Hadal trench shows integration of landscapes of plate tectonics, geological evolutions of trenches, surface and deep-water circulations, biogeochemical cycles and others.  On these environmental components, we can understand historical backgrounds of benthic organisms. I have long been worked on the deep sea benthic foraminiferal communities at the Western Pacific.  We analyzed localities of the western Pacific deep-sea, from bathyal to abyssal depths, in particular to hadal depths. Hadal foraminiferal community consists of monothalamous soft-shelled forms, agglutinated forms, porcelaneous forms, hyaline forms and large xenophyophores.  In contrast to the bathyal to abyssal depths, the hadal depths are much challenging.   Because, a lot of accidental events take place naturally, such as collisions, subductions, separations or fusion of trenches.  Trenches are fascinating natural laboratories for thinking about evolution of benthic organisms in connection to trenches.

Here, I try to discuss what kind of changes should take place when trench fuse respectively.  Case studies will be given from the late Cenozoic marine strata of the Central Kwanto regions at the central Japan (Kitazato, 1997).

How to cite: Kitazato, H.: Hadal trenches are experimental fields for geological and biological systems, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14425, https://doi.org/10.5194/egusphere-egu24-14425, 2024.

Calcifying organisms, including scleractinian corals and coralline algae, play a pivotal role in supporting benthic habitats and their associated ecosystem functions. However, many of them are threatened by ocean warming and acidification caused by anthropogenic CO₂ emissions. Our understanding of their capacity to adapt to changes in their natural environment remains limited. To address this knowledge gap, we introduce a non-invasive method to quantify calcification from the simultaneous measurement of H⁺ ion and O₂ fluxes utilizing the aquatic eddy covariance technique. Because calcification is a net source of H⁺ ions, it can be quantified as a source of H⁺ ions in excess of those generated by organic carbon metabolism. To examine the effect of ocean acidification on calcification by coralline algae epiphytes, we measured H⁺ and O₂ fluxes at a seagrass meadow at a CO₂ vent and at a control meadow, 670 m away. At both meadows we found that opposing flows were enriched in vent CO₂. Additionally, vent CO₂ diffused upwards through sediments at both sites. Because of this, we were unable to completely separate the calcification signal (non-metabolic H⁺ ion production) from the persistent background signal of vent CO₂. However, we use these data as a demonstration of how H⁺ and O₂ eddy covariance can reveal a subtle time-varying signal consistent with calcification in a benthic ecosystem. Based on the results of this study, H⁺ and O₂ eddy covariance can quantify changes in benthic calcification over time, and therefore it can support better-informed management of scleratinian corals, coralline algae, and other benthic calcifiers. 

How to cite: Koopmans, D., Schaap, A., Meyer, V., Färber, P., Queiss, L., Montilla, L. M., Loucaides, S., Ahmerkamp, S., and Cardini, U.: Aquatic eddy covariance pH and O2 fluxes, a technique for observing calcification in benthic ecosystems, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18922, https://doi.org/10.5194/egusphere-egu24-18922, 2024.

The Mg/Ca ratio in foraminiferal shells is commonly used as a proxy for reconstructing sea surface and bottom water temperatures. However, its incorporation results from complex interactions between seawater conditions and biologically regulated factors. While the former effects are well-constrained, poorly understood biological factors contribute to interspecies variations in Mg/Ca-temperature calibrations and a notable difference in Mg sensitivity compared to inorganically precipitated calcium carbonates. Here we show that temperature significantly influences cellular ion modulation in low-Mg species, leading to elevated enzymatic reaction rates that enhance H⁺ removal (J = 0.67 to 5.00 nmol^-s) during calcification, and boost the precipitation rate. On high-Mg species, on the other hand, a similar fivefold increase in H⁺ local flux was observed (J = 0.08 to 0.40 nmol^-s), but its impact on the calcification rate was mild. In both cases, H⁺ pumping rates align with Mg uptake, indicating a potential (indirect) link between temperature-sensitive behavior of transporters and Mg partitioning.

How to cite: Do Nascimento Silva, D. F., de Nooijer, L., and Reichart, G.-J.: Temperature Influence on Proton Pumping and Mg-Incorporation in Foraminifera, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16323, https://doi.org/10.5194/egusphere-egu24-16323, 2024.

Climate reconstructions are important for validating climate models and hence constrain climate change predictions. Such reconstructions are based on indirect tools (proxies) in which a fossil or chemical remnant corresponds to an environmental parameter. When employing foraminifera as proxies, elemental concentrations in their shells have been shown to correlate with environmental parameters including temperature (that determines the calcite’s Mg/Ca), seawater [HCO₃^-] (Sr/Ca and B/Ca) and [CO₃^2-] (S/Ca). When reconstructing theses parameters on longer geological timescales (i.e. millions of years), the seawater’s major ion concentrations may affect these proxy relationships. Especially the concentration of calcium will affect all of these calcitic elemental ratios and therefore, we varied [Ca²⁺] in controlled growth experiments to test its effect on incorporation of Mg, Sr, B and S in the benthic foraminifer Amphistegina lessonii. For the divalent cations we find a decrease in the partition coefficient (D) for Mg (D_Mg) with a changing [Ca²⁺] (and hence seawater Mg/Ca) while D_Sr does not vary significantly with [Ca²⁺]. For SO₄^2- and B(OH)₄^- against S/Ca_sw and B/Ca_sw respectively, we observe a significant decrease in the partition coefficients with decreasing [Ca²⁺]. These results gives new information for SO₄^2- and B(OH)₄^- incorporation and represents a step forward towards comprehending the impact of [Ca²⁺]_sw alterations on foraminiferal calcite chemistry and hence their application as paleoproxies in deep time. 

