Flood Cycle Research Articles

Activity, foraging mode, and abundance of the aquatic coral snake Micrurus surinamensis (Cuvier, 1816) (Serpentes: Elapidae) in the western Brazilian Amazonia

ABSTRACT Elapids of the genus Micrurus actively search for their prey. Here we present new information on the foraging ecology of the aquatic coral snake Micrurus surinamensis based on observations in the western Amazon of Brazil. Eleven individuals of M. surinamensis were observed at night, four of them moving, four hunting in ambush posture, and three actively hunting. Here, we show that M. surinamensis is active mainly at night in aquatic environments and may also be active on the terrestrial environments. Land activity may be related with the search for fish which may eventually be found in this substrate, as well as with the search for water bodies, following the hydrological cycles of flooding and drought. When hunting, the snake uses both foraging modes, being able to actively search for its prey, or ambush it, by keeping the body partially in the water, with the head on the surface. Due to the greater availability of aquatic environments and available prey (fish), M. surinamensis should be more abundant in floodplain forest ecosystems. Additional field observations may help in elucidating the biology on this ecologically differentiated species within the genus Micrurus.

An improved method to study Phytophthora cinnamomi Rands zoospores interactions with host

Phytophthora cinnamomi Rands is a highly prevalent phytopathogen worldwide, ranking among the top ten in terms of distribution. It inflicts crown rot, canker, and root rot on numerous plant species, significantly impacting the biodiversity of both flora and fauna within affected environments. With a host range spanning over 5,000 species, including important plants like Quercus suber, Quercus ilex, Castanea sativa, and commercially significant crops such as avocado (Persea americana), maize (Zea mays), and tomato (Solanum lycopersicum), Phytophthora cinnamomi poses a substantial threat to agriculture and ecosystems. The efficient dissemination of the oomycete relies on its short-lived asexually motile zoospores, which depend on water currents to infect host roots. However, managing these zoospores in the laboratory has long been challenging due to the complexity of the life cycle. Current protocols involve intricate procedures, including alternating cycles of growth, drought, and flooding. Unfortunately, these artificial conditions often result in a rapid decline in virulence, necessitating additional steps to maintain infectivity during cultivation. In our research, we sought to address this challenge by investigating zoospore survival under various conditions. Our goal was to develop a stable stock of zoospores that is both easily deployable and highly infective. Through direct freezing in liquid nitrogen, we have successfully preserved their virulence. This breakthrough eliminates the need for repeated culture transfers, simplifying the process of plant inoculation. Moreover, it enables more comprehensive studies of Phytophthora cinnamomi and its interactions with host plants.

Enhancing urban flood resilience: A coupling coordinated evaluation and geographical factor analysis under SES-PSR framework

Urban flooding has emerged as a significant urban issue in cities worldwide, with China being particularly affected. To effectively manage and mitigate urban floods, a holistic examination of the interaction between urban subsystems is required to improve urban flood resilience. However, the interactions and mechanisms between urban subsystems under flood disaster haven't been addressed adequately in previous studies. Therefore, this paper established a conceptual framework for illustrating the interactions between urban natural-ecological and social-economic subsystem considering urban pressure, state, and response within flood cycle. The objective is to investigate the coupling coordination degree (CCD) between these subsystems and identify the driving factors with a geographical detector model, and the cities in Yangtze River Delta are selected as an empirical example. The findings reveal an overall upward trend towards coordination for the whole area with notable variability among the cities. The resilience of the state dimension emerges as a crucial aspect in determining the CCD of the urban flood resilience of the area. Key driving factors for the coordinated development of urban flood resilience are identified as air pollution, global warming, technological innovation, governance power, financial strength, and urbanization. Based on the findings and the interactions among the driving factors, this paper presents potential implications that can serve as effective guidance and offer insights for policymakers, planners, and researchers in their efforts to enhance urban flood resilience for sustainable development in the future.

