Adjacent Slope Research Articles

Two new tanaidaceans (Crustacea: Peracarida) from Portuguese submarine canyons (NE Atlantic, West Iberian Margin)

The Tanaidacea are ubiquitous and amongst the most abundant taxa in the deep sea. However, their diversity in submarine canyons remains largely unknown. Here, two new species and a new genus of Paratanaoidea are described. Paranarthrura cousteaui sp. nov. is distinguished by the combination of the following characters: post-cheliped sclerites not fused, presence of one seta in the maxilliped endite, one long midventral seta in cheliped, one penicillate seta in the basis of pereopods 4–6, uropod endopod bi-articulated and uropod exopod shorter than endopod article 1. This species was found at the upper reaches of three Portuguese canyons, Cascais, Setúbal and Nazaré Canyons, and the adjacent open slope, between 897 and 1001 m water depths. Tirana vallis gen. et sp. nov. presents a combination of the characters that define the other two genera of Paranarthrurellidae, Paranarthrurella and Armatognathia, but also unique characters within the family: the antenna, cheliped and uropod are more elongate than the rest of the species; the pereopods 4–6 carpus spines reach at least half of the length of the propodus and the propodus of pereopods 4–6 have ramified subdistal spines. This species was found at the middle reaches of Setúbal Canyon (3214–3219 m water depth).

Продуктивність поліпшених та культурних сіножатей і пасовищ в басейнах малих і середніх річок зони Лісостепу

Goal. To determine the efficiency of agricultural use of floodplains of rivers and adjacent areas for improved and cultivated hayfields and pastures as well as areas for improving the environmental situation in the context of climate change in the Forest-Steppe. Methods. Field, laboratory, statistical, energy and systems analysis. Results. Growing perennial grasses on drained peat soils provides both high land productivity and environmental protection. Yield at the application of phosphorus-potassium fertilizers (P45K120) on improved pastures is 7.13-7.41 t/ha of dry weight and 0.86-0.93 t/ha of crude protein; on cultivated pastures, respectively — 7.16-7.8 t/ha and 0.86-1.04 t/ha. On the background of N90R45K120 the productivity of improved and cultivated pastures increases respectively to 8.49-8.64 t/ha and 1.08-1.15 t/ha. Creating improved pastures also provides energy and resource savings. On cultivated hayfields in the conditions of climatic changes and with the use of modern varieties of cereal grasses productivity is high and makes on the background of P45K120 to 6,4-8,5 t/ha of forage units, and at the use of N90R45K120 — 8,1-10,4 t/ha accordingly. Application of nitrogen fertilizers on pastures and cultivated hayfields should begin from the 2nd year of grassland use. From the 2nd year of grassland use, the content of nutrients in the soil does not exceed the maximum allowable concentrations and confirms the great protective ability of meadow grasslands as a natural filter that protects the environment from pollution. The analogy is the effect of perennial grasses on the adjacent sloping lands. The approximate duration of the grazing period is 170-180 days, and of mowing conveyors — for 145 days. It is expedient to use such conveyors both from the economic and from the energy point of view. Conclusions. For the rational use of drained peat soils and adjacent slopes, taking into account economic, energy, and environmental feasibility, they should create improved and cultivated hayfields and pastures with a productivity of 7.13-11.5 t/ha of dry matter (at the use of P45K120), and 8.49-13.2 t/ha (at the use of complete mineral fertilizer). The duration of the grazing period is 185 days, and the green conveyor is 145 days. These lands are the natural filter that protects rivers from pollutants and combines their highly productive use with improving the environmental conditions of river basins.

Soil Organic Carbon Distribution in a Humid Tropical Plain of Cameroon: Interrelationships with Soil Properties

