Seasonal Climate Research Articles

Research on Resilient Modulus Prediction Model and Equivalence Analysis for Polymer Reinforced Subgrade Soil under Dry-Wet Cycle.

The subgrade soil of asphalt pavement is significantly susceptible to changes in moisture content, and therefore many projects introduce polymer-based reinforcement to ensure soil performance. This paper aims to incorporate a variable representing the dry-wet cycle into the prediction model of resilient modulus of polymer reinforced soil. The polymer adopted is a self-developed subgrade soil solidification material consisting of sodium dodecyl sulfate and polyvinyl oxide. The current resilient modulus prediction model is improved, notably involving the effects of the dry-wet cycle. Combined with finite element method (FEM) analysis, the actual stress state of pavement and the coupling effect of dry-wet cycle and vehicle load on the resilient modulus are studied. The deterioration in resilient modulus with the variation in seasonal climate and load response is also investigated. Results show that the deviator stress is negatively correlated with the resilient modulus while the bulk stress has a linearly positive relation. The decreasing rate at low deviator stress is larger than that at the high level. Moreover, the dry-wet cycle can reduce the resilient modulus and the reducing amplitude is the largest at the first dry-wet cycle. FEM analysis shows that the middle position of the subgrade slope has the largest initial resilient modulus with decreasing amplitude in the first year of dry-wet cycles, while the upper position shows a smaller change. The variation in resilient modulus is closely related to the changes in cumulative volumetric water content. Considering that different positions of subgrade bear the external vehicle load, the equivalent resilient modulus is more realistic for guiding the subgrade design.

Influence of landscape position and climatic seasonality on soil water and gas conductivity properties in agricultural soils

Agricultural landscape management and climate seasonality can influence soil structure, hydraulic conductivity, and air permeability within the context of soil water and soil gas mobility. To investigate this, in situ and laboratory-based data were collected from three agricultural landscape positions within a watershed in eastern Ontario, Canada during a growing season. Macropore classification, water infiltration tests, and air permeability measurements were conducted in situ and standard soil characterizations were carried out on soil samples. Hydraulic conductivity of the soil matrix, based on grain size data, indicated that the highest values were consistently measured in the B horizon at each landscape setting. Macropores were found to be more abundant within uncultivated drainage ditch bank soils, compared to the adjacent cropped fields. Macropores in the ditch bank soils were exclusively consisted of circular biopores, while both circular and linear macropores were observed in the cultivated field soils. Air permeability, vertical hydraulic conductivity, and horizontal hydraulic conductivity were also greater in the uncultivated soils, relative to the cultivated soils. Field saturated hydraulic conductivity measurements offered evidence of anisotropy, likely due to the vertical nature of the macropore features. Macropore disposition and extent varied over the growing season, especially in the cultivated field soils where tillage and field trafficking are physically disruptive. Seasonality of macropore development will influence temporal changes in advection-based mass exchange of gas and water in the vadose zone. Modeling of mass exchange in agricultural soils should consider time variability in macroporosity to more realistically characterize infiltration and soil gas emissions.

Relationships of stomatal morphology to the environment across plant communities

The relationship between stomatal traits and environmental drivers across plant communities has important implications for ecosystem carbon and water fluxes, but it has remained unclear. Here, we measure the stomatal morphology of 4492 species-site combinations in 340 vegetation plots across China and calculate their community-weighted values for mean, variance, skewness, and kurtosis. We demonstrate a trade-off between stomatal density and size at the community level. The community-weighted mean and variance of stomatal density are mainly associated with precipitation, while that of stomatal size is mainly associated with temperature, and the skewness and kurtosis of stomatal traits are less related to climatic and soil variables. Beyond mean climate variables, stomatal trait moments also vary with climatic seasonality and extreme conditions. Our findings extend the knowledge of stomatal trait–environment relationships to the ecosystem scale, with applications in predicting future water and carbon cycles.

