Substrate Depth Research Articles

Stormwater retention capacity of blue-green roofs with various configurations: Observational data and modelling

Although dynamic changes in stormwater retention capacity (SRC) determine overall stormwater retention performance of blue-green roofs, few previous studies have investigated the dynamic changes of SRC of blue-green roofs with various configurations. In this research, an experiment was designed to observe hydrological processes of blue-green roofs in Beijing. Based on the water balance theory, a conceptual hydrological model was developed by integrating a modified FAO-56 Penman-Monteith model, an AET formula with a water stress coefficient and Dalton’s equation. Then the proposed model was validated using experimental data. Results show that the model can simulate the SRC dynamics well, with the Nash-Sutcliffe and determination coefficients both exceeding 0.6. The consumption and recovery of the SRC in blue-green roofs are mainly driven by rainfall and actual evapotranspiration, respectively. As actual evapotranspiration decreases with seasonal changes, the fluctuation amplitude of SRC in blue-green roofs diminishes, ranging from 32.53 mm to 11.34 mm. Although increasing the depth of substrate and storage layers is able to enhance the SRC of blue-green roofs, there are optimal upper limits for these depth because of regional climate conditions. In Beijing, the optimal upper limits for substrate and storage layer depths are 300 and 30 mm, respectively. This information can assist designers in evaluating the cost-effectiveness of design choices for blue-green roofs. The developed model serves as an effective tool for simulating SRC and is expected to aid in the design of blue-green roofs.

Modelling and Experimental Validation of the Flame Temperature Profile in Atmospheric Plasma Coating Processes on the Substrate

This work presents a characterisation model for the temperature distribution at different substrate depths during the atmospheric plasma spray (APS) coating process. The torch heat flow in this model is simulated as forced convection defined by a surface, a temperature profile, and a convection coefficient. The simulation model considers three plasma temperature profiles of the Al2O3 coating on a 5 mm thickness flat aluminium substrate. The simple and low-cost experimental procedure, based on a thermocouple, measures the plasma plume temperature distribution of the APS coating system, and their results are used to obtain the parameter values of each of the three proposed plasma temperature profiles. The experimental method for in situ non-contact temperature measurements inside the substrate is based on an infrared pyrometry technique and validates the simulation results. The Gaussian temperature profile shows excellent accuracy with the measured temperatures. The Gaussian approach could be a powerful tool for predicting residual stress through a coupled one-way thermal-mechanical analysis of the APS process.

Gastropods on the green roof of a high-rise building in a large European city

Understanding the distribution and diversity of terrestrial snails on green roofs (GR) can facilitate insights into the ecological functioning of these urban habitats. While green roofs have been shown to provide suitable habitat for mobile species such as birds and insects, there needs to be more research concerning the colonisation and persistence of less mobile animal groups, including terrestrial gastropods. The present study investigates the species richness of terrestrial gastropods on green roofs of high-rise buildings in Bratislava, Slovakia. The study examined four distinct types of green roofs: The green roofs were classified according to their management intensity, resulting in four categories: extensive, semi-intensive GR-A, semi-intensive GR-B, and intensive. The categories differed in terms of vegetation, substrate depth, irrigation, and sun exposure. The survey employed a variety of methods, including pitfall trapping, vegetation sweeping, soil sampling, and microhabitat investigations. The survey yielded evidence of 11 species of terrestrial gastropods (six snails and five slugs) inhabiting three GR types. The semi-intensive GR-A, which is characterised by dense vegetation and minimal management, supported all 11 species. No gastropods were observed on the extensive GR with shallow substrate and Sedum sp. vegetation. The presence of native and non-native species, including the non-native slug Ambigolimax valentianus, indicates that terrestrial gastropods can colonise GR. These findings emphasise the potential of GR to support urban biodiversity and highlight the need for further research on less mobile species in these habitats.

Evaluating the Performance of Cocopeat and Volcanic Tuff in Soilless Cultivation of Roses.