Soil organic carbon (SOC) determination is very important in the assessment of agronomic potential of a soil. The objective of this study was to determine SOC contents and stock distribution with depth in relation to selected soil properties. Five types of soils, namely, Mollic Endoaquents, Oxyaquic Paleudalfs, Oxyaquic Udifluvents, and Mollic Udifluvents from a humid tropical plain and Typic Eutrudepts from an adjacent foot slope, were studied. The soils have all developed from fluvial sediments. Morphological and physicochemical characteristics of the soils were obtained using standard methods. Soil texture varied across the different sites and within soil profiles with textural classes of genetic horizons ranging from sandy loam to heavy clay. The soils are generally young soils under development as indicated by their high silt/clay ratios which ranged between 0.23 and 2.45. All the soils were generally acidic with pH-H2O values ranging from 4.5 to 6.2. Exchangeable H+ and Al3+ ranged from 0.5 to 2.3 and 0.2 to 3.3 cmolckg−1, respectively. SOC contents are generally higher in surface horizons and decrease with depth. In general, SOC correlated significantly with bulk density (BD) (r = −0.648, p < 0.01 ), water holding capacity (r = 0.589, p < 0.01 ), exchangeable Al3+ (r = 0.707, p < 0.01 ), and exchangeable H+ (r = 0.456, p < 0.05 ). The correlation between SOC and exchangeable Al3+ was strongest in the Mollic Endoaquents (r = 0.931, p < 0.01 ). SOC contents correlated significantly with Munsell soil color attributes, explaining between 40 and 57% of SOC variation. Total SOC stocks at a depth of 100 cm varied between 260.1 and 363.5 t·ha−1, and the variation in SOC stocks across a profile appears to be controlled by genetic horizon depth, while land use type influences SOC stock variations across genetic surface horizons.

Cross-shelf export of particulate organic carbon in the northern South China Sea: Insights from a 234Th mass balance

Cross-shelf transport of particulate organic carbon (POC) is an essential but poorly quantified process regulating the POC flux and the biological pump efficiency in marginal seas. Here, we estimated the cross-shelf export flux of 234Th and POC from the northern South China Sea (NSCS) shelf based on a dataset of 234Th in the water column and the underlying sediments over the shelf (bottom depth ≤ 200 m) and the adjacent slope (bottom depth > 200 m). Based on a full mass balance of 234Th throughout the water column and the underlying sediments, we found that besides radioactive production and decay, sedimentary accumulation and cross-shelf export associated with drifting particles were the most important processes in the 234Th budget. The input via horizontal shelf-slope water exchange and along-shelf water transport was a 234Th source to the shelf water, and neglecting this component would underestimate the actual vertical 234Th and POC fluxes by ~10–33%. The POC flux via vertical export from the euphotic zone was 26 ± 1 mmol m−2 d−1 while that via cross-shelf transport was 9.9 ± 3.4 mmol m−2 d−1. The cross-shelf exported POC presumably inject into the intermediate/deep waters and could be trapped for several decades in the SCS. Our results highlight the importance of cross-shelf POC transport in regulating carbon storage in the SCS on seasonal to longer time scales. A compilation of the case studies regarding cross-shelf transport suggests its role in the carbon cycle might be more important than previously recognized and needs to be re-evaluated.

The role of habitat heterogeneity and canyon processes in structuring sediment macrofaunal communities associated with hard substrate habitats in Norfolk Canyon, USA

Topographic and hydrodynamic complexity in submarine canyons promotes steep gradients in food availability and geophysical parameters which affect ecological assemblages and beta diversity. While habitat heterogeneity in submarine canyons is known to support diverse and abundant megafaunal communities, due to difficulty in sampling little is known about infaunal communities adjacent to hard substrate habitats, their contribution to canyon assemblages, and overall deep-sea diversity. Sediments were collected in three distinct habitat types: within Norfolk Canyon (western Atlantic) adjacent to hard substrate habitats including canyon walls and large boulders, along the main axis of the canyon, and on the adjacent continental slope to quantify macrofaunal (>300 μm) density, diversity and community composition, and sediment geochemical parameters including grain size, organic content, and stable isotope composition. While macrofaunal densities were similar among habitats sampled at comparable depths, diversity was higher near the hard substrate environments. Discrete communities were present in each habitat type, while annelid functional composition was similar between hard substrate adjacent and canyon axis habitats. Although diversity and abundance of hard substrate adjacent sediment communities did not change with depth, communities were driven by sediments with low organic matter content, whereas canyon and slope community assemblages were best explained by depth and higher organic content. Beta diversity among hard substrate adjacent sediments and canyon axis communities was high, with 27% of canyon taxa and 10% of regional taxa only occurring in hard substrate habitats. Given the thousands of submarine canyons worldwide, our results highlight the overall importance of substrate habitat heterogeneity within canyons in supporting deep-sea benthic diversity and suggest that both within-canyon and regional diversity are underestimated.

