Methanesulphonic acid (MSA) stratigraphy from a Talos Dome ice core as a tool in depicting sea ice changes and southern atmospheric circulation over the previous 140 years

Firn core methanesulphonic acid (MSA) stratigraphy from Talos Dome (East Antarctica) was compared with anomalies of the satellite-measured sea ice extent (1973–1995) in the Ross Sea and Wilkes Land oceanic sector. In spite of the sparseness of sea ice data, the MSA maxima fit with many positive sea ice anomalies in the Ross Sea. This evidence suggests that marine biogenic activity enhanced by large sea ice cover is an important, but not exclusive, factor in controlling MSA concentration in snow precipitation at Talos Dome. Other than source intensity, differences in regional atmospheric transport mechanisms affect the arrival of MSA-rich aerosol at Talos Dome. To clarify the role of transport processes in bringing biogenic aerosol to Talos Dome, a spectral analysis was applied to the MSA, SOI (South Oscillation Index), and SAM (Southern Annular Mode) record. Synchronicity or phase shift between the chemical signature and atmospheric circulation modes were tested. The variations in the MSA profile have a periodicity of 6.9, 4.9, 3.5, and 2.9 years. The 6.9 and 2.9 year periodicities show a strong positive correlation and are synchronous with corresponding SOI periodicity. This variability could be related to an increase in MSA source intensity (by dimethylsulphide from phytoplanktonic activity) linked to the sea ice extent in the Ross Sea area, but also to an increased strength in transport processes. Both of these factors are correlated with La Niña events (SOI positive values). Furthermore, SAM positive values are related to an increased sea ice extent in the Ross Sea sector and show two main periodicities 3.3 and 3.8 years. These periodicities determine the MSA variability at 3.5 years. However, the effect of intensification of the polar vortex and the consequent reduction in transport process intensity, which reduce the delivery of air masses enriched in MSA from oceanic areas to Talos Dome, make the effect of the SAM on the MSA concentration at Talos Dome less active than the SOI. In this way, snow deposition at the Talos Dome records larger MSA concentration by the combined effects of increased source emissions and more efficient transport processes. The MSA record from Talos Dome can therefore be considered a reliable proxy of sea ice extent when the effect of changes in transport processes in this region of Antarctica is considered. Over the previous 140 years, these conditions occur with a periodicity of 6.9 years.     

Maternal metabolomic profiling and congenital heart disease risk in offspring: A systematic review of observational studies

Aetiological understanding and screening methods for congenital heart disease (CHD) are limited. Maternal metabolomic assessment offers the potential to identify risk factors and biomarkers. We performed a systematic review (PROSPERO CRD42022308452) investigating the association between fetal/childhood CHD and endogenous maternal metabolites. Ovid-MEDLINE, Ovid-EMBASE and Cochrane Library were searched between inception and 06/09/2022. Case control studies included analysing maternal blood or urine metabolites in pregnancy or postpartum where there was foetal/childhood CHD. Risk of bias assessment utilised the Scottish Intercollegiate Guidelines Network methodology checklist and narrative synthesis was performed. A total of 134 records were screened with eight eligible studies (n = 3242 pregnancies, n = 842 CHD-affected offspring). Five studies performed metabolomic analysis in pregnancy. Metabolites distinguishing case and control groups spanned lipid, glucose and amino-acid pathways, with the development of sensitive risk prediction models. No single metabolite consistently distinguished cases and controls across studies. Three studies performed targeted analysis postnatally with altered lipid and amino acid metabolites and raised homocysteine and markers of oxidative stress identified in cases. Included studies reported small sample sizes, analysing different biosamples at variable time points using differing techniques. At present, there is not enough evidence to confidently associate maternal metabolomic profiles with offspring CHD risk. However, several identified pathways warrant further investigation.     

Mercury levels in sediments of central Mediterranean Sea: a 150+ year record from box-cores recovered in the Strait of Sicily

To evaluate the degree of anthropogenic mercury pollution, Hg contents have been measured for box-core sediments sampled along three nearshore–offshore transects in the Strait of Sicily and well constrained for their mineralogy, bulk geochemistry and TOC%. Hg values are generally low (from 15 to 70 μg kg⁻¹); however, depth profiles clearly display upcore rising concentrations (up to 202 μg kg⁻¹ near the SE Sicily coast) that are attributed to anthropogenic load. Based on ²¹⁰Pb chronology, these trends are more dramatic across the last 20–30 years. Geogenic influence is thought to explain some anomalies related to volcanic emission and geothermal activity. Combined effects due to eastward flowing of the Modified Atlantic Water (MAW) and sea bottom morphology drove major anthropogenic accumulation.     

