Ephemeral Water Research Articles

A Comprehensive Evaluation of Mean and Extreme Climate for the Conformal Cubic Atmospheric Model (CCAM)

Abstract This study evaluates the performance of the Conformal Cubic Atmospheric Model (CCAM) in dynamically downscaling fifth major global reanalysis produced by European Centre for Medium-Range Weather Forecasts (ECMWF) (ERA5) reanalysis data from 1985 to 2014, following a 5-yr spinup period. It focuses on daily maximum and minimum temperatures and daily precipitation, comparing CCAM to ERA5 and the Australian Gridded Climate Data (AGCD). The CCAM effectively reduces warm biases in daily minimum temperatures but struggles with cold biases in daily maximum temperatures, particularly in northern Australia during the wet season, possibly due to high-level cloud overestimation. Precipitation tends to be overestimated, especially in extreme rainfall events, though offset by an underestimation of low rainfall. The study showcases improvements in the annual minimum of daily minimum temperatures across most of Australia, while identifying challenges in forecasting cooler extreme temperatures. It adds value to annual maximum daily maximum temperatures in southern Australia but less so in the north. The analysis of the 5% annual exceedance probability (AEP5%) yields mixed results influenced by location and potential ocean temperature changes. Some coastal areas exhibit lost value, possibly linked to ocean temperature shifts. Furthermore, CCAM’s representation of maximum annual daily and 5-day rainfall reveals lost value, particularly in eastern Australia due to an overestimate of extreme rainfall. Despite the challenges of comparing a dynamical downscaling model like CCAM to ERA5, this study highlights its benefits in reducing biases, especially in temperature representation. Given the larger biases in phase 6 of Coupled Model Intercomparison Project (CMIP6) global climate models, CCAM appears suitable for dynamic downscaling in climate projections, emphasizing the need for ongoing model enhancements, including addressing biases related to ephemeral water bodies and extreme rainfall. Significance Statement This study critically assesses the performance of the Conformal Cubic Atmospheric Model (CCAM) in dynamically downscaling ERA5 reanalysis data from 1985 to 2014, offering valuable insights into climate modeling. Focusing on temperature and precipitation, CCAM proves effective in mitigating warm biases in daily minimum temperatures but encounters challenges with cold biases in daily maximum temperatures, particularly in northern Australia. The analysis reveals the overestimation of precipitation, especially in extreme events, yet identifies improvements in annual minimum daily minimum temperatures across Australia. The study underscores CCAM’s potential in reducing biases compared to CMIP6 global climate models, making it a promising tool for dynamic downscaling in climate projections. It emphasizes the necessity for ongoing model enhancements, particularly addressing biases related to ephemeral water bodies and extreme rainfall.

Local environmental factors drive distributions of ecologically-contrasting mosquito species (Diptera: Culicidae)

Mosquitoes are important vectors of disease pathogens and multiple species are undergoing geographical shifts due to global changes. As such, there is a growing need for accurate distribution predictions. Ecological niche modelling (ENM) is an effective tool to assess mosquito distribution patterns and link these to underlying environmental preferences. Typically, macroclimatic variables are used as primary predictors of mosquito distributions. However, they likely undervalue local conditions and intraspecific variation in environmental preferences. This is problematic, as mosquito control takes place at the local scale. Utilising high-resolution (10 × 10 m) Maxent ENMs on the island of Bonaire as model system, we explore the influence of local environmental variables on mosquito distributions. Our results show a distinct set of environmental variables shape distribution patterns across ecologically-distinct species, with urban variables strongly associated with introduced species like Aedesaegypti and Culexquinquefasciatus, while native species show habitat preferences for either mangroves, forests, or ephemeral water habitats. These findings underscore the importance of distinct local environmental factors in shaping distributions of different mosquitoes, even on a small island. As such, these findings warrant further studies aimed at predicting high-resolution mosquito distributions, opening avenues for preventative management of vector-borne disease risks amidst ongoing global change and ecosystem degradation.