Windows of opportunity for predicting seasonal climate extremes highlighted by the Pakistan floods of 2022

Skilful predictions of near-term climate extremes are key to a resilient society. However, standard methods of analysing seasonal forecasts are not optimised to identify the rarer and most impactful extremes. For example, standard tercile probability maps, used in real-time regional climate outlooks, failed to convey the extreme magnitude of summer 2022 Pakistan rainfall that was, in fact, widely predicted by seasonal forecasts. Here we argue that, in this case, a strong summer La Niña provided a window of opportunity to issue a much more confident forecast for extreme rainfall than average skill estimates would suggest. We explore ways of building forecast confidence via a physical understanding of dynamical mechanisms, perturbation experiments to isolate extreme drivers, and simple empirical relationships. We highlight the need for more detailed routine monitoring of forecasts, with improved tools, to identify regional climate extremes and hence utilise windows of opportunity to issue trustworthy and actionable early warnings.

Performance-Based Evaluation of CMIP5 and CMIP6 Global Climate Models and Their Multi-Model Ensembles to Simulate and Project Seasonal and Annual Climate Variables in the Chungcheong Region of South Korea

Extreme climate change events are major causes of devastating impacts on socioeconomic well-being and ecosystem damage. Therefore, understanding the performance of appropriate climate models representing local climate characteristics is critical for future projections. Thus, this study analyses the performance of 24 GCMs from the Coupled Model Intercomparison Project Phases 5 and 6 (CMIP5 and 6) and their multi-model ensembles in simulating climate variables including average rainfall, maximum (Tmax), and minimum (Tmin) temperatures at annual and seasonal scales over the Chungcheong region of South Korea from 1975 to 2015. A trend analysis was conducted to estimate the future trends in climate variables in the 2060s (2021–2060) and 2080s (2061–2100). Inverse distance weighting and quantile delta mapping were applied to bias-correct the GCM data. Further, six major evaluating indices comprising temporal and spatial performance assessments were used, after which a comprehensive GCM ranking was applied. The results showed that CMIP6 models performed better in simulating rainfall, Tmax, and Tmin at both temporal and spatial scales. For CMIP5, the top three performing models were GISS, ACCESS1-3, and MRI-CGCM3 for rain; CanESM2, GISS, and MPI-ESM-L-R for Tmax; and GFDL, MRI-CGCM3, and CanESM2 for Tmin. However, the top three performing models in the CMIP6 were MRI-ESM2-0, BCC_CSM, and GFDL for rain; MIROC6, BCC_CSM, and MRI-ESM2-0 for Tmax, and GFDL, MPI_ESM_HR, and MRI-ESM2-0 for Tmin. The multi-model ensembles (an average of the top three GCMs) performed better in simulating rain and Tmin for both CMIP5 and CMIP6 compared with multi-model ensembles (an average of all the GCMs), which only performed slightly better in simulating Tmax. The trend analysis of future projection indicates an increase in rain, Tmax, and Tmin; however, with distinct changes under similar radiative forcing levels in both CMIP5 and CMIP6 models. The projections under RCP4.5 and RCP8.5 increase more than the SSP2-4.5 and SSP5-8.5 scenarios for most climate conditions but are more pronounced, especially for rain, under RCP8.5 than SSP5-8.5 in the far future (2080s). This study provides insightful findings on selecting appropriate GCMs to generate reliable climate projections for local climate conditions in the Chungcheong region of South Korea.