Roses are increasingly being grown in soilless systems to increase productivity and reduce the challenges associated with soil-based cultivation. This study investigates the effects of using cocopeat and volcanic tuff substrates, the particle size of tuff, and substrate depth on the growth and flower quality of roses (Rosa hybrida L. cv. top secret) grown under greenhouse conditions. The treatments were cocopeat, tuff, cocopeat-tuff mixture, and tuff of particle size of 2 to 4 mm, 0 to 4 mm, and 0 to 8 mm at depths of 20 cm and 40 cm. The results showed that cocopeat had the highest water-holding capacity and photosynthetic rate. Tuff substrates had higher chlorophyll content throughout the growing season. Although flower numbers per plant in cocopeat and tuff from 0 to 8 mm at a depth of 20 cm were statistically similar, tuff from 0 to 8 mm had longer flowering stems and larger post-harvest flower diameters than cocopeat. An increase in the tuff depth from 20 to 40 cm decreased the flower number and main stem diameter. In conclusion, while cocopeat promotes rapid initial growth, volcanic tuff substrates, particularly tuff from 0 to 8 mm at a depth of 20 cm, provide long-term benefits for flower quality and plant health.

Burrowing for answers: Investigating Syrian hamster welfare through owner surveys.

Syrian hamsters are a relatively common pet species in the UK. However, we know very little about how they are kept. The aim of this study was to identify areas of good and poor practices among Syrian hamster owners using owner surveys. A survey of pet hamster owners was conducted with questions on husbandry, behaviour and health. There were 548 survey responses. Over 95% of the owners provided a wheel, hideaway or chew toy, and over 90% housed their hamster alone. However, 18.4% of the owners used hamster balls, hamsters may have been fed a diet that was not entirely appropriate, and over 45% of respondents reported that their hamsters were housed in close proximity to predator species. Most (65.9%) hamsters had never been taken to a veterinarian. Hamster ball use, shallower substrate depth and more frequent handling were significantly associated with greater owner observations of bar biting. A key limitation is that the respondents may not be representative of the average pet hamster owner, so this research does not provide a complete picture of the current state of hamster welfare. There are some welfare concerns regarding the way Syrian hamsters are currently kept in the UK.Therefore, attempts to better distribute information about hamster care to owners should be made.

Effects of Design Factors and Multi-Stage Environmental Factors on Hydrological Performance of Subtropical Green Roofs

Environmental and design factors determine the stormwater management capacity of green roofs; however, the design and environmental factors that impact their hydrological performance in subtropical humid regions are poorly understood. In particular, meteorological factors have received little attention. Meteorological factors vary greatly at different stages of a rainfall event (e.g., during the rainfall and outflow). Therefore, the impact of meteorological factors at different stages on hydrological performance should be considered separately to obtain a more accurate picture of their effects on hydrological performance. In this study, experimental green roofs were established based on four substrate types and two depths. For the first time, this study systematically explored the effects of design factors for the substrate (type and depth) and multi-stage environmental factors on the hydrological performance of green roofs. Environmental factors, including meteorological factors, from three critical stages (before and during a rainfall event and during the outflow), and rainfall characteristics (e.g., rainfall depth and rainfall duration) were incorporated to determine the variation in hydrological performance. The effects of multi-stage environmental factors on retention and peak reduction were analyzed, with a ranking of each factor’s relative importance. Environmental factors played a leading role in determining hydrological performance. However, the impact of multi-stage environmental factors was not as important as that of rainfall depth and antecedent volumetric water content. Differences in hydrological performance were compared across combinations of design factors. No significant differences were observed across substrate types and depths. However, potential interactive effects might exist, though these were not significant compared to environmental factors (e.g., rainfall depth and rainfall duration). These results confirmed that the meteorological factors in the different event-related stages significantly impacted the hydrological performance. Quantifying the effects of design and environmental factors is critical for hydrological performance evaluation. The results provided a broader perspective on understanding influence mechanisms of hydrological performance and highlighted the impact of microclimates on hydrological performance.