Biochemical composition and trophic strategies of the amphipod Eurythenes gryllus at hadal depths (Atacama Trench,South Pacific)

Amphipods Eurythenes gryllus were collected at 7800?m depth in the Atacama Trench (South Pacific) for studying their biochemical composition (in terms of proteins, lipids and carbohydrates and fatty acid content) and to gather information on bioenergetic strategies and trophic habits of organisms living in this extreme environment. The effect of long-term formalin storage on the biochemical determinations was also determined. Proteins were the dominant biochemical class of organic compounds (39–53%D.W.), whereas carbohydrates accounted for a very small fraction (1–2%D.W.). Lipid concentrations of E. gryllus accounted for 7–18%D.W. and were much lower than those reported for other deep-sea amphipods. These differences are likely to be more dependent upon food availability in the Atacama Trench rather than upon temperature. Lipid composition of E. gryllus revealed the dominance of monounsaturated fatty acids with polyunsaturated fatty acids accounting for a very small fraction, suggesting that hadal amphipods are higher dependent upon lipid reserves than amphipods inhabiting at shallow depths. The ratio of C18:1Δ⁹ to C18:1Δ¹¹ was >11 confirming the necrophagous trophic habits of this hadal amphipod.     

Assessment of the radiological impacts of a zircon sand processing plant

The paper presents the results of a study on radiological impacts resulting from a zircon sand processing plant located in the North-Eastern part of Italy. Activity concentrations of radionuclides found in materials associated with this industrial process are presented as well as the results of the assessment of the annual effective doses to the workers and the members of the public. Gamma-spectrometric analyses were performed on "raw" sands, end-products, and soils sampled near the plant. Thermoluminescent dosimeters, electric pumps and electret ion chambers were used to measure the external irradiation, the indoor dust concentrations and the radon concentrations, respectively. The ground-level air concentration of radioactive particulate near the plant and the deposition of particulate matter were estimated by a Gaussian model (ISCLT3). Finally, the annual effective doses, calculated as provided for by Directive 96/29/Euratom, were estimated to be 1.7 mSv y(-1) for workers and 4.4 microSv y(-1) for members of the public.     

STREAM MEANDER RESTORATION1

ABSTRACT: Stream meander restoration designs currently used by many state and local government agencies are often based on empirical equations, such as those developed by Leopold and Wolman (1957; 1960). In order to assess the suitability of these equations and propose alternative strategies, 18 sites in Central Maryland were selected and data on channel planform, cross-sections, sediments, and spacing and sizing of the pools and riffles were collected and analyzed to characterize the channel type in the study area. A large bias was found comparing the meander parameters measured to those computed using the Leopold and Wolman equations for the streams in central Maryland. Based on these results, appropriate empirical equations for the study area that can assist in stream restoration designs were investigated. An additional approach that can assist in stream restoration consists of the application of a detailed stream reconnaissance to verify that the restoration project is consistent with the natural form and processes of the river.     

Properties of agricultural aerosol released during wheat harvest threshing, plowing and sowing

This study shows for the first time a chemical and morphological characterization of agricultural aerosols released during three important agricultural operations： threshing, plowing and sowing. The field campaigns were carried out in the eastern part of the Po Valley, Italy, in summer and autumn 2009. The aerosol particles were sampled on quartz fiber filters and polytetrafluoroethylene membranes in order to allow Inductively Coupled Plasma Mass Spectrometry （ICP-MS） analysis and Scanning Electron Microscopy equipped with an Energy Dispersive X-ray Spectrometer （SEM-EDS） investigations, respectively. The organic carbon mass concentrations were measured with a Sunset Laboratory Dual-Optical Organic Carbone/Elemental Carbon （OCEC） Aerosol analyzer. The morphological and chemical analyses by SEM-EDS allowed recognizing four main particle classes： organic, silica, calcite and clay minerals. The organic particles contribute to both fine and coarse aerosol fractions up to ca. 50% for all three agricultural activities. This was also confirmed by OCEC analysis for fine fraction. Most of the agricultural aerosols, about 60%, were single particles and the remaining 40% were agglomerations of particles. The ICP-MS results showed that threshing and plowing produce more aerosol particles than sowing, which was characterized by important amounts of clay minerals produced from land soils.     

