Photography Research Articles

Development of methodology for calculating flooded area and flood volume in small urban areas based on unmanned aerial vehicle images

Climate change has intensified flooding and increased localized torrential rainfalls, leading to disasters such as landslides, infrastructure collapse, and urban floods. The extent and accuracy of flood damage information significantly impact recovery processes. While previous studies primarily utilized satellite and aerial imagery for broad flood assessments, they often lacked the precision needed for accurate damage analysis. This study addresses the gap between rapid assessment needs and precise damage quantification in flood inundation analysis. This research introduces a novel image-based investigation approach to enhance the speed and accuracy of flood inundation assessment. By leveraging unmanned aerial vehicles (UAVs) and image-based spatial data technology, aerial images of flooded areas are rapidly captured to construct three-dimensional disaster site terrain information. The proposed methodology employs advanced techniques in aerial photography, image processing, and geographic analysis to quantitatively analyze flood inundation scale using only aerial images and geographic information systems (GIS). The research yielded a calculated flood inundation area of 3,847.36 m2 and a flood volume of 13,895.13 m3. This methodology complements existing flood inundation assessment techniques and has the potential to significantly improve disaster management efforts by providing rapid, accurate, and actionable data for decision-makers.

Experience, knowledge, practices and attitudes of emergency department medical staff regarding teledermatology.

The present study aimed to assess self-reported experience, knowledge, practices and attitudes of ED medical staff regarding teledermatology. Online questionnaire of ED medical staff at Prince of Wales Hospital (Sydney, Australia). Seventy-nine staff completed the questionnaire. Photographic technique and compliance with medicolegal policies were variable: 1% obtained written consent and 45.6% documented verbal consent for photography. 54.4% of respondents had concerns about the quality of their photographs. Skin photography image quality, knowledge and adherence to medicolegal policy were poor among ED medical staff. Education could reduce risk and improve outcomes.

Measurement Service Productivity: The Case Study of the Wedding Photography Businesses in Khon Kaen Province

There is an attempt of measuring service productivity in order to analyze performance of the service business. Since wedding photography businesses are struggling due to a variety of issues, service productivity has decreased. The purpose of this research is to measure and analyze the service productivity of 15 wedding photography businesses located in Khon Kaen province. In-depth semi-structured interviews were conducted to gather input and output variables over a one-month period from the 15 wedding photography businesses. The collected data were analyzed using Data Envelopment Analysis (DEA) with an input-oriented approach. The productivity measurement of the wedding photography businesses consists of 3 input variables and 2 output variables. The findings indicated that 6 wedding photography businesses were efficient under the CRS model, and 7 were efficient under the VRS model. The guideline from efficient wedding photography businesses is recommended to improve service productivity in the wedding photography business in terms of operations management by using the best practice units as a benchmark for inefficient DMUs. The results of this research are expected to benefit wedding photography businesses operating in similar contexts and contribute to the broader service sector for further study.

Cruising Europe in World War II: Epistemological Challenges of German Vernacular Trophy Photography