Fish diversity in the Nile system and ephemeral water bodies in Sudan: Records and a review

Fish diversity in the Nile system and ephemeral water bodies in Sudan: Records and a review

Tetradactyl footprints and plant material from the Jurassic-Cretaceous boundary, Tarapaca Region, Northern Chile

We report new ichnites corresponding to a trackway composed of three tetradactyl pedal footprints and plant remains near Southeastern Guatacondo, Tarapacá Region, within the transition of Majala and Chacarilla Formations (Late Jurassic-Early Cretaceous). The fossils were found in the context of a Copper Mining road construction at the PK23 site, Quebrada Blanca Phase 2 project, by the Teck Mining Company Quebrada Blanca S.A.We performed stratigraphical, paleobotanical, and paleoichnological studies, along with the footprint characterization and comparisons by Principal Component Analysis, and Discriminant Analysis of I-II, II-III and III-IV interdigital angles, using a large tetradactyl footprint morphological database of potential producers (dinosaurs, crocodiles, lepidosaurs, and pterosaurs). Additionally, we performed 3D pedal computer modeling kinematic analysis of the Chilesaurus diegosuarezi's 3D tetradactyl foot under two different sedimentary conditions (i.e. hard soil with superficial impression, and soft sediment with a penetrative impression), to test it as a potential trackmaker.The stratigraphic section reveals an association of siliciclastic facies, formed by the intercalation of fine-grained sandstones and wackes, with ripple marks, cross and horizontal lamination, evidencing intermittent moderate to low sedimentation energy.Among the plant material, several organs of the family Cheirolepidiaceae were identified such as, leaves and leafy branches of Brachyphyllum type, Classostrobus pollen cone, ovuliferous scales, and wood fragments related to Cupressinoxylon. The monodominance of Cheirolepidiaceae among the preserved macroflora allows inferring the characteristics of the environment in which the plants lived, highlighting halophytic, and temporarily arid conditions. Evidence as a whole, permits to interpret the depositional environment as an arid deltaic-littoral plain, temporarily covered with an ephemeral water layer associated with a stunted woody vegetation, in which terrestrial vertebrates walked by.Despite the low predictive power of the multivariate analysis, due to the various sources of morphological variability inherent to footprint formation, the PK23 footprints seem to better correspond to Dinosauria or Avialae as the most likely producers, rather than to Lepidosauria or Crocodylia, discarding the dinosaur Chilesaurus due to very low interdigital mediolateral rotation capabilities.

Nocturnal stomatal behaviour and its impact on water use strategies of desert herbs in the Gurbantunggut Desert, Northwest China

Nocturnal stomatal behaviour has the potential to exert a profound influence on plant-water relations, especially water use efficiency. However, we know very less about plant functional type differences in nocturnal stomatal conductance and their roles in plant stress adaptation, especially drought adaptation. To address this critical knowledge gap, we assessed diel leaf gas exchanges in eight ephemeral and perennial herbs growing on the southern edge of the Gurbantunggut Desert, Northwest China. For both ephemeral and perennial herbs, the nocturnal stomatal conductance (gs) exceeded 30 % of daytime gs, except for an ephemeral herb (Malcolmia scorpioides). The nocturnal gs in the studied perennial herbs were significantly higher than it in the ephemeral herbs. The results suggest that circadian-driven stomatal priming plays a pivotal role in accelerating the attainment of steady-state gs during the morning for perennial herbs, thereby enhancing their capacity for carbon capture. Moreover, the nocturnal stomatal behaviour of the ephemeral herbs favored water retention in the morning, consequently enhanced intrinsic water use efficiency and long-term water use efficiency. In summary, plant functional type differences in the magnitude of nocturnal stomatal opening were related to differences in water acquisition and utilization and highlighted diverse water use strategies in the desert plants.

Structure of Zoocenoses in the Ephemeral Pond Lilov Vir, Western Bulgaria

This study aimed to observe the development of zoocenoses in an ephemeral karst water body providing a dynamically changing habitat and unstable hydrological regime with an emphasis on assessing the main factors influencing the structure of the macrozoobenthos and zooplankton communities. The study was conducted in Pond Lilov Vir near Karlukovo Vil., Western Bulgaria. The main physicochemical parameters and the concentrations of nutrients were recorded. The macrozoobenthos (MZB) and zooplankton samples were taxonomically determined and statistical analyses of the obtained results were performed. The results have shown that the pond supports a variety of species and species typical to temporary waters. The variation in hydroperiod (HP) duration over the years leads to the formation of different communities. Longer HPs suggest greater biodiversity. In drying pools, especially those with a short HP, the leading factor for structuring communities is the abiotic environmental factors-HP and water volume (WVOL). Biotic factors, such as competition and predation, are not leading, due to the lack of fish and insufficient time for the development of invertebrate predators.

