Artificial Substrates Research Articles

Recent advances in enzymatic properties, preparation methods, and functions of glycoside hydrolase from Bifidobacterium: a review.

Bifidobacterium is a major probiotic of intestinal gut flora and exerts many physiological activities, and it is widely applied in the fields of food and medicine. As an important part of Bifidobacterium, glycoside hydrolase plays a role in its physiological activity. With the continuous development and improvement of genetic engineering technology, research on this type of enzyme will play a crucial role in promoting the further development of Bifidobacterium in the field of probiotics. In this review, the preparation methods, enzymatic properties, and functions of glycoside hydrolase extracted from Bifidobacterium are described and summarized. The common method for preparing glycoside hydrolase derived from Bifidobacterium is heterologous expression in Escherichia coli BL21. The optimal pH range for these glycoside hydrolase enzymes is between 4.5 and 7.5; the optimal temperature is between 30 and 50 °C, which is close to the optimal growth condition of Bifidobacterium. Based on substrate specificity, these glycoside hydrolase could hydrolyze synthetic substrates and natural oligosaccharides, including a series of pNP artificial substrates, disaccharide, and trisaccharides, while they have little ability to hydrolyze polysaccharide substrates. This review will be expected to provide a basis for the development of Bifidobacterium as a probiotic element.

Novel beta-glucocerebrosidase chaperone compounds identified from cell-based screening reduce pathologically accumulated glucosylsphingosine in iPS-derived neuronal cells.

The beta-glucocerebrosidase (GBA1) gene encodes the lysosomal beta-glucocerebrosidase (GCase) that metabolizes the lipids glucosylceramide (GlcCer) and glucosylsphingosine (GlcSph). Biallelic loss-of-function mutations in GBA1 such as L444P cause Gaucher disease (GD), which is the most prevalent lysosomal storage disease and is histopathologically characterized by abnormal accumulation of the GCase substrates GlcCer and GlcSph. GD with neurological symptoms is associated with severe mutations in the GBA1 gene, most of which cause impairment in the process of GCase trafficking to lysosomes. Given that recombinant GCase protein cannot cross the blood-brain barrier due to its high molecular weight, it is invaluable to develop a brain-penetrant small-molecule pharmacological chaperone as a viable therapeutic strategy to boost GCase activity in the central nervous system. Despite considerable efforts to screen potent GCase activators/chaperones, cell-free assays using recombinant GCase protein have yielded compounds with only marginal efficacy and micromolar EC50 that would not have sufficient clinical efficacy or an acceptable safety margin. Therefore, we utilized a fluorescence-labeled GCase suicide inhibitor, MDW933, to directly monitor lysosomal GCase activity and performed a cell-based screening in fibroblasts from a GD patient with homozygotic L444P mutations. Here, we identified novel compounds that increase the fluorescence signal from labeled GCase with L444P mutations in a dose-dependent manner. Secondary assays using an artificial cell-permeable lysosomal GCase substrate also demonstrated that the identified compounds augment lysosomal GCase L444P in the fibroblast. Moreover, those compounds increased the total GCase L444P protein levels, suggesting the pharmacological chaperone-like mechanism of action. To further elucidate the effect of the compounds on the endogenous GCase substrate GlcSph, we generated iPSC-derived dopaminergic neurons with a GBA1 L444P mutation that exhibit GlcSph accumulation invitro. Importantly, the identified compounds reduce GlcSph in iPSC-derived dopaminergic neurons with a GBA1 L444P mutation, indicating that the increase in lysosomal GCase resulting from application of the compounds leads to the clearance of pathologically-accumulated GlcSph. Together, our findings pave the way for developing potent and efficacious GCase chaperone compounds as a potential therapeutic approach for neurological GD.

