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Map of Aerolito Cave in Cozumel Island. Located below sea-level, the cave network promotes seaward material transport and a hydrologically interconnected environment between the sea and the aquifer, providing access to the subterranean estuary. The terrestrial sinkhole opening, colloquially known as Cenote El Aerolito, is partially surrounded by mangroves. Sediment cores (orange circles) were obtained from downstream (Core 5, Core 6, Core 7, and Core 8) and upstream (Core 1, Core 2, Core 3, and Core 4) passages. Map is adapted after Mejía-Ortíz et al. (2007).
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Subsurface mixing of seawater and terrestrial-borne meteoric waters on carbonate landscapes creates karst subterranean estuaries, an area of the coastal aquifer with poorly understood carbon cycling, ecosystem functioning, and impact on submarine groundwater discharge. Caves in karst platforms facilitate water and material exchange between the mari...
Citations
... The obtained average carbonate contents vary from 1 to 4% ( Figure 4b). These carbonates are abundant in the coarse fraction (site 2) which is accompanied by a low percentage of organic matter (Brankovits et al., 2021). Calcareous soil is soil containing free CaCO 3 in sufficient quantity to present a visible effervescence under the action of cold diluted HCl. ...
The peri-urban solid waste in the Kenitra region is experiencing a significant change in terms of quantity and quality. High concentrations of both inorganic and organic materials are present in these wastes, posing a significant
threat of pollution. This research sought to analyze the extent of soil contamination by heavy metals, providing
valuable insights to prompt proactive interventions and propose alternative solutions for sustainable waste management. The objective of this work was to study peri-urban soil contamination in the Kenitra region-Morocco. For
that purpose, several soil contamination indicators were analyzed, namely: nitrogenous, fertilizer and heavy metals
concentration, soil pH, etc. The analyzed soil samples were taken from water from the different points at the levels
of the studied region. The analysis shows that the studied soils are polluted with Zn, Mg, Cu, Ni, Cr, Cd, Pb, and
other chemical elements. The results obtained suggest a correlation between soil pollution and the concentrations
of the measured heavy metals. Furthermore, the analysis shows that heavy metals, contamination is particularly
related to the presence of lead, cadmium, and zinc. The zinc contamination in the soil is about 390 mg/kg for a
standard of between 0.2 and 2 mg/kg. Lead concentrations are 53 mg/kg for a standard of 0.3 mg/kg. On the basis
of Moroccan standards, the soil is contaminated by lead, cadmium, and zinc.
... Marine caves are formed by karst activity due to freshwater dissolution processes along coastal environments (Romano et al., 2022) and by combining sea level changes and tectonic movements (Antonioli et al., 2004;D'Angeli et al., 2015;Florea and Vacher, 2006). Their position at the edge between the terrestrial and marine domains makes them a powerful marker of the short (seasonal, annual) and long (millennial) term environmental changes through cave sediments and living organisms (Brankovits et al., 2021;Gerovasileiou et al., 2021). ...
... Benthic foraminifera have been extensively studied in the submerged caves of Bermuda Archipelago (North Atlantic Ocean) and Sardinia Island (Tyrrhenian Sea), demonstrating their reliability as environmental indicators of the different cave habitats (Cresswell and van Hengstum, 2022;van Hengstum and Scott, 2011). Paleoenvironmental reconstructions based on benthic foraminifera from sediment cores indicated that these communities are primarily controlled by groundwater salinity changes and secondarily by the supply of organic carbon (Brankovits et al., 2021;Cresswell and van Hengstum, 2022). Moreover, the sedimentological aspects of cave sediments (clastic and chemical) have been recognized as of scientific interest for hydrogeological and paleoclimatological records (van Hengstum et al., 2010). ...