Queen quality, performance, and winter survival of imported and domestic honey bee queen stocks

Canadian beekeepers have faced high colony mortality each winter over the last decade. Frequently citing “poor queen quality” as a top contributing factor to colony loss, Canadian beekeepers report needing to replace half their queens each year. Domestic queen production exists throughout Canada but is limited due to the short season and can be further limited when colony mortality is high. Consequently, Canadian beekeepers import over 260,000 queens annually, primarily from locations with warmer climates. In this study, newly mated imported queens from Hawaii (USA) and New Zealand were compared to domestic Canadian queens produced in British Columbia; these stocks were evaluated on their morphological and sperm storage characteristics. Stock quality was also evaluated in the field at two locations in Alberta, Canada over two production seasons. Our results show initial variation in queen morphology and fertility among imported and domestic queen stocks. Most striking, the New Zealand queens weighed 10–13% less than the Hawaii and British Columbia queens, respectively upon arrival. Colony performance over a two-year field study suggests: (1) brood pattern solidness has a positive nonlinear correlation with honey production regardless of queen stock and environment; (2) environment (i.e., apiary location) and queen stock variably predict colony health and productivity depending on year; specifically, apiary site appears to be a stronger predictor of colony health and productivity than queen stock in year one, but in year two, queen stock appears to be a stronger predictor than apiary site; (3) high clinical symptoms of chalkbrood may explain the prevalence of poor brood patterns in colonies headed by queens from New Zealand; (4) domestic queens are 25% more likely to survive winter in Alberta than imported queens. Therefore, it is important to consider possible mismatches in disease immunity and climate conditioning of imported queen stocks heading colonies in temperate regions that face drastically different seasonal climates and disease ecology dynamics.

Changes in air temperature, but not in precipitation, determine long-term trends in water chemistry of high mountain lakes of the Alps with and without rock glacier influence

Climate change has strongly affected lakes around the world, but the relative effects of warmer air temperatures and changing precipitation on the water chemistry of alpine systems are not well understood. Here we tested the effect of monthly and seasonal climate on the water chemistry of six high mountain lakes located in the Alps. From 1982 to 2020, water samples were collected annually from different depths during the autumn mixing. We observed a simultaneous increase in electrical conductivity, ionic content, and pH with air temperature. In lakes with rock glacier influence, the increase in conductivity, ionic content, and especially in sulfate was even more pronounced, but accompanied by a strong decrease in pH. These differences are attributed to the direct influence of acidic meltwater from active rock glaciers in catchments with acidic bedrock. We then analyzed changes in lake chemistry, taking into account seasonal trends in air temperature and precipitation, using redundancy analysis. Temperature increase significantly affected water chemistry in five of the six lakes, especially at times of ice breakup. Increasing warming explained 17% to 32% of the changes in electrical conductivity, alkalinity, pH, major ions, and nitrogen. In contrast, precipitation had little effect on the changes of those parameters. Nevertheless, late spring snowfall and high snowfall in early fall, which result in prolonged ice cover, had a dampening effect on the impact of climate warming on lake chemistry. Our results confirm that climate warming remains a major driver of chemical changes in alpine lakes, but provide new evidence that late spring temperatures are the most important triggers.

Modelling groundwater recharge, actual evaporation, and transpiration in semi-arid sites of the Lake Chad basin: the role of soil and vegetation in groundwater recharge

Abstract. The Lake Chad basin, located in the centre of northern Africa, is characterized by strong climate seasonality with a pronounced short annual precipitation period and high potential evapotranspiration. Groundwater is an essential source for drinking-water supply, as well as for agriculture and groundwater-related ecosystems. Thus, assessment of groundwater recharge is very important although also difficult because of the strong effects of evaporation and transpiration, as well as the limited available data. A simple, generalized approach, which requires only limited field data, freely available remote sensing data, and well-established concepts and models, is tested for assessing groundwater recharge in the southern part of the basin. This work uses the FAO dual-Kc concept to estimate E and T coefficients at six locations that differ in soil texture, climate, and vegetation conditions. Measured values of soil water content and chloride concentrations along vertical soil profiles together with different scenarios for E and T partitioning and a Bayesian calibration approach are used to numerically simulate water flow and chloride transport using Hydrus-1D. Average groundwater recharge rates and the associated model uncertainty at the six locations are assessed for the 2003–2016 time period. Annual groundwater recharge varies between 6 and 93 mm and depends strongly on soil texture and related water retention and on vegetation. Interannual variability of groundwater recharge is generally greater than the uncertainty of the simulated groundwater recharge.

