Taxonomic and functional responses of benthic macroinvertebrate communities to hydrological and water quality variations in a heavily regulated river

Aquatic macroinvertebrates are frequently used to evaluate river system conditions and restoration project performance. A better understanding of macroinvertebrate community responses to multiple stressors is a primary challenge for river science. In this paper, macroinvertebrate responses to hydrological and water quality variability were studied in the regulated Oglio River (northern Italy). We hypothesized that in regulated rivers the hydrological, rather than the physico-chemical conditions, would affect macroinvertebrate communities and biomonitoring tools (taxonomic metrics and functional indices). Repeated sampling (six times a year) was performed at four sites downstream of four dams in a 30 km river stretch during 2014 and 2015. Data were analysed using a linear mixed effect framework, to take into account random variation due to site and sampling date, and with multivariate analysis to track changes in community structure. A total of 69 families and 134,693 organisms were identified. The investigated metrics were mainly affected by the coefficient of variation of discharge, minimum discharge, ammonium, and temperature. The short-term dynamics of hydrological and physico-chemical variables were generally less important than the overall random effects as drivers of macroinvertebrate-based metrics. However, the relevance of a random effect (site, time, their interaction) differed depending on the biological metrics analysed. Understanding potential differences in response to short term and short stretch conditions would benefit biomonitoring and restoration procedures in both regulated and natural rivers

Prograde LWS-KY Transition During Subduction Of The Alpine Continental Crust Of The Sesia-Lanzo Zone : The Ivozio Complex

The first occurrence of the lawsonite-kyanite transition is described in the Ivozio complex eclogites of the central Sesia-Lanzo Zone (Western Austroalpine Domain, Italian Alps). The transition from prograde lawsonite to kyanite-bearing eclogites was recorded during a clockwise subduction-exhumation P-T-t-d path. The P-T-t-d evolution of the Ivozio complex is characterized by an Alpine multistage structural and metamorphic re-equilibration: D1 deformation, represented by a penetrative foliation, is the relic of a prograde low-T history, which took place under the epidote-blueschists facies conditions (T = 350-500°C and P ≤ 1.2 GPa). Post-D1a re-equilibration stage is marked by the growth of Omp and Lws in eclogites: during this stage T was 520 ± 30 °C at P = 1.4 to 2.2 GPa (eclogite facies conditions). During post-D1b stage the stable association of Omp + Ky + Ep (in lawsonite-eclogites) developed at T 610 ± 20°C and P ≥ 2.0 GPa. This assemblage coincided with Tmax-PTmax conditions. During D2 a penetrative foliation marked by Omp + phengitic/paragonitic white mica + Amp + Ep in eclogites and amphibole-schists was imprinted. In ultramafics (including serpentinites) S2 is widespread as a planar fabric, marked by serpentine + chlorite + amphibole ± ilmenite ± clinopyroxene ± carbonate ± talc. This stage is characterized by temperatures spanning from 500 to 600°C at P ≤ 2.0 GPa. D3 deformation, developed under greenschists facies conditions, is associated with a crenulation cleavage or discrete shear bands. The early stages of this subduction-exhumation cycle mainly occurred under a low-T regime (i.e. lawsonite-bearing conditions); subsequently the temperature increased (kyanite-eclogite conditions) before the exhumation of the Ivozio complex, marked by the transition to paragonite-eclogite conditions under a steady state thermal regime

How hydromorphological constraints and regulated flows govern macroinvertebrate communities along an entire lowland river

Macroinvertebrates\u2019 response to hydromorphological alterations and regulated flows along lowland rivers is still poorly known despite ecohydrology\u2019s fundamental role in river science. Along the Oglio River (Northern Italy), several water abstractions and dams break it into segments with varying hydraulic and morphological properties. Three types of a priori different environments were identified (dammed, downstream and free flowing sections), and macroinvertebrate communities were sampled from each zone. This study aimed (i) to investigate patterns of macroinvertebrate communities along a regulated lowland river by testing the a priori zones; (ii) to find macroinvertebrate taxa that served as indicators of the various hydrological conditions and (iii) to verify hydromorphological control over ecological macroinvertebrate traits resulting in different trait values in each identified zone. Macroinvertebrate community was characterized in a total of 63 stations by means of two quantitative approaches, each exploring a surface of 0.5m2. The lowest richness values were found in dammed sites that tended toward lentic conditions. Ecnomidae (dammed zones), Limoniidae (downstream zones) and Heptageniidae (free flowing section) were identified as the best indicators of varying hydrological conditions. As suggested by the results of 4th Corner Method, environmental constraints define communities with different ecological traits. These results highlight hydromorphological control over macroinvertebrate community structure and reflect how regulated flows affect the Oglio River in terms of biodiversity, indicator taxa and ecological traits. The authors wish to stress the importance of considering the ecological effects of dams and impoundments on river systems in upstream areas as well as downstream

