Arsenic (As) is an element with important environmental and human health implications due to its toxic properties. It is naturally occurring since it is contained in minerals, but it can also be ...enriched and distributed in the environment by anthropogenic activities. This paper reports on the historic As contamination of agricultural soils in one of the most important national relevance site for contamination in Italy, the so-called SIN Brescia-Caffaro, in the city of Brescia, northern Italy. These agricultural areas received As through the use of irrigation waters from wastewater coming from a factory of As-based pesticides (lead and calcium arsenates, sodium arsenite). Pesticide production started in 1920 and ended in the ‘70. Concentrations in the areas are generally beyond the legal threshold values for different soil uses and are up to >200 mg/kg. Arsenic contamination was studied to assess the long-time trend and the dynamics related to the vertical movement of As down to 1 m depth and its horizontal diffusion with surface irrigation in the entire field. Arsenic fractionation analysis (solid phase speciation by sequential extraction procedure) was also performed on samples collected from these areas and employed in greenhouse experiments with several plant species to evaluate the long-term contamination and the role of plant species in modifying As availability in soil. The results of this work can help in the evaluation of the conditions controlling the vertical transfer of As towards surface aquifers, the bioaccumulation likelihood in the agricultural food chain and the selection of sustainable remediation techniques such as phytoextraction.
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•Arsenic was measured in industrially polluted agricultural soils in Italy.•As pesticide production wastewater was used as irrigation water for 50 years.•Vertical (up to 1 m) and horizontal (field wide) gradients were obtained for soil.•Concentrations were between 10 and 200 mg/kg and mostly in the plow layer.•Fractionation of As species was related to specific plant species potted in soil.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Accumulation of potentially toxic elements (PTEs) in agricultural soils has become an increasingly global issue driven by industrialization. A credible knowledge of their distribution and diverse ...sources in soils is essential to developing effective measures of identifying accumulation of PTEs in rural and periurban environments. However, the assessment of PTE pollution levels and discrimination of anthropogenic and natural sources remain a serious challenge. In China, most studies are focused on highly industrialized and/or urbanized regions, while limited attention has been given to agricultural areas where diffuse source contamination prevails. Therefore, a large dataset of 5207 surface soil samples (1 × 1 km) and 1311 subsoil samples (2 × 2 km) were collected from an agriculturally dominated region in eastern China. Soil total concentrations of As, Cd, Cr, Cu, Hg, Ni, Pb and Zn were analyzed along with additional edaphic variables relevant to PTE accumulation in soils (e.g., pH, SOC). Concentrations of Cr, Ni, Pb and Zn for all sites were lower than those of the risk-screening values. However, elevated concentrations of Cd and Hg observed in surface soils were associated with anthropogenic activities. Land use pattern had a significant impact on the spatial variation of PTEs. Elevated levels of Cd were uniquely associated with high phosphorus and soil organic matter (SOM) contents, and elevated Hg was associated with coal-fired power plants and historical application of fertilizer and Hg-containing pesticides. The data presented herein indicated that geogenic process likely caused a net depletion of As, Cr, Cu, Ni, Pb and Zn in topsoil, despite surface deposition from anthropogenic sources. The result of this study revealed that using subsoil concentrations of PTEs to establish background or reference concentrations might lead to an erroneous assessment of pollution levels in surface soils.
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•A high-density sampling of topsoil (n = 5207, 1 × 1 km) and subsoil (n = 1311, 2 × 2 km) was conducted in agricultural soils of Anhui, China.•Only 2 sites for topsoil As, 23 sites for Cd, 3 sites for Cu and 7 sites for Hg had concentrations exceeding threshold values.•Land use pattern had a significant impact on the spatial variation of potentially toxic elements (PTEs).•Using subsoil PTE concentrations to establish background levels may lead to an erroneous assessment of pollution levels.
Using subsoil concentrations of PTEs to establish background or reference concentrations might lead to an erroneous assessment of pollution levels in surface soils.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Abstract
Knowledge of blue marlin, Makaira nigricans, movement patterns across a range of spatiotemporal scales is important for understanding the ecology of this epipelagic fish, informing ...responsible management strategies, and understanding the potential impacts of a changing ocean climate to the species. To gain insight into movement patterns, we analyzed data from 66 blue marlin satellite-tagged between 2001 and 2021 throughout the North Atlantic. We recorded migrations connecting west and east Atlantic tagging locations, as well as long-term residency within small sub-regions. Blue marlin showed a pattern of latitudinal migration, occupying lower latitudes during cooler months and higher latitudes in warmer months. Diving data indicate blue marlin primarily inhabited a shallow vertical habitat with deeper diving associated with higher sea surface temperatures and dissolved oxygen content. Consistent patterns in diel vertical habitat use support the hypothesis that these fish are visual hunters, diving deeper during the day, as well as dawn, dusk, and full moon periods. The wide-ranging movements of blue marlin indicate that traditional spatial management measures, such as static marine reserves, are unlikely to be effective in reducing the fishing mortality of this species. Longer tag deployment durations are required to delineate its annual and multi-annual migratory cycle.