This study was conducted in the Middle Branch of Bue Marino Cave (Sardinia, Italy) to reconstruct paleoecological conditions during the Holocene through microfaunal proxies in seven surface sediment samples and a short sediment core (BMD-2018, 18 cm), all collected in 2018 and another core sampled in 2021 (BMD-2021, 28 cm). The first attempt at dating cave sediment through luminescence was conducted on BMD-2021; the derived age was 6.04 ± 0.47 ka at 18 cm depth. Although continuous sedimentation and constant rates are not probable in the cave, this indicates that the sedimentary record dates to the early times after the Holocene flooding of the cave by the sea. Benthic foraminifera and grain size were analyzed in all surface samples and core BMD-2018, while only benthic foraminifera were studied in BMD-2021. The recent foraminiferal assemblages, studied from an ecological point of view, were applied as modern analog to reconstruct the paleoecological conditions in sediment cores. Significant changes in the sedimentary environment were excluded; the two cores showed a similar foraminiferal turnover at a similar depth, from an older assemblage with prevailing indifferent Ammonia inflata to a younger one with prevailing opportunist Eggerelloides advena. This turnover was attributed to changes in the amount and/or quality of available nutrients. Based on these results, this event is likely related to possibly attributable to the effects of climate changes that occurred in the Holocene. However, more extensive studies are necessary to better understand the effects of the climatic/environmental events in the Late-Holocene in the caves. Although it represents a first attempt at paleoenvironmental reconstruction based on sediments from a Mediterranean marine cave, this study demonstrated that benthic foraminifera are refined paleoenvironmental proxies and that the integrated approach with the luminescence dating produces reliable results for studying the effects of global changes in these environments.
... Indirect mortality (i.e., changes that provoke the alteration of other parameters affecting the fauna) could mainly be due to changes in the organic matter entering deeper sites as a consequence of alterations of the community in adjacent sections of the cave (Ban et al., 2008). Subtle changes in organic matter composition and concentration cause an increase in heterotrophic microbes leading to oxygen depletion (Brankovits et al., 2021;Cresswell & van Hengstum, 2021), thus affecting food and oxygen availability. ...
The impact of meteorological phenomena on ecosystem communities of karst subterranean estuaries (KSEs) remains unknown. KSEs are characterized by vertically stratified groundwater separated by a halocline and host endemic aquatic cave-adapted fauna (stygobionts). In October 2015, 8 days of heavy precipitation caused the first recorded mortality event in the KSE. This event was marked by a halocline shift 5 m deeper. The present study aimed to provide insights into resilience of KSEs faunal communities to temporal shifts in temperature and precipitation. Cave water temperature decreased on average 0.0068°C per mm of accumulated precipitation over 4 days, which can add up to, and surpass, the interannual temperature variation in cases of heavy precipitations. Biological surveys (2012-2021) conducted within cave systems El Aerolito and La Quebrada, in Cozumel, indicated that change in community structure was not detected and stygobionts were resilient; however, marine species inhabiting the caves were impacted. Overall, the faunal community at KSEs remains resilient within short-term meteorological phenomena despite shifts of non-stygobionts.
... The δ 34 S composition suggests a major contribution from anaerobic reoxidation of sulfate in sulfides compounds, suggesting a microbial process from sulfur compounds, particularly in the inner part of the cave (Liu et al., 2021). Brankovits et al. (2021) interpreted the origin of the organic matter in sediments of Mexican flooded karst caves through the values of C/N versus δ 13 C, discriminating terrestrial and marine contributions. Using this approach, we may deduce that in the SED_4, SED_5, and SED_6c samples, the organic matter is of marine origin. ...
This study investigates for the first time the presence of microplastics in sediment, water, and benthic organisms (foraminifera) of a marine cave in the Gulf of Orosei (Sardinia, Italy). Microplastics were found in all water, and sediment samples with similar shapes, sizes, and compositions; identified items were mainly fragments and fibers constituted by PVC and polyethylene. Their provenance was supposed to be predominantly from the sea than from the seasonal freshwater supplies from the karst system. Foraminiferal assemblages were mainly constituted by calcareous hyaline taxa in the outer station, while in the inner ones, the agglutinated Eggerelloides advenus was dominant. FTIR analyses on agglutinated shells identified polyethylene. Microplastic items are collected by the foraminifers and sediment grains building the shell chambers. This is the first study providing evidence that
marine caves may be collectors of microplastics and that, in these habitats, microplastics enter the biotic matrix at the protist’s level.
