Reproductive impairment of sea urchin upon chronic exposure to cadmium. Part II: Effects on sperm development

Chronic pollution may impair the reproductive success of adult organisms through a decrease in the quality of gametes. Our parallel study on gamete quality, showed that male sea urchins were more sensitive than the females towards cadmium pollution. The effects of chronic exposure to 0.01 and 1 ppm Cd2+ on sperm development of the sea urchin Anthocidaris crassispina were studied. Despite the fact that no significant change in gonad index was observed when sea urchins were exposed to both levels of Cd2+ for 4 weeks, deposition of electron-dense materials was conspicuous at the wall and intracellular space of male gonads. Apparent cytological alterations were observed in sperm cells, including changes in morphology of nuage in spermatogonia. The discrete, granular bodies of nuage were replaced by a large electron-dense body. Spermatozoa with short, incomplete 'broken' tails (scanning electron microscope observation) or tails of spermatids/spermatozoa with extraordinary electron-density (transmission electron microscope observation) were more abundant in gonads exposed to both levels of Cd2+. Mitochondrial cristae deformation was observed for sperm cells at all stages of development. Sperm plasma membrane also became more convoluted but acrosome remained intact. The observed cytological distortion of sperm tails and mitochondria/midpiece could help to explain the decline in motility as well as poor perseverance in sperm produced by sea urchins exposed to cadmium observed in our earlier study.     

Porous FeOx/BiVO4-δS0.08：Highly efficient photocatalysts for the degradation of Methylene Blue under visible-light illumination

Porous S-doped bismuth vanadate with an olive-like morphology and its supported iron oxide （y wt.% FeOx/BiVO4-δS0.08, y = 0.06, 0.76, and 1.40） photocatalysts were fabricated using the dodecylamine-assisted alcohol-hydrothermal and incipient wetness impregnation methods, respectively. It is shown that the y wt.% FeOx/BiVO4-δS0.08 photocatalysts contained a monoclinic scheetlite BiVO4 phase with a porous olive-like morphology, a surface area of 8.8-9.2 m^2/g, and a bandgap energy of 2.38-2.42 eV. There was co-presence of surface Bi^5＋, Bi^3＋, V^5＋, V^3＋, Fe^3＋, and Fe^2＋ species in y wt.% FeOx/BiVO4-δS0.08. The 1.40 wt.% FeOx/BiVO4-δS0.08 sample performed the best for Methylene Blue degradation under visible-light illumination. The photocatalytic mechanism was also discussed. We believe that the sulfur and FeOx co-doping, higher oxygen adspecies concentration, and lower baudgap energy were responsible for the excellent visible-light-driven catalytic activity of 1.40 wt.% FeOx/BiVO4-δS0.08.     

Hydrothermal fabrication and visible-light-driven photocatalytic properties of bismuth vanadate with multiple morphologies and/or porous structures for Methyl Orange degradation

Monoclinic BiVO₄ with multiple morphologies and/or porous structures were fabricated using the hydrothermal strategy. The materials were characterized by means of the XRD, Raman, TGA/DSC, SEM, XPS, and UV-Vis techniques. The photocatalytic activities of the BiVO₄ materials were evaluated for the degradation of Methyl Orange under visible-light irradiation. It is observed that pH value and surfactant exerted a great effect on the morphology and pore structure of the BiVO₄ product. Spherical BiVO₄ with porous structures, flower-cluster-like BiVO₄, and flower-bundle-like BiVO₄ were generated hydrothermally at 100℃ with poly(vinyl pyrrolidone) (PVP) and urea (pH = 2) and at 160℃ with NaHCO₃ (pH = 7 and 8), respectively. The PVP-derived BiVO₄ showed much higher surface areas (5.0-8.4 m²/g) and narrower bandgap energies (2.45-2.49 eV). The best photocatalytic performance of the spherical BiVO₄ material with a surface area of 8.4 m²/g was associated with its higher surface area, narrower bandgap energy, higher surface oxygen vacancy density, and unique porous architecture.     

A NEW METHOD FOR ESTIMATING FUTURE RESERVOIR STORAGE CAPACITIES1

ABSTRACT: A new method has been developed for estimating future reservoir storage capacities, allowing for sediment deposition and compaction. Reservoir sedimentation surveys for 117 reservoirs, conducted by the Illinois State Water Survey over the past 60 years, were used to determine regional constants K to represent the severity of sediment deposition in the reservoirs. More than half of the 82 water supply reservoirs investigated had records of reservoir sedimentation surveys, and their K values were calculated by using data from those sediment surveys. The average K values of the remaining non-surveyed water supply reservoirs were estimated from the regional distribution of the K values. Other important factors considered in the estimation of future reservoir storage capacities are the trap efficiency of the reservoirs and the variation of density of sediment deposits due to compaction. The model can also be used for analyzing the economics of alternative sites and of design features that can be incorporated in dams for reducing reservoir sedimentation.     