Detecting causal relationship of non-floodplain wetland hydrologic connectivity using convergent cross mapping

The hydrologic connectivity of non-floodplain wetlands (NFWs) with downstream water (DW) has gained increased importance, but connectivity via groundwater (GW) is largely unknown owing to the high complexity of hydrological processes and climatic seasonality. In this study, a causal inference method, convergent cross mapping (CCM), was applied to detect the hydrologic causality between upland NFW and DW through GW. CCM is a nonlinear inference method for detecting causal relationships among environmental variables with weak or moderate coupling in nonlinear dynamical systems. We assumed that causation would exist when the following conditions were observed: (1) the presence of two direct causal (NFW → GW and GW → DW) and one indirect causal (NFW → DW) relationship; (2) a nonexistent opposite causal relationship (DW → NFW); (3) the two direct causations with shorter lag times relative to indirect causation; and (4) similar patterns not observed with pseudo DW. The water levels monitored by a well and piezometer represented NFW and GW measurements, respectively, and the DW was indicated by the baseflow at the outlet of the drainage area, including NFW. To elucidate causality, the DW taken at the adjacent drainage area with similar climatic seasonality was also tested as pseudo DW. The CCM results showed that the water flow from NFW to GW and then DW was only present, and any opposite flows did not exist. In addition, direct causations had shorter lag time than indirect causation, and 3-day lag time was shown between NFW and DW. Interestingly, the results with pseudo DW did not show any lagged interactions, indicating non-causation. These results provide the signals for the hydrologic connectivity of NFW and DW with GW. Therefore, this study would support the importance of NFW protection and management.

Seasonal climate models for national wheat yield forecasts in Brazil

National wheat yield depends on climate conditions and usually remains unknown until harvest. In-season knowledge can be provided by wheat yield forecast systems, supporting the decision-making of farmers, food traders, or policymakers. In this study, we improved a previously developed statistical wheat yield model to forecast trend-corrected wheat yield in Brazil with monthly temperature and precipitation data from seasonal climate models (SCM) from the last three months before harvest. We chose SCM from the European Center for Medium-Range Weather Forecasts (ECMWF), the National Centers for Environmental Prediction (NCEP), and the UK-based Met-Office (UKMO). A multi-model ensembles (MME) approach from the three individual models as well as a climatology (CLIMATE) approach were also tested. Wheat yield forecasts were issued at the beginning of each month from planting in April to harvest in November. Each month, features from future months are forecasted by SCM, and past features are supplemented with observations from weather stations. Our approach shows a 12% RMSE in forecasting yield early in the season, from April to June. Forecasts start to improve from July onwards, with shorter lead times and including observed features from September onwards. At the beginning of October, about two months before harvest is completed, wheat yield can be forecasted with 7.6%, 7.9%, 7.9%, 9.1%, and 9.3% RMSE using climate data from UKMO, ECMWF, MME, NCEP, and CLIMATE respectively. Seasonal climate models can be useful tools to forecast national wheat yield, even shortly before harvest to prepare for possible food shortages. Our approach could be applied to other staple crops and regions.

Thermal Comfort for various Altitudes and Land Covers in North Sumatra

Thermal comfort refers to the suitability of meteorological conditions for humans with the environment. Temperature is the main meteorological variable, which determines the thermal comfort as expressed in various climate indices. This study aims to analysis the distribution of thermal comfort, and to identify environmental factors influencing the comfort situated in North Sumatra, Indonesia. We applied the Universal Thermal Climate Index (UTCI) to determine the heat stress level for 2011 - 2020. The higher UTCI value indicates more uncomfortable conditions related to the higher heat stress. The results showed that the average value of UTCI in North Sumatra was categorised at moderate heat stress. Densely urbanised area in the eastern region contributed to high heat stress, whereas mountainous areas in central to west regions were at low level. Our findings found that climate season affected the distribution of heat stress level. The low heat stress occurred in December-February, while high heat stress happened in June-August. Further, findings revealed that altitude and land cover have contributed to UTCI variation by more than 75% variance.

