Biota communities influence on nutrients circulation in hyporheic zone—a case study in urban spring niches in Bialystok (NE Poland)

Hyporheic zone (HZ) is an interstitial part of groundwater. Complex physical, chemical and biological processes in HZ impact water quality. We hypothesized that groundwater upwelling improves surface water with biogenic compounds in lowland spring niches, and it depends on among others biota communities. The research was conducted in two spring niches in suburbs of Białystok. Interstitial samples were collected with mini-piezometers. In the field, the physical parameters of water were examined, and the micro and macro elements were determined in the laboratory. The analysis of biota included: vascular plants and bryophytes, diatoms, macroinvertebrates and bacteria. The springs studied differed in their richness of organisms, which is associated with varying degrees of abiotic conditions and human transformation. In spring niche with high degree of naturalness were twice less nitrate ions in the surface water than in interstitial water, which indicates the assimilation of nitrate ions by plants growing on the bottom of the niche. Hydrophilic vegetation performs a stabilizing function by assimilating nitrogen compounds and contributing to a variation in nutrients concentration. Groundwater upwelling enrich surface water with DOC and TON. In spring niche No.1 with patches of vegetation, the largest number of macrozoobenthos was recorded. While, the heterogeneous bottom of spring niche No.2 affected the diversity of habitats, and greater biodiversity of benthic fauna. In interstitial waters, there were about twice as few bacteria as in spring waters. Psychrophilic bacteria were present in interstitial waters that influence natural hyporheic processes including circulation of organic matter in the microbiological loop and self-purification of water.

Evaluation of the Environmental Risk of Contaminated Materials: Advice on the Most Appropriate Environmental Remediation Techniques

This work addresses the contamination of the sediments of an alluvial plain and riverbed of a tributary of the San Francisco River, in the Brazilian state of Minas Gerais, by potentially toxic elements from an industrial unit of metallic alloys production. This area was subdivided into four areas (A1, A2, A3, and A0 (background area)) where sediment samples have been collected followed by geochemical characterization and spatial distribution of the contaminants. This characterization was based on the (1) analysis of dissolved elements in the interstitial waters, (2) identification of exchangeable and carbonates bounded fractions, and (3) leaching tests using deionized water adjusted to the local pH. This analysis revealed high levels mainly in Cd, Pb, and Zn, in the interstitial waters and in the more soluble phases of sediments. The comparison between the levels of these elements in the leached extracts and the more soluble fractions corroborates the high capacity of these elements to be leached from the alluvium following precipitation episodes. The geochemical characterization and spatial distribution of the contaminants will allow, in the near future, a choice of the most appropriate environmental remediation technique(s) for the environmental requalification of this area.

Two Paradoxostomatidae (Ostracoda) species from South Korea with a key to genera of the family

Cytherois gajinensissp. nov. is described and Violacytherois sargassicola (Hiruta, 1976) is redescribed. The species have been collected from littoral and interstitial waters in South Korea. They belong to Cytheroisinae, one of the three Paradoxostomatidae subfamilies. Both species are the first taxonomic records of the subfamily in Korea. Taxonomic keys to the living Paradoxostomatidae genera are provided in an attempt to clarify the position of some of the currently included genera as well as a key to East Asian Cytheroisinae species in order to facilitate further biodiversity research in the region.

Meiofaunal communities and nematode diversity characterizing the Secca delle Fumose shallow vent area (Gulf of Naples, Italy)

Hydrothermal venting is rather prevalent in many marine areas around the world, and marine shallow vents are relatively abundant in the Mediterranean Sea, especially around Italy. However, investigations focusing on the characterization of meiofaunal organisms inhabiting shallow vent sediments are still scant compared to that on macrofauna. In the present study, we investigated the meiobenthic assemblages and nematode diversity inhabiting the Secca delle Fumose (SdF), a shallow water vent area located in the Gulf of Naples (Italy). In this area, characterized by a rapid change in the environmental conditions on a relative small spatial scale (i.e., 100 m), we selected four sampling sites: one diffusive emission site (H); one geyser site (G) and two inactive sites (CN, CS). Total meiofauna abundance did not vary significantly between active and inactive sites and between surface and deeper sediment layers due to a high inter-replicate variability, suggesting a pronounced spatial-scale patchiness in distribution of meiofauna. Nematofauna at site H presented the typical features of deep-sea vents with low structural and functional diversity, high biomass and dominance of few genera (i.e., Oncholaimus; Daptonema) while from site G we reported diversity values comparable to that of the inactive sites. We hypothesized that site G presented a condition of “intermediate disturbance” that could maintain a high nematode diversity. Environmental features such as sediment temperature, pH, total organic carbon and interstitial waters ions were found to be key factors influencing patterns of meiofauna and nematofauna assemblages at SdF. Even though the general theory is that nematodes inhabiting shallow vent areas include a subset of species that live in background sediments, this was not the case for SdF vent area. Due to a marked change in nematode composition between all sites and to the presence of many exclusive species, every single investigated site was characterized by a distinct nematofauna reflecting the high spatial heterogeneity of SdF.