Bryozoans in fouling communities on artificial substrates in Kazachya bay of the Black Sea

Study of the formation of fouling communities on artificial substrates is actual due to the development of mariculture in the Black Sea. Some representatives of macrofoulers are able to influence the process of colonization and development of cultivated organisms. Purpose of work. The main tasks of the study are the revealing the peculiarities of the formation of the fouling community on the experimental plates of the various materials in the environment of the Kazachya bay in the Black Sea and the role of bryozoans in the fouling community. Materials and methods. The experimental plates which were made from the different materials (plastic, aluminum, rubber, galvanized iron) were installed in September 2017 at a depth of 5 m in Kazachya bay (Black Sea). The plates were lifted every month during the year, a total of 480 plates were examined. Results. The peculiarities of the formation of the fouling community on the experimental plates of different materials in the Kazachya bay (Black Sea) were studied. Totally, 22 species were found in the macrofouling community formed on the experimental plates in the Kazachya bay during the year, comprising the following 8 taxa: hydroid polyps - 1, barnacles - 1, sea anemones - 1, bryozoans - 4, polychaetes - 4, bivalve mollusks - 1, tunicates - 2, macrophytes - 8. During the year, the succession of the fouling community of the experimental plates developed through the stage of dominance of microorganisms - barnacle Amphibalanus improvisus , and then - bryozoan Cryptosula pallasiana. Conclusion: the bryozoan Cryptosula pallasiana is the dominant species in the fouling community at four to twelve months old at a depth of five meters.

Unveiling the Diversity of Periphytic Cyanobacteria (Cyanophyceae) from Tropical Mangroves in Penang, Malaysia.

Cyanobacteria are one of the most important groups of photoautotrophic organisms, contributing to carbon and nitrogen fixation in mangroves worldwide. They also play an important role in soil retention and stabilisation and contribute to high plant productivity through their secretion of plant growth-promoting substances. However, their diversity and distribution in Malaysian mangrove ecosystems have yet to be studied in detail, despite Malaysia hosting a significant element of remaining mangroves globally. In a floristic survey conducted in Penang, peninsular Malaysia, 33 morphospecies of periphytic cyanobacteria were identified and described for the first time from a mangrove ecosystem in Malaysia. Sixteen genera, comprising Aphanocapsa, Chroococcus, Chroococcidiopsis, Cyanobacterium, Desmonostoc, Geitlerinema, Leptolyngbya, Lyngbya, Microcystis, Myxosarcina, Oscillatoria, Phormidium, Pseudanabaena, Spirulina, Trichocoleus and Xenococcus, were obtained from field material growing on diverse natural and artificial substrata. Oscillatoriales was the dominant order with Phormidium the dominant genus at nine of the 15 sampling sites examined. Three of the morphospecies, Aphanocapsa cf. concharum, Xenococcus cf. pallidus and Oscillatoria pseudocurviceps, are rare and poorly known morphospecies worldwide. Chroococcus minutus, Phormidium uncinatum, P. amphigranulata, and some species of Oscillatoriales are considered as pollution indicator species. This study provides important baseline information for further investigation of the cyanobacterial microflora present in other mangrove areas around Malaysia. A complete checklist will enhance understanding of their ecological role and the potential for benefits arising from useful secondary metabolites or threats via toxin production to the ecosystem.

Biocontrol of Botrytis cinerea as Influenced by Grapevine Growth Stages and Environmental Conditions.

The growth of four commercial biocontrol agents (BCAs: Bacillus amyloliquefaciens (BAD), Aureobasidium pullulans (APD), Metschnikowia fructicola (MFN), and Trichoderma atroviride (TAS)) was evaluated using turbidimetric assays on artificial substrates mimicking the chemical berry composition at four stages: pea-sized berries, veraison, softening, and ripe berries. The response of BCA growth differed among BCAs. Subsequently, the BCAs' population size was assessed after 1 to 13 days of incubation on the substrate mimicking ripe berries at 15 to 35 °C. The population size of BAD increased with temperatures, while that of MFN decreased; the population sizes of APD and TAS showed bell-shaped patterns with lower growth at 15 or 35 °C. Finally, the BCAs were applied to ripe berries and then incubated at 15 to 30 °C. After 1 to 13 days, the berries were inoculated with B. cinerea and incubated for 7 days, after which the BCA control efficacy was assessed. The highest control was observed at 25 °C for BAD and APD, at 15 to 20 °C for MFN, and at 25 to 30 °C for TAS. The results confirm that the plant substrates and temperature affect the population size of the BCA following application; temperature also affects the preventative efficacy of BCA against B. cinerea.