... Anchialine ecosystems are typically oligotrophic environments with low dissolved oxygen content and, therefore, they can easily transition into anoxic eutrophic habitats when organic matter inputs increase from either terrestrial or marine sources (e.g., at sinkholes, cenotes, or other cave openings) (Pohlman, 2011). The inputs, composition, and bioavailability of organic matter are sensitive to changes in nearby surface habitats, human activities and pressures, tidal fluctuations, seasonal changes in precipitation, and extreme weather events, such as hurricanes and tropical storms (e.g., Brankovits et al., 2021). ...
... Thus, sinkholes are most common in areas of limestone or with abundant salt domes (i.e., sedimentary rock structure caused by massive salt uplift, often trapping oil and/or natural gas), with rainy or formerly rainy climates, but humans can accelerate sinkhole formation. The majority of archival publications document how sinkholes provide unique niches for a wide array of bacteria, including large sulfur bacteria (e.g.,Sharrar et al. 2017) and cyanobacteria(Biddanda et al. 2015), along with zooplankton (Montes-Ortiz and Elias-Gutierrez 2018), and marine meiofaunal(Brankovits et al. 2021) communities, amphibians(Greenberg et al. 2015), and fossilized evidence of much larger animals (e.g.,Shunk et al. 2009;Crowley and Godfrey 2019), and form in interesting biogeochemical environments (e.g.,Haas et al. 2018;Fazi et al. 2019). However, ...
Louisiana, U.S.A., is among the most vulnerable areas globally to coastal natural hazards, with risk vulnerability likely increasing. The risks associated with non-tropical-cyclone hazards in Louisiana’s coastal zone have been understudied. This research enhances present and future (i.e., 2050) Louisiana risk assessment using locally-weighted, model-based hazard frequency/intensity and population projections.
Results suggest that property risks associated with extreme cold temperature and tornado are and will remain costlier than those for hail and lightning. Property risks of extreme cold temperature and hail are projected to decrease with the expected warming temperatures, with those of all four of these hazards peaking in urban areas. Drought is and will remain a far greater risk to crops than these four hazards and extreme high temperatures, with perhaps 95 percent of the crop losses. Despite projected warming, extreme cold will remain a greater crop risk than extreme heat, though the latter often accompanies drought.
Regarding present and future (i.e., 2050) Louisiana property risk to other non-severe-weather environmental hazards, wildfire risk peaks in west-central, east-central, extreme northwestern, and southwestern coastal Louisiana. Expansive soil risk peaks in southeastern and extreme southwestern Louisiana, and urban areas. Spatial patterns will remain similar for both hazards, but annual absolute and per capita losses are expected to increase substantially by 2050. The sinkhole risk is relatively small statewide, but property risk for some localized areas is substantial.
To assess property risk from flood, ground-zero information collected at the individual building scale offers additional and likely improved building inventory attribute accuracy over existing information sources. A case study of Grand Isle, Louisiana, reveals that the 100-year pluvial flood event today of almost 9-foot flood depths will increase by about 15 percent by 2050, causing a 20 percent increase in structure and content losses to approximately $203 million (2020$). A method is demonstrated to characterize the flood risk through the flood depth vs. return period relationship using the Gumbel distribution and spatial interpolation techniques, for areas of unknown flood depths.
Collectively, these results will assist in allocating resources for mitigating and adapting to natural hazards in one of the most weather-hazard-vulnerable U.S. states.
