: Our findings suggest that the genetic structure of the G. crenulata group reflects the interplay of geological topography, historical climates, and anthropogenic disturbance during the Pliocene-Pleistocene-Holocene periods in subtropical China. The observed IBD pattern, particularly prominent in western China, highlights the role of limited dispersal and gene flow, possibly influenced by physical barriers or decreased connectivity over geographic distance. Furthermore, the east-to-west trend of gene flow, potentially facilitated by the East Asian monsoon system, underscores the complex interplay of biotic and abiotic factors shaping the genetic dynamics of pioneer species in subtropical China's secondary forests. These findings can be used to assess the impact of environmental changes on the adaptation and persistence of biodiversity in subtropical forest ecosystems.


Subject(s)
Forests , Genetic Variation , China , DNA, Chloroplast/genetics , Population Dynamics , Biodiversity , Gene Flow
19.
Mar Pollut Bull ; 204: 116561, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38838392

ABSTRACT

In 2015, > 460,000 L of aqueous film-forming foam (AFFF) and fire suppressors containing per- and polyfluoroalkyl substances (PFAS) were used to combat a fire at a petrochemical fuel storage terminal in the Port of Santos (Brazil). Sediments from seven sites were sampled repeatedly from 2 weeks to 1 year after the fire (n = 30). Æ©15PFAS concentrations ranged from 115 to 15,931 pg g-1 dry weight (dw). Perfluorooctane sulfonic acid (PFOS) was the most frequently detected compound with concentrations ranging from 363 to 4517 (average = 1603) pg g-1dw to <47.1 to 642 (average = 401) pg g-1 dw, followed by perfluorohexanoic acid (PFHxA) (from 38.8 to 219 (average = 162) pg g-1 dw after 15 days and from <20.8 to 161 (average = 101) pg g-1 dw one year later). Together, the hydrodynamics and fire events documented in the region were important features explaining the spread of PFAS.


Subject(s)
Alkanesulfonic Acids , Environmental Monitoring , Fluorocarbons , Water Pollutants, Chemical , Fluorocarbons/analysis , Water Pollutants, Chemical/analysis , Alkanesulfonic Acids/analysis , Brazil , Geologic Sediments/chemistry , Caproates/analysis
20.
Fundam Res ; 4(1): 103-112, 2024 Jan.
Article in English | MEDLINE | ID: mdl-38933835

ABSTRACT

Oceanic uptake and storage of anthropogenic CO2 (CANT) are regulated by ocean circulation and ventilation. To decipher the storage and redistribution of CANT in the western North Pacific, where a major CANT sink develops, we investigated the water column carbonate system, dissolved inorganic radiocarbon and ancillary parameters in May and August 2018, spanning the Kuroshio Extension (KE, 35-39 °N), Kuroshio Recirculation (KR, 27-35 °N) and subtropical (21-27 °N) zones. Water column CANT inventories were estimated to be 40.5 ± 1.1 mol m-2 in the KR zone and 37.2 ± 0.9 mol m-2 in the subtropical zone. In comparison with historical data obtained in 2005, relatively high rates of increase of the CANT inventory of 1.05 ± 0.20 and 1.03 ± 0.12 mol m-2 yr-1 in the recent decade were obtained in the KR and subtropical zones, respectively. Our water-mass-based analyses suggest that formation and transport of subtropical mode water dominate the deep penetration, storage, and redistribution of CANT in those two regions. In the KE zone, however, both the water column CANT inventory and the decadal CANT accumulation rate were small and uncertain owing to the dynamic hydrology, where the naturally uplifting isopycnal surfaces make CANT penetration relatively shallow. The findings of this study improve the understanding of the spatiotemporal variations of CANT distribution, storage, and transport in the western North Pacific.

SELECTION OF CITATIONS
SEARCH DETAIL