Ascidian diversity and abundance in North Carolina seagrass meadows

AbstractAscidians are sessile marine invertebrates found all over the world in a variety of natural and artificial habitats. The objective of this study was to provide the first inventory of ascidian diversity and abundance in North Carolina (NC) seagrass meadows. Eight sites along the NC coast were surveyed in May and June 2021 and at each site, 20 quadrats were deployed. All ascidian species within the quadrats were counted and identified based on morphological characterization and sequencing of the barcoding gene. Seagrass percent cover, biomass, and shoot density were also quantified. Ascidians were found in six sites and four species were recorded: the solitary species Molgula manhattensis, Styela plicata, and Bostrichobranchus sp., and the colonial Didemnum lutarium. Colonial specimens were generally attached to hard substrate, while solitary species were often found attached to seagrass rhizomes and leaves. S. plicata and M. manhattensis haplotype diversity were equivalent to previous descriptions from individuals collected on artificial substrates and other locations. Ascidian abundance was positively correlated with seagrass biomass but not with seagrass percent cover. A fifth species, the solitary Styela canopus, appeared in a site revisited in October 2021. Temperate ascidians are known to have seasonal cycles, thus further research should include monthly surveys to assess ascidian diversity and abundance over time.

Seasonal distribution of solitary and colonial benthic ascidians (Chordata) with ecological gradients in and around Andaman and Nicobar Islands, India

AbstractAscidians are rapidly emerging biofouling organisms that generally occur on the natural and artificial substratum of the marine environment. However, very few studies have been reported on their species diversity and distribution patterns. This present investigation focuses on the seasonal impact on ascidians diversity. The distributions of ascidians were recorded by the collection of samples in six sampling stations from Andaman and Nicobar Islands. A total of 43 species of ascidians (32 colonial, 11 solitary) were recorded and most of the species are under the Didemnidae family. Various diversity indexes were utilized to examine the diversity, richness and evenness of species and to look at the assorted variety among tests and their likeness regarding species composition. The greatest (3.227) individuals were observed during summer season in Pigeon Island and the lowest (2.063) number of species were recorded during the monsoon season in Haddowharf harbour. The Margalef richness (d) fluctuated between in the range of 2.033 and 5.53 during the monsoon in Haddowharf harbour and Carbyns Cove beach in summer seasons. The Pielou's evenness record (J′) changed from 0.7409 to 0.9713. Diversity indexes were recorded as followed the order of 0.9642, 0.9552, 0.9482 and 0.9292 at Carbyns Cove shoreline, Burmanella, Pigeon Island and Campbell Bay individually during summer season. Present findings in the cluster examination uncovered that the species at various stations have framed four gatherings. Most elevated species rates were spread in summer. Field observation shows that species distribution is able to tolerate temperature ranges of 26.9–30.3°C and salinity of 32.1–34.64 ppt. Occasional examples of space occupation by colonial ascidians corresponded with seasonal changes in seawater temperature and salinity.

Microalgae diversity in varying habitat characteristics in Pasuruan and Sidoarjo coastal areas, East Java, Indonesia

Abstract. Mahmudi M, Arsad S, Fitrianesia F, Ramadhan SF, Arif AR, Savitri FR, Dewinta AA, Ongkosongo AD, Musa M, Lusiana ED. 2023. Microalgae diversity in varying habitat characteristics in Pasuruan and Sidoarjo coastal areas, East Java, Indonesia. Biodiversitas 24: 4418-4426. Microalgae are microscopic eukaryotic organisms which live in various types of habitats. The purpose of this study was to identify the types and the abundance of microalgae in several sub-habitats, namely sediments, mangroves, water columns, and artificial substrates; and to analyze the environmental factors that affect the abundance of microalgae. The research was conducted in several sites in the coastal areas in Pasuruan and Sidoarjo, East Java, Indonesia. A quantitative descriptive method was applied with data collection used a purposive sampling method. Samples were collected using net for planktonic microalgae and using sampling plot for epiphytic and benthic microalgae. The microalgae were grouped using NMDS (non-metric multidimensional scaling) and the relationships between microalgae abundance and water quality parameters were analyzed using CCA (canonical correspondence analysis). The results show that Bacillariophyceae, Cyanophyceae, and Chlorophyceae classes were found in all study sites, but Trebouxiophyceae and Dinophyceae were only found in Pasuruan Beach. The highest abundance of microalgae was found in sediment habitat in Wughoyo Beach, Sidoarjo with 706,605 ind. cm-2. The diversity, the evenness, and the dominance index in both coastal areas ranged from 1.43-2.61; 0.71-0.96; and 0.06-0.27, respectively. Similarity analysis using the NMDS showed that there was no similarity among the three sites, suggesting each site had high microalgal variation. The CCA analysis showed that Bacillariophyceae were found in all sites, indicating its high adaptability. The results of this analysis imply that particular habitat has a unique microalgae diversity, thus preserving diverse habitat types is important.