Paleoflood Reconstruction in the Lower Yellow River Floodplain (China) Based on Sediment Grain Size and Chemical Composition

Alluvial sedimentary records in the North China Plain are essential in expanding flood history and understanding hazard patterns in the Yellow River basin where inundation risk exists and would probably increase under future global change. A detailed study of the Longwangmiao profile in the lower Yellow River floodplain reveals ancient flooding records over the late Holocene. Slackwater deposits are distinguished by typical sedimentary features and share similarities with those in the upper and middle Yellow River. This indicates that the traditional method can still be applied for paleoflood research beyond the gorge. However, unlike confined bedrock gorges, multiphase flood deposits of slackwater and overbank deposits represent different stages of flood events. These sedimentary assemblages recorded six flooding periods, further confirmed by the analysis of grain size and geochemistry. The profile was broadly subdivided into two flood-poor phases (3.7–6.7 ka, 0.8–1.7 ka) and three flood-rich phases (before 6.7 ka, 1.7–3.7 ka, after 0.8 ka) based on the dating results. Compared with the existing related research in the nearby area, the synchronous deposition cycles of floods and inter-floods are mainly controlled by the hydrodynamic conditions of the old Yellow River course. This study provides an analogue of paleoflood research in the lower Yellow River and similar alluvial plains. It explores the potential of interlinking paleoflood records in the whole Yellow River basin.

Impact of wettability on capillary phase trapping using pore-network modeling

The impact of rock wettability on phase mobility and capillary trapping is significant in the valuation of geologic carbon sequestration scenarios. Wetting conditions of CO2/brine/rock systems can vary from site to site and over time due to changes in temperature, pressure, salinity, mineral composition and surface roughness. Therefore, effective predictability of CO2 mobility and trapping in underground formations requires a thorough exploration of the relationship between wetting conditions and phase saturation over a wide range of contact angles. In this paper, we use pore-network modeling to investigate the effect of wettability on phase mobility and capillary trapping. We simulate different wetting and nonwetting conditions during secondary flooding cycles where the initial phase saturations are varied significantly. Characteristic initial-residual (IR) saturation curves and the locus of residual phase connectivity and saturation are determined for each wettability condition.Simulations show that when the receding phase is the wetting phase, there is reduced trapping of that phase owing to piston-like advance by the nonwetting phase and sustained layer flow of the wetting phase. Such flow regimes cause nonlinearity in the characteristic initial-residual (IR) saturation curve, which is not captured by traditional trapping models. A proposed extended Land-based model matches the IR trends for all wettabilities. Simulations also show that the loci of residual phase saturation and phase connectivity are a strong function of wettability. When the receding phase is strongly nonwetting, the locus remains nearly constant in phase connectivity, while at increasingly wetting conditions, the locus forms a closed-loop in the saturation-connectivity space, where the endpoint of the locus is constrained by pore topology as residual saturations approach low values.

Epidemiology of horse pythiosis in the Pantanal of Mato Grosso: Exploring the host-parasite-vector relationship

Horse pythiosis is considered an endemic disease in the Brazilian Pantanal region, causing devastating health and economic losses. This study aimed to enhance the understanding of pythiosis epidemiology, map the distribution of horse body lesions, and investigate the correlation between these lesions and warm body surface areas, potentially implicating hematophagous vectors in the disease's transmission. A prospective study was conducted on equids in the Pantanal Mato-grossense and adjacent areas from 2012 to 2022, with 112 horses and three mules diagnosed with pythiosis. Clinical and epidemiological data, lesions' photographic records, and healthy equids' thermal imaging were collected. Most pythiosis cases occurred between January and March, correlating with regional flood cycles. Most lesions were found on limbs and the ventral abdomen, with dark-colored horses exhibiting a higher frequency of lesions. Interestingly, the thermal mapping revealed that warm areas on a healthy horse's body overlapped significantly with lesion distribution – blood-sucking insects also prefer these areas. The results suggest that pythiosis lesions in horses correlate with warmer areas of the animal body, reinforcing the hypothesis of vector involvement in disease transmission. This study underscores the need for further observational research to fully understand the complex epidemiological dynamics of pythiosis in horses.