Optimum Solar Cell Power Conversion Efficiency-Based Patterned Planar Solar Surface Morphology with Various Solar Cell Absorber Structures

This paper simulated the optimum solar cell power conversion efficiency-based planar solar surface morphology with various solar cell absorber structures. The spectral light intensity, reflected, absorbed, and transmission coefficients versus wavelength band spectrum varied from 300[Formula: see text]nm to 1300[Formula: see text]nm through the visible to near-infrared regions. The optimum solar cell performance parameters or key parameters are studied with different solar cell structure designs based on different surface contact and back contact layers. Cumulative generation current, cumulative electron–hole pair generation rate and electron–hole pair generation rate are clarified versus substrate depth for various solar cell structure designs. The absorbed current in substrate is optimized for various solar cell structure designs. Maximum power voltage and current are also optimized for the proposed solar cell structure design. The effective solar cell power efficiency is also demonstrated based on the optimized maximum power current and maximum power voltage.

Influence of Bed Depth on the Development of Tropical Ornamental Plants in Subsurface Flow Treatment Wetlands for Municipal Wastewater Treatment: A Pilot-Scale Case.

The aim of this 2-year study was to evaluate the influence of bed depth (40 and 60 cm) on the development of tropical ornamental species (Alpinia purpurata, Heliconia latispatha and Strelitzia reginae) and on the removal of different contaminants such as chemical oxygen demand (COD), nitrate (N-NO3), ammonium (N-NH4), total nitrogen (TN), total phosphorus (TP), total suspended solids (TSS), total coliforms (TCs) and fecal coliforms (FCs), in horizontal subsurface flow constructed wetlands (HSSF-CWs) for municipal wastewater treatment. The results showed that the depth of 60 cm favored the removal of COD, with removal efficiencies of 94% for the three plant species. The depth of 40 cm was most effective for the removal of N-NH4 (80-90%). Regarding the removal of TN, the removals were similar for the different plants and depths (72-86%). The systems only achieved up to 60% removal of TCs and FCs. The depth of the CWs substrate and its saturation level influenced the development of ornamental vegetation, particularly flower production. For Heliconia latispatha, a bed depth level of 60 cm was more suitable, while for Alpinia purpurata 40 cm was better, and for Strelitzia reginae in both cases there was no flower production. The impact of bed depth on contaminant removal depends on the specific type of contaminant.

The effect of the substrate depth on hydrological performance of a vegetation roof: Laboratory study

The effect of the substrate depth on hydrological performance of a vegetation roof: Laboratory study

Cardiac magnetic resonance to evaluate 3D ventricular substrate depth: Prognostic implications for VT ablation approach

Abstract Background The decision to perform a high-risk endo-epicardial approach for VT ablation is controversial and mostly based on previous endocardial failure or very specific etiologies. We systematically evaluated the 3D distribution of the automatically-detected conducting channels by CMR with the aim of assessing whether tissue thickness in those areas could allow for an endocardial-only approach independently of the etiology of the cardiomyopathy. This could have an important impact in terms of procedural planning. Purpose To study CMR channel depth as a predictor of VT recurrence after endocardial VT ablation. Methods Fifty-one consecutive patients with left scar-related VT undergoing ablation after CMR (October 2018 to June 2022) were included (median age 65.56±11.46 years, 94.1% male, median ejection fraction 31.82±8.76%, ischemic cardiomyopathy 72.5%). CMR channels were calculated with ADAS3D software. The depth of CMR channels was assessed based on the involved layers and the total wall thickness (WT) of the affected segment. Patients were prospectively followed for VT recurrence for one year. Results One-year VT recurrence was 13.7%. Overall, 159 CMR channels were analyzed (3.10±2.01 channels per patient). Univariate analysis showed that both the maximal depth of channel and the presence of an epicardial channel were the only predictors of VT recurrence during follow-up (OR 1.85 (1.11, 3.13), p=0.02 and OR 1.22 (1.05, 1.41), p=0.04 respectively). The presence of a channel with a maximal depth of more than 7.2mm from the endocardium had a sensitivity= 100%, specificity= 61.36%, negative predictive value (NPV)= 100% and positive predictive value (PPV)=29.0% with an area under the curve of 0.81 for VT recurrence. The presence of an epicardial channel showed, as well, sensitivity=100% and NPV=100% but a worse specificity (27.27%) and PPV (17.95%) compared with maximal depth of the channel. Non-ischemic cardiomyopathy was not significantly associated with a higher risk of VT recurrence after endocardial ablation in our study (OR 2.25 (0.43, 11.66), p 0.34). Conclusions The maximal depth of CMR channels is a predictor of VT recurrence in the follow up in patients with left scar-related VT who underwent endocardial ablation. A cutoff of maximal CMR channel depth of 7.2mm could be a better tool to select VT ablation approach than considering the type of cardiomyopathy or the presence of epicardial substrate.Examples of CMR channel depthProbability of VT recurrence