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•We provide 14-year-long leveling results across plate suture of Philippine Sea and Eurasia.•Along the LVF, shallow locked in north, and rapid creeping without locking in south.•The ...leveling data imply blind slip on the deeper part of the Central Range fault.•Active creeping occurs on a nearly vertical contact along the Chimei fault.
To better characterize the vertical movements and the deformation behaviors across the plate suture of an arc-continent collision, we conducted annual repeated measurements on two precise leveling routes in a length of 34 and 37 km, respectively, across the middle part of the Longitudinal Valley in eastern Taiwan in 2004–2018. The 14-year-long results showed that the Longitudinal Valley fault (LVF) dominates the surface deformation: a) the middle LVF (Juisui fault) exhibited partially locked in the upper few kilometers, with a cumulative uplift rate of 9–10 mm/yr in a distance of 4 km; b) the southern LVF (Chihshang fault) showed a creeping behavior with a vertical rate of 24–27 mm/yr. In addition, we are able to characterize other features, including 1) tilting upward to the west in the eastern Central Range, suggesting activity on the west-dipping Central Range fault; 2) the hanging wall of the LVF showed tilting downward behavior to the east; 3) the Chimei fault, a suspected active fault, revealed active slip on the sub-vertical fault plane, that caused a vertical rate of 8–9 mm/yr. Putting the results under global ITRF system, the whole Juisui route was moving downward, supporting the notion that NNW subduction of the Philippine Sea plate starts around the latitude of the middle of the Longitudinal Valley. Finally, the co-seismic vertical deformation of the 2013 ML6.4 Juisui earthquake was characterized by tilting upward to the west, consistent with stick–slip on the deeper part of a west-dipping interface of the forearc basement.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The Longgang volcanic field is one of the most active volcanoes in modern China. It is situated in the central region of the Longgang mountains on the west slopes of Changbaishan in Jilin. The ...present three-dimensional crustal movement velocity fields in the different periods were obtained by processing Global Navigation Satellite System (GNSS) observations from 2010 to 2020 and data for the leveling profiles from 1970s to 2010s in the area. The horizontal velocities of GNSS stations were larger in the eastern region than in the western regions, indicating that the eastern region is mainly tensile. The results of the continuous surface strain rates showed that a volcanic field is located in the expansion area. The results of the first-order leveling data for the Changfu profile and the Danfu profile showed that the vertical movements were predominantly uplift, with rates of 0.55~1.83 mm/a for most of the sites. The area with relatively higher uplifting rates of more than 1.0 mm/a was Fusong-Xianrenqiao-Laosha
Precise leveling data observed in the period of 1970–2014 around the Ordos block were collected and processed to estimate present-day crustal vertical movement. Vertical rates of 6 GPS sites were ...employed as a priori constraints to define the reference frame. The velocity field shows that the interior of the Ordos block moves upward at a rate of 3 mm/a as a stable block. With respect to the central Ordos, the grabens and rifts around the Ordos block are undergoing subsidence, while the northeastern and southwestern Ordos uplift at the average rates of 2 and 1 mm/a, respectively. To the southeastern margin of the Ordos block, the Weihe and southern Shanxi grabens are subsiding at the rates of 4–6 mm/a. The subsidence of the Shanxi graben indicates that the graben is experiencing extensional movement on a long timescale. To the northwestern margin of the Ordos block, the Hetao and Yinchuan rifts are subsiding at the rates of 2–3 mm/a. A 2-D buried faulting model is used to infer the normal or reverse dip-slip rates. Our solution shows that most of the normal slip rates along the faults in the grabens and rifts are ~2 mm/a.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Integrated analysis of the vertical and horizontal movements of epipelagic fishes requires high-resolution data from tags that have been attached to animals for long periods. The recovery of a SPLASH ...tag deployed on a whale shark
Rhincodon typus
for 3 mo enabled access to archival data of horizontal and vertical movements of the shark that travelled 5380 km from Christmas Island to the Banda Sea. We examined water temperature and bathymetry to compare movements of the shark with key oceanographic features. Over 89 d, we identified 1931 dives and grouped these into 5 broad categories depending on dive shape. To investigate the potential for these dives to reflect behavioural thermoregulation, we used boosted regression trees to model the relationship between pre- and post-dive surface durations and dive characteristics. The movements of the shark were correlated with water temperatures, with the animal following frontal systems while remaining in a sea surface temperature (SST) range of 24-29°C. Across the continental shelf off north-western Australia, the shark mostly remained near the seafloor, likely avoiding very warm SSTs and strong currents at the surface. U- (foraging) and V- (searching) shaped dives accounted for ~78% of dives. Foraging dives during the day descended to 200-500 m and were preceded and followed by extended periods at the surface, whereas at night, the shark rarely dived below 200 m, likely foraging near the thermocline. Our results show how water temperatures influence the movement of this whale shark, with ‘basking’ at the surface during the day likely to gather environmental heat for thermoregulation, aiding to maintain body temperatures.