Impacts of Constructed Water Pans on Mammal Distribution and Abundance. A Case of Mt. Kenya Wildlife Conservancy, Kenya

Aim: To assess the impacts of constructed water pan utilization on wildlife distribution and abundance in Mount Kenya Wildlife Conservancy. Study Design: Ecological survey design. Place and Duration of Study: The study was conducted in the dry season (June 2022) and wet season (October 2022) at Mount Kenya Wildlife Conservancy, Kenya. Methodology: Systematic sampling using belt transects was used in collecting data on mammals’ distribution and abundance. Results: Distribution patterns differed with species between seasons. For the dry season, results show that eland(r=-0.516, p=0.295), impala(r=-0.714, p=0.111), warthog(r=-0.754,p=0.08), waterbuck(r=-0.986,p=0.0003), and zebra(r=-0.657,p=0.156) had a strong negative correlation with distance from water pans. During the wet season, impala (r = -0.49, p=0.329), wildebeest (r = -0.26, p=0.623), and waterbuck (r = -0.71, p=0.111) showed a negative correlation, while warthog (r = 0.60,p=0.208) and zebra (r = 0.26, p=0.62)showed a positive correlation with increased distance from water. Conclusion: many mammals concentrated near the constructed water pans during the dry season due to the presence of forage and drinking water but dispersed out when ephemeral water sources and forage availability increased during the wet season.

Distribution of Algae According to Habitat Preferences in Saline Coastal Reservoirs of Pryazov National Natural Park (Ukraine)

This study focused on the distribution of algae in the saline coastal water bodies of Pryazov National Nature Park according to their habitat preferences. This research revealed that aquatic species form the basis of the algal flora. Among these, diatoms were predominant in terms of species richness and frequency of occurrence. In the lake-type estuaries and ephemeral water bodies, an increased number of amphibious species were found, which can be attributed to the fluctuating water level. Among the amphibious species, <i>Cyanoprokaryota</i> representatives dominate. Hierarchical clustering of the water bodies demonstrated a connection between the species composition of algae and the type of water body, which is consistent with their genesis and transformation.

Butterfly Diversity in the Campus area of University of North Bengal, West Bengal, India.

Butterflies play a crucial role as bio-indicators, signaling the health of ecosystems and biodiversity, making their conservation vital. The northern region of West Bengal in eastern India is renowned for its remarkable butterfly diversity. The University of North Bengal campus, spanning 315.99 acres at the Eastern Himalayan foothills (26°42′34.03″N; 88°21′14.96″E), is home to diverse flora and fauna. The surrounding area offers a variety of habitats, including forests, grasslands, tea gardens, and wetlands, which support numerous animal species. This study aimed to assess butterfly diversity in three distinct geographical sites within the university campus: the Tea garden area (dominated by tea and rubber plants), Salkunja (a forested area with a semi-perennial stream dominated by Sal trees), and Magurmari (an area with semi-perennial streams, ponds, ephemeral water bodies, paddy fields, and grasslands). Monthly butterfly observations were conducted from December 2021 to January 2023. The study documented 55 butterfly species from six families (Hesperiidae, Lycaenidae, Nymphalidae, Papilionidae, Pieridae, and Riodinidae), with Nymphalidae being the most prevalent and Riodinidae the least. Notably, the ecotone area of Magurmari exhibited the highest butterfly species diversity. Four species protected under the Wildlife (Protection) Act (WPA), 1972, were also identified. This research aims to analyze butterfly diversity in relation to their habitats and conservation needs within the university campus, contributing to the development of a concise checklist specific to this district for effective conservation efforts. The study underscores the significant butterfly diversity found on the campus, emphasizing the urgent need for focused conservation actions.