The Nazi regime outfitted the Wehrmacht with the best photographic technology and its soldiers were far better equipped than their allies or nemeses. More than ten per cent of the eighteen million German combatants possessed a fast-shutter 35-mm camera. German soldier-photographers documented their wartime activities extensively, in turn leaving behind a gigantic, private and largely underexplored archive that poses multiple epistemological and ethical challenges. Military historians and Holocaust scholars approach soldierly photographs primarily as sources of information, including proof of crimes. This article shifts these lenses and argues that reading them as visual images, and not solely as historical sources and circulating artefacts, reveals a medium that equally affects its practitioners as well as the observers. Drawing upon public archives and private collections, I focus on highly performative images of victory and conquest over enemy countries and peoples and conceptualise them as ‘trophy photographs’. I examine recurrent motifs within this genre, in particular sexual encounters with enemy women and photographs of male bonding, which arguably constitute the most prevalent images snapped by soldier-photographers who ‘cruised’ Nazi-occupied Europe. Borrowing from Queer Studies, the concept of cruising allows me to probe soldiers’ mobility in semipublic spaces and also acknowledge the voyeuristic and visually alluring quality of their photographs. Seductive, exciting, these trophy photographs lure in their audience(s) with sexually charged, often (homo)erotic overtones. In turn, these images provoke diverse ways of seeing and interpreting their content: how can we best frame the soldier-photographer’s gaze and capture the polysemic quality of the images, especially when dealing with violence, racism, sexism and/or homoeroticism? What effect do trophy images of conquest potentially have on the historical actors who shot and circulated those photographs and what impact do they have on contemporary observers? Finally, acknowledging multidirectional and fractious lives of images, how do we understand the complex relationship between public history and the ethics of seeing? Because photographic images are historically contingent and open-ended, this article casts light on the complexity of mediation and competing visions between diverse publics of the past, present and future.

Exploration and practice of teaching mode of "one core and three combinations" in photography course

Photography is the art of expressing the instantaneous beauty. Photography teaching is hierarchical. With the rapid popularization of digital photography technology, Beijing Open University as a remote open, education university, in the photography professional photography teaching, on the basis of construction theory, adhering to the teaching design concept of quality education, explore with the characteristics of open education"One core and three combination" teaching mode, make full use of online education technology to cultivate students' innovation ability, improve artisticaccomplishment, and vigorously promote the deepening of teaching reform.

Graph Neural Networks: A Bibliometric Mapping of the Research Landscape and Applications

Graph neural networks (GNNs) are deep learning algorithms that process graph-structured data and are suitable for applications such as social networks, physical models, financial markets, and molecular predictions. Bibliometrics, a tool for tracking research evolution, identifying milestones, and assessing current research, can help identify emerging trends. This study aims to map GNN applications, research directions, and key contributors. An analysis of 40,741 GNN-related publications from the Web Science Core Collection reveals a rising trend in GNN publications, especially since 2018. Computer Science, Engineering, and Telecommunications play significant roles in GNN research, with a focus on deep learning, graph convolutional networks, neural networks, convolutional neural networks, and machine learning. China and the USA combined account for 76.4% of the publications. Chinese universities concentrate on graph convolutional networks, deep learning, feature extraction, and task analysis, whereas American universities focus on machine learning and deep learning. The study also highlights the importance of Chemistry, Physics, Mathematics, Imaging Science & Photographic Technology, and Computer Science in their respective knowledge communities. In conclusion, the bibliometric analysis provides an overview of GNN research, showing growing interest and applications across various disciplines, and highlighting the potential of GNNs in solving complex problems and the need for continued research and collaboration.

Analysis of The Architecture and Decoration of Isfahan Masjid-E Jameh in Syntactic Dimension

In this research, the general architectural features and decorations of the Friday Mosque of İsfahan, Iran, which belongs to the 11th century Great Seljuk State period, one of the most important works of Islamic architecture, are examined. This mosque, which is also called Atiq Mosque, Masjid-e Jameh and Great Mosque today, is among the most important structures that have witnessed hundreds of years of history. This study on the expressibility of the semantic dimension of the structure in the syntactic dimension is important in terms of its contribution to the literature. For this purpose, information about the Great Seljuk mosque architecture and the historical development process of Friday Mosque in terms of architecture is given and the subject and purpose of the researches on this mosque are stated. Then, the method to be used in expressing the architectural structure and decorations in the syntactic dimension is explained. In order to obtain the data about the mosque, on-site visual-observation and examination technique and photography technique were used. Basic design principles were used in the analysis of the data. As a result, the architectural features and ornamental motifs used in this mosque, which is an important mosque of the Great Seljuk period, have been revealed with this method. The findings obtained about the structure and ornaments can be used in religious buildings as well as other architectural structures, ornaments, clothing, furniture and decoration