Habitat specialization predicts demographic response and vulnerability of floodplain birds in Amazonia.

The annual flooding cycle of Amazonian rivers sustains the largest floodplains on Earth, which harbour a unique bird community. Recent studies suggest that habitat specialization drove different patterns of population structure and gene flow in floodplain birds. However, the lack of a direct estimate of habitat affinity prevents a proper test of its effects on population histories. In this work, we used occurrence data, satellite images and genomic data (ultra-conserved elements) from 24 bird species specialized on a variety of seasonally flooded environments to classify habitat affinities and test its influence on evolutionary histories of Amazonian floodplain birds. We demonstrate that birds with higher specialization in river islands and dynamic environments have gone through more recent demographic expansion and currently have less genetic diversity than floodplain generalist birds. Our results indicate that there is an intrinsic relationship between habitat affinity and environmental dynamics, influencing patterns of population structure, demographic history and genetic diversity. Within the floodplains, historical landscape changes have had more severe impacts on island specialists, making them more vulnerable to current and future anthropogenic changes, as those imposed by hydroelectric dams in the Amazon Basin.

Influence of seasonality on the physical-chemical properties of water for human consumption by residents of floating villages in the interior of the Amazon

Abstract The aim of this study was to evaluate the physicochemical properties of the water consumed by residents of floating houses and the influence of the hydrological cycles of flood and drought on these parameters. The sample consisted of 44 floating domestic units per hydrological cycle, located on the edges of the cities of Codajás, Coari and Tefé. Sociodemographic data and data related to water consumption and storage habits were collected using a semi-structured questionnaire. Water samples were collected and analyzed in accordance with the Standard Methods for the Examination of Water and Wastewater. Data were analyzed in the dry and flood hydrological phases and compared to the maximum values allowed by Ordinance GM/MS No. 888/2021. The results showed that the nitrite, manganese and free residual chlorine parameters were not in accordance with the legislation. Manganese (p = .035) and aluminum (p < .001) showed significant differences between the hydrological phases. The considerable increase in aluminum content during the flood period, even though it was within the limits of the ordinance, was also highlighted. Accordingly, even with periodic control by the supply companies, it is important to monitor the water at the point of consumption of the population.

Climate-associated risks for reliability, resilience, vulnerability and sustainability of irrigation reservoirs in small ungauged watersheds

Climate change poses an existential threat to the functional integrity of the network of agricultural reservoirs responsible for sustaining rice production in South Korea. Anthropogenic interventions have triggered a cycle of droughts and floods by magnifying the already existing supply–demand gap, which is seriously hampering reservoir performance. The watersheds of most agricultural reservoirs in South Korea are ungauged, and inflow and outflow data are not measured. In this study, recorded volumetric water storage data from five reservoirs were used to derive observed inflow data based on the hydrological reasoning and reservoir operation rule curves. These data were then used to evaluate the performance of a lumped rainfall-runoff model in simulating the runoff generated in upstream ungauged watersheds. A water balance analysis was conducted for 400 major agricultural reservoirs spread throughout the country during 1973–2017. Performance indices were estimated based on inflow availability in the reservoirs and downstream irrigation demands. Empirical relationships were derived to predict performance indices by using the reservoirs’ physical characteristics as input variables. Generally, reservoirs received substantially higher inflows compared to irrigation demands, suggesting sufficient water availability during the rice growing season (Apr−Sep). An out-of-phase cycle of peak inflow generation and water demand periods induced frequent failure events during the rice nursery transplanting period (May−Jun), and reservoir sustainability was minimal in these months. Southern and southwestern major agricultural regions with a higher density of small- to medium-sized reservoirs would be at higher risk of climate-induced water scarcity. Upsizing storage capacity could alleviate the water deficit in reservoirs associated with watersheds featuring higher means and lower standard deviations of runoff. A watershed-to-irrigated area ratio > 5 indicated acceptable reservoir sustainability.

Dynamic Production of Hydroxyl Radicals during the Flooding-Drainage Process of Paddy Soil: An In Situ Column Study.