Algae distribution according to locality in saline coastal water bodies of the Pryazov National Nature Park (Ukraine)

The study focuses on the distribution of algae in the saline coastal water bodies of the Pryazov National Nature Park according to their habitat preferences. The research revealed that aquatic species form the basis of algal flora. Among them, diatoms are predominant in terms of species richness and frequency of occurrence. In the lake type estuaries and ephemeral water bodies, an increased number of amphibious species was found, which can be attributed to the varying inundation conditions of these water bodies. Among the amphibious species Cyanoprokaryota representatives dominate. Hierarchical clustering of the water bodies demonstrated a connection between the species composition of algae and the type of water bodies, which is consistent with their genesis and transformation.

Rainfall infiltration and slope stability of alpine colluvial terraces subject to storms (NE Italy)

In the alpine environment, rainfall-induced shallow landslides can involve thin covers of colluvial soil (50–300 cm) on terraced belts that were formed as a result of fill-and-cut sedimentary processes that followed the deglaciation of the alpine valleys. Notably, research on shallow slope failures involving alpine terraces consisting of a near-flat upper ground surface (“tread”) and a moderately steep scarp (“riser”) is lacking in the literature. This paper describes the engineering geological characteristics and failure mechanisms of a large number of shallow landslides (soil slips or slide-debris flows) that were activated on alpine stratified colluvial terraces due to a rainstorm that hit the mountain area of the Friuli Venezia Giulia Region (NE Italy) on 21–22 June 1996. The paper reports data on the geomorphological and engineering geological characteristics of the soil slips acquired through extensive fieldwork and shows the outcomes of some two-dimensional seepage and slope stability analyses that were carried out in order to investigate the critical hydrological conditions and mechanisms that were responsible for the soil slip activation during and after rainfall. The soil slip activation can occur at two different stages during the infiltration process, based on the interacting water flows through the terrace tread and riser. The first critical stability condition is reached during the phases of greater precipitation intensity or at the end of the rainstorm because of the saturation of the top soil layer on the terrace riser and the subsequent formation of an ephemeral water table accompanied by a seepage sub-parallel to the slope face. The second critical condition is achieved some hours after the end of rainfall as a result of a tread-to-riser water outflow that is supplied by the water amount stored within the near-flat terrace tread during the peak rainfall stages (reservoir-like effect). This study also shows that a critical value of rainfall intensity of about 40–45 mm/h can cause the activation of soil slips in mountain basins characterised by a humid continental climate and by the occurrence of colluvial deposits with a high content of fine fraction. This critical value of rainfall intensity should be considered as a rainfall threshold for a basin-scale under geomorphological and geological conditions similar to those investigated in this paper.

Earth Observation Data Synergy for the Enhanced Monitoring of Ephemeral Water Bodies to Anticipate Karst-Related Flooding

With the increasing availability and diversity of satellite imagery, the multisensor fusion of data can more effectively address the improved monitoring of temporary water bodies. This study supports the attempt to apply well established methods to detect spatial and temporal changes in ephemeral shallow lakes in lowland karst terrain, as well as to improve the understanding concerning the dynamics of water storage and hydrological mechanisms during extreme precipitation events. Based on the joint analysis of Copernicus Sentinel SAR and optical mission data, as well as soil moisture and EO-based rainfall observations over the period of 2015–2020, we demonstrated the control of the karst system on the ephemeral lake appearances in the broader area of Chalkida (Evvia, Greece). A connection between the prolonged and extended water coverage in the ephemeral lakes and flooding in the area is documented. Our EO-supported findings may serve as indicators for flood alerts in future extreme precipitation events, improving responses in cases of emergencies.