ANALYZING COLLAGE AS A COMMUNICATION ACT IN THE DIGITAL AGE BASED ON THE DADAISM RENEWAL MOVEMENT'S SPIRIT

Collage combines the semiotic tradition of Roland Barthes, the phenomenological tradition of Edmund Husserl, the critical tradition of Karl Marx, and the point of view of Jurgen Habermas in visual communication. The collage technique creates trans-aesthetic elements and double codes, a Dadaist method of encoding signs. Building on previous research, this study explores collage art as a communication act and its process in the digital era. Digital photography technology and computer software facilitate quicker and easier creation of collage art, emphasizing the fundamental concept of "paste." This pasting-sticking process mirrors the communication process of art and design in the digital era, illustrating cyclical communication capable of transcending space and time. The research has several conclusions. (1) By enhancing visual communication strategies and efficiency based on the spirit of the Dadaism renewal movement, unique collages can be created as a personal sign of message(s). (2) Collages as communication act in the digital era represent dialogue in trans-aesthetics code. (3) On the other hand, with the spirit of Dadaism that contains a free mind, open creation, and emphasis on social-cultural issues, collages as a communication process are also possible to frame messages and create fallacy.

NAROO program: Analysis of USNO Galilean observations 1967–1998

The New Astrometric Reduction of Old Observations (NAROO) program is dedicated to the measurement of astrophotographic plates and the analysis of old observations for scientific purposes. One of the main objectives of the NAROO program is to provide accurate positional measurements of planets and satellites to improve our knowledge of their orbits and dynamics, and to infer the accuracy of the planet and satellite ephemerides. We digitized 553 astronegatives of the Galilean satellites taken with the McCormick 26-inch refractor in 1967/68 and the U.S. Naval Observatory 26-inch refractor from 1973 to 1998, resulting in 2650 individual observations. We measured and reduced these observations through an optimal process that includes image, instrumental, and spherical corrections using Gaia-DR3 catalog to provide the most accurate equatorial (RA, Dec) ICRS (Gaia-CRF3) positions. 4819 positions of the Galilean satellites have been determined with an accuracy of 55 mas (160 km at Jupiter), near the limit of the photographic technique for such work. These data can help to improve the equatorial positions of Jupiter. They also can be used in the context of quantifying tidal effects and will still be useful when Europa Clipper and Juice data will become available.

Novel additive-manufactured tracking solar concentrating system for cooking applications: Design, geometry assessment, and optical evaluation

A novel solar concentrating system for cooking applications was developed, featuring a stationary reflector and a flat heliostat with equatorial tracking. This design allows for simple one-axis tracking at a constant speed with no need for deformable reflectors, ensuring the direction of the concentrated radiation in the cooking area remains steady and a quasi-constant power capture regardless of the Sun's position. The concentrator is made from 3D printed flat tiles, allowing for an easy do-it-yourself manufacturing process and avoiding highly focused irradiance on the receiver. The geometry of the reflector was scanned and compared to an ideal CAD reflector model, revealing some assembly imperfections, and a slightly concave tile geometry which causes a moderately sharp concentration peak. The irradiance distribution on a plane target near the effective focus of the reflector was analysed with a photographic flux mapping technique, and the results were compared to those obtained from ray tracing simulations of the ideal CAD model, confirming the tile concavity predicted by the geometrical examination. Conversely, it shows a reduction in the total energy gathered on the entire target plate when compared with ray tracing outcomes.

Effect of the Surface Peak-Valley Features on Droplet Impact Dynamics under Leidenfrost Temperature.