LANDSLIDE MONITORING IN A BUILT-UP AREA

The article deals with the evaluation and comparison of measured data from geotechnical monitoring of a gabion wall and an adjacent slope. In 2015, new anomalous phenomena related to deformations and a shift in the area of previously activated landslide were recorded on some monitoring elements in the area of the gabion wall. Measurements carried out in previous stages had revealed the re activation of landslides, probably due to a significant rise in groundwater levels, whose fluctuation has been up to 3 m. A proper evaluation of the obtained results cannot be quantified without the determination of warning status or without a stability calculation. Only the trend and magnitude of the measured values can be evaluated.

An investigation of snow drifting on low-sloped gable roofs: Wind-tunnel tests and CFD simulations

In this paper, a series of wind-tunnel tests and steady Reynolds-averaged Navier–Stokes (RANS) simulations were conducted to investigate the influence of roof slope upon snow drifting and flow characteristics around low-sloped gable roofs. First, the fresh-dry-snow-drifting processes on four gable roofs with inclinations of 5°, 10°, 15° and 20° were investigated via wind-tunnel tests using silica sand, and three reference wind velocities (namely 4.7 m/s, 5.85 m/s and 7.0 m/s) were taken into consideration. The snow-redistribution, peak-position, trapping-efficiency and transport-rate characteristics on model roofs were carefully discussed. The results of the wind-tunnel tests showed that roof slope significantly influenced snow depth on the leeward surface, that trapping efficiency increased along with roof slope, and that snow depth on the windward side was more affected by wind velocity. Sensitivity analyses for grid resolutions and inflow profiles were performed; the distributions of friction velocity, streamlines, positions of time-averaged vortex cores, and turbulence kinetic energy around buildings were investigated via numerical simulations. The change in the wind-flow pattern between inclinations of 10° and 15° resulted in the greatest transport-rate difference of all adjacent roof slopes. Finally, an empirical equation was provided that allowed the differential value between friction velocity and threshold friction velocity to estimate the snow-transport rate on the building roof.

Macrofaunal diversity and community structure of the DeSoto Canyon and adjacent slope

Northern Gulf of Mexico canyons are centers of organic matter accumulation and biodiversity, but studies of their finer-scale (sub-100 km) ecological patterns are scarce. Detailed sampling of macrofauna within the DeSoto Canyon was undertaken along 3 depth transects on the canyon wall, axis, and adjacent slope. Sediment, terrain, and water mass parameters were also compiled for the same stations. Within the canyon, macrofaunal abundance decreased, evenness increased, and richness followed the expected parabolic curve with depth, peaking at 1100 m. Cluster analysis identified 3 canyon depth groups that conformed to established bathymetric boundaries for the non-canyon Gulf of Mexico slope: Group I at <500 m, Group II at 669-1834 m, and Group III at >2000 m. Explanatory environmental models indicate that canyon community structure was strongly correlated with oxygen concentration and fluorescence, with a weaker potential influence from any of salinity, particulate organic carbon, sediment organic carbon, or slope. Comparisons of the habitats indicated that abundances were highest on the canyon wall. Slope community structure differed from that of either of the canyon habitats. Environmental models consisted of single variables including oxygen concentration, sediment organic carbon, slope, and temperature with similar explanatory values. Community differences within the canyon and between the canyon and adjoining slope contradict previous findings of a single faunal zone for the whole study area. Factors that may contribute to inter-habitat heterogeneity include potential hydrocarbon seepage, organically enriched sediment deposits along channels, or remnant influence from the Deepwater Horizon spill, warranting more research into this dynamic ecosystem.

Структурно-морфометрический анализ малого речного бассейна реки Ихе-Ухгунь (бассейн реки Иркут)