How to cite: Pacho, L., de Nooijer, L., and Reichart, G.-J.: Partitioning of multiple elements as a function of seawater [Ca2+]: results from foraminiferal culture experiments. , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18686, https://doi.org/10.5194/egusphere-egu24-18686, 2024.

We investigated the δ¹¹Bisotope profiles in Cretaceous benthic foraminifera, focusing on the epibenthic species Notoplanulina rakauroana and Nuttallinella coronula. This study aims at understanding the implications of changes in δ¹¹B isotope signatures for pH, associated with paleoenvironmental factors during the beginning of the Late Cretaceous cooling in the Santonian in the southern high latitudes.

We examine 10 levels through the Santonian of International Ocean Discovery Program (IODP) Site U1513 in the Mentelle Basin, some kilometres offshore Western Australia. Following a biostratigraphic framework relying on planktonic foraminifera and calcareous nannofossils, foraminiferal samples of Notoplanulina and Nuttallinella, representing significant elements of bottom water fauna through this period of significant cooling in surface and bottom waters, have been processed.

The geochemical signals preserved in the tests of epibenthic foraminiferal species are supposedly less prone to representing vital effects as some stability in the paleohabitat in bottom waters is implicit (see Rae et al. 2011). The analysis of well-preserved foraminiferal tests by Inductively Coupled Plasma Mass Spectrometry (ICPMS) is imperative of a cleaning protocol that involves several steps of ultrasonic baths in clear water and alcohol (see Henehan et al. 2019).

The results of benthic foraminiferal δ¹¹B add information to our understanding of the relationbetween climate shifts and changes in the geochemical composition visible in foraminiferal tests. Results help to reconstruct prevailing pH of bottom waters during the documented reorganization of oceanic pathways in the southern high latitudes and offer a further perspective on the extent of paleoenvironmental change in the bottom waters.

References:
Rae, JWB, Foster, GL, Schmidt, DN, Elliott, T, 2011. Boron isotopes and B/Ca in benthic foraminifera: Proxies for the deep ocean carbonate system, Earth and Planetary Science Letters, 302, 3–4.
Henehan, MJ, Ridgwell, A, Thomas, E, et al., 2019. Rapid ocean acidification and protracted Earth system recovery followed the end-Cretaceous Chicxulub impact. PNAS, 116, 45, 22500-22504.

How to cite: Wolfgring, E., Amaglio, G., and Petrizzo, M. R.: Boron isotope signals of benthic foraminifera during the Santonian, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15333, https://doi.org/10.5194/egusphere-egu24-15333, 2024.

Proxy based records of past changes in the polar surface ocean-cryosphere-climate interactions can provide invaluable constraints on ongoing and future climate change. However, studying polar ocean palaeoceanography remains challenging largely due to a lack of robust proxy calibrations. For example, the commonly used foraminiferal Mg/Ca paleothermometer does not have a reliable calibration at polar conditions and there are currently limited trace element proxies for other environmental variables such as salinity or carbonate chemistry. In addition, Neogloboquadrina pachyderma, the dominant foraminifera species in polar regions, sometimes grows a thick calcite crust outside its main growth phase calcite with different geochemical composition. This poses a challenge to the Mg/Ca paleothermometer as the crusts have lower Mg/Ca than the ontogenetic calcite.

To address this, we cultivated >1500 individual specimens of N. pachyderma over a wide range of temperatures (2 to 9°C), salinities (~30 to 36.5), pHs (~7.7 to 8.4 total scale), carbonate ion concentrations (~100-250 µmol/mol at stable and variable pH), and Ba concentrations (2-4 times natural). The experimental water was spiked with ¹³⁵Ba to label laboratory-grown calcite. Elemental ratios in the specimens have been analysed using laser ablation mass spectrometry (LA-ICP-MS), providing high resolution elemental profiles of intra-shell variability.

Our microscopic observations and element ratios results suggest the growth and addition of crust in all treatments, allowing, for the first time, laboratory-based proxy calibrations for N. pachyderma’s crust. A preliminary data analysis show variability in trace element ratios in relation to variable temperature, salinity, barium concentration and carbonate chemistry. Our results also indicate significant distinction in trace element ratios between crust and ontogenetic calcite components of the N. pachyderma tests when both are grown in culture. We are in the process of developing separate laboratory-based proxy calibrations for the crust and ontogenetic calcite which will significantly improve the applicability of the proxy calibrations as well as our understanding of crust formation in this species. We aim to present Mg/Ca-temperature calibrations for the crust and ontogenetic parts separately as well as detailing the respective effects of salinity and carbonate chemistry on Mg/Ca ratios.  