Micromechanical effects of substrate hardness on graphene nano-cutting quality

In the nanocutting process of graphene, the mechanism on the atomic scale of the effect of substrate hardness on the edge quality of graphene nanoribbons has not been thoroughly investigated. In this paper, we construct a diamond probe (radius of 5 Å) to cut graphene (190 Å × 113 Å) models with different substrates (silicon/sapphire/silicon carbide), molecular dynamics simulations were used to study the effect of substrate hardness and cutting depth on the atomic structure of graphene nanoribbon edges by observing the atomic morphology, the number of C-C bonds, the radial distribution function and friction. The results show that during the nanoindentation stage, when graphene is in the critical damage state, the substrate with high hardness has high deformation strength, the substrate deformation is small, and graphene undergoes deformation is also small, but the force Fz on the probe, the critical graphene stress σz and the equivalent stress are all large, and the number of C atoms with CN=3 is large; At the nano-cutting stage, the breakage of C-C bonds and the generation of edge defects are caused by local stress concentration, and the graphene stress σxx along the x-direction has a clear directionality. With the same cutting depth (critical damage depth of silicon substrate), silicon substrate hardness is small, the graphene nanoribbon obtained has less number of circular defects generated at the edge, less total number of defective atoms, more number of CN=3 atoms, large peak of radial distribution function of graphene after cutting, and graphene integrity is better. The hardness of the silicon carbide substrate is large, and the number of C-C bond breaks in graphene during the cutting process is high. Each substrate is cut at its own critical damage depth, and the substrate hardness has no significant effect on the number of C-C bond breaks, the number of circular defects, the total number of defective atoms, and the number of CN=3 atoms in graphene. When the silicon substrate was used, the stable force of the probe is small, the edge structure of graphene has little impact, the edge effect obtained is good. The cutting depth and substrate hardness have little effect on the graphene temperature during the nano-cutting process. In this paper, the atomic structure of graphene edges after cutting is analysed and investigated on the atomic scale, and the above results are combined to provide theoretical guidance for obtaining efficient and high-quality and low-damage graphene nanoribbon cutting.

Integration of Building Information Modeling and Stormwater Runoff Modeling: Enhancing Design Tools for Nature-Based Solutions in Sustainable Landscapes

Building information modeling (BIM) has been used by the architectural and engineering disciplines to streamline the building design, construction, and management process, but there has been much more limited experience in extending the application to landscape design and implementation. This study integrated BIM software (Autodesk InfraWorks 2024.1) with a dynamic, process-oriented, conceptual hydrologic/hydraulic model (PCSWMM 2023, version 7.6.3665) to enhance the analytical tools for sustainable landscape design. We illustrate the model integration through a case study that links an existing nature-based solution (NbS) development, the PTT Metro Forest Park, Bangkok, Thailand, with theoretical new-build NbS for an adjacent property. A BIM school building was virtually situated on an empty lot beside the Metro Forest Park and seven NbS scenarios were run with design storms having 2-year, 5-year, and 100-year return intervals. The combination of a rain garden, permeable pavement, a retention pond, and a green roof was effective in sustainably managing runoff from the theoretical new-build site discharging to the Metro Forest. NbS design characteristics such as rain garden substrate depth and green roof area were optimized using the hydrologic/hydraulic model. Model results showed that even with the 100-year rainfall event, the existing Metro Forest pond storage capacity was sufficient so that flooding on the property would not occur. The consideration of connectivity between NbS features is facilitated by the modeling approach, which is important for NbS planning and assessment at a regional scale.