... One of the main characteristics of the hydrogeology of Yucatán is the presence of "cenotes": water-filled dolines formed by the dissolution and collapse of limestone rock (Gaona-Vizcaino et al. 1980). Cenotes are highly heterogenous regarding their geomorphology, given distinct paths of dissolution and diagenesis of carbonate (MacSwiney et al. 2007;Brankovits et al. 2021). Most cenotes are, therefore, unique in shape and structure, with highly variable internal features such as subterranean passages, caves, conduits, and display different degrees of interaction with marine and terrestrial environments. ...
We studied benthic assemblages through X-Batún, a continental freshwater cenote and its associated submerged cave located in San Antonio Mulix (Yucatán, Mexico). Using cave diving techniques, we collected sediment samples at four zones of the system. We extracted and counted individuals of benthic species in three replicates of 5 grams of wet sediment at each site. The biological composition was integrated by 15 species from eight higher taxonomic groups. Non-metric multidimensional scaling distinguished four assemblages that coincided with surface, open water, cavern and cave zones. ANOSIM test revealed significant differences between the assemblages. In the deeper zones of the cenote characterized by twilight and total darkness, Ostracoda and Gastropoda show the highest diversity and abundance, with practical absence in surface sediments. This pattern may suggest ecological interactions with chemosynthetic bacterial activity. Surface shows an assemblage typical of epigean environments. Environmental variables along the cenote varied little from the upper layers to bottom. Linear correlation and detrended canonical analysis revealed that light is the main driver of benthic species assemblages. Temperature, pH, and dissolved oxygen exert higher influence at individual biological benthic assemblage in X-Batún.
... One of the main characteristics of the hydrogeology of Yucatán is the presence of "cenotes": water-filled dolines formed by the dissolution and collapse of limestone rock (Gaona-Vizcaino et al. 1980). Cenotes are highly heterogenous regarding their geomorphology, given distinct paths of dissolution and diagenesis of carbonate (MacSwiney et al. 2007;Brankovits et al. 2021). Most cenotes are, therefore, unique in shape and structure, with highly variable internal features such as subterranean passages, caves, conduits, and display different degrees of interaction with marine and terrestrial environments. ...
... Temperature and food availability have been identified as the most important environmental drivers that regulate meiofauna abundances in freshwater habitats [37,41]. For example, the lowest meiofauna abundance and MTD in the output water, as compared to the TAR or to the input waters, could be the result of limited underground food resources [103,104]. Vegetation cover has been reported to be positively related to the abundance and species richness of subterranean copepods in the caves of the Pădurea Craiului Mountains [105]. ...
Karst aquifers are both a valuable resource for humankind and a habitat for unique biota. The quality of freshwater sources may be easily affected by natural (e.g., geology, climate, and vegetation) and anthropogenic (e.g., agriculture, livestock, and tourism) changes, particularly in karst landscapes with highly vulnerable groundwater reservoirs. We seasonally monitored nine representative freshwater sources (i.e., six springs, a well, a surface stream, and a cave stream resurgence) in the karst system of the Runcuri Plateau (KSRP) (Western Romanian Carpathians) during seven sampling campaigns in 2019–2021. We assessed how these natural and anthropogenic factors influenced the water quality based on the European and national standards for drinking water. The geological structure (i.e., tectonics and lithology) of the KSRP was reassessed, and the environmental variables of the freshwater sites were investigated in order to evaluate their impact on the physicochemical profile, the microbial contamination, and on the meiofauna presence. Multivariate statistics were performed to gain insights into the interplay among all these factors and to evaluate the self-purification capacity of the KSRP for chemical and microbial pollutants. The most relevant drivers shaping the microbial content of the freshwater sources were the altitude of the sampling sites, the normalized difference vegetation index (NDVI), and air temperature, followed by the physicochemical profile of the waters (i.e., calcium hardness, magnesium hardness, nitrites, nitrates, conductivity, phosphates, total dissolved solids, and iron concentrations). The meiofauna presence was influenced mostly by precipitation, air temperature, and NDVI. Our results reflected the effect of the geological structure and environment on water chemistry and biota assemblages. A pollutant attenuation trend was observed in discharging waters, even though the self-purification capacity of the studied karst system was not statistically supported. More investigations are needed to comprehend the processes developed in the black box of the KSRP.