How to cite: Westgård, A., Meilland, J., Sykes, F. E., Chalk, T. B., Foster, G. L., Chierici, M., and Ezat, M. M.: Developing trace element proxy calibrations for reconstructing polar surface ocean hydrography based on laboratory-grown planktonic foraminifera Neogloboquadrina pachyderma, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19630, https://doi.org/10.5194/egusphere-egu24-19630, 2024.

Biogeochemical archive such as tree rings, corals, and stalagmites have proven effective in reconstructing past paleoclimate patterns at year-month resolutions. However, they are not suitable for investigating weather changes on a day-hour scale. Tridacna, the largest bivalve in the world, which inhabits the Tropical-subtropical Pacific-Indian Ocean area, exhibits unique daily growth bands ranging from 5 to 60μm. This characteristic grants Tridacna the potential to reconstruct extreme weather events in the past, thus paving the way for paleoweather studies. Tridacna engages in symbiosis with zooxanthellae and relies on photosynthesis for energy. The growth rate and pattern of its daily growth bands correlate with diurnal alternations. Currently, the utilization of Tridacna daily growth bands and high-resolution geochemical element ratios holds potential for establishing a daily resolution biogeochemical proxy. However, the precise mechanism of the circadian rhythm during Tridacna's growth period in natural conditions remains unclear. Consequently, our comprehension of the pattern exhibited by Tridacna's daily growth bands is limited, impeding progress in the development of hourly scale paleo-weather analysis. In this study, a 30-day artificial experiment was conducted on Tridacna derasa to investigate the significance of shell daily growth bands and hourly element ratios in reflecting environmental conditions. The results of calcein labeling revealed that the wide dim areas in the daily growth bands corresponded to daytime and exhibited valley values in Sr/Ca ratio, while the narrow bright areas corresponded to nighttime and showed peak values in Sr/Ca ratio. At the daily-hourly scale, when the water temperature remained constant, the Sr/Ca daily variation showed potential for recording the light daily cycle. However, it is important to note that the influence of the light daily cycle on the Sr/Ca variation may be indirect. As a result, a hypothesis was proposed: the Sr/Ca variation is directly controlled by the internal regulation of Tridacna. During the daytime, the Sr/Ca ratio was primarily regulated by physiological activities. Due to light stimulation, the activity of certain enzymes in the inner mantle was enhanced, leading to an increase in Ca²⁺ concentration and a decrease in Sr/Ca ratio. During the nighttime, the Sr/Ca ratio was mainly regulated by organic matrices. In the extrapallial fluid (EPF), the presence of high Sr²⁺-selective organic matrices promoted the incorporation of Sr²⁺ into the shell, resulting in a higher Sr/Ca ratio.

How to cite: Yang, H., Yan, H., and Liu, C.: The daily growth bands pattern of Tridacna - evidence from culture experiments., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1819, https://doi.org/10.5194/egusphere-egu24-1819, 2024.

Frequent occurrences of high-temperature records have become commonplace during the summer seasons in regions adjacent to the western Arabian Gulf, such as Bahrain, Saudi Arabia, and Qatar. On a daily basis, the fluctuation in daytime and nighttime temperatures, along with varying afternoon temperatures, poses a potential threat to organisms inhabiting intertidal and shallow water environments, whether residing above the substrate or submerged beneath. Surprisingly, there has been no prior scientific investigation into the resilience of these coastal communities, especially from a non-anthropocentric perspective, focusing on the marine calcifying organism that inhabits one of the world's most extreme marine environments. To address this gap, we aimed to determine the upper thermal limits of intertidal calcifying benthic organisms in the western Arabian Gulf region. For this purpose, we selected three representative species among the diverse inhabitants, comprising two gastropod species and one ostracod species. These specimens were subjected to controlled environmental conditions inside a thermal incubator over a short-term period (three hours), with temperature exposures ranging from 40°C to 60°C. We considered different scenarios that replicated their natural ecological conditions: full exposure, partial exposure, and full coverage/submerged underwater. Our comprehensive results revealed that different gastropod species exhibited varying levels of resilience to higher thermal exposure, depending on the scenario (heat comma temperature/HCT ranged between 39°C-48.5°C versus 42.1°C-44.1°C). In contrast, the ostracod displayed remarkable tolerance to higher temperatures than the gastropod specimens before succumbing to complete mortality or entering a comatose state (temperature range of 39.1°C-53.5°C). Furthermore, post-exposure recovery demonstrated that higher heat exposure substantially prolonged the recovery time. In the case of the gastropod specimens subjected to the highest thermal exposure, no successful recovery was observed. Our findings underscore the importance of conducting ecological experiments that involve prolonged exposure to high temperatures. However, it is imperative to recognize that even short-term periods of elevated temperatures can have fatal implications for the target organisms. This is particularly relevant in light of the ongoing warming trend and the recording of extreme temperatures in our regional area in the western Arabian Gulf, which may eventually be deemed a potential "kill zone" during the peak of summer seasons within a short timeframe.

How to cite: Prayudi, S. D., Korin, A., and Kaminski, M.: An Ecological Perspective on Short-Term Heat Exposure Experiments with Marine Calcifying Organisms from the Western Arabian Gulf Region: Insights into a Summer Heatwave Scenario, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-46, https://doi.org/10.5194/egusphere-egu24-46, 2024.