Examination of the amount of GEDI data required to characterize central Africa tropical forest aboveground biomass at REDD+ project scale in Mai Ndombe province

The Global Ecosystem Dynamics Investigation (GEDI) is the first spaceborne LiDAR designed to improve quantification of vegetation structure and forest aboveground biomass (AGB) including in the tropics where forest AGB inventory data are limited. GEDI is a sampling instrument on the International Space Station (ISS) and does not provide data on a regular, systematic basis. Reducing Emissions from Deforestation and Degradation and enhancement of carbon stocks (REDD+) projects require forest AGB inventories to quantify avoided carbon emissions achieved by conserving forest biomass. Although there is high confidence that GEDI can retrieve measurements that allow estimation of AGB at scale, less is known about how well its operational deployment performs for measurement of AGB to support REDD+ projects. This includes an understanding of the appropriate time period required to collect sufficient GEDI observations for reliable forest AGB assessment. This paper describes the first study to examine the amount of GEDI data needed to characterize tropical forest AGB at REDD+ project scale. In tropical Africa, the average REDD+ project size documented by the Center for International Forestry Research is equivalent to a square area of approximately 50 × 50 km (250,000 ha). Recently available good quality GEDI footprint-level AGB product data acquired over a 31 month period over Mai Ndombe province in the west of the Democratic Republic of the Congo were considered. A global 30 m percent tree cover product, updated with contemporary mapped forest cover loss, was used to map the intact forest across the province. Fifteen 50 × 50 km test sites, representing example REDD+ project areas with >80% forest cover and good quality AGB forest footprint data distributed across each site, were selected. The sites were selected from five AGB stratum defined from the GEDI data, and with three sites selected per stratum that had low, medium and high semivariogram sill values that reflect increasing within-site AGB spatial variation. The overall mean GEDI AGB (OMGA) was derived from all the good quality forest GEDI footprint AGB values acquired over the 31 months of GEDI operation at each site. The expected minimum number of GEDI orbits (norbitsp) required to characterize the OMGA to within p = ±5%, ±10%, and ±20% was derived by considering different combinations of GEDI orbits randomly selected from the 31 months of GEDI data. The expected minimum number of days (ndaysp) required to characterize the AGB over each site was derived by multiplying the site norbitsp values with a scalar coefficient of 13.03 days. The scalar coefficient was found by counting the temporal intervals between successive GEDI orbits containing good quality forest AGB data and is equivalent to the average number of days required to obtain a GEDI orbit containing good quality forest AGB data at 50 × 50 km scale. Among the 15 sites, observation periods ranging from 65 to 221 days (0.18 – 0.61 years), 143 – 534 days (0.39 – 1.46 years), and 390 – 742 days (1.07 – 2.03 years) were required to characterize the AGB to within ±20%, ±10%, and ±5% of the site OMGA, respectively. The Intergovernmental Panel on Climate Change (IPCC) recommended accuracy requirement for forest AGB estimates is 10%. Thus, to meet this accuracy requirement the findings of this study indicate that at least 534 days (1.46 years) would be required for REDD+ site monitoring using GEDI in Mai Ndombe province. In other central African tropical forest localities these observations periods may be different depending on the forest AGB and spatial variation, cloud cover, ephemeral surface water presence, and GEDI AGB retrieval sensitivity to the forest conditions.

Nonmarine ostracod fauna from the Lower Cretaceous Shinekhudag Formation (southwest Mongolia): taxonomy, biostratigraphy, and paleoecology

AbstractThis work provides the detailed investigation (taxonomy, biostratigraphy, and paleoecology) of a nonmarine ostracod fauna from the Shinekhudag Formation in Gobi–Altai area, southwest Mongolia. The samples from two sections (Tsagaan Tsuvarga and Oshih Hollow East) yielded various ostracods assigned to nine species belonging to six genera: Cypridea verrucata Neustrueva, 1974, C. ihsienensis Hou, 1958, C. unicostata Galeeva, 1955, C. tumefacta Neustrueva, 1974, Yumenia cf. Y. oriformis Hou, 1958, Scabriculocypris subscalara Zhang and Chen in Ye et al., 2003, ?Trapezoidella sp., Candona sp., and Vlakomia ulanense Neustrueva, 1977. The biostratigraphic application of our taxonomic results suggests that the age of the Shinekhudag Formation is Barremian–Aptian. In addition, the ostracod fauna shows strong affinities to faunas from northeast China and potentially northwest China, providing evidence of faunal exchanges between these regions and southwest Mongolia. The new discovery of Vlakomia ulanense indicates that mid-Cretaceous (Albian) species in northeast China probably originated in Mongolia at the time of deposition of the Shinekhudag Formation. Two ostracod assemblages in the studied sections reflect that different paleoenvironment settings have existed during deposition; the Tsagaan Tsuvarga Section represents a shallow-littoral zone of athalassic (inland) saline lake under arid climate, and the dominance of cypridoideans of the Oshih Hollow East Section is indicative of ephemeral water bodies.