This study explores the kinetic behavior of droplets impacting microtextured surfaces under a Leidenfrost temperature, employing high-speed photography and picosecond laser micromachining techniques. The investigation focuses on two types of microtextured surfaces with totally different surface peak-valley features: a negatively skewed surface with micropit arrays (Ssk < 0) and a positively skewed surface with micropillar arrays (Ssk > 0). The results indicate that both microtextured surfaces contribute to a higher Leidenfrost temperature compared with the original smooth surface, which is consistent with previous studies. However, it is worth noting that the Leidenfrost points of the micropit and micropillar surfaces showed opposite trends with the microtexture area occupancy. Specifically, the Leidenfrost temperature on micropit surfaces increases with greater micropit area occupancy, while it decreases on micropillar surfaces under similar conditions, which is mainly attributed to the differential impact of area occupancy on droplet heat transfer efficiency. When the microtexture area occupancy is 50%, it is worth noting that the micropit and micropillar surfaces have nearly same roughness (Sa), but the Leidenfrost temperature was notably higher on the micropit surface with negative skewness (Ssk < 0), which was related to differences in vapor flow dynamics. We further find that the Weber number (We) significantly influences the Leidenfrost point, with the droplet impact wall behavior going through the states of film bounce back, ejecting tiny droplets and bounce back, and ultimately droplet breakup as the We increases. The dynamic Leidenfrost point was found to be generally higher than the static point and increases with the We. Finally, we compare the cooling efficiency of these surfaces, and it is found that the micropit surfaces with a negative skewness exhibit superior heat dissipation performance under the same conditions, which proved that the negatively skewed surface may have great potential in high-density heat dissipation technology.

Precision estimation of winter wheat crop height and above-ground biomass using unmanned aerial vehicle imagery and oblique photoghraphy point cloud data.

Crop height and above-ground biomass (AGB) serve as crucial indicators for monitoring crop growth and estimating grain yield. Timely and accurate acquisition of wheat crop height and AGB data is paramount for guiding agricultural production. However, traditional data acquisition methods suffer from drawbacks such as time-consuming, laborious and destructive sampling. The current approach to estimating AGB using unmanned aerial vehicles (UAVs) remote sensing relies solely on spectral data, resulting in low accuracy in estimation. This method fails to address the ill-posed inverse problem of mapping from two-dimensional to three-dimensional and issues related to spectral saturation. To overcome these challenges, RGB and multispectral sensors mounted on UAVs were employed to acquire spectral image data. The five-directional oblique photography technique was utilized to construct the three-dimensional point cloud for extracting crop height. This study comparatively analyzed the potential of the mean method and the Accumulated Incremental Height (AIH) method in crop height extraction. Utilizing Vegetation Indices (VIs), AIH and their feature combinations, models including Random Forest Regression (RFR), eXtreme Gradient Boosting (XGBoost), Gradient Boosting Regression Trees (GBRT), Support Vector Regression (SVR) and Ridge Regression (RR) were constructed to estimate winter wheat AGB. The research results indicated that the AIH method performed well in crop height extraction, with minimal differences between 95% AIH and measured crop height values were observed across various growth stages of wheat, yielding R2 ranging from 0.768 to 0.784. Compared to individual features, the combination of multiple features significantly improved the model's estimate accuracy. The incorporation of AIH features helps alleviate the effects of spectral saturation. Coupling VIs with AIH features, the model's R2 increases from 0.694-0.885 with only VIs features to 0.728-0.925. In comparing the performance of five machine learning algorithms, it was discovered that models constructed based on decision trees were superior to other machine learning algorithms. Among them, the RFR algorithm performed optimally, with R2 ranging from 0.9 to 0.93. In conclusion, leveraging multi-source remote sensing data from UAVs with machine learning algorithms overcomes the limitations of traditional crop monitoring methods, offering a technological reference for precision agriculture management and decision-making.