Enrichment patterns of redox- and biosensitive trace elements (TEs) are powerful tools to reconstruct depositional conditions during sedimentation in continental marine sediments. For several TEs (e.g., U, Cr, As and V), the mechanisms that lead to their accumulation in the sediment are not fully understood yet. To complement the discussion, we analyzed several major elements and TEs (P, Ca, Sr, U, V, As and Cr) in fish scales from two short cores (30 cm sediment depth) from the central and southern shelf of the Namibian anoxic-euxinic continental margin (from 67 and 100 m water depth). We found both fresh, young scales in the upper sediments and clearly altered scales, in deeper sections of the cores. The P, Ca and Sr values appear to be good indicators of the changing condition of the respective fish scales, as Ca, Sr and P decrease with the sediment depth from which the fish scales were taken. The lower the Ca, Sr and P values, the more altered the fish scales and the higher the TE enrichment. These more altered fish scales have high values of U (up to 88 ppm), Cr (up to 97 ppm) and V (up to 130 ppm), raising the importance of fish scales as a sink for these elements in shelf sediments, leading to extreme enrichments that are not primarily related to redox conditions. In contrast to the high TE values in altered scales, high values of As (up to 140 ppm) were found in fresh fish scales in core top sections and a decrease with sediment depth. Previous studies showed that high bulk U content in central Namibian shelf sediments is due to high anthropogenic U input by mining activities (in addition to U enrichment during authigenic apatite formation in the sediments). This U-mining activity in the central Namibian hinterland is further reflected in higher U values in the core from the central shelf compared to the core from the southern shelf. The increase of all TEs in scales with increasing sediment depth indicates authigenic enrichment over time within the sediment. Therefore, we suggest that fish scales are an important authigenic sink of several TEs which may be substantial for the element budget calculations in continental margins.

How to cite: Gäng, F., Göller, L., Brüchert, V., Lahajnar, N., Pahnke, K., and Böning, P.: High enrichment of U, Cr, As and V in fish scales from the Namibian shelf of the Benguela Upwelling System., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5631, https://doi.org/10.5194/egusphere-egu24-5631, 2024.

How to cite: Zhang, Q., Zhang, S., Dong, W., Wang, Z., and Mo, Z.: Cropland Microplastics in Xinjiang: Unveiling Distribution and Impact of Mulching Film Residues, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2520, https://doi.org/10.5194/egusphere-egu24-2520, 2024.

The presence of plastic litter and microplastics in freshwaters has raised concern about their potential transport and accumulation in water and sediments over time. However, several direct and indirect environmental consequences are still not well understood. In this study, we investigated the role of plastic as a carrier of algal species favouring their dispersal in freshwaters, and we assessed the potential effects on water biodiversity and chemical features in a pilot, laboratory-based study. We simulated an algal community using 5 algal species commonly found in freshwaters and we exposed this community to both pristine and biofouled polypropylene fragments of 5 × 5 × 0.3 mm in size. The biofouled plastic was generated by incubating similar polypropylene fragments with 2 other freshwater algal species, which were different from those in the simulated community. In addition, we evaluated the effect of the dispersal of algae from plastic without the presence of a simulated pelagic community. The experiment lasted 15 days in total. At different time intervals, we assessed: total algal growth and photosynthetic efficiency, algal community composition and the concentration of macronutrients and minor elements in the water. We observed changes in the algal community composition and marked chemical alterations driven by the presence of the biofouled plastics. The presence of pristine plastic, instead, did not show significant changes in the community composition and in the concentration of dissolved elements. The dispersal of algal species from the biofilm on plastic and competitive interactions between the plastic biofilm and the pelagic community were, therefore, likely responsible for the changes in the algal diversity. These results confirmed the hypothesis that plastic can influence dispersal and biodiversity of the algal community. Biofouled plastic from environmental samples and environmental communities selected from natural freshwater bodies will be used in future experiments. This will help to unravel the potential consequences of plastic pollution for ecosystem functioning and microbial biodiversity.

How to cite: Binda, G., Carnati, S., Costa, M., Hostyeva, V., Leu, E., Skjelbred, B., Spanu, D., Šupraha, L., Trotta, S., Vogelsang, C., and Nizzetto, L.: Effects of biofouled plastics on phytoplankton community assembling and water chemistry: pilot study and implications for freshwater environments, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4077, https://doi.org/10.5194/egusphere-egu24-4077, 2024.

The Danube River, an important pathway connecting the western, central, and eastern Europe, serves as a route for various pollutants that ultimately accumulate in the Danube Delta and the broader Black Sea basin. These historically pristine regions now face escalating pressures from extensive tourism, intense fishing activities, regional conflicts, and inadequate waste disposal across the whole Danube basin. The imbalance in sediment flow, mainly caused by numerous upstream hydropower plants, aside the abovementioned anthropogenic factors, poses a severe threat to the deltaic and coastal ecosystems.