The article is devoted to the structural and morphometric analysis of a small rivers using the example of the Ihe-Ukhgun river basin (left tributary of the Irkut river), which is based on a complex processing of a digital elevation model (DEM). The author has prepared a hydrologically correct DEM based on the ALOS Digital Surface Model (DSM) satellite data, carried out an automated calculation and mapping of the basin erosion network based on the DEM data, calculated the structural indicators of the third-order basins for analyzing the basin organization of the small rivers network. Structural and morphometric analysis using GIS was practically not used for the Ihe-Ukhgun river basin which is placed in different landscapes, geological and geomorphological conditions. The work is based on geomorphometric and structural morphometric methods as well as the method of geoinformation mapping and relief modeling for analyzing lower-order basins. Thalweg erosion network modeling up to the fourth order of the river basin Ihe-Uhgun was carried out with using of DEM analysis in the ArcGIS 10 program. The map of the erosional network of the basin was constructed, morphometric indicators of rivers (length, area of basins, sum of slopes, coefficient of basin asymmetry, etc.) were obtained, and then the indices of the basin structure (structure of bifurcation, lengths, areas and slopes) were calculated. As a result, an asymmetric erosion network was revealed, which indicates a great work in the transfer of matter of first-order streams. First-order streams exceed those of the second and third orders streams in terms of catchment area, length and steepness of adjacent slopes. The interrelation of morphometric characteristics of different-order streams within third order sub-basins are most fully traced with the using of structural indices and their comparison with modal indicators. In general, the Ihe-Ukhgun river basin is characterized by a heterogeneous structure of the streams ratio of the first, second and third orders. The basins of the Khurguta, Khubyty and Ulan-Gol rivers have the highest degree of homogeneity. At the same time, for the Ihe-Ukhgun river basin, there is no direct relationship with the area of the third order drainage basins.

Monitoring of an embankment dam in southern Spain based on Sentinel-1 Time-series InSAR

Abstract Deformation monitoring is a common practice in most of dams to ensure their structural health and safety status. Systematic monitoring is frequently carried out by means of geotechnical sensors and geodetic techniques that, although very precise an accurate, can be time-consuming and economically costly. Remote sensing techniques are proved to be very effective in assessing deformation. Changes in the structure, shell or associated infrastructures of dams, including adjacent slopes, can be efficiently recorded by using satellite Synthetic Aperture Radar Inteferometry (InSAR) techniques, in particular, Muti-Temporal InSAR time-series analyses. This is a mature technology nowadays but not very common as a routine procedure for dam monitoring. Today, thanks to the availability of spaceborne satellites with high spatial resolution SAR images and short revisit times, this technology is a powerful cost-effective way to monitor millimeter-level displacements of the dam structure and its surroundings. What is more, the potential of the technique is increased since the Copernicus C-band SAR Sentinel-1 satellites are in orbit, due to the high revisit time of 6 days and the free data availability. ReMoDams is a Spanish research project devoted to provide the deformation monitoring of several embankments dams using advances time-series InSAR techniques. One of these dams is The Arenoso dam, located in the province of Cordova (southern Spain). This dam has been monitored using Sentinel-1 SAR data since the beginning of the mission in 2014. In this paper, we show the processing of 382 SLC SAR images both in ascending and descending tracks until March 2019. The results indicate that the main displacement of the dam in this period is in the vertical direction with a rate in the order of -1 cm/year in the central part of the dam body.

Examining relationships between entrainment-driven scalar dissimilarity and surface energy balance underclosure in a semiarid valley

A surface energy budget underclosure, equivalent to an undersampling of sensible and latent heat fluxes at the surface, is commonly observed in the daytime convective boundary layer over land. The two mechanisms currently held responsible for such underclosure are, on one hand, entrainment-induced reduction of heat fluxes due to low-frequency circulations spanning the depth of the convective boundary layer, and on the other hand, horizontal advection effects induced by surface horizontal heterogeneity. Given the involvement of both heat fluxes in the budget equation, it is expected that the turbulent perturbations of variables involved in these fluxes (potential temperature θ′ and specific humidity q′) contain the signature of both mechanisms. Here, we assess to what extent non-local entrainment effects contribute to the budget underclosure in complex terrain using a quadrant analysis and multiresolution flux decomposition approach.We use data collected in the semi-arid Owens Valley, CA, USA, during the Terrain-Induced Rotor Experiment (T-REX) campaign. The budget components are sampled near the surface of the valley floor and the adjacent slope, with turbulence flux measurements, pyranometers, pyrgeometers, as well as ground heat flux measurements. We found that the budget underclosure was within the range of underclosures reported in past studies, with a systematically poorer closure over the valley slope. Although quadrant analysis revealed a dominance of scalar-similar events, associated with convective boundary layer overturning, a high degree of disagreement was found between the scalar-dissimilar quadrants which represent the counter-gradient motions. Specifically, those turbulent motions associated with entrainment of free tropospheric air to the surface, were found to be of minor importance in degrading scalar similarity. Instead, we postulate that local horizontal advection and hectometre-scale land-use heterogeneity in the vicinity of both the valley floor and slope sites, are the major factors in controlling the relationship between the budget underclosure and scalar similarity.