Experimental study on the change of the orientation of high aspect ratio nozzle slit relative to the airflow

An experimental study to investigate the flow of liquid jet issued from a high aspect ratio nozzle slit into an incoming airflow by changing the orientation angle from the incoming free-stream was performed. A two-dimensional liquid sheet emerged from the narrow slit into the subsonic air crossflow. Different orientation angles between 0 and 90 degrees were studied. High-speed photography and shadowgraphy techniques were utilized to visualize the flow physics. The influence of the slit orientation angle on the flow morphology and the flow regimes of liquid sheets was investigated. Some fluid flow parameters were obtained by analyzing the images. The changes in breakup height of different orientations were measured. A model was offered for the breakup height of the liquid sheet based on the liquid-to-gas momentum ratio, gas Weber number, and a new non-dimensional parameter as a representation of the angle of slit orientation. Also, the defined sheet trajectory for each orientation angle was obtained, and the variations were examined. Empirical correlations for the defined trajectory of the sheet in terms of liquid to gas momentum ratio and gas Weber number for each orientation angle were proposed.

Experimental study on attenuation effect of liquid viscosity on shockwaves of cavitation bubbles collapse

How to precisely control and efficiently utilize the physical processes such as high temperature, high pressure, and shockwaves during the collapse of cavitation bubbles is a focal concern in the field of cavitation applications. The viscosity change of the liquid will affect the bubble dynamics in turn, and further affect the precise control of intensity of cavitation field. This study used high-speed photography technology and schlieren optical path system to observe the spatiotemporal evolution of shockwaves in liquid with different viscosities. It was found that as the viscosity of the liquid increased, the wave front of the collapse shockwave of the cavitation bubble gradually thickened. Furthermore, a high-frequency pressure testing system was used to quantitatively analyze the influence of viscosity on the intensity of the shockwave. It was found that the pressure peak of the shockwave in different viscous liquid was proportional to Lb (L represented the distance between the center of bubble and the sensor measuring point), and the larger the viscosity was, the smaller the value of b was. Through in-depth analysis, it was found that as the viscosity of the liquid increased, the proportion of the shockwave energy of first bubble collapse to the maximal mechanical energy of bubble gradually decreased. The proportion of the mechanical energy of rebounding bubble to the maximal mechanical energy of bubble gradually increased. These new findings have an important theoretical significance for the efficient utilization of ultrasonic cavitation.

Algologies: an artistic exploration of the entangled relationship between seaweed, women and science through a BioArt methodology

ABSTRACT This paper describes the “Algologies” project, an art project about seaweed exploring the entangled relationships between seaweed, women and science. The project was created in 2021, during the COVID-19 Pandemic, through the Living Coast Art Residency awarded by Fabrica Gallery and The Living Coast UNESCO World Biosphere and the coastline to the East of Brighton. The project plays with the Victorian word algology which used to mean the study of seaweed and its contemporary meaning as the study and medical treatment of pain and highlights the calming nature of the coastal environment during a time of collective global trauma. The “Algologies” project drew links between Victorian seaweed collectors, the use of seaweed-based agar jelly in contemporary biology, and seaweed growth as a barometer of climate change and the environment as well as a strategy for carbon capture. The transdisciplinary project fused fine art, performance and BioArt techniques with biohacking and DIY science, as well as digital technologies and resulted in a series of outputs including a public sculpture. Central to “Algologies” was the examination of the historical role of women in seaweed collection and scientific observation. In Victorian Britain, where patriarchal norms prevailed, women were often relegated to domestic roles but found opportunities for scientific engagement through activities like seaweed collecting. Figures such as Mary Philadelphia Merrifield and Anna Atkins emerged as pioneers in the study of seaweed, making significant contributions to botanical research and early photographic techniques. Notably, the project highlighted the pivotal role of Angelina (Lina) Fannie Hesse in suggesting the use of seaweed-derived agar in microbiology, a contribution that continues to impact scientific practices today. Beyond historical perspectives, “Algologies” addresses contemporary issues such as climate change and invasive species of seaweed and how the public can be engaged in these topics through art. The paper concludes by discussing the potential of seaweed for carbon capture and its role as a barometer of environmental health, as well as its use biotechnology

Multiplexed Microfluidic Platform for Parallel Bacterial Chemotaxis Assays.