Damage and ethology of Cryptarcha sp. in the cactus Opuntia ficus-indica(L.) Mill. Ayacucho, Perú

In prickly pear (Opuntiaficus-indica(L.) Mill.) of the semiarid forest of Ayacucho, Chryptarchasp. infests and damages the tender organs of the cactus. The objective of the study was to determine the damage of the insect during a year and its behavior. Fortnightly during the year, in 60 prickly pear plants, the number of young leaves, flower buds, flowers and green fruits, healthy and damaged by the insect and its behavior were monitored. Using the PAST 4.12 software, the annual cycle of damage occurrence and the annual cycle of the vegetative period of the prickly pear were diagrammed, to relate them to the climatic seasons; likewise, the principal component analysis (PCA) to establish the most affected tender organs and the period of infestation to the cactus. It turned out that during theyear the flower bud and the green fruit were significantly damaged. It infests the tuna mainly from November to March of the following year, which corresponds to the hot and humid season; in which it managed to damage 35.9% of flowers, 14.7% of tender leaves, 9.7% of green fruits and 0.7% of flowers. It has phytophagous and saprophagous behavior, being attracted by the juice of ripe fruit damaged by other agents, by the ferments of the stems of the prickly pear and other cacti in the process of putrefaction, and by the fresh feces of the pig.

Long-term maintenance rate fertilisation increases soil bacterial-archaeal community diversity in the subsoil and N-cycling potentials in a humid crop season

Among agronomical practices, fertilisation greatly influences soil microbial diversity and functionality and severely disturbs the global nitrogen (N) cycle. In this study, we assessed the effect of 16 years of mineral fertilisation (NPS) on soil bacterial-archaeal communities in a no-tillage experiment in a humid climate season. We used 16S rRNA amplicon sequencing and functional prediction of marker genes involved in the N cycle at two soil depths (0–5 and 5–10 cm). Samples were taken after soybean harvest in a wheat/soybean-maize crop sequence. At both soil depths, fertilisation increased the abundance of Proteobacteria while reducing the abundance of Verrucomicrobiota. Indicator species analyses revealed that MB-A2–108 (Actinobacteriota) and Nitrososphaeraceae (Archaea) were indicators of the low fertiliser rates at 0–5 cm. Instead, Rokubacteriales (Methylomirabilota) and Nitrolancea (Chloroflexi) were indicators of low and high rates, respectively, at 5–10 cm. Biological N–fixation genes (nifA, nifV nifHD1, and nifHD2) showed an inconsistent response depending on the soil depth. Yet, the high abundance of nifA revealed the presence of N-fixing microorganisms even at high levels of N fertilisation. The predominance of genes involved in the dissimilatory (nirB and nirK) and assimilatory (nirA) reduction of nitrate was steadily found at higher fertilisation. Given that the predecessor crop was a legume that did not receive N, our results revealed the substantial legacy of long-term N inputs on soil bacterial-archaeal diversity and N-cycling genes that might have been umpired by the current humid conditions.

Spatiotemporal analysis of rainfall and temperature variability and trends for climate resilient maize farming system in major agroecology zones of northwest Ethiopia

ABSTRACTSpatiotemporal studies of the annual and seasonal climate variability and trend on an agroecological spatial scale for establishing a climate-resilient maize farming system have not yet been conducted in Ethiopia. The study was carried out in three major agroecological zones in northwest Ethiopia using climate data from 1987 to 2018. The coefficient of variation (CV), precipitation concertation index (PCI), and rainfall anomaly index (RAI) were used to analyze the variability of rainfall. The Mann-Kendall test and Sen’s slope estimator were also applied to estimate trends and slopes of changes in rainfall and temperature. High-significance warming trends in the maximum and minimum temperatures were shown in the highland and lowland agroecology zones, respectively. Rainfall has also demonstrated a maximum declining trend throughout the keremt season in the highland agroecology zone. However, rainfall distribution has become more unpredictable in the Bega and Belg seasons. Climate-resilient maize agronomic activities have been determined by analyzing the onset and cessation dates and the length of the growth period (LGP). The rainy season begins between May 8 and June 3 and finishes between October 26 and November 16. The length of the growth period (LGP) during the rainy season ranges from 94 to 229 days.

