First record of Branchinella spinosa (Milne-Edwards) (Crustacea: Branchiopodacolon; Anostraca) from Greece

As the result of a first screening of temporary inland water habitats,Branchinella spinosa is here recorded for the first time in Greece. This finding extends the circum-Mediterranean part of its vast distribution. The species was collected from a shallow astatic coastal salt-marsh that is mainly fed by rainwater, where it coexists but rarely co-occurs withArtemia parthenogenetica. Branchinella spinosa is only the fourth anostracan species currently known from Greece. The poor knowledge of anostracan richness and abundance is mainly due to limited sampling efforts in this area. As temporary aquatic habitats are threatened by several anthropogenic activities, especially agriculture and land clearing for urbanisation and tourism, there is an urgent necessity for further monitoring and protection of these precious habitats.     

Correction of inertial oscillations by assimilation of HF radar data in a model of the Ligurian Sea

This article aims at analyzing if high-frequency radar observations of surface currents allow to improve model forecasts in the Ligurian Sea, where inertial oscillations are a dominant feature. An ensemble of ROMS models covering the Ligurian Sea, and nested in the Mediterranean Forecasting System, is coupled with two WERA high-frequency radars. A sensitivity study allows to determine optimal parameters for the ensemble filter. By assimilating observations in a single point, the obtained correction shows that the forecast error covariance matrix represents the inertial oscillations, as well as large- and meso-scale processes. Furthermore, it is shown that the velocity observations can correct the phase and amplitude of the inertial oscillations. Observations are shown to have a strong effect during approximately half a day, which confirms the importance of using a high temporal observation frequency. In general, data assimilation of HF radar observations leads to a skill score of about 30% for the forecasts of surface velocity.     

Sediment flux-driven channel geometry adjustment of bedrock and mixed gravel–bedrock rivers

Sediment supply (Q_s) is often overlooked in modelling studies of landscape evolution, despite sediment playing a key role in the physical processes that drive erosion and sedimentation in river channels. Here, we show the direct impact of the supply of coarse-grained, hard sediment on the geometry of bedrock channels from the Rangitikei River, New Zealand. Channels receiving a coarse bedload sediment supply are systematically (up to an order of magnitude) wider than channels with no bedload sediment input for a given discharge. We also present physical model experiments of a bedrock river channel with a fixed water discharge (1.5 l min⁻¹) under different Q_s (between 0 and 20 g l⁻¹) that allow the quantification of the role of sediment in setting the width and slope of channels and the distribution of shear stress within channels. The addition of bedload sediment increases the width, slope and width-to-depth ratio of the channels, and increasing sediment loads promote emerging complexity in channel morphology and shear stress distributions. Channels with low Q_s are characterized by simple in-channel morphologies with a uniform distribution of shear stress within the channel while channels with high Q_s are characterized by dynamic channels with multiple active threads and a non-uniform distribution of shear stress. We compare bedrock channel geometries from the Rangitikei and the experiments to alluvial channels and demonstrate that the behaviour is similar, with a transition from single-thread and uniform channels to multiple threads occurring when bedload sediment is present. In the experimental bedrock channels, this threshold Q_s is when the input sediment supply exceeds the transport capacity of the channel. Caution is required when using the channel geometry to reconstruct past environmental conditions or to invert for tectonic uplift rates, because multiple configurations of channel geometry can exist for a given discharge, solely due to input Q_s. © 2020 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd     

Petrography of alluvial sands as a past and present environmental indicator: Case of the Loire River (France)

Four sample sets of the Upper and Middle Loire river sands were analyzed in order to study the impact of natural and anthropogenic factors on their petrographic composition in space (on an 800 km stretch) and time. Composition was determined by modal analysis of three sand-size fractions using a polarizing optical microscope and calculated for each sample (“standard sand” = Sst). The watershed is composed mainly of endogenic (Massif Central) and sedimentary (southern Parisian Basin) rocks. B-set sands collected in channels for different water flows in 1996 show that Sst compositions vary by only 5 %. Present-day sands in the Upper Loire and Middle Loire have very high petrographic immaturity comparing to others worldwide fluvial sands, although bio-climatic conditions favor sand maturation by source-rock weathering in the watershed. This shows the strong impact of the Massif Central on sediment yield due to relief rejuvenation as a consequence of the formation of the Alps during the Quaternary. Fluvial sands stored during the Weichselian and the Holocene in the Middle Loire floodplain, although partly weathered since their deposition, show higher inputs from the endogenic rocks of the Massif Central than present-day deposits. This can be explained by Weichselian periglacial conditions and the development of crop farming since the Neolithic, which favored mechanical erosion, particularly in the Massif Central which is characterized by a cold, humid climate and steep slopes. The upstream-downstream change in the composition of presently deposited sand is low in the diked area. It shows however that basalt and some heavy mineral grains are vulnerable to abrasion during transport and indicates a marked sediment yield from ancient sediment stored in the floodplain. This is in line with the high incision of the river bed over the last 150 years partly due to dam construction and aggregate mining.     