Belowground plant traits and their ecosystem functions along aridity gradients in grasslands

Ecosystem responses to environmental change are usually studied solely using aboveground (usually leaf) traits. However, belowground plant traits, such as fine roots and coarse belowground organs, likely play a crucial role in ecosystem response, especially under aridifcation. We conducted a literature survey on belowground plant traits along aridity gradients in temperate grasslands to propose which effect traits might be connected with abrupt vegetation changes that would occur with aridification due to environmental change. With increasing aridity, seasonal regeneration decreasingly relies on recruitment from the belowground bud bank and increasingly relies on regeneration from seeds. This leads to greater inter-annual variability in biomass production. Other belowground traits, such as bud bearing organs and fine root distribution in the soil, also shifts along the aridity gradient. As aridifcation begins, we propose that plants would become more conservative in their belowground traits producing lower amounts of belowground litter. Increasing aridifcation would lead to the loss of rhizomatous plants from the community and a prevalence of deep rooting plants leading to changes in soil resource utilization and increasing susceptibility to soil erosion. Under extreme aridification, perennial plants, except those with bulbs, would be lost from the community and replaced by annuals which produce low amounts of litter and use only ephemeral water resources in the upper soil layers. Belowground plant traits, such as belowground clonal growth organs, bud banks, and fine root distributions, may provide a more mechanistic understanding behind shifts in ecosystem functioning due to environmental change.

Effects of environmental factors on the ecology and survival of a widespread, endemic Cerrado frog

AbstractUnderstanding the mechanisms that affect habitat use by vertebrates is critical for understanding how species are distributed across landscapes and how they cope with habitat change. The Brazilian Savanna (the Cerrado) has vegetation ranging from grassland to woodland savannas and harbors a rich and diverse amphibian fauna impacted by accelerated habitat loss. Here, we test the influence of vegetation type (from grassy scrubland to woodland) and distance from breeding sites (ephemeral water bodies) on body size, abundance, and survival of the frog Physalaemus nattereri in a natural metapopulation system of south‐central Brazil. We also test whether body size is a significant predictor of population abundance. We found that the abundance of P. nattereri varies according to the mean snout–vent length of each metapopulation (sampling unit), as well as a higher estimated mortality rate in woodlands compared with typical Cerrado. Furthermore, we found no difference in estimated mortality among sampling units located far or close to ephemeral water bodies. Thus, our results highlight variable responses of P. nattereri metapopulations to environmental factors, despite the observed high heterogeneity among sampled habitats and the importance of ephemeral water bodies for reproduction. These findings highlight that land cover and availability of breeding sites might not always interact to explain population persistence of Cerrado frogs.

Evolution of Alkaline Mine Drainage and Unique Biodiversity on Soil-Free Mine Substrates, Southern New Zealand

Relatively impermeable soil-free substrates (clay-rich outcrops and sediments) exposed at eight abandoned placer gold mines generate alkaline mine drainage through evaporation and minor interaction between water and rock in a semi-arid rain shadow climate. Original mine sluicing a century ago created drainage channels over the land surface that still control the flow of ephemeral surface waters, with localised construction of erosional outwash pans. Ephemeral surface waters and associated evaporitic salts are dominated by halite derived from marine aerosols in rain, yielding circumneutral pH and electrical conductivity (EC) values locally exceeding 50 mS/cm. Weakly altered schist basement rocks and Miocene mudstone exposed at the surface contain abundant calcite, and surface waters are supersaturated with respect to Ca-carbonate minerals with a pH of ≈ 8 and an EC of ≈ 1 mS/cm. Water interaction with albite increases the dissolved Na/Cl molar ratio to > 1, and evaporative formation of Na-carbonate precipitates can raise the pH to > 10. Pyrite oxidation does not offset the alkaline pH in any of these processes, although dissolved sulfate can rise to high levels (> 2000 mg/L; EC ≈ 5 mS/cm), forming evaporative sulfate minerals. Ephemeral waters drain down outcrops and the relatively impermeable erosional pans, leaving salt encrustations with variable mineralogy and associated waters with pH and EC values that are partially controlled by rates of dissolution and reprecipitation of the minerals in the salts. The saline alkaline chemistry of the pans excludes most vegetation and has allowed development of salt-tolerant ecosystems with rare endemic halophytic plants. Maintenance of soil-free halophytic surfaces has potential applications in dryland mine sites around the world, especially as climate change enhances and extends aridity.