Different microbial assemblage colonized on microplastics and clay particles in aerobic sludge treatment

In this study, a combination of property analysis and high–throughput sequencing was used to investigate the microbial colonization ability and their community structures and functions in polypropylene microplastics (PPMPs), polystyrene microplastics (PSMPs) and montmorillonite (MMT), respectively as the representatives of artificial and natural substrates in aerobic sludge treatment. After 45 d of incubation, the surface properties of substrates were altered with the increased oxygen functional groups and surface roughness, indicating microbial settlement. Moreover, MPs had different microbial structures from that of MMT, and PSMPs exhibited higher microbial diversity and abundance than PPMPs and MMT. Also, these substrates changed the inherent ecological niche in sludge. Especially, the abundance of some pathogens (e.g., Pseudomonas, Klebsiella and Flavobacterium) was increased in MPs, and the disease risk of Kyoto Encyclopedia of Genes and Genomes metabolic pathway (e.g., Infectious diseases: Bacterial, Infectious diseases: Parasitic and Immune diseases) was higher. Also, the presence of MPs inhibited the decomposition of organic matter including soluble chemical oxygen demand and protein compared to natural substrates. The findings revealed the crucial vector role of MPs for microbes and the effect on aerobic sludge treatment, highlighting the necessity of MP removal in sludge.

In Situ Optimized Substrate Witness Plates: Ground Truth for Key Processes on the Moon and Other Planets

AbstractFuture exploration efforts of the Moon, Mars, and other bodies are poised to focus heavily on persistent and sustainable survey and research efforts, especially given the recent interest in a long‐term sustainable human presence at the Moon. Key to these efforts understands a number of important processes on the lunar surface for both scientific and operational purposes. We discuss the potential value of in situ artificial substrate witness plates, powerful tools that can supplement familiar remote sensing and sample acquisition techniques and provide a sustainable way of monitoring processes in key locations on planetary surfaces while maintaining a low environmental footprint. These tools, which we call Biscuits, can use customized materials as wide ranging as zircon‐based spray coatings to metals potentially useable for surface structures, to target specific processes/questions as part of a small, passive witness plate that can be flexibly placed with respect to location and total time duration. We examine and discuss unique case studies to show how processes such as water presence/transport, presence and contamination of biologically relevant molecules, solar activity related effects, and other processes can be measured using Biscuits. Biscuits can yield key location sensitive, time integrated measurements on these processes to inform scientific understanding of the Moon and enable operational goals in lunar exploration. While we specifically demonstrate this on a simulated traverse and for selected examples, we stress all groups interested in planetary surfaces should consider these adaptable, low footprint, and highly informative tools for future exploration.

Development of a slow-wave artificial dielectric substrate-based microstrip line in X band

This paper presents a slow-wave artificial dielectric substrate for planar microstrip device miniaturization. The proposed substrate supports the improvement of the permittivity of a given substrate, and in turn offers guided wavelength reduction, leading to obtaining size reduction using low cost printed circuit board (PCB) process. In this structure, two rows of metal vias are located on either side of a microstrip line (ML), which are connected to the ground plane of the substrate. In addition, a row of metal mushroom-shaped vias is placed and connected at the center of the line, which is inserted inside the dielectric media. This would lessen the effective distance between the microstrip line and the ground, and so, the capacitance per unit length is increased leading to obtaining a slow-wave substrate. The proposed structure is numerically investigated using full wave software for specified parameters and the microstrip line characteristics are compared with those of the conventional line. A prototype of the introduced line is implemented and its measured propagation features, including phase constant and effective permittivity, are reported. Results show a perfect agreement with those of simulation, which confirms that a 50.6% longitudinal size reduction is feasible.