Frequent cycles of flooding and drainage in paddy soils lead to the reductive dissolution of iron (Fe) minerals and the reoxidation of Fe(II) species, all while generating a robust and consistent output of reactive oxygen species (ROS). In this study, we present a comprehensive assessment of the temporal and spatial variations in Fe species and ROS during the flooding-drainage process in a representative paddy soil. Our laboratory column experiments showed that a decrease in dissolved O2 concentration led to rapid Fe reduction below the water-soil interface, and aqueous Fe(II) was transformed into solid Fe(II) phases over an extended flooding time. As a result, the •OH production capacity of liquid phases was reduced while that of solid phases improved. The •OH production capacity of solid phases increased from 227-271 μmol kg-1 (within 1-11 cm depth) to 500-577 to 499-902 μmol kg-1 after 50 day, 3 month, and 1 year incubation, respectively. During drainage, dynamic •OH production was triggered by O2 consumption and Fe(II) oxidation. ROS-trapping film and in situ capture revealed that the soil surface was the active zone for intense H2O2 and •OH production, while limited ROS production was observed in the deeper soil layers (>5 cm) due to the limited oxygen penetration. These findings provide more insights into the complex interplay between dynamic Fe cycling and ROS production in the redox transition zones of paddy fields.

Application of Machine Learning Techniques to Detect and Understand the Impacts of Global Warming on Southeast Australia

Abstract: Australia is adversely affected by global warming (GW), as its well-known cycles of droughts, floods, and extreme weather events are increasingly amplified by GW. Here, the focus is the impacts of GW on populous southeast Australia. Machine Learning attribution techniques have been applied to identify the main drivers of these impacts. This article presents the detection examples of the most relevant drivers, individually and in combination, responsible for observed trends in precipitation and temperature due to GW.

Pyrolysis temperature and biochar redox activity on arsenic availability and speciation in a sediment

Biochar is widely used for water and soil remediation in part because of its local availability and low production cost. However, its effectiveness depends on physicochemical properties related to its feedstock and pyrolysis temperature, as well as the environmental conditions of its use site. Furthermore, biochar is susceptible to natural aging caused by changes in soil or sediment moisture, which can alter its redox properties and interactions with contaminants such as arsenic (As). In this study, we investigated the effect of pyrolysis temperature and biochar application on the release and transformations of As in contaminated sediments subjected to redox fluctuations. Biochar application and pyrolysis temperature played an important role in As species availability, As methylation, and dissolved organic carbon concentration. Furthermore, successive flooding cycles that induced reductive conditions in sediments increased the As content in the solution by up to seven times. In the solid phase, the application of biochar and the flooding cycle altered the spatial distribution and speciation of carbon, iron (Fe) and As. In general, the application of biochar decreased the reduction of Fe(III) and As(V) after the first cycle of flooding. Our results demonstrate that the flooding cycle plays an important role in the reoxidation of biochar to the point of enhancing the immobilization of As.

A cycle of floods and relocations: Metro Manila’s history of disaster-related resettlements

ABSTRACT Metro Manila has had numerous cases of state-led, disaster-related resettlements, especially in response to floods. Historicizing the trajectory of these relocations reveals important insights about the dynamics between the changing nature of the Philippine state and the geography of the metropolis. Whereas flood-related resettlements were virtually absent in the colonial period, relocation became an articulation of state power after gaining independence. State power flexes its might by demarcating hazardous and safe spaces, a maneuver that also underlines another juxtaposition, that of between a supposedly rational state and an irrational populace. The demarcation, however, defies geographical logic, considering how economic costs have greatly influenced how administrations from the 1960s to the present have allocated spaces along waterways for commercial activities, while forcing vulnerable families to move to far-flung hazardous sites that surround the metropolis.