Inorganic geochemistry of saline substrates associated with coastal turf, Otago Peninsula, New Zealand

ABSTRACT Halophytic plant communities have developed on exposed coastal landforms to form low-stature turf in several locations around New Zealand. We quantify the inorganic geochemistry, mineralogy and simulated ephemeral surface water composition of saline soil-free bare ground at a well-preserved site at Maori Head on Otago Peninsula, where halophytes have colonised from adjacent coastal turf. The community at this site is dominated by Leptinella dioica, Samolus repens, Disphyma australe and Selliera radicans. Maori Head substrates are dominated by clay-altered basalt colluvium and show a general trend from high electrical conductivity (EC > 10 mS/cm) and weakly acid pH (< 6) on bare ground to low EC (< 1 mS cm−1) and higher pH (> 7) in turf and adjacent pasture soils. High salinities on dry substrates and in simulated ephemeral surface waters result from surface evaporation of airborne sea spray and contain halite (NaCl) with some gypsum (CaSO4.2H2O). Chemical interactions with the substrate are minor. The high surface salinities were maintained despite a major winter rain event with strong onshore winds. However, surface salinity is frequently leached by rain and shallow groundwater, whereas inland saline sites (pH 8–11) have substantial salt accumulations driven by lower rainfall, high evaporation and chemical interaction with Otago Schist-derived substrates.

Toponyms: a neglected asset within the water framework and flood directives implementation process; the case study of Greece

Proxy data and qualitative information are important assets in water resources and floods management. In the research, the river water bodies with characteristic toponyms (hydronyms) in Greece that potentially reflect the water’s quality or the occurrence of floods are evaluated in comparison to the European Union’s (EU) Water Framework and Flood Directives implementation process outputs. For doing so, after identifying the river water bodies with characteristic toponyms which form the 10.2% of the Greek water bodies, the toponyms are cross correlated with the water bodies quality status as retrieved by the Directives’ databases to validate the existence of linkages between the names and the quality. Similarly, the significant floods, as derived from the Flood Directive, are spatially allied with the water bodies with characteristic toponyms to ground truth the connection between significant floods and water bodies whose toponyms imply flood prone areas. The research outputs indicate a high degree of correlation both in terms of water quality and floods, meaning that in almost all cases the water body toponym depicts the good or bad quality of the water body or the occurrence of flood events. Moreover, it is established that almost 90% of the water bodies with characteristic names are intermittent and ephemeral ones. The water bodies’ toponyms, hence, are proposed as an auxiliary criterion during the Directives implementation process that could foster increased water quality and flood-related knowledge, especially in intermittent and ephemeral water bodies which are generally lacking observations, and can be applied not only in all EU-Member States’ waters, but also in global scale.

Aqueous alteration of the Vastitas Borealis Formation at the Tianwen-1 landing site

The Vastitas Borealis Formation is a Hesperian-aged sedimentary unit that mainly covers the Martian northern plains. Its environment of formation is uncertain but may be related to an ancient Martian ocean, outflow channel deposits, compaction and drainage activities, or subsurface ice-related processes. Here we investigate the geological evolution of the Vastitas Borealis Formation using geochemical and mineralogical data acquired by the Mars Surface Composition Detector on board the Zhurong rover at the Tianwen-1 landing site. We find that the fine-grained soil is very similar to the ubiquitous surface dust at other landing sites on Mars but mixed with calcium-rich and magnesium-poor local materials. These materials are mostly igneous minerals mixed with allophane and imogolite/opal and appear to have a low degree of chemical alteration. We suggest that these deposits likely formed by alteration of extensive volcaniclastic soils in limited or ephemeral water under cold conditions, which largely supports the hypotheses of a frozen ocean and sublimation.