Multi-Objective Design of a Horizontal Flow Subsurface Wetland

An artificial wetland is used to treat gray, waste, storm or industrial water. This is an engineering system that uses natural functions of vegetation, soil and organisms to provide secondary treatment to gray water. In the physical design of each artificial wetland, there are various action factors that must meet certain characteristics so that the level of gray-water pollution is reduced. In this sense, several design methodologies have been developed and reported in the literature, but some are customized designs and often do not meet the required decontamination objectives. This challenge increases as the complexity of the task in its structure also increases. Particularly in this work, a multi-objective evolutionary algorithm is used to optimize the physical design of a horizontal flow subsurface wetland (HFSW) for gray-water treatment. The study aims to achieve two objectives: first, to minimize the physical volume, and second, to maximize the contaminant removal efficiency. The defined objective functions depend on six design variables called hydraulic retention time, width, length, water depth inside the wetland, substrate depth and slope. Three constraint functions are also defined: removal efficiency greater than 95%, physical volume below 500 m3 and compliance with a length–width ratio is 3:1, varying the population size and number of generations equal to 200, 400, and 600. The set of solutions according to the number of generations as well as the Pareto front corresponds to the best solution that complies with the constraints of the problem of oversizing the HFSW, and the Pareto front shows the interaction between the objectives and their behavior, reflecting the problem’s nature as minimization–maximization.

Characteristics and mechanisms of phosphine production in sulfur-based constructed wetlands

Phosphine (PH3) is an important contributor to the phosphorus cycle and is widespread in various environments. However, there are few studies on PH3 in constructed wetlands (CWs). In this study, lab-scale CWs and batch experiments were conducted to explore the characteristics and mechanisms of PH3 production in sulfur-based CWs. The results showed that the PH3 release flux of sulfur-based CWs varied from 0.86±0.04 ng·m−2·h−1 to 1.88±0.09 ng·m−2·h−1. The dissolved PH3 was the main PH3 form in CWs and varied from 2.73 μg·L−1 to 4.08 μg·L−1. The matrix-bound PH3 was a staging reservoir for PH3 and increased with substrate depth. In addition, the sulfur-based substrates had a significant improvement on PH3 production. Elemental sulfur is more conducive to PH3 production than pyrite. Moreover, there was a significant positive correlation between PH3 production, the dsrB gene, and nicotinamide adenine dinucleotide (NADH). NADH might catalyze the phosphate reduction process. And the final stage of the dissimilatory sulfate reduction pathway driven by the dsrB gene might also provide energy for phosphate reduction. The migration and transformation of PH3 increased the available P (Resin-P and NaHCO3-P) from 35 % to 56 % in sulfur-based CW, and the P adsorption capacity was improved by 12 %. The higher proportion of available P increased the plant uptake rate of P by 17 %. This study improves the understanding of the phosphorus cycle in sulfur-based CW and provides new insight into the long-term stable operation of CWs.

Contribution to advancing aquifer geometric mapping using machine learning and deep learning techniques: a case study of the AL Haouz-Mejjate aquifer, Marrakech, Morocco