Assessing Seasonal and Inter‐Annual Marine Sediment Climate Proxy Data

AbstractThree recently published papers including Napier et al. (2022, https://doi.org/10.1029/2021PA004355) utilize novel microanalytical approaches with varved marine sediments to demonstrate the potential to reconstruct seasonal and inter‐annual climate variability. Obtaining paleoclimate data at a resolution akin to the observational record is vitally important for improving our understanding of climate phenomena such as monsoons and modes of variability such as the El Niño Southern Oscillation, for which appraisals of past inter‐annual variability is critical. The ability to generate seasonal and inter annual resolution sea surface temperature proxy time series spanning a thousand years or more is revolutionary and has the potential to fill gaps in our knowledge of climate variability. Although generally limited to sediments from regions with oxygen depleted bottom waters, there is great potential to integrate shorter seasonal resolution climate “snap shots” from other archives such as annually banded corals into composite time series. But as paleoceanographic data are used more by the observational and modeling fields, we make the case for conducting a thorough case‐by‐case assessment of the processes that influence the climate signal recovered from proxies, using careful replication to validate new approaches. Understanding or exploring the potential influence of processes which effectively filter the climate signal will lead to more quantitative paleoceanographic data that will better serve the broader climate science community.

Classification of forest and shrubland vegetation in central and eastern Euxine Turkey and SW Georgia

AbstractQuestionsWhat are the main vegetation types of forest and shrubland vegetation in central and eastern Euxine Turkey and SW Georgia? What are the main environmental factors affecting their diversity? What is their syntaxonomic position? Can we integrate them into the European vegetation classification system?LocationCentral and eastern Euxine Turkey and SW Georgia.MethodsWe collected 3104 vegetation plots of forest and shrubland vegetation in the study region and performed Two‐Way Indicator Species Analysis (TWINSPAN) classification. We described vegetation types based on the classification results, expert knowledge and information from literature sources. We defined diagnostic species and prepared distribution maps for each vegetation type. To determine the most significant environmental variables on floristic differentiation, we used canonical correspondence analysis. Detrended correspondence analysis with passive projection of most significant environmental variables was run to interpret the environmental variation of vegetation types.ResultsThe studied vegetation was divided into 29 vegetation types related to seven main vegetation groups: relict Mediterranean forests and shrubland (mainly along the coastline, beside some inland localities), lowland to submontane forests, central Euxine mountain forests, eastern Euxine (Colchic) mountain forests, subeuxine forests, azonal riparian forests and subalpine and alpine shrubland. Elevation is the most important factor causing the differentiation in vegetation. It is followed by longitude and latitude. Among climatic variables, temperature seasonality, annual precipitation and precipitation of the wettest quarter are the most significant factors for vegetation differentiation. These factors correlate with the reduction of maritime climate and geomorphological features.ConclusionsVegetation types mostly correspond to the syntaxa accepted in the EuroVegChecklist. However, some of them do not appear in the EuroVegChecklist since they appear only beyond Europe. We described three syntaxa as new: Abietion equi‐trojani, Querco cerridis‐Carpinion orientalis and Piceo orientalis‐Fagenion orientalis. The study revealed high vegetation diversity of the region that should be taken into consideration in ecosystem management and used as a reference in restoration and mitigation of the effects of global changes.