Abstract
From 2010 to 2012, 246 data storage tags were deployed on European seabass in the Iroise Natural Marine Park, a marine protected area (MPA) off west Brittany, France. A return rate of 14.6% ...associated with long time series of data provided new information on fish ecology (e.g. maximum experienced depth greater than 225 m, temperature range 6.80–21.87°C). Depth and temperature series were used to infer individual migration using an innovative hidden Markov model (HMM) especially developed for seabass geolocation. Reconstructed fish tracks revealed that seabass is a partially migratory species, as individuals exhibited either long-distance migrations towards the Bay of Biscay or the Celtic Sea, or residency behaviour in the Iroise Sea. Fidelity to summer feeding areas and to winter spawing areas was demonstrated. These results suggest that the population is spatially structured. The Iroise Sea is likely a mixing zone for different stocks or sub-populations, and may also shelter a resident population. At the population scale, such findings may impact ICES stock assessment and the resulting decisions from EU managers. At the local scale, conservation action could be taken by MPA managers. Besides, this study demonstrates the high potential of archival tags for investigating multi-year behavioural patterns such as site fidelity to offshore spawning areas.
Abstract
Species interactions are important for explaining community dynamics and population trends, but very time- and effort-consuming to assess. Although diel vertical movements (DVM) and spatial ...correlations for various fish species have been explored to assess species interactions in aquatic communities, there is lack of cost-efficient approaches to studying both aspects concurrently. In this study, we proposed a single-species spatio-temporal model to quantify diel variations in the probabilities of a non-empty catch (p) and catch rates given that the catch is non-empty (λ). The model is applied to investigate patterns in DVM of nine dominant fish and shrimp species in the Yellow Sea (YS) using bottom trawl survey data. Subsequently, we utilized the spatio-temporal models built for the nine species to hindcast the spatial distributions of p and λ by year and species, which were further used to calculate between-species spatial correlation coefficients (corspatial). Results showed the nine species exhibited three different patterns of diel variation in p or λ, indicating they utilize the water column swept by the bottom trawls at different times of a day. Moreover, for the nine species in the YS those with limited interactions generally have negative corspatial or positive corspatial < 0.2 in λ, and others linked by strong predator–prey relationships or major food overlaps have corspatial ≥ 0.46 in λ. The strength of the positive spatial correlations in λ of different fishes shows some correspondence with the intensity of predation and competition between species and may be a supplementary tool to assess species interactions.
Abstract
Swordfish (Xiphias gladius) are large, highly-migratory pelagic, fishes that make diel, vertical excursions from the warm, surface layer (e.g. 18–24 °C) to the cold waters (∼8 °C) below the ...thermocline (300–600 m). They possess anatomical traits e.g. medial red muscle (RM) position and an associated vascular rete that could enable metabolic heat-retention and result in RM temperature elevation above ambient, or RM endothermy. We herein provide: (i) expanded anatomical descriptions of the RM-associated vasculature (i.e. central rete and lateral blood vessels), (ii) new measurements of in vivo temperature, and (iii) heat transfer models to assess the capacities for RM endothermy and physiological thermoregulation during vertical movements. Despite the presence of a medial RM and two associated blood-flow pathways (one of which forms a rete), swordfish exhibited a limited capacity for RM endothermy, with muscle temperatures approaching ambient during prolonged periods above or below the thermocline. Our heat transfer models suggest, however, that swordfish may control rates of heat loss or gain during vertical movements, possibly by altering the route of blood flow supplying the RM. Such physiological thermoregulation likely contributes to the ability of swordfish to capitalize on food resources below the thermocline, which are out of range for most other active, pelagic fishes.
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