The sensing of and response to ambient chemical gradients by microorganisms via chemotaxis regulates many microbial processes fundamental to ecosystem function, human health, and disease. Microfluidics has emerged as an indispensable tool for the study of microbial chemotaxis, enabling precise, robust, and reproducible control of spatiotemporal chemical conditions. Previous techniques include combining laminar flow patterning and stop-flow diffusion to produce quasi-steady chemical gradients to directly probe single-cell responses or loading micro-wells to entice and ensnare chemotactic bacteria in quasi-steady chemical conditions. Such microfluidic approaches exemplify a trade-off between high spatiotemporal resolution of cell behavior and high-throughput screening of concentration-specific chemotactic responses. However, both aspects are necessary to disentangle how a diverse range of chemical compounds and concentrations mediate microbial processes such as nutrient uptake, reproduction, and chemorepulsion from toxins. Here, we present a protocol for the multiplexed chemotaxis device (MCD), a parallelized microfluidic platform for efficient, high-throughput, and high-resolution chemotaxis screening of swimming microbes across a range of chemical concentrations. The first layer of the two-layer polydimethylsiloxane (PDMS) device comprises a serial dilution network designed to produce five logarithmically diluted chemostimulus concentrations plus a control from a single chemical solution input. Laminar flow in the second device layer brings a cell suspension and buffer solution into contact with the chemostimuli solutions in each of six separate chemotaxis assays, in which microbial responses are imaged simultaneously over time. The MCD is produced via standard photography and soft lithography techniques and provides robust,repeatable chemostimulus concentrations across each assay in the device. This microfluidic platform provides a chemotaxis assay that blends high-throughput screening approaches with single-cell resolution to achieve a more comprehensive understanding of chemotaxis-mediated microbial processes. Key features • Microchannel master molds are fabricated using photolithography techniques in a clean room with a mask aligner to fabricate multilevel feature heights. • The microfluidic device is fabricated from PDMS using standard soft lithography replica molding from the master molds. • The resulting microchannel requires a one-time calibration of the driving inlet pressures, after which devices from the same master molds have robust performance. • The microfluidic platform is optimized and tested for measuring chemotaxis of swimming prokaryotes.

Method of Digital Processing of Optical Spectra of Magnetron Discharge Plasma

To solve the actual problems associated with the development of the theory of magnetron discharge and the expansion of its practical application, a digital method of recording and processing the discharge plasma luminescence spectra is proposed in this work. To obtain the discharge plasma glow spectra, a photographic technique was used, which allowed simultaneous recording of the entire radiation spectrum in the 390.0-700.0 nm region. An additional advantage of this technique is the ability to track spatial changes in the composition and properties of the plasma in the discharge in the selected direction. A Canon EOS 80D digital camera with remote control was used to record the optical signal. A graphical application OSA was created to process digital images of the discharge plasma luminescence spectra. The paper describes the functionality of this application: determination of the wavelength of a spectral line and its belonging to a certain chemical element; measurement of the spatial distribution of the intensity of a spectral line along the selected direction of radiation registration. Determining the wavelength of a spectral line in the application is possible in two modes of operation - automatic and manual. In the first mode, the algorithm developed in this paper determines the wavelength for all spectral lines whose intensity exceeds the background value at a height of 10 % of the lower spectral limit. The second mode allows you to independently select a single spectral line or several to determine their wavelengths. The first mode is used for quick analysis, while the second mode allows you to determine the length of the spectral line with greater accuracy. To interpret the spectral lines, the methodology of reference lines from the databases of spectral line tables for various elements is used. The possibility of both full automatic verification, where all elements are sequentially searched, and selective verification, where one or more elements are selected, is provided. The paper shows that the spatial distribution of the intensity of tungsten spectral lines, and thus of excited atoms in a magnetron discharge, is a complex function of the distance from the cathode, which depends on the discharge parameters. The proposed digital methodology makes it possible to significantly speed up the process of obtaining physical information and increase the accuracy in determining the spectrum parameters.