Morphologic, Atmospheric, and Oceanic Drivers Cause Multi‐Temporal Saltwater Intrusion on a Remote, Sand Island

AbstractSmall‐island populations disproportionately rely on fresh groundwater resources, which are increasingly threatened by salinization from changing ocean and climate conditions. This study investigates island groundwater dynamics and salinization over multiple timescales in response to marine, atmospheric, and morphologic drivers. New geophysical and hydrological data sets were collected on a remote sand island in the Northwest Atlantic Ocean between 2020 and 2022 and compared to historical baseline data from the 1970s. Data reveal saltwater intrusion due to multi‐decadal erosion, seasonal climate patterns, tidal forcing, and episodic flooding from Atlantic hurricanes. Long‐term dune erosion has caused the freshwater lens to thin and become asymmetrical; however, a lagged groundwater response causes the freshwater lens to be in disequilibrium with present island morphology. The maximum vertical lens thickness is seasonally constant, but the lateral transition zone along the coast thickens and moves seaward in spring when the water table is high from precipitation and frequent beach flooding. Groundwater level and electrical conductivity along low‐lying beaches significantly increase following Atlantic hurricanes due to seawater flooding, and reach a maximum of 1.93 m above sea level and 38 mS/cm, respectively. While groundwater levels recover quickly, conductivity (salinity) remains elevated due to the short intervals between winter flood events that outpace freshening from meteoric recharge. Results emphasize the importance of multi‐temporal groundwater dynamics and feedbacks between coastal flooding, erosion, and salinization. Field‐based studies considering multiple drivers and timescales of saltwater intrusion are critical for understanding and managing coastal freshwater resources in an age of rapid environmental change.

ASSESSMENT OF THE QUALITY OF DOMESTIC WATER RESOURCES: CASE OF THE SAN-PEDRO RIVER AT THE FAYE HYDROELECTRIC DAM (SOUTHWEST COTE DIVOIRE)

Surface waters are the most vulnerable to pollution and variations in the hydrological cycle. These waters are polluted by anthropogenic pollutants such as pesticides from agricultural activities and heavy metals from agro-industrial activities. The waters of the San-Pedro River reservoir at the Faye dam are expected to be used for the drinking water supply of the population of the city of San-Pedro. The objective of this study is to assess the chemical quality of the water in the San-Pedro River at the Faye dam based on the calculation method of the Water Quality Index (WQI). Thirteen (13) stations were sampled during the four (4) climatic seasons in 2021 and 2022. These seasons are: the large dry season (LDS), large rainy season (LRS), small dry season (SDS), and small rainy season (SRS). Chemical analyses were conducted on 27 physico-chemical and chemical parameters. The results of the Water Quality Index calculation indicate water unsuitable for drinking in all seasons. The quality of these waters is influenced by trace metal elements (TME) with average WQIavg, TME values of 1079.6 864.5 3007.6 and 3645.2 in LDS, LRS, SDS, and SRS, respectively. On the other hand, organic parameters have a less significant influence on the quality of this water, as evidenced by WQI values of 35.7 in LDS 53.9 in LRS 80.1 in SDS and 33.5 in SRS. Therefore, this water requires appropriate treatment before any use.

Sedimentology and stratigraphy of silicified fossil trunks bearing Missão Velha Formation (late jurassic-early cretaceous), Araripe Basin, Northeastern Brazil: Paleoclimatic implications