Occurrence and fate of pharmaceuticals and personal care products in drinking water in southern China

Occurrence and fate of pharmaceuticals and personal care products (PPCPs) in drinking water was investigated in southern China. Fifteen and twelve PPCPs were detected with concentrations of 0-36 ng L(-1) in source water and of 0-20 ng L(-1) in treated water, respectively. Four PPCPs were detected with concentrations of approximately 1 ng L(-1) in drinking water of distribution network. Conventional water treatment processes removed the types and average concentrations of PPCPs by 30% and above 50%, respectively. Advanced water treatment processes were more efficient in the removal of most PPCPs, with the types and concentrations reduced by 50% and approximately 90%, respectively. Molecular properties of PPCPs had an important influence on their behaviors during water treatment. pK(a) (acidity coefficient) and K(oc) (organic carbon partition coefficient) of PPCPs appeared to have a combined effect on PPCPs removal during coagulation and oxidation. Adsorption and biodegradation were two possible mechanisms responsible for PPCPs removal during sand filtration.     

Prey dynamics affect foraging by a pelagic predator (Stenella longirostris) over a range of spatial and temporal scales

Studies have shown that pelagic predators do not overlap with their prey at small scales. However, we hypothesized that spinner dolphin foraging would be affected by the spatio-temporal dynamics of their prey at both small and large scales. A modified echosounder was used to simultaneously measure the abundance of dolphins and their prey as a function of space and time off three Hawaiian islands. Spinner dolphin abundance closely matched the abundance patterns in the boundary community both horizontally and vertically. As hypothesized, spinner dolphins followed the diel horizontal migration of their prey, rather than feeding offshore the entire night. Spinner dolphins also followed the vertical migrations of their prey and exploited the vertical areas within the boundary layer that had the highest prey density. Cooperative foraging by pairs of dolphins within large groups was evident. The geometric and density characteristics of prey patches containing dolphins indicate that dolphins may alter the characteristics of prey patches through this cooperative foraging. The overlap of Hawaiian spinner dolphins and their prey at many temporal and spatial scales, ranging from several minutes to an entire night and 20 m to several kilometers, indicates that the availability of truly synoptic data may fundamentally alter our conclusions about pelagic predator-prey interactions.     

Understanding the Underwater Behaviour of Scuba Divers in Hong Kong

Diving-related activities may constitute a major threat to coral reefs. This study aimed to quantify the impact of diving in Hong Kong on hard corals and understand how socio-economic characteristics and experience level of divers influence diver-inflicted damage. We recorded and analysed the underwater behaviour of 81 recreational divers. On average, a diver was in contact with marine biota 14.7 times with about 40 % of contacts involved corals and 38 % were damaging contacts with corals or other biota in a single dive. The most harm-inflicting groups included inexperienced and camera-carrying divers. Although Hong Kong divers did not make many damaging contacts with corals, there is still an imminent need to determine the scale of damage from diving activities on the marine ecosystem given the rapid development of marine-based tourism and the limited coral-inhabited areas in Hong Kong where the marine environment is already under stress from anthropogenic activities.     

Zur Problematik der Anwendung von Hintergrundwerten beim Vollzug des Bodenschutzrechts

The knowledge about background levels of heavy metals in soils is essential for the use of the precautionary values for heavy metals as provided by the German Soil-Protection-Act. In the northeast of Bavaria the 90th percentiles in the back-ground levels of heavy metals in the soil exceed the precautionary values in many cases. Background levels were determined separately for soils of different parent materials of rocks, soil horizons and land use (agricultural or forest soils), with the parent material of rock having the strongest influence on the content of heavy metals in different soils. Precautionary values are highly exceeded by chrome and nickel in basic and ultrabasic rocks. High variability of heavy metal contents was found even in soils of the same parent material (C-horizons), which is due to the natural geochemical variability of rocks and the mixing of different parent materials during the Pleistocene. For an effective use of the German Soil-Protection-Order, areas must be defined where the probability is high that the 90th percentiles of the background levels of heavy metals exceed the precautionary values. It has to be determined, how the risk of mobilisation of heavy metals can be estimated within these areas and what has to be done if heavy metal contents in soils exceed not only the precautionary values but also the background levels.     

Are barnacle larvae able to escape from the threat of UV?

Earlier laboratory experiments suggested that environmental levels of UV-B radiation can damage the eyes of barnacle naupliar larvae and impair their phototactic behaviors. However, since barnacle larvae may avoid UV by migrating to deeper waters, it is not known whether such impairment would actually occur under field conditions. For the first time, this study provides both field and laboratory evidences to show that prevailing UV-B in the natural habitat of barnacle larvae could be an important environmental factor affecting natural barnacle populations. We here showed that although barnacle nauplii may avoid UV-B irradiation by downward migration, the amount of UV energy (9.8 × 10⁻⁶ J) received by a naupliar eye during downward migration in the natural water column is within the same order of magnitude as the total energy (7.5 × 10⁻⁶ J) sufficient to cause damages to naupliar eye and impair their phototactic responses. It is possible that solar UV-B prevailing at shallow waters would pose a similar threat to other zooplankton species over large geographic scale.     

Cover Image

The cover image is based on the Original Article Noninvasive prenatal paternity testing by means of SNP-based targeted sequencing by Jacqueline Chor Wing Tam et al., https://doi.org/10.1002/pd.5595 .