Among the emerging pollutants, litter stands out prominently, with anthropic macro-objects pervading natural environments. Microplastics (MPs) constitute a category of the litter, characterized by solid, petroleum-based items sized between 1 µm and 5 mm. These particles are either preformed within these dimensions or result from the fragmentation of larger plastic debris due to natural weathering. Known for their fast spreading across diverse environments, MPs possess a porous texture that might absorb substantial amounts of various pollutants, significantly impacting the entire food chain, particularly aquatic species.

Given the limited data on MPs pollution in Black Sea coastal areas, the precise impact on the natural environment remains largely uncertain. Furthermore, the correlation between MPs pollution in aquatic environments and the concentration of MPs within mussels and fish has yet to be established. To address these knowledge gaps, our study investigated the abundance of MPs in the water surface layer (average concentration of 0.63 MPs/m³) and in two distinct species: (i) the mackerel - Alosa immaculata – a pelagic fish captured at the Saint Geoge branch mouth of the Danube Delta during inland migration for reproduction, with an average concentration of 11.8 MPs/individual, and (ii) Mytilus galloprovincialis – a filter feeder mollusc collected near the Constanța harbour – with an average concentration of 6.05 MPs/individual.

Our findings indicate that fibers represent the predominant morphology of MPs found in both species, while fragments dominate the surface water layer. Notably, before the tourist season, the distribution of MPs types differs, suggesting potential influences from coastal natural factors such as wind, waves, and currents on the variety of MPs encountered. This research underscores the urgency of further investigations to comprehend the intricate dynamics of MPs pollution in these vital ecosystems and the cascading effects on marine life.

How to cite: Pojar, I., Baboș, T., Dobre, O., and Dobre, C.: Microplastic occurrence in coastal waters and aquatic faunas of the Western Black Sea , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8769, https://doi.org/10.5194/egusphere-egu24-8769, 2024.

The impact of mine waters is currently one of the most severe environmental problems in the water environment. The Odiel River catchment is a clear worldwide example of a river network intensely affected by acid mine drainage, transporting large pollutant loads towards the Ría de Huelva estuary, and ultimately the Atlantic Ocean [1]. The release of acidity and metals, and the longevity of the process, represent a major source of pollution which treatment or possible solutions have been the subject of research in recent years. Prior to the adoption of restoration measures in the region, involving a large economic investment, it was proposed to build a hydrogeochemical model that represents the current situation of the pollution, and serves as a management tool for the Odiel River network. In this sense, its design allows to simulate remediation actions and evaluate their impact on the water quality. The model is based on a set of mixtures modeled with PHREEQC code [2] as analogs to the numerous river confluences. The "MIX" command was used, which enables the mixing two or more aqueous solutions at different mixing ratios. Each ratio theoretically assumes how much each member contributes to the final mixture. Each member is defined as a’ solution with the command "SOLUTION_SPREAD" including the physicochemical parameters and element concentrations, obtained experimentally and in the field. Coupling the "EQUILIBRIUM_PHASES" command includes the equilibrium reactions with Fe and Al mineral phases and the atmosphere. Consequently, each modeled and equilibrated mixture will be mixed again downstream in new confluences until a global modeling of the catchment is achieved. In this way, the model makes it possible to estimate changes in the physicochemical parameters, the evolution of metal concentrations, and variations in the saturation rates of the mineral phases (precipitation, dissolution or equilibrium). This kind of model is a useful tool for simulating reductions in the pollutant loads of sources predicting how real restoration actions will affect the water quality conditions along the Odiel River catchment. The proposed approach could be applied to other real case scenarios where mine waters originate from various sources, mainly different mines, within a complex river network, stablishing itself as an environmental tool for the management of mine water-polluted catchments.

Acknowledgements

This work is part of the I + D + i TRAMPA project (PID2020-119196RB-C21), funded by MCIN/AEI/10.13039/501100011033/. Jonatan Romero-Matos is financed by a FPU program of the Spanish Ministry of Education of Vocational Training (FPU20/04441).

[1] Nieto, J. M., Sarmiento, A. M., Canovas, C. R., Olias, M., & Ayora, C. (2013). Acid mine drainage in the Iberian Pyrite Belt: 1. Hydrochemical characteristics and pollutant load of the Tinto and Odiel rivers. Environmental Science and Pollution Research, 20, 7509-7519.

[2] Parkhurst, D. L., & Appelo, C. A. J. (2013). Description of input and examples for PHREEQC version 3—a computer program for speciation, batch-reaction, one-dimensional transport, and inverse geochemical calculations. US geological survey techniques and methods, 6(A43), 497.

How to cite: Romero-Matos, J., Macías, F., Nieto, J. M., Sánchez-López, L., León, R., Millán-Becerro, R., and Pérez-López, R.: Hydrogeochemical modeling as a tool for the environmental management of mine water polluted river catchments: An application to the Odiel River network (Huelva, Spain), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8029, https://doi.org/10.5194/egusphere-egu24-8029, 2024.