Sponging up diversity: Evaluating metabarcoding performance for a taxonomically challenging phylum within a complex cryptobenthic community

AbstractDespite their ecological importance, sponges are often avoided in biodiversity studies and monitoring programs because they are notoriously difficult to identify using morphological or molecular methods. Here, we investigate the metabarcoding performance of universal degenerate cytochrome c oxidase subunit I (COI) primers in detecting species from this challenging phylum in a cryptobenthic community. Twenty‐two modified Autonomous Reef Monitoring Structures (ARMS) were deployed for 2 years in mesocosms receiving unfiltered seawater from an adjacent reef slope. Upon recovery, each unit was inspected by a marine sponge taxonomist who used a combination of taxonomy, imagery, and DNA barcoding (28S rRNA and COI) to identify sponges and generate a validated taxonomic richness value for each ARMS unit. A total of 69 unique sponge barcoded morphologies (BMs) were identified from the classes Calcarea, Demospongiae, and Homoscleromorpha. Metabarcoding identified 41 unique sponge molecular operational taxonomic units (MOTUs) from Demospongiae and Homoscleromorpha but the primers failed to amplify any species from the class Calcarea which comprised 22% of the BMs. Sponge richness did not differ between BMs and MOTUs assigned to the classes Demospongiae and Homoscleromorpha. However, assignments at the order and family level in Demospongiae underscore known limitations in sponge taxonomic resolution using the COI gene. The prevalence of false positives within the order Suberitida and the pervasiveness of false negatives within the order Haplosclerida highlighted both technical and biological constraints in the metabarcoding method. Overall, these results confirm the need for discretion in sponge MOTU assignments using universal degenerate barcoding primers that target a short fragment of the COI gene. However, they also demonstrate that COI metabarcoding is capable of capturing sponge richness from a complex natural community.

Riparian wetland properties counter the effect of land-use change on soil carbon stocks after rainforest conversion to plantations

Progressive conversion of tropical rainforests to agricultural monocultures in South East Asia increasingly affects landscape types such as riparian areas. The impacts of conversions on soil organic matter (SOM) vary with changing landforms. However, this was often not accounted for in previous studies where SOM in soils in riparian areas was combined with SOM from well-drained adjacent slopes. Because riparian areas have a high carbon (C) storage potential, our objectives were i) to assess their C stocks after conversion to rubber and oil palm plantations in Sumatra (Indonesia) and ii) to compare the impacts of land use conversion on C stocks between riparian and well-drained areas. Average soil C stock losses from the top 30 cm were about 14% and 4% following conversion of riparian forest to rubber and oil palm plantations, respectively, indicating a high resistance of C to mineralization. C losses from well-drained areas were twice as high as from riparian areas after the respective conversion. δ13C values from riparian areas showed clear heterogeneity down soil profiles that was explained i) by alternating oxic and anoxic conditions, leading to reduced SOM and litter decomposition in riparian areas and ii) by mineral sediments and organic matter deposition and accumulation by erosion from adjacent slopes covered by plantations. We conclude that riparian areas are more resilient in terms of soil C storage towards land-use change than well-drained areas because of sediment deposition and reduced oxygen availability. On this basis, we developed a conceptual model of the effects of land-use change and various ecotone characteristics on SOM mineralization in the top- and subsoil of riparian areas.

Depositional and erosional signatures in sedimentary successions on the continental slope and rise off Prydz Bay, East Antarctica– implications for Pliocene paleoclimate