The paper focuses on the sedimentological, stratigraphic, and climatic implications of silicified fossil trunks found in the Missão Velha Formation (MVF) of the Araripe Basin in Northeastern Brazil. The rich fossiliferous plant assemblages in the MVF are primarily dominated by conifers, specifically a group known as Agathoxylon, and are associated with coarse sandstone and conglomerate fluvial beds. The MVF represents a late Jurassic-early Cretaceous formation deposited during the Early Rift phase of the basin. Silicified fossil trunks and woods from the MVF have been known since 1863, and previous studies have discussed their morphology, internal structure, and paleogeographic implications. Taphonomically, these macrofossils have been interpreted as hypautochthonous, meaning they originated from their growth sites. However, some authors have suggested an allochthonous origin for these fossils. Despite their significance, the sedimentological and stratigraphic characteristics of these fossil associations have received limited attention in previous research. We have collected the fosil trunks exclusively in the MVF, and they are restricted to the upper parts above an internal unconformity. Two main taphofacies were identified: T1 comprises coarse-to medium-sandstones, locally conglomeratic, with planar and trough cross-stratifications, with abundant fossil wood and trunks, and T2 defined as well-stratified pebbly conglomerates, with horizontal to cross bedding, with larger common fossil wood and trunks fragments. T1 taphofacies occur in most of the cross-stratified sandstones of the upper part of the MVF, T2 taphofacies (larger wood logs) are primarily concentrated in a coarse sandstone to conglomeratic bed strata at the top of the MVF. The preservation of the trunks is characterized by uncompressed fragments with poorly rounded edges. The cell walls are preserved by permineralization, with the spaces filled by silica, indicating short transport and rapid burial. The silicified fossil woods are found in foresets of planar and trough cross-stratifications, associated with coarse-grained to conglomeratic sandstones. These sandstones are highly abundant, sometimes forming anomalous concentrations, such as in the Grota Funda outcrop. The dimensions of the fossil trunks range from 5 cm up to 2 m in length, with some exceptionally large trunks measuring approximately 1.70 × 1.40 m. The investigated trunks exhibit various orientations, with some concordant and others dissenting from the surrounding strata. However, the majority of the fossil trunks do not show a preferential orientation. Orientation analysis of more than twenty logs suggests a predominant south paleocurrent direction trend, likely resulting from monsoon storms originating from a source area to the north. The assemblages were likely formed through putrefaction processes and late fragmentation, followed by size-selection through fluvial transport. The relatively short transport distance is indicated by the preserved edges, lack of preferential position, and the size of the trunks. Consequently, it is inferred that the trunks originated within the basin itself rather than being transported from the basement area, supporting their hypautochthonous character. The MVF and the associated plant remains bear resemblance to deposits of similar age in other Northeast Brazilian basins, such as the Recôncavo-Tucano-Jatobá, Sergipe-Alagoas, and Camamu-Almada basins, as well as the Gabon Basin in Western Africa. Evidence from the trunk taphofacies, stratigraphy and sedimentology of the MVF is consistent with a warm, seasonal, hot, and humid climate, indicative of a monsoon climate similar to other conifer forests in Gondwana during the Mesozoic era.

Environmental and Anthropogenic Influences on Coliform Concentrations in the Octopus insularis Production Chain in the Veracruz Reef System, Gulf of Mexico.

Coliforms are relatively common in aquatic environments, but their concentrations can be increased by environmental changes and anthropogenic activities, thus impacting fisheries resources. To determine the microbiological quality in the octopus production chain (capture, post-capture, processing and commercialization), total (TC) and fecal (FC) coliforms were quantified in sea water, fresh octopus, fresh water, ice and octopus in two presentations: packed in ice and boiled. Samples came from fishing zones Enmedio, Chopa and La Gallega at the Veracruz Reef System (VRS) during dry, rainy and windy seasons. The coliforms were determined using the most probable number technique (MPN). The most relevant results indicated that octopus packed in ice coming from the commercialization stage had FC levels >540 MPN/100 g, which exceeded the permissible limits (230 MPN/100 g). Therefore, these products present a risk for human consumption. Differences in FC were observed in octopuses between the three fishing zones (H = 8.697; p = 0.0129) and among the three climatic seasons, increasing during the rainy season, highlighting La Gallega with 203.33 ± 63 MPN (H = 7.200; p = 0.0273). The results provide evidence of the environmental and anthropogenic influences on coliform concentrations and the urgent need to implement an efficient cold chain throughout octopus production stages with adequate handling practices to reverse this situation.