Estuaries are dynamic systems that play a crucial role in the transfer of trace elements from continent to ocean. The Ría de Huelva estuary is formed by the confluence of the Tinto and Odiel rivers, which are severely contaminated by acid mine drainage (AMD), transporting high pollutant loads of sulfates and metal(loid)s to the estuary and ultimately to the Atlantic Ocean. Despite extensive research on this estuary, the behavior of oxyanions has not yet been adequately addressed. This work assesses the variations of the concentration of oxyanion-forming elements such as As, Sb, V, and Mo within the fluvial domain of the Tinto River estuary. Two sampling campaigns were conducted under low river flow, one with a low tidal coefficient (26-30) and the other with a high tidal coefficient (99-102). Dissolved and particulate (>0.45 µm) As, Sb, V, and Mo concentrations were measured in samples of surface water collected by an autosampler Teledyne ISCO with high temporal resolution (hourly) for 24 hours. Additionally, physicochemical parameters were measured for each sample. During both sampling periods, several complete tidal cycles were recorded. The pH and EC values ranged from 4.0 to 6.3 and from 43.2 to 51.9 mS cm^-1, respectively, with low tidal coefficient. With high tidal coefficient, the pH and EC values ranged from 4.4 to 7.6 and from 43.7 to 53.0 mS cm^-1, respectively. Highest values were recorded during high tide conditions due to greater influence of seawater. Particulate oxyanions proportion displayed a general increase along with increasing pH, being retained by Fe-oxyhydroxisulfate precipitates like schwertmannite as demonstrated in previous research [1]. Data obtained suggest that during high tide with low tidal coefficient, oxyanions remain mainly in the particulate phase (55-100%). Nevertheless, at high tidal coefficient, a significant decrease in the particulate phase proportion is observed when pH is above 6.43 with total concentrations found in the dissolved phase (reaching 100%). This increase in the dissolved phase is probably associated with desorption processes related to the zero-point charge of schwertmannite in circumneutral water environments. During the seawater neutralization of the Tinto River’s acidic waters, when pH values are above 6, the schwertmannite surface becomes negatively charged, and since oxyanions are negatively charged, their desorption is expected [1]. Special attention should be paid to As, Sb, V, and Mo, as they return to solution when precipitates reach pH values above 6.43, contributing to the total amount discharged by the Tinto River, which later reaches the ocean.

Acknowledgments

This work is part of the I + D + i TRAMPA project (PID2020-119196RB-C21), funded by MCIN/AEI/10.13039/501100011033.

[1] Pérez-López, R., Millán-Becerro, R., Basallote, M. D., Carrero, S., Parviainen, A., Freydier, R., Macías, F., Cánovas, C. R. (2023). Effects of estuarine water mixing on the mobility of trace elements in acid mine drainage leachates. Marine Pollution Bulletin, 187, 114491.

How to cite: Sánchez-López, L., Romero-Matos, J., León, R., Millán-Becerro, R., Freydier, R., Macías, F., and Pérez-López, R.: Tracing the behavior of metallic oxyanions in an acid mine drainage polluted estuary (Tinto River estuary, SW Spain), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7953, https://doi.org/10.5194/egusphere-egu24-7953, 2024.

Fluoroquinolone antibiotics are widely used in animal husbandry and human medicine and are therefore released into environmental systems in significant quantities. Because of its targeted antibacterial action, it directly disrupts the soil microbial ecosystem and alters soil carbon fixation. In order to maintain soil microbial communities and prevent groundwater pollution, it is essential to know what physicochemical properties a soil must have to be safe for sewage sludge application and irrigation with treated wastewater. To understand the effects of land use on the adsorption properties of Luvisols, three different land use areas (arable land, grassland, and forest) and two organic matter (OM) pools (fast and slow) were investigated. The soils were separated to a > 53 µm fraction related to the fast OM pool and a < 53 µm fraction containing the slow OM pool, to investigate the physicochemical properties that affect adsorption capacity. Ciprofloxacin, norfloxacin, and ofloxacin were chosen for adsorption experiments because they are widely detected in environmental systems. The effect of land use on adsorption was only observed in the slow pool in the ascending order of arable land, grassland, and forest. Principal component analysis showed that OM content and composition influenced adsorption in the slow pool. However, the adsorption of bulk soils and fast pools is primarily controlled by the physical soil properties rather than by soil OM. These findings indicate that the OM composition of the < 53 µm fraction with the slow pool can determine the adsorption of bulk soils. However, in the present study, this did not affect the adsorption of bulk soils because either 1) the ratio of the slow pool was small, but its adsorption capacity was high, as in the forest, or 2) the ratio of the slow pool was large but its adsorption capacity was low due to its OM composition, as in arable land and grassland. Therefore, irrigation with treated wastewater and sludge discharged on agricultural lands is more likely to leach pollutants into groundwater. Consideration should be given to the disposal of sludge in an area with a high aliphatic soil OM content, where the slow pool rate is high.

This research was supported by the National Research, Development, and Innovation Office (NKFIH), Hungary (project identification number: 2020–1.1.2-PIACI-KFI-2021-00309; 2021–1.2.4-TÉT-2021-00029, and K-142865). Project no. KDP-1015196 has been implemented with the support provided by the Ministry of Culture and Innovation of Hungary from the National Research, Development and Innovation Fund, financed under the KDP-2020 funding scheme. This study has also been supported by the Doctoral Excellence Program (DKOP-23) of the Ministry for Culture and Innovation, Hungary, from the source of the National Research, Development and Innovation Fund.