The Prydz Bay region of Antarctica is the immediate recipient of ice and sediments transported by the Lambert Glacier, the single largest outflow from the East Antarctic Ice Sheet. The continental slope and rise provide records covering multiple glacial cycles and containing paleoclimatic information. Marine geological and geophysical data collected from the continental shelf and adjacent slope of Prydz Bay, Antarctica, including seismic reflection data, bathymetry, and core records from ODP drilling sites, reveal the history of glacial sediment transport and deposition since the early Pliocene times. Seismic facies are interpreted in terms of episodes of slope progradation, contourite, turbidite, trough-mouth fan, and mass transport deposition. Two seismic units with estimated age of early to late Pliocene and late Pliocene to recent have been analyzed in detail for the area immediately offshore the Lambert Glacier and Prydz Bay and the adjacent Mac. Robertson margin. The upper slope is dominated by episodic mass transport deposits, many of which accumulated to form a trough mouth fan since Early Pliocene times. The trough mouth fan contrasts with the adjacent steep (4–6°) continental slope of the Mac. Robertson margin, where glacigenic sediments have been transported down slope as high-velocity turbidity currents via submarine channels. The distal region exhibits evidence for contrasting effects of high-energy, traction-dominated versus lower-energy, fallout-dominated suspension flows. The counter-clockwise Coriolis force modifies the erosion and deposition patterns of turbidity currents creating an asymmetric channel-levee architecture. Since the early Pliocene, turbidite sedimentation surpassed the amount of sediment reworked and transported by westward-flowing contour currents along the base of slope. On the continental rise, contourites and sediment waves were deposited in response to enhanced bottom-water formation, which is consistent with climatic cooling since late Pliocene times. This study, based on existing seismic reflection and ODP data, highlights the need for a future scientific ocean drilling proposal on the Prydz Bay continental slope and rise in order to more accurately determine the timing of the important events that have influenced the evolution of this margin.

Моделювання дії навантаження від транспортних засобів на стан дорожнього одягу та прилеглих схилів за даними геоакустичних спостережень

Моделювання дії навантаження від транспортних засобів на стан дорожнього одягу та прилеглих схилів за даними геоакустичних спостережень

Species and Functional Diversity of Deep-Sea Nematodes in a High Energy Submarine Canyon

Gaoping Submarine Canyon (GPSC) off southwestern Taiwan is a high energy canyon connected to a small mountain river with extremely high sediment load (~10 kt km-2 y-1). Due to heavy seasonal precipitation (>3000 mm y-1) and high tectonic activity in the region, the GPSC is known for active sediment transport processes and associated submarine geohazards (e.g., submarine cable breaks). More importantly, strong internal tides have been recorded in the GPSC to drive head-ward, bottom-intensified currents, which result in sediment erosion and resuspension in response to the tidal cycles. To understand the effects of extreme physical conditions on marine nematodes, we sampled the surface sediments along the thalweg of upper GPSC and adjacent slope (200-1100 m) using a multicorer in the summer and fall of 2015. We found that the nematode species, functional, trophic diversity and maturity dropped significantly in the GPSC as compared with slope communities, but the nematode abundances were not affected by the adverse conditions in the canyon. The non-selective deposit-feeding, fast colonizing nematodes (e.g., Sabatieria, Daptonema, Axonolaimus, and Metadesmolaimus) dominated the canyon seafloor. In contrast, other species of non-selective deposit feeders (Setosabatieria and Elzalia), epigrowth feeders (Craspodema), omnivores/predators (Paramesacanthion), and other species constituted the diverse nematode assemblages on the slope. We found that the strong bottom currents in the GPSC may depress the local nematode diversity by removing the organic-rich, fine-grained sediments; therefore, only the resilient or fast recovering nematode species could survive and prevail. The high species turnover with depth and between the canyon and slope habitats demonstrates that strong environmental filtering processes were the primary mechanism shaping the nematode community assembly off SW Taiwan. Between the canyon and slope, a considerable contribution of nestedness pattern also indicates some degree of local extinction and dispersal limitation in the dynamic GPSC.

Geomorphology of the upper Mkhomazi River basin, KwaZulu-Natal, South Africa, with emphasis on late Pleistocene colluvial deposits

ABSTRACT We present a 1:50 000 scale geomorphological map of the upper Mkhomazi River basin, located in the foothills of the Drakensberg mountains in KwaZulu-Natal Province, South Africa. The sub-horizontal strata of the Permo-Triassic Beaufort Group forms plateau interfluves with a concave valley slope morphology. Locally, thick sequences of late Pleistocene colluvial deposits and associated buried paleosols (Masotcheni Formation) infill first-order tributary stream valleys and extend across the adjacent lower slopes. Surface runoff processes preferentially incise into the poorly consolidated, highly erodible sediments causing severe gully erosion that is responsible for widespread land degradation and desertification phenomena. The main purpose of this work is to derive a geomorphological map of the study area focussing on the erosional landforms to understand their spatial distribution and their relation to the colluvial deposits. Finally, a local and regional stratigraphic correlation of colluvial deposits and associated buried palaeosol profiles is proposed.