Groundwater resources in Morocco often face sustainability challenges due to increased exploitation and climate change. Specifically, the Al-Haouz-Mejjate groundwater in the Marrakesh region is faced with overexploitation and insufficient recharge. However, the complex subsurface geometries hamper hydrogeological modeling, characterization, and effective management. Reliably estimating aquifer substrate topography is critical for groundwater models but is challenged by limited direct measurements. This study develops nonlinear machine learning models to infer substrate depths by fusing sparse borehole logs with regional geospatial data. A Gaussian process regression approach provided robust holistic mapping, leveraging flexibility, and uncertainty quantification. Supplementary neural network architectures focus on isolating specific variable relationships, like surface elevation–substrate. Model accuracy exceeded 0.8 R-squared against validation boreholes. Spatial visualizations confirmed consistency across landscape transects. Elevation and piezometric data proved most predictive, though multivariate inputs were required for the lowest errors. The results highlight the power of statistical learning to extract meaningful patterns from disparate hydrological data. However, model opacity and the need for broader training datasets remain barriers. Overall, the work demonstrates advanced machine learning as a promising avenue for illuminating complex aquifer geometries essential for sustainability. Hybrid approaches that use both data-driven and physics-based methods can help solve long-standing problems with hydrogeological characterization.

Ecology and Phenology of the Subtidal Brown Alga Sargassum furcatum (Ochrophyta, Fucales), a Likely Non-Indigenous Species from the Mediterranean Sea

This study provides new insights regarding the ecology and phenology of the likely non-indigenous canopy-forming species Sargassum furcatum on the central-eastern coast of Sicily (Italy, Central Mediterranean). This species was described for St. Thomas (Virgin Islands), and it was reported for the first time in the Mediterranean in 1995 in the Chafarinas islands (Spain, western Mediterranean). After the first report, this species was found in 2021 in several sites located along the eastern coast of Sicily (Italy), along the French Mediterranean coastline, in Corsica, and recently also in the Aeolian Islands (Italy). No phenological studies on this species have been ever carried out in the Mediterranean Sea. To conduct this study, a visual census activity was performed in three sites along the Ionian coast of Sicily throughout 2023, during which the length of the main axis of S. furcatum specimens was measured and the frequency of findings of the species during the year was noted. In this study, it was observed that S. furcatum shows a wide adaptability in terms of range of depth, temperature, light exposure, and type of substrate. Since the distribution of this species is mostly centralized in the western Atlantic Ocean, it is likely that S. furcatum entered the Mediterranean through the Gibraltar Strait. Consequently, the entrance of this species in this Basin could be further proof of the ongoing seawater warming and tropicalization of Mediterranean waters. From this point of view, it is important to keep monitoring the dynamics of S. furcatum in the Mediterranean Sea in order to understand its putative impacts on autochthonous communities.

Drivers of Macroinvertebrate Communities in Mediterranean Rivers: A Mesohabitat Approach

We investigated the relationship between benthic macroinvertebrate community attributes (richness, abundance, biodiversity, and climate-specific and resistance forms) and the physical characteristics of distinct mesohabitats (hydromorphological unit types) discretized into fast (e.g., riffles or rapids) and slow (e.g., pools or glides) flow types in four Mediterranean rivers of Spain. Key attributes of hydromorphological units, including length, width, depth, shade, substrate composition, embeddedness, abundance of aquatic vegetation, and density of woody debris, were considered. Through a comprehensive suite of multivariate analyses, we unraveled taxonomic and habitat distinctions among rivers and hydromorphological unit types, with a notable influence of spatial proximity (greater similarity within the same river basin). In slow hydromorphological units, aquatic vegetation, depth, and abundance of coarse substrate emerged as pivotal factors shaping macroinvertebrate assemblages, whereas in fast-flowing units, vegetation, substrate embeddedness, and density of woody debris were the most important. Contrary to the remaining community attributes, the studied resistance forms (absent, eggs, cocoons, and cells against desiccation and diapause) exhibited uniformity across rivers despite observed variations in macroinvertebrate communities, underscoring regional functional analogies in biological and ecological mechanisms within the investigated Mediterranean river basins. This study contributes valuable insights for anticipating the repercussions of ongoing climate change, particularly in regions where fast-flowing hydromorphological units are more susceptible to depletion during drought periods.