Climate change outpaces adaptive potential via hybridization in nesting female Saltmarsh and Nelson’s Sparrows

Abstract Hybridization and introgression can promote adaptive potential and evolutionary resilience in response to increased pressures of climate change; they can also disrupt local adaptation and lead to outbreeding depression. We investigated female fitness consequences of hybridization in two sister species that are endemic to a threatened tidal marsh ecosystem: Saltmarsh (Ammospiza caudacutus) and Nelson’s (Ammospiza nelsoni) sparrows. We found increasing nest flooding rates due to rising sea levels are outpacing potential adaptive benefits of hybridization due to very low overall nesting success in both the Nelson’s and Saltmarsh sparrows. In the center of the hybrid zone across two years, we determined the success of 201 nests of 104 pure and admixed Saltmarsh and Nelson’s Sparrow females, genotyped using a panel of single nucleotide polymorphisms (SNPs) from double digest restriction-site associated DNA (ddRAD) sequencing. We evaluated 5 metrics of female fitness and modeled nesting success in relation to genotypic, environmental, and nesting characteristics. We found differential fitness among Saltmarsh, Nelson’s, and hybrid females, such that birds with predominantly Saltmarsh Sparrow alleles had higher reproductive success than birds with predominantly Nelson’s Sparrows alleles, and hybrids were intermediate. Fledging success increased with two known tidal marsh nesting adaptations: nest height and nesting synchrony with tidal cycles. We found a positive relationship between hybrid index and fitness in daily nest survival in 2016, but not in 2017, likely due to differing levels of precipitation and nest flooding between years. The strongest and most consistent predictors of daily nest survival were nesting synchrony with lunar tidal flooding cycles and daily maximum tide height. Fitness patterns suggest that there may be an adaptive benefit of interspecific geneflow for the Nelson’s Sparrow at the detriment of the Saltmarsh Sparrow; however, flooding rates are so high in many years they mask any fitness differences between the species, and all females had poor nesting success, regardless of genetic makeup.

Breaking the cycle of emotional flooding: the protective role of women's emotional intelligence in couple's conflict.

One of the most damaging aspects, both for people's well-being and for close relationships, is conflict. Beyond different stressors, the emotions evoked, their regulation and an appropriate conflict resolution strategy will reduce negative consequences. Emotional Intelligence facilitates social relationships, but little applied research has been done on the relationship with couple conflict and emotional flooding, particularly from the perspective of women. Therefore, the present study analyzes the role of Perceived Emotional Intelligence (PEI) and the mediating effect of Positive Conflict Resolution strategies (PCR) in couples' conflicts from women's perspective, examining its effect on Emotional Flooding (EF) and Satisfaction. Through a cross-sectional design, the relationships between variables were analyzed using group comparisons and means of a structural equation model (SEM) in a sample of 692 women. Significant differences were found between the groups by age, length of relationship, and motherhood. The SEM revealed a good fit. PEI predicted 71.8% of the variance in EF and 35% in Satisfaction through PCR and Conflict.

Functional Response of Aquatic Macroinvertebrate Communities to Temporality in Tropical Temporary Ponds

Temporary or stationary wetlands (ponds) are bodies of shallow water that experience periodic droughts and an irregular flood cycle throughout the year. Although these wetlands are widely distributed in the Colombian territory, there have been few studies on their ecology. The aim of this research is to determine the effects of hydroperiod on the functional diversity of aquatic and semiaquatic macroinvertebrates in five temporary ponds in the department of Magdalena (Colombia). The samplings were performed during the hydroperiods of the filling and drying phases. Samples were collected from all the microhabitats present (sediment, littoral, and limnetic zones). Correlation analyses were performed between the traits and sites in the two hydroperiods, and a multidimensional and comparative analysis of functional diversity was performed, where indices of distance, richness, and functional dispersion were calculated in each hydroperiod. Statistical differences in functional replacement were found for only one of the ponds; however, the other ponds showed a similar trend. These results fit the functional turnover ecological hypothesis in that the response of the aquatic and semiaquatic macroinvertebrate communities was associated with the hydroperiod of the ponds based on the habitat “templet” theory.