Salt Marsh Migration Potential at Cape Cod National Seashore (Massachusetts, U.S.A.) in Response to Sea-Level Rise

Smith, S.M., 2020. Salt marsh migration potential at Cape Cod National Seashore (Massachusetts, U.S.A.) in response to sea-level rise. Journal of Coastal Research, 36(4), 771–779. Coconut Creek (Florida), ISSN 0749-0208.Salt marshes can adjust to sea-level rise (SLR) through vertical elevation gain and horizontal expansion into terrestrial environments. The latter depends on the topography of adjacent uplands and the availability of suitable substrate for halophyte colonization. Within Cape Cod National Seashore (CCNS), calculations of marsh migration potential in response to 1-m of SLR were completed using ArcGIS (version 10.4) based on real-time kinematic GPS marsh elevations, local tide data, land-use, and upland topography derived from 2011 LIDAR scans of CCNS. These estimates were combined with marsh-loss predictions from a previous study within their present-day footprint under the same SLR scenario. The results suggest that individual marshes will respond quite disparately, as dictated by their position in the tidal frame, adjacent terrestrial slopes, land-use, and barrier-beach losses. Most sites are expected to gain or lose relatively small amounts of marsh area under few or no migration constraints. However, there could be a large increase (∼144–240 ha) at one site and an almost a complete loss at another (∼260–290 ha). Where migration was constrained to slopes ≤1%, opportunities for marsh expansion diminished the most—even more so when barrier-beach losses are simulated. Overall, losses at five marsh sites were offset by gains at Hatches Harbor and Pleasant Bay, Massachusetts, such that the total area of salt marsh actually increases with 1-m of SLR, except under the strictest slope constraints. Changes in the spatial distribution and total extent of salt marsh within the CCNS will influence both the quality and quantity of ecosystem services they provide. For coastal land managers, understanding the potential for overland marsh migration is critical for the kind of land-use planning that accommodates these transitioning salt marshes.

Forebays of the poligonal cross-section of the irrigating pumping station

The article discusses the use of the design of the forebays of a polygonal cross-section to improve the hydraulic characteristics of the water intake structures of pumping stations, in which the longitudinal slope in the direction of the middle chamber is i = 0.1, the adjacent longitudinal slope is 0.15 and with the extreme chambers the longitudinal the slope is 0.2. The faces of each chamber with a forebay have a transverse slope equal to i c = 0.1 and the angle of taper of the forebays in the plan is α = 35°. In the joint operation of 5 pumps, for the forebays of a polygonal cross-section, the total resistance coefficient is ∑ξ total ext. = 0.568 and for a typical ∑ξ total ext. = 0.72. With the simultaneous operation of 5 pumps, the average supply of 3 pumps is 0.0051 m3/s, 2, and 4 pumps, respectively 0.00498 … 0.00504 m 3 /s, for 1 and 5 pumps, 0.00478, and 0.00481 m 3 /s, respectively at the extreme pumps, the flow rate increases by 4.9…6.3% relative to the standard forebays.

On the Challenges of Soil Phosphorus Prospections in Heterogeneous Environments\u2014a Case Study on the Iron Age Altenburg Hillfort (Niedenstein, Hesse, Germany)

Heterogeneous environments might be considered inadequate for geoarchaeological soil phosphorus (P) prospections due to the manifold potential alterations of archaeologically relevant soil P contents. To elucidate if this assumption is correct, we conducted a case study in the heterogeneous environment of the Iron Age Altenburg hillfort near Niedenstein (Hesse, Germany). We introduce the least influenced area (LIA) approach to deduce the native soil P contents of the local soils inductively from own soil P data. The native P contents are crucial for further data evaluation in any P prospection. Moreover, we develop two parameters to quantify and compare soil P enrichment in pedogenically heterogeneous areas: the mean enrichment ratio (MER) and the maximum enrichment ratio (XER). Finally, we modify and discuss the approach of Lorch (The Science of Nature 28(40/41):633–640, 1940) to interpret spatial patterns of soil P enrichment with regard to prehistoric land use. Our study shows that soil P prospections can be conducted in heterogeneous environments. Still, they require a systematic field work strategy and soil scientific support. Moreover, instead of absolute soil P contents, alternative parameters must be derived from the data to evaluate soil P enrichment adequately for a heterogeneous area. Using such alternative parameters on the basis of our data, the Iron Age Altenburg hillfort was significantly larger than formerly assumed. Only the Altenburg plateau and the directly adjacent slopes seem to have been densely covered with buildings. The neighboring areas might have been used for different purposes including agriculture, livestock grazing, and economic activities.