... Similar to coastal estuaries, KSE can be divided into lower estuarine zone of saline groundwater that is intruding from the adjacent ocean, and an upper estuarine zone of meteoric water that is resupplied by infiltrating rain. Modern transect studies have investigated the regulators of environmental conditions and biologic response in meteoric lenses, across modern zones of mixing or density interfaces, and in the saline groundwater (Fichez, 1991a;Fichez, 1991b; van Hengstum et al., 2008;van Hengstum and Scott, 2011;Radolovićet al., 2015;Brankovits et al., 2017;Chavez-Solıś et al., 2020;Brankovits et al., 2021;Ballou et al., 2022). Like their subaerial counterparts, however, the geochemical and biological processes that occur within each individual water mass are complex, and necessarily impact their hosted benthic and pelagic fauna. ...
... In Bermuda, Spirophthalmidium emaciatum is known to colonize cave areas that (i) are flooded by oxygenated saline groundwater, and achieve highest proportional abundances in areas that are distal to direct connections with adjacent coastal environments , and (ii) have accumulating carbonate sediment with lower TOC concentrations (Cresswell and van Hengstum, 2021). This taxa also occurs elsewhere, including carbonate sediment in marine caves flooded by oxygenated saline groundwater in Spain and Cozumel (Brankovits et al., 2021). Outside of caves in Bermuda ( van Hengstum and Scott, 2012), Rotaliella is known in the deep-sea at 1980 mbsl on the Lomonosov Ridge off northeast Greenland (Scott and Vilks, 1991) and at 4450 mbsl on the Bermuda Rise in the Sargasso Sea (Pawlowski, 1991). ...
... This is because the proxy requires favorable sedimentary and biologic processes to leave a stratigraphic record of this event. For example, sedimentation may not initiate with cave floor flooding or anytime thereafter (Fornoś et al., 2009), cave sediment supply may be linked to changes in adjacent coastal and terrestrial environments (Collins et al., 2015;Gregory et al., 2017), or sediment may be reworked and transported out of a cave by groundwater currents or extreme rainfall events (Brankovits et al., 2021). Basal organic-rich sedimentary deposits dated cores 10, 14, and 15 from Palm Cave are very closely aged to the expected timing of cave floor inundation by concomitant sea-level and groundwater rise during the middle Holocene (~9,800 years, within dating uncertainties). ...
The environmental conditions and habitats in Bermudian underwater caves have responded to vertical aquifer migration and groundwater salinity changes associated with sea-level rise since the last glacial maximum. Recently, a large database of modern benthic foraminifera in Bermudian caves were found to be highly sensitive to both the amount and source of particle organic carbon (POC) transported to the sediment-water interface, consistent with similar timewise analysis of foraminifera in a Mexican flooded cave. Here we provide evidence that while benthic meiofaunal communities in Bermuda’s underwater caves are primarily controlled by groundwater salinity changes on millennial timescales from sea-level change, they are secondarily controlled by the POC source and supply deposited in the cave through time. Benthic foraminiferal assemblages were evaluated in the best-preserved stratigraphic succession currently known from an underwater cave. In the case of Palm Cave, POC flux changes were driven by changes in seawater-groundwater circulation dynamics caused by flooding on the carbonate banktop, and the inherited geometry of the cave system itself. These results demonstrate that benthic meiofaunal communities in anchialine environments are highly sensitive to changes in the source and quantity of POC through time. This work also enables a better understanding of the environmental conditions associated with preserved meiofaunal remains in global cave sediment. These results indicate that if the POC flux to the subsurface increases from coastal urbanization on karst landscapes, subsurface anchialine communities are likely to respond.