The complexity of nectar: secretion and resorption dynamically regulate nectar features

In this paper, we review the phenomenon of nectar resorption, focusing on its physiological and ecological meaning. Nectar resorption is a phenomenon that has long been known but was rarely reported until the1990s. It has more recently been demonstrated in several species by various direct and indirect methodologies. It has generally been demonstrated in senescent flowers as a phenomenon separate in time from, and independent of, nectar secretion. The significance of this type of resorption is generally recognized as a resource-recovery strategy, recycling at least some materials invested in nectar production. Nevertheless, nectar resorption can occur concomitantly with nectar secretion. Nectar production is therefore best considered as a unified process comprising nectar secretion and resorption. The modulation of these two opposite phases allows nectar concentration to be maintained in a range suitable for pollinators (nectar homeostasis). The mechanism of nectar resorption at the cell level has received little attention, and its molecular basis can only be hypothesized on the basis of recent studies concerning sugar sensing.     

Ancient settlement dynamics and predictive archaeological models for the Metapontum coastal area in Basilicata,southern Italy: from geomorphological survey to spatial analysis

In the ancient territory of the Greek settlement of Metaponto and its Chora (Ionian sector of Basilicata, southern Italy) geomorphological mapping, GIS-supported statistics, and landform topographic features were investigated and combined to extract settlement rules and site dynamics. Analyses of environmental dynamics as well as of spatial and temporal settlement evolution were carried through an integrated approach that, starting from a detailed geomorphological analysis, tried to extract the spatial relationships between archaeological site locations and landform/landscape features. Spatial analysis was used to investigate the relationships between environmental parameters and archaeological sites. The advantages to develop a predictive model using Archeological Spatial Evaluation (ASE) analysis lay in the possibility to deeply study the relationships between man and the environment. In the present study, the analysis was carried out in a pioneering way in the ~400 km² Metaponto territory in order to robustly validate - in the aftermath data - human and territorial dynamics. A model describing interactions between sites and parameters such as elevation, slope, aspect, landforms, land use, and distances from rivers was constructed. Sensibility maps were produced, which will help archaeologists to know how many and which are the parameters increasing the probability to find new archaeological sites as well as how the main geomorphological features of the study area, contextualized within the most likely paleoclimate scenario, affect ancient site arrangement though time. The preferential occupation of mid-altitude marine terraces, and the consequence spreading of agriculture on these territories, is likely due to the existence of well-developed soil profiles on them. Clearly colonists recognized that on these landform units there were the better conditions for the development of massive agricultural practices: since the SP age (4,1 to 2,0 Kyr B.P.) the settlers expands inland looking for most fertile territories as well as for areas sufficiently protected (being far away from the coast). The increase in farmhouses on the top of marine terraces from the FC up to EC-EE periods and the modifications of settlement distribution (gradual abandonment of alluvial) in the Metaponto area is likely related to the acceleration of alluvial processes. The progressive decrease of human occupation during the Hellenistic up to the Roman Age is clearly consequence of the Roman conquest. However, a role played by the increase in flooding occurrence in the coastal plain/floodplains of the main rivers in triggering the abandonment of these territories and marking the beginning of the decadent phases should not be neglected. Productive areas (locally associated to farmhouses) are preferential set along the fluvial incisions (sometime associated to farmhouses), thus implying that productive area setting is strongly linked to the presence of rivers, and of their lower rank tributaries, both as an intrinsic need of manufacturing and to facilitate the spreading of products. From the Classical to the Hellenistic Age until the Roman Age, Necropolis are spread in the entire area, from marine terraces to alluvial plain. On the other hand, Sacred areas - which appearance is recorded starting from the Colony Foundation Age - exhibits a settlement continuity in the study area starting from this time up to the entire Roman period, and the sacred areas setting is strictly associated to the category of Settlement.