Enhancing digital marketing of MSMEs through comprehensive photography training in Hendrosari Village, Gresik

MSMEs in Hendrosari Village have been struggling with digital marketing due to a lack of expertise in creating compelling visual content, which has led to poor online visibility and stagnating sales. Additionally, these businesses face challenges in keeping up with ever-evolving digital trends, limited access to affordable digital tools, and insufficient training opportunities, further hampering their ability to compete in a growing online marketplace. An extensive photography training program was launched, aimed at equipping 15 MSMEs in Hendrosari Village, the target groups of this service initiative, with essential skills in lighting, composition, and post-processing techniques. This program aims to enhance their visual content creation capabilities, helping them improve their online presence and market competitiveness. The program combined theoretical lessons with hands-on practice, allowing participants to immediately apply what they learned. The community service team conducted observations and interviews before and after the training to assess changes in product photo quality and the impact on sales. The average photo quality assessment score increased from 3 to 4.5. In addition, some participants reported a 15 percent increase in income after learning new photography techniques. Based on the evaluation process, it shows that the photography training has strong potential to improve the competitiveness of MSMEs in Hendrosari village, which can inspire similar programs in other areas.

Optimasi Konten Instagram dalam Strategi Promosi Bisnis Foto Pernikahan Sekawan Stories

Photography has grown rapidly, especially in the wedding photography industry which now requires an effective business promotion strategy. This research aims to identify how business people utilize Instagram as a promotional medium and strengthen Instagram content in Sekawan Stories' wedding photography business promotion strategy. Using a descriptive qualitative method, this study collected data through interviews and virtual ethnographic observations to understand how Sekawan Stories utilizes Instagram as a promotional medium. The results show that Sekawan Stories effectively utilizes various Instagram features, such as Feed, Instastory, Highlight, Video Reels, and Instagram Ads to increase visibility and audience engagement. Their marketing strategies include endorsements with well-known vendors, use of the Answer Question feature, conducting giveaways, and offering discounts at certain moments. Instagram provides a great opportunity for wedding photography businesses to expand their market reach and increase promotional effectiveness. By optimizing their content and marketing strategies on Instagram, Sekawan Stories managed to attract the attention of new customers, increase interaction, and strengthen relationships with existing customers. Overall, Instagram proved to be a highly effective platform in digital marketing strategies in the wedding photography industry.

Still waters and deep: Habitat characteristics, density and distribution of a lake-dwelling population of the freshwater pearl mussel Margaritifera margaritifera

The freshwater pearl mussel, Margaritifera margaritifera is widely considered to be confined to fast-flowing, near-pristine rivers, and is highly endangered throughout its Holartic range. Here we describe a large population of some 150–200,000 individuals of the freshwater pearl mussel living in an oligotrophic Irish lake.Employing underwater photographic techniques and snorkel diving, mussels were found in two separate locations in the lake. In the first location, 200 m from the shore, mussels were found at a maximum density of 43 m−2, in a largely random distribution in the sandy bed substrate of the lake, up to 9.5 m deep. In the second shoreline location, mussels were observed in dense aggregations up to 118 individuals m−2, in sandy pockets in between boulders and bedrock, in waters 1–2 m deep. In both locations, mussels were found associated with macrophytes – the charophyte Nitella sp. in the deeper location and the quillwort Isoetes lacustris in the shallower shoreline location. Juvenile mussels (>1.5 cm length) were observed lying exposed on the sediment surface in the shallow littoral location, indicating that recruitment occurs in this population, although no estimates of juvenile density were obtained.The discovery of a large population of lentic Margaritifera margaritifera has significant implications for the species’ conservation and indicates that there may be substantial lentic populations of the species elsewhere. The environmental envelope of the species is clearly much wider than thought and our discovery challenges assumptions about the fundamental feeding and reproductive biology of this endangered species.