Lack of synsedimentary chemical alteration in polar carbonates (Ross Sea, Antarctica): Resolution of a conundrum

ABSTRACT Although rare in space and time, skeletal carbonates deposited on polar shelves hold great potential for improving understanding of the oceanography of the high latitudes. Low temperatures, low carbonate saturation states, and strong seasonality govern not only the nature of carbonate communities, but also how their deposits translate into the rock record. To understand the effects of early seafloor processes on preservation, we investigated late Quaternary carbonates recovered in piston cores from the Ross Sea, Antarctica. Sediments are unconsolidated skeletal gravels and sands that mantle areas of the outer shelf swept by strong bottom currents. Deposits are dominated locally by either stylasterine hydrocorals, barnacles, or bryozoans, which comprise assemblages with strong similarities to modern benthic communities. Radiocarbon ages indicate that carbonate factories were most prolific during the lead-up to the Last Glacial Maximum (Tartanian), when sediment input was minimized, and have been mostly dormant since. Results show that synsedimentary alteration is not substantially different in the temperate and polar realms with the significant exception of chemical diagenesis. As is common in temperate deposits, skeletal grains undergo disarticulation, fracturing, abrasion, and intense bioerosion. By contrast, cementation is absent and rare aragonite grains are preserved, indicating that taphonomic loss is not as prevalent as in temperate deposits. Primary skeletal microstructures and stable-isotope compositions are preserved, indicating that chemical alteration of grains is negligible. The preservation of aragonite in polar settings is herein attributed to low rates of organic-matter burial and very low temperatures, which strongly limit microbial activity. These factors allow interstitial waters to remain weakly supersaturated with respect to aragonite. Comparison with Permian analogs indicates that lithification is delayed until deposits reach burial depths at which chemical compaction proceeds. The ultimate end product is limestone with prominent compaction features and a tightly packed fabric. Calcitic skeletal material can retain primary geochemical compositions through the lithification process, although growth of burial cement in intraparticle porosity complicates selective sampling of unaltered material. In providing a cold-water end member for the spectrum of synsedimentary diagenetic processes, results highlight specific differences that should be accounted for when interpreting the deposits of polar, cold-water carbonate systems.

Oxygen isotope composition of waters recorded in carbonates in strong clumped and oxygen isotopic disequilibrium

Paleoenvironmental reconstructions, which are mainly retrieved from oxygen isotope (δ18O) and clumped isotope (Δ47) compositions of carbonate minerals, are compromised when carbonate crystallization occurs in isotopic disequilibrium. To date, knowledge of these common isotopic disequilibria, known as vital effects in biogenic carbonates, remains limited and the potential information recorded by δ18O and Δ47 offsets from isotopic equilibrium values is largely overlooked. Additionally, in carbonates formed in isotopic equilibrium, the use of the carbonate δ18O signature as a paleothermometer relies on our knowledge of the paleowaters' δ18O value, which is often assumed. Here, we report the largest Δ47 offsets observed to date (as much as −0.270 ‰), measured on microbial carbonates, that are strongly linked to carbonate δ18O offsets (−25 ‰) from equilibrium. These offsets are likely both related to the microorganism metabolic activity and yield identical erroneous temperature reconstructions. Unexpectedly, we show that the δ18O value of the water in which carbonates precipitated, as well as the water-carbonate δ18O fractionation dependence to temperature at equilibrium can be retrieved from these paired δ18O and Δ47 disequilibrium values measured in carbonates. The possibility to retrieve the δ18O value of paleowaters, sediments' interstitial waters or organisms' body water at the carbonate precipitation loci, even from carbonates formed in isotopic disequilibrium, opens long-awaited research avenues for both paleoenvironmental reconstructions and biomineralization studies.

The behavior of trace elements in the interstitial water and sediments of the Black Sea

Generalization of the results of years of research on the geochemistry of trace elements in the interstitial waters and sediments of the Black sea. The works were carried out in different areas, but in more detail described the material on the deep-water basin and facies profiles Yalta, Sochi landfills and profile directed from the Kerch Strait to SE. The behavior of biogenic elements (N, P, Si), B, J, Br and 18 metal elements according to ISP and ISP-MS is studied. Average concentrations of elements for 3 stratigraphic horizons are calculated. Factor analysis was used to process the results.

A new water mite species from a karstic cavern in southwestern Anatolia: Acherontacarus burduricus n. sp. (Acari, Hydrachnidia)

A new species of Acherontacarus (Acari, Hydrachnidia), Acherontacarus burduricus n. sp., is described from interstitial waters of a small karstic cavern, in Burdur province (southwestern Anatolia). This is the third record of the genus from Turkey.