Integrative taxonomy approach to detect spatial and temporal variability of the Mediterranean benthic communities through artificial substrate units (ASUs)

Monitoring spatial and temporal changes of marine benthic communities using standardized procedures is essential to take necessary steps towards conservation of marine ecosystems. In this study we combined Artificial Substrate Units (ASUs) for sampling of benthic communities, with integrative taxonomy approach that incorporated morphological identification of organisms and COI DNA metabarcoding, to characterize the diversity of communities at three locations across the Central Mediterranean Sea (Livorno and Palinuro, Italy; Rovinj, Croatia) in 2019 and 2020. Significant differences in the communities’ structure were observed both at large spatial scale between sampled locations, and at small spatial scale (less than ten kilometers) between sites. Moreover, significant temporal variability in species richness and structure of benthic assemblages was detected, with higher richness in 2020. Revealed variability can probably be attributed to the peculiar geomorphological, oceanographical, and ecological features of locations, but also to the influence of interplaying local chemical and physical factors and biological processes such as species settlement, competition, and migration that can act at small spatial and temporal scales. The similarity in the species composition and community structure accessed by morphological and metabarcoding approaches was low, with only 16% of the species (out of 133 species identified overall) commonly detected by both approaches. This is mostly both due to a lack of data on COI sequences of numerous benthic invertebrates in the public barcoding databases on the one hand, and difficulties in detecting small and cryptic taxa through morphological analyses on the other. This suggests that combining of two approaches is required to fully describe the biodiversity of benthic assemblages. Finally, comparison of the spatial variability of the benthic communities’ structure with two approaches at different taxonomic levels, indicated that genus and family levels give results that are consistent to those obtained by the species level. This suggests that family level might be satisfactory in monitoring the spatial-temporal variability of Mediterranean hard bottom benthic communities.

Latitudinal distribution of skeleton shrimps (Amphipoda, Caprellidae) in artificial habitats throughout the eastern South Pacific coast of Peru

ABSTRACT Biodiversity tends to decrease poleward and increase towards the equator. However, these patterns remain unknown for many invertebrate taxa throughout Peru's eastern South Pacific coast, particularly for caprellid crustaceans which are conspicuous in artificial habitats. Three biogeographical units have been proposed for the Peruvian coast: Panamic and Humboldt provinces with a transition zone in between, but a few invertebrates support this classification. We evaluated if the diversity of caprellids decreases towards high latitudes and if the assemblages of caprellids depicted the biogeographic zonation proposed for the Peruvian coast. From 15th to 31st October 2021, caprellids were collected from biofouling communities colonizing boat hulls, buoys, and ropes throughout the Peruvian coast (3.74°–17.99° S). The caprellid assemblage consisted on six species: Caprella penantis [sensu lato], C. penantis f. gibbosa, C. equilibra, C. scaura, Paracaprella pusilla, and Deutella venenosa. Overall, caprellids' abundance, species richness, and diversity decreased southwards. Specific caprellid assemblages showed affinities for each of the three biogeographical units. The dissimilarity of the caprellid assemblages increased at approximately every one degree of latitude. Although artificial substrates can alter biodiversity patterns, caprellids showed the canonical pattern of high diversity towards the equator and resembled the biogeographic zonation proposed for the Peruvian coast.