How to cite: Vancsik, A., Szabó, L., Bauer, L., Király, C., Pirger, Z., Kondor, A. C., Jakab, G., and Szalai, Z.: The impact of land use on the adsorption of fluoroquinolone antibiotics: a study on bulk soils and organic matter pools, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8888, https://doi.org/10.5194/egusphere-egu24-8888, 2024.

In the last couple of decades, the utilization of different Pharmaceutically Active Compounds (PhACs) significantly has increased. The applications of the treated wastewater (discharge into surface waterbodies, sewage sludge disposal), have resulted that those PhACs world-wildly can be detected in the environment. Due to the negative effects of these PhACs on ecosystems, it is indispensable to analyze their behavior in the soil environment. In the soil solution systems (SSS) the sorption mechanisms of the PhACs are significantly being influenced by various environmental factors like pH, and temperature. In our research, PhACs with different physicochemical properties have been studied such as 17α-ethynylestradiol (EE2), diclofenac-sodium (DFC), and lidocaine (LID). Owing to these facts, the main questions of our research were: (a) How to estimate the Van’t Hoff equation’ parameters in fixed-bed SSS? (b) How does the temperature change affect the intermolecular reactions of the PhACs on the solid/liquid interface in the single and multi-component systems? Single and multicomponent fixed-bed sorption experiments were carried out. All of the sorption experiments have been investigated at 5 different temperatures. The fixed-bed sorption experiments have been performed at the ploughed layer of calcareous, humic sandy soil. The adsorbate-adsorbate and adsorbent-adsorbate interactions have been evaluated by different empirical formulas. To conduct the results of our study, different statistical analyses (2-way ANOVA, Principal Component analysis, regression analysis, and Pearson correlation have been performed. In the scientific literature, the thermodynamical parameters had been carried out in batch experiments. Nevertheless, this way of sorption analysis in an environmental system often overestimates the equilibrium constant (K_c) in the Van’t Hoff equation. Due to this fact, we hypothesized that if the experiment is implemented in a fixed-bed SSS, the real K_c value can be calculated from the real empirical q_e value, which could provide the optimal results of the thermodynamical parameters. Our results show that in single-component systems EE2, LID, and DFC have got spontaneous endotherm sorption reactions. While in a multicomponent SSS system, the LID and EE2 had an exothermic enthalpy-driven reaction. Furthermore, in all cases, the Gibbs free energy has been decreased when the temperature was increased.

This research was supported by the National Research, Development, and Innovation Office (NKFIH), Hungary (project identification number: 2020–1.1.2-PIACI-KFI-2021-00309; 2021–1.2.4-TÉT-2021-00029, and K-142865). Project no. KDP-1015196 has been implemented with the support provided by the Ministry of Culture and Innovation of Hungary from the National Research, Development and Innovation Fund, financed under the KDP-2020 funding scheme. This study has also been supported by the Doctoral Excellence Program (DKOP-23) of the Ministry for Culture and Innovation, Hungary, from the source of the National Research, Development and Innovation Fund. And The Hungarian National Research, Development and Innovation Fund OTKA-142865

How to cite: Bauer, L., Szabó, L., Vancsik, A., Kondor, A., Jakab, G., and Szalai, Z.: Fixed-bed thermodynamical analysis of the sorption mechanisms of Pharmaceutically Active Compounds (PhACs) in sandy soil, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9323, https://doi.org/10.5194/egusphere-egu24-9323, 2024.

Pharmaceutically active compounds (PhACs) in cultivated areas have become an important issue and have received significant public attention because of their availability to plants during nutrient uptake. This study highlights the effects of low-molecular-weight organic acids (LWMOAs) generated in the root environment on the sorption processes of PhACs in cultivated sandy soil. Sorption experiments are conducted using three PhACs characterised by different physicochemical properties: carbamazepine (CBZ), 17α-ethynylestradiol (EE2), and diclofenac-sodium (DFC). The results suggest that the adsorption of EE2 is more intense than the other two PhACs, whereas DFC and CBZ are primarily dominated by desorption. Additionally, LMWOAs mainly provide additional low-energy adsorption sites for the PhACs, and slight pH changes do no significantly affect the sorption mechanism. During competitive adsorption, the high-energy sites of the adsorbents are initially occupied by EE2 owing to its high adsorption energy. In addition, during multicomponent adsorption, new low-energy binding sites enhance the adsorption of DFC and CBZ. Our results show that LMWOAs promoted the adsorption of PhACs into the root environment, thus rendering PhACs available to plants.

This research was supported by the National Research, Development, and Innovation Office (NKFIH), Hungary (project identification number: 2020–1.1.2-PIACI-KFI-2021-00309; 2021–1.2.4-TÉT-2021-00029, and K-142865). Project no. KDP-1015196 has been implemented with the support provided by the Ministry of Culture and Innovation of Hungary from the National Research, Development and Innovation Fund, financed under the KDP-2020 funding scheme. This study has also been supported by the Doctoral Excellence Program (DKOP-23) of the Ministry for Culture and Innovation, Hungary, from the source of the National Research, Development and Innovation Fund.