Pesticides Removal by Filtration over Cactus Pear Leaves: A Cheap and Natural Method for Small‐Scale Water Purification in Semi‐Arid Regions

This study aims to examine the efficiency of Opuntia ficus‐indica for removing organochlorine pesticides from surface waters. Adsorption properties such as size, dose, and time of O. ficus‐indica for aldrin, dieldrin, and dichlorodiphenyltrichloroethane (DDT) were studied through stirring and column methods. Because of their high affinity and swelling characteristics, dried O. ficus‐indica was studied in stirring while fresh unpeeled O. ficus‐indica was applied in both stirring and column experiments and proved to be well‐suited to column application. Before removing pesticides, the column was flashed with distilled water eliminate the turbidity and smell from fresh unpeeled cactus. The removal of pesticides increased with an increasing adsorbent dose and decreased with adsorbent particle sizes. The optimum adsorbent dose is 10 g for dried and 15 g for fresh unpeeled O. ficus‐indica. The experimental results show that O. ficus‐indica possesses strong adsorption ability for aldrin, dieldrin, and DDT, and the adsorption isotherm data obeyed the Freundlich model. The results of our small‐scale experiments suggest a strong potential to develop local small‐scale water treatment units that can be used at the level of individual households or local communities, using a widely available adsorbent.     

Environmental health impacts of mobility and transport in Hai Phong, Vietnam

Traffic is an essential part of modern society and mobility is part of its socio-economic setting. However, signs of counter productivity arise as the current mobility patterns substantially affect our health, including the consequences from traffic accidents, air pollution—which causes even more victims than traffic accidents—and traffic-noise. The use of private motorised vehicles also contributes to sedentarism, climate change and psychological effects. This paper reviews these mobility related health effects and applies them to the situation in Hai Phong, a Vietnamese port-city in fast development and facing growing mobility patterns. In his Master Plan the city developed a view on its development together with the transportation infrastructure up to 2020. Together with the fast changing mobility patterns, such as a modal change from bicycles to motorcycles and cars, this lead to an increase in motorized vehicles and non-negligible environmental health risks. Applying the methodology of a Health Impact Assessment as used in previous studies the current health burden is estimated, focussing on particulate matter (PM) and noise. For PM₁₀ 1287 deaths per year were calculated for the current situation, where the estimated number of deaths by 2020 doubled up to 2741. Hospital admissions due to PM₁₀ raised from 44,954 now to 51,467 in 2020 and for PM_2.5 the restricted-activity days were calculated, accounting for 852,352 per year. For noise only calculations for the current state (2007) were performed. The total estimated DALYs due to noise was 4758.     

Structural changes of humic acids from sinking organic matter and surface sediments investigated by advanced solid-state NMR: Insights into sources, preservation and molecularly uncharacterized components

Knowledge of the structural changes that particulate organic matter (POM) undergoes in natural systems is essential for determining its reactivity and fate. In the present study, we used advanced solid-state NMR techniques to investigate the chemical structures of sinking particulate matter collected at different depths as well as humic acids (HAs) extracted from these samples and underlying sediments from the Saguenay Fjord and the St. Lawrence Lower Estuary (Canada). Compared to bulk POM, HAs contain more non-polar alkyls, aromatics, and aromatic C-O, but less carbohydrates (or carbohydrate-like structures). In the two locations studied, the C and N contents of the samples (POM and HAs) decreased with depth and after deposition onto sediments, leaving N-poor but O-enriched HAs and suggesting the involvement of partial oxidation reactions during POM microbial degradation. Advanced NMR techniques revealed that, compared to the water-column HAs, sedimentary HAs contained more protonated aromatics, non-protonated aromatics, aromatic C-O, carbohydrates (excluding anomerics), anomerics, OC_q, O-C_q-O, OCH, and OCH₃ groups, but less non-polar alkyls, NCH, and mobile CH₂ groups. These results are consistent with the relatively high reactivity of lipids and proteins or peptides. In contrast, carbohydrate-like structures were selectively preserved and appeared to be involved in substitution and copolymerization reactions. Some of these trends support the selective degradation (or selective preservation) theory. The results provide insights into mechanisms that likely contribute to the preservation of POM and the formation of molecules that escape characterization by traditional methods. Despite the depletion of non-polar alkyls with depth in HAs, a significant portion of their general structure survived and can be assigned to a model phospholipid. In addition, little changes in the connectivities of different functional groups were observed. Substituted and copolymerized carbohydrates and fused-ring aromatics detected in the present study likely represented an important part of molecularly uncharacterized components (MUC).