Effects of substratum type and orientation on the recruitment of bryozoans in an artificial area of the Western Atlantic

Bryozoans are commonly associated with various artificial structures in marine environments and have been responsible for several bioinvasion events worldwide. Understanding the interactions between bryozoans and artificial structures is therefore essential to prevent the establishment and spread of potential bioinvaders. This study investigated bryozoan recruitment on four different substrates (PET, nautical ropes, metal, and PVC) placed in three orientations (vertical, horizontal facing down and facing up) in an area of the Western Atlantic. In total, 15 species of bryozoans were found. The results revealed significant variations in assemblages’ richness, with bryozoans showing a preference for settling on PVC (14 species found) and on the underside of horizontal substrates (15 species found), resulting in the higher representativity observed in this study. Cryptogenic (nine species) and exotic (five species) bryozoans dominated the assemblages in all treatments, indicating that the type of substrate (especially artificial) and its orientation can favor the settlement of bryozoans, particularly non-native species. Therefore, the availability of multiple types of artificial substrates in marine environments should be treated as a cause for concern.

Changes in Environment and Management Practices Improve Foot Health in Zoo-Housed Flamingos.

Foot lesions are a highly prevalent phenomenon among zoo-housed flamingos, with up to 99.8% of birds affected. These lesions are a recognized welfare concern, increasing the likelihood of bacterial infections, and even septicemia. Although several risk factors have been linked to foot lesions in flamingos (including age, climate, and substrate), there have been few studies looking at changes in foot lesions over time. This study tracked changes in foot lesions for an individual flock of Chilean Flamingos (97 birds) at Dublin Zoo, Ireland, over an 18-month period in response to a mandatory indoor housing order imposed by the Irish Government as a seasonal precautionary measure to prevent the spread of avian influenza. Using a pre-defined scoring system for four common types of foot lesions (hyperkeratosis, fissures, nodular lesions, and papillomatous growths), we show that providing unrestricted access to outdoor habitats and natural substrates (both terrestrial and aquatic) can improve the health and wellbeing of zoo-housed flamingos. This longitudinal study highlights the importance of regular foot health monitoring in flamingos, and the importance of natural aquatic substrates when managing flamingos. As many zoo-housed birds have been spending more time indoors on artificial substrates over recent years due to avian influenza housing orders, it is critical that we assess the impact of such changes in management and habitat access on bird health and welfare.

Community structure of periphyton at floating net cages and non-floating net cages in Laut Tawar Lake, Aceh Tengah

Many activities are carried out around the Laut Tawar lake, one of which is the cultivation of floating net cages that can contribute nutrients to the waters. One of the organisms that can take advantage of the abundance of nutrients in the waters is periphyton. This study aims to examine the community structure of periphyton as natural food in Laut Tawar Lake. This research was conducted in January-April 2022. The results showed that there are 9 classes of periphyton at the KJA station, namely Bacillariophyceae, Chlorophyceae, Cyanophyceae, Rhizopoda, Dinophyceae, Euglenophyceae, Trebouxiophyceae, Klebsormidiophyceae and Coscinodiscophyceae. While, at non-KJA stations there are 7 classes where the Klebsormidiophyceae class and the dinophyceae class are not found at non-KJA stations. The highest abundance at the KJA station was on the 7th day with a value of 108,655 cells/cm2 and non-KJA was 24,552 cells/cm2. The lowest abundance occurred on day 14 at both stations. Periphyton diversity index at KJA and non-KJA stations ranged from 1.88-2.76, which was moderate. The evenness index of periphyton species ranging from 0.61-0.75 was classified as high, while the dominance index ranging from 0.09-0.24 was classified as low. Based on the values obtained, the community structure of periphyton on artificial substrates in the KJA and non-KJA areas in Laut Tawar Lake experienced moderate ecological stress with the community in a stable condition. The t-test results obtained that the abundance values at KJA stations and non-KJA stations had the difference that the abundance of periphyton at KJA stations was greater than at non-KJA stations.

Organic Catalytic Activity as a Method for Agnostic Life Detection.

An ideal life detection instrument would have high sensitivity but be insensitive to abiotic processes and would be capable of detecting life with alternate molecular structures. In this study, we propose that catalytic activity can be the basis of a nearly ideal life detection instrument. There are several advantages to catalysis as an agnostic life detection method. Demonstrating catalysis does not necessarily require culturing/growing the alien life and in fact may persist even in dead biomass for some time, and the amplification by catalysis is large even by minute amounts of catalysts and, hence, can be readily detected against abiotic background rates. In specific, we propose a hydrolytic catalysis detection instrument that could detect activity in samples of extraterrestrial organic material from unknown life. The instrument uses chromogenic assay-based detection of various hydrolytic catalytic activities, which are matched to corresponding artificial substrates having the same, chromogenic (preferably fluorescent) upon release, group; D- and L-enantiomers of these substrates can be used to also answer the question whether unknown life is chiral. Since catalysis is a time-proportional product-concentration amplification process, hydrolytic catalytic activity can be measured on a sample of even a minute size, and with instruments based on, for example, optofluidic chip technology.