How to cite: Szabó, L., Vancsik, A., Bauer, L., Kondor, A. C., Jakab, G., and Szalai, Z.: Effects of root-derived organic acids on sorption of pharmaceuticals in cultivated sandy soil, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8943, https://doi.org/10.5194/egusphere-egu24-8943, 2024.

India has a rich environmental ecosystem, stretching from high-rise mountains to coastal areas. The surge in industrialization and economic growth in the country has imposed a considerable burden on the environment, hindering progress toward sustainable development goals. One critical concern in this context is mercury (Hg) pollution, where special attention is needed. On June 18^th 2018, India ratified the Minamata Convention to address Hg pollution. However, a significant data gap exists regarding comprehensive baseline information from different environmental compartments in India, which is crucial for assessing the convention's effects. To bridge this research gap, an effort was made to access Hg distribution and speciation in various environments. For this study, soil and sediments samples were collected from diverse regions: the metropolitan city (Kochi, Kerala, India), agricultural lands (Dhapa, Kolkata), hilly areas (Tea Garden, Darjeeling), and the coastal sediments (collected from continental shelf/slope of the west coast of India). The total soil Hg concentration in metropolitan soil, agricultural soil, and tea garden soil ranged from 16 ± 0.84 µg/kg to 2674 ± 133 µg/kg, 726 ± 36 µg/kg to 2318 ± 115 µg/kg, and 158 ± 7 µg/kg to 9441 ± 472 µg/kg, respectively. Meanwhile, the total Hg concentration in the studied continental shelf sediment samples varied from 8 ± 0.14 µg/kg to 50 ± 2 µg/kg. This result shows that a significantly higher total concentration of Hg in the tea garden soil, whereas lowest Hg concentration were observed in the coastal sediment. Chemical speciation of Hg was carried out using thermo-desorption technique. It was found that the major part of the total Hg was predominantly associated with organic matter in the soil as well as in the coastal sediments. This indicates that organic matter was key host for Hg in soil as well as in coastal sediments. Interestingly, the second-highest fraction in the all types of soil was Hg⁰, indicating more reduction of Hg in the soil. The elevated Hg⁰ levels in the soils raises concerns due to its high volatility at ambient temperatures. The evasion of Hg⁰ from the soil can serve as a significant non-point source of Hg, posing potential risks to individuals living in these areas. Prolonged exposure to this toxic metal could lead to adverse health effects for the local population. Further in the sediments, Hg associated with sulphide was the second dominant Hg fraction, playing crucial role in Hg stability. Overall, these findings not only help to stakeholders and policy makers in addressing Hg pollution, but also contributes to progress towards achieving Sustainable Development Goals.

How to cite: Padalkar, P., Chakraborty, P., Dey, A., and Bhattacharya, M.: Mercury(Hg) Speciation in different environmental compartments of the India: A Thermo-desorption-Driven Approach, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17428, https://doi.org/10.5194/egusphere-egu24-17428, 2024.

Panarea, an island in the Tyrrhenian Sea, Mediterranean Sea, is distinguished for its hydrothermal vent ecosystems that substantially influence the local biodiversity. While hydrothermal vents are recognised for their mineral-rich composition, the potential release of mercury (Hg), a non-essential metal, into the surrounding environment raises environmental concerns. This study investigates the oxidative stress status and cellular energy allocation of the autochthonous marine gastropod Phorcus turbinatus (Born, 1778), collected from rocky shores at two distinct hydrothermal vents, Bottaro and La Calcara, characterized by different hydrothermal vent activities. Our results show a higher THg input at La Calcara vent (864 pM) when compared to Bottaro (45.9 pM), suggesting exposure by diet. Accordingly, significantly higher levels of oxidative damage, measured as lipid peroxidation (LPO), were observed in gastropods from La Calcara compared to their counterparts from Bottaro. This observation aligns with lower catalase (CAT) activity and total glutathione levels (tGSH) in these gastropods, indicating compromised antioxidant defenses against reactive oxygen species (ROS). No significant differences were observed in energy metabolism when comparing cellular energy allocation (CEA) between snails from the two locations. Nevertheless, gastropods from La Calcara exhibited significantly reduced levels of available sugars, suggesting potential energetic costs of dealing with higher levels of oxidative stress due to increased Hg exposure. Understanding the complex relationships among hydrothermal vent activity, Hg inputs, Hg transfer in food webs, and biota responses provides valuable insights for conservation and management efforts in these unique and fragile ecosystems. Future research should focus on elucidating the long-term effects of Hg exposure at several hydrothermal vent locations, their biodiversity, and ecosystem dynamics, contributing to the broader understanding of metal contamination in marine environments.

How to cite: Rodrigues, A. C. M., Petrova, M. V., Torres-Rodriguez, N., Dufour, A., Cosio, C., Malengros, D., Marschal, C., Lazzaro, G., Longo, M., and Heimbürger-Boavida, L.-E.: Hydrothermal Vents in Panarea, Italy: Investigating Mercury inputs and evaluating Biota Oxidative Stress Status with a focus on Phorcus turbinatus as a Bioindicator of Mediterranean Sea Health, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17814, https://doi.org/10.5194/egusphere-egu24-17814, 2024.