Plan of prehistoric stilt village in Maranhão Brazil may resemble the Pleiades

Archaeological surveys conducted in the Maranhão estuaries of Brazil, near the Atlantic coast, revealed the remnants of 21 prehistoric stilt villages constructed on piles of Tabebuia handroanthrus hardwood above three seasonal flood water estuaries. Radiocarbon dates of 27 samples from 11 of those sites yielded an Archaic Period of construction (6622 ± 119 calibrated years before present) followed much later by consecutive construction periods from approximately the first century B.C. to the thirteenth century A.D. (1994 to 728 cal. yrs BP). The Formoso site—currently dated as the longest occupied site (1509 to 930 cal. yrs BP)—yielded early Incised-Punctate/Arauquinoid pottery, a previously unreported pottery style in the Amazon region. Additionally, using StarryNight astronomy software, the night sky at Formoso was compared with a map of the pile dwelling layout, revealing a statistically significant resemblance to the Pleiades. This paper focuses on the Formoso site, suggesting that it may have served cultural significance to the Pleiades as early evidence for the later widespread ethnographic use of the star cluster’s annual sighting to mark the seasonal flood cycles and the management of agricultural and ecological activities throughout tropical South America.

A Study of Drought and Flood Cycles in Xinyang, China, Using the Wavelet Transform and M-K Test

Accurately identifying and predicting droughts can provide local managers with a basis for decision-making. The Xinyang region is prone to droughts and floods, which have a large impact on local agriculture and socio-economics. This paper employs precipitation data from the Xinyang region to provide a scientific basis for drought and flood control measures in this region. The data are first treated with standardized precipitation indices (SPIs) on three-month, six-month, and nine-month time scales. Subsequently, a Morlet wavelet analysis is performed for each of the three time scales analyzed for the SPI. The results show multiple time scales of drought and flood disasters in the Xinyang region. The cycles of drought and flood disasters in the Xinyang region show different fluctuations on different SPI scales. The SPI time series reflect a strong fluctuation period of 17a for drought and flood disasters in the Xinyang region. An analysis of the variance of the wavelet coefficients showed that the first main cycle of drought and flood disasters in the Xinyang region is 7a, and the second and third sub-cycles are 4a and 13a, respectively. We conclude that floods are more frequent than droughts in Xinyang and are more likely to occur from 2017 to 2021, with a subsequent shift to droughts. Local managers should put drought prevention measures in place to deal with droughts after 2021.

Revisiting recycled water for the next drought; a case study of South East Queensland, Australia

Australia has long been observed to experience the ENSO (El Niño Southern Oscillation) of periodic alternation of flooding and drought. Australia has experienced consecutive years of the La Niña cycle of heavy rain and flooding. At some stage, this will revert to one or more years of drought, often severe. In previous years of drought, consideration was given to alternative water supply, including recycled wastewater. This paper reflects on the case of the previous period of El Niño drought in South East Queensland (SEQ), aiming to contribute to drought mitigation planning through reviving consideration of recycled water.

The Hydrological Cycle of the Lower Amazon in Brazil Determines the Variation in Local Fishing Patterns

Fishery catches on the Lower Amazon River were analyzed in relation to the hydrological cycle, temporal shifts in fishing effort, and the use of nets or lines in lakes and rivers. The study was based on a temporal series of catch data collected between January 1993 and June 2011. The variables analyzed were the total catch, use of gillnets or lines, the environment targeted (lakes or rivers), and fishing effort. Temporal trends in the data series were analyzed using the Mann–Kendall test. An Analysis of Covariance (ANCOVA) was used to evaluate whether gillnet and line catches had independent effects on the catch data. Duncan’s test was applied to identify the groups (months) of means that were significantly different from each other. The majority of the catch landings were taken with gillnets (98.65%) in a lake environment (64.98%). The temporal series showed a significant decline over time in the gillnet catches from both lakes and rivers, as well as in fishing effort. The influence of the annual flood cycle was reflected in the catches and the flood pulse regulated fishing productivity patterns in the region. The fishers who adapt their activities to this flood pulse have good traditional knowledge of the environment. The results of the study also indicated that any changes in this dynamic system may impact traditional local fisheries and affect the economic wellbeing of local fisher populations.