Taxonomic and functional responses of benthic macroinvertebrate communities to hydrological and water quality variations in a heavily regulated river

Aquatic macroinvertebrates are frequently used to evaluate river system conditions and restoration project performance. A better understanding of macroinvertebrate community responses to multiple stressors is a primary challenge for river science. In this paper, macroinvertebrate responses to hydrological and water quality variability were studied in the regulated Oglio River (northern Italy). We hypothesized that in regulated rivers the hydrological, rather than the physico-chemical conditions, would affect macroinvertebrate communities and biomonitoring tools (taxonomic metrics and functional indices). Repeated sampling (six times a year) was performed at four sites downstream of four dams in a 30 km river stretch during 2014 and 2015. Data were analysed using a linear mixed effect framework, to take into account random variation due to site and sampling date, and with multivariate analysis to track changes in community structure. A total of 69 families and 134,693 organisms were identified. The investigated metrics were mainly affected by the coefficient of variation of discharge, minimum discharge, ammonium, and temperature. The short-term dynamics of hydrological and physico-chemical variables were generally less important than the overall random effects as drivers of macroinvertebrate-based metrics. However, the relevance of a random effect (site, time, their interaction) differed depending on the biological metrics analysed. Understanding potential differences in response to short term and short stretch conditions would benefit biomonitoring and restoration procedures in both regulated and natural rivers

Is flood irrigation a potential driver of river-groundwater interactions and diffuse nitrate pollution in agricultural watersheds?

In the Po plain, northern Italy, rivers within agricultural basins display steep summer increases in nitrate (NO3-) concentrations. Flood irrigation in overfertilized, permeable soils may drive such diffuse pollution, facilitating interactions between NO3--rich groundwater and surface waters. We discuss multiple, indirect evidence of this mechanism in the Adda, Oglio, and Mincio rivers. These rivers drain agricultural soils with elevated nitrogen (N) surpluses, averaging 139, 193, and 136 kg ha(-1) in the Adda, Oglio, and Mincio watersheds, respectively. The three rivers cross a transitional area between highly permeable and impermeable soils, where summer NO3- concentrations may increase by one order of magnitude over short distances (8-20 km). Upstream of this transitional area, a major fraction of the river flow is diverted for flood irrigation, a traditional and widespread irrigation technique for permeable soils. We speculate that diverted water solubilizes soil N excess, recharges the aquifer, and transfers soil N surplus into groundwater, resulting in NO3- pollution. Groundwater-river interactions were estimated experimentally, via water and NO3- budgets in 0.3 to 1 m(3) s(-1) km(-1) and in 1500 to 5400 kg NO3--N day(-1). The data suggest a pronounced east-west gradient of groundwater to river diffuse water inputs among the three adjacent basins, reflecting the soil permeability and the width of the river-groundwater interaction zone. Given the large stock of NO3- in groundwater, management interventions performed at the basin scale and aimed at decreasing N excess will not produce an immediate decrease in river NO3- pollution

Neuronal Cells Confinement by Micropatterned Cluster-Assembled Dots with Mechanotransductive Nanotopography

Artificially grown neuronal cultures of brain cells have been used for decades in the attempt to reproduce and study in vitro the complexity of brain circuits. It soon became evident that this alone was insufficient, because of the random architecture of these artificial networks. Important groundwork therefore resulted in the development of methods to confine neuronal adhesion at specific locations to match predefined network topologies and connectivity. Despite this notable progress in neural circuitry engineering, there is still need for micropatterned substrates that recapitulate better biophysical cues of the neuronal microenvironment, taking into account recent findings of their significance for neuronal differentiation and functioning. Here, we report the development and characterization of a novel approach that, by using supersonic cluster beam deposition of zirconia nanoparticles, allows the patterning of small nanostructured cell-adhesive areas according to predefined geometries onto elsewhere nonadhesive antifouling glass surfaces. As distinguishing features, compared to other micropatterning approaches in this context, the integrated nanostructured surfaces possess extracellular matrix-like nanotopographies of predetermined roughness; previously shown to be able to promote neuronal differentiation due to their impact on mechanotransductive processes, and can be used in their original state without any coating requirements. These micropatterned substrates were validated using (i) a neuron-like PC12 cell line and (ii) primary cultures of rat hippocampal neurons. After initial uniform plating, both neuronal cells types were found to converge and adhere specifically to the nanostructured regions. The cell-adhesive areas effectively confined cells, even when these were highly mobile and repeatedly attempted to cross boundaries. Inside these small permissive islands, cells grew and differentiated, in the case of the hippocampal neurons, up to the formation of mature, functionally active, and highly connected synaptic networks. In addition, when spontaneous instances of axon bridging between nearby dots occurred, a functional interdot communication between these subgroups of cells was observed