Water’s path from moss to soil Vol. 2: how soil-moss combinations affect soil water fluxes and soil loss in a temperate forest

AbstractMosses are key components of many ecosystems and particularly related to water cycling. In principle, the importance of mosses for water-related processes is known; however, their influence is rarely quantified in scientific studies. To fill this research gap, this study concentrates on the influence of mosses of different species on surface runoff, the amount of percolated water, soil loss, and the temporal dynamics of soil water content. For this purpose, an experimental approach consisting of an ex situ rainfall simulation (45 mm h− 1 for 30 min) with infiltration boxes equipped with biocrust wetness probes was applied. On average, mosses significantly reduced surface runoff by 91% and soil loss by almost 100%, while the amount of percolated water was increased by 85% compared with bare soils. These processes were superimposed by desiccation cracks, and partly water repellency, with the result that the respective influences could not be quantified individually. However, by simultaneously measuring the water content in the substrates during rainfall simulations, we were able to achieve a better understanding of the water flows in the substrates. For instance, water content at 3 cm substrate depth was higher under mosses than in bare soils, implying that mosses facilitated infiltration. In this study, we were able to demonstrate that mosses play an important role in soil hydrology and in protecting the soil from erosion, and it is imperative that further experiments will be conducted to elucidate the apparently underestimated effects of mosses and their specific traits on soil water fluxes and sediment transport.

Shallow Hard-Bottom Benthic Assemblages of South Bay (Antarctic Peninsula): An Update 40 Years Later

This work completes and updates the information about the diversity and distribution of benthic assemblages in an Antarctic fjord (South Bay, Antarctic Peninsula) 40 years after the first and only community-level study was conducted there. To determine the community changes, a photographic survey was conducted at four sites with different substrate inclinations along a bathymetric gradient of 5–20 m depth. In total, 160 photoquadrats were analyzed, resulting in a total area of 40 m2. Sixty taxa represented by 12 phyla were identified, of which eight phyla corresponded to animals. The remaining species corresponded to macroalgae and benthic diatoms, both taxa presenting the highest coverages of the entire study area. The highest richness and diversity values were obtained at greater depths and at the sites with the steepest slopes. Here, we discuss the role of substrate inclination and depth in the structure of the benthic assemblages concerning possible variations in the presence and frequency of physical disturbances (e.g., ice disturbance and sedimentation). The abundances, densities, and distributions of all species found are detailed, updating the ecological data of the benthic ecosystem of this Antarctic fjord from the previously published assessment four decades ago. In a continent where rapid environmental changes are being experienced due to climate-induced processes, we discuss the first massive record of benthic diatoms in this fjord and the striking absence of the sea urchin Sterechinus neumayeri, an abundant species from previous records from the early 1980s.

Earlier Flowering Phenology and Pollinator Visitation on Urban Green Roofs Compared to Ground-Level Gardens

Urban green space, green infrastructure, and horticultural installations are gaining recognition for their potential to foster biodiversity. Green roofs are challenging growing environments for plants, characterized by extreme substrate temperatures, high light intensity, limited moisture availability, and limited substrate depth. Plants have a variety of physiological responses to these unique conditions, but little is known about how green roof growing conditions affect ecological characteristics like plant flowering phenology. Meanwhile, studies are only just uncovering the degree to which green roofs can provide habitat and support urban pollinator biodiversity. We evaluated the flowering phenology and made in situ pollinator observations of 15 plant taxa growing both on green roof systems and at ground level in Denver, Colorado, over two growing seasons. We found that flowering phenology occurs substantially earlier on green roofs compared to ground level among the observed plant taxa and observed a greater number of pollinators on green roofs early in the season, compared to ground level, presumably due to the availability of floral resources among the observed plant taxa. We observed significantly higher substrate temperatures along with wider diurnal temperature amplitude during the growing season that may contribute to the observed phenological patterns. Divergence in flowering phenology between individual plants of the same species on green roofs and plants at ground-level may have implications for organisms that rely on floral resources in urban environments. Earlier flower initiation on green roofs may provide pollinators with unique foraging opportunities and aid targeted conservation where early-season floral resources are limited.