An Assessment of the Toxicity of Pesticide Mixtures in Periphyton from Agricultural Streams to the Mayfly Neocloeon triangulifer.

Residual concentrations of pesticides are commonly found outside the intended area of application in Ontario's surface waters. Periphyton are a vital dietary component for grazing organisms in aquatic ecosystems but can also accumulate substantial levels of pesticides from the surrounding water. Consequently, grazing aquatic organisms are likely subjected to pesticide exposure through the consumption of pesticide-contaminated periphyton. The objectives of the present study were to determine if pesticides partition into periphyton in riverine environments across southern Ontario and, if so, to determine the toxicity of pesticides in periphyton when fed to the grazing mayfly Neocloeon triangulifer. Sites with low, medium, and high pesticide exposure based on historic water quality monitoring data were selected to incorporate a pesticide exposure gradient into the study design. Artificial substrate samplers were utilized to colonize periphyton in situ, which were then analyzed for the presence of approximately 500 pesticides. The results demonstrate that periphyton are capable of accumulating pesticides in agricultural streams. A novel 7-day toxicity test method was created to investigate the effects of pesticides partitioned into periphyton when fed to N. triangulifer. Periphyton collected from the field sites were fed to N. triangulifer and survival and biomass production recorded. Survival and biomass production significantly decreased when fed periphyton colonized in streams with catchments dominated by agricultural land use (p < 0.05). However, the relationship between pesticide concentration and survival or biomass production was not consistent. Using field-colonized periphyton allowed us to assess the dietary toxicity of environmentally relevant concentrations of pesticide mixtures; however, nutrition and taxonomic composition of the periphyton may vary between sites. Environ Toxicol Chem 2023;42:2143-2157. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Smart soils track the formation of pH gradients across the rhizosphere

AimsOur understanding of the rhizosphere is limited by the lack of techniques for in situ live microscopy. Current techniques are either destructive or unsuitable for observing chemical changes within the pore space. To address this limitation, we have developed artificial substrates, termed smart soils, that enable the acquisition and 3D reconstruction of chemical sensors attached to soil particles.MethodsThe transparency of smart soils was achieved using polymer particles with refractive index matching that of water. The surface of the particles was modified both to retain water and act as a local sensor to report on pore space pH via fluorescence emissions. Multispectral signals were acquired from the particles using a light sheet microscope, and machine learning algorithms predicted the changes and spatial distribution in pH at the surface of the smart soil particles.ResultsThe technique was able to predict pH live and in situ within ± 0.5 units of the true pH value. pH distribution could be reconstructed across a volume of several cubic centimetres around plant roots at 10 μm resolution. Using smart soils of different composition, we revealed how root exudation and pore structure create variability in chemical properties.ConclusionSmart soils captured the pH gradients forming around a growing plant root. Future developments of the technology could include the fine tuning of soil physicochemical properties, the addition of chemical sensors and improved data processing. Hence, this technology could play a critical role in advancing our understanding of complex rhizosphere processes.

Underwater macrophotogrammetry to monitor in situ benthic communities at submillimetre scale

Abstract Larval settlement and recruitment of sessile organisms are key ecological processes for population recovery and maintenance that occur at scales invisible to the human eye. Accordingly, proxies of recruitment have commonly been quantified using artificial substrata such as settlement tiles made of diverse materials and shapes, which are typically transported to the laboratory for examination. However, it is unknown how much bias is introduced with this sampling strategy and how recruitment quantified on tiles relates to recruitment on nearby natural substrata. Here, we applied techniques that combine macrophotography with photogrammetry (macrophotogrammetry) underwater to monitor benthic communities at submillimetre scale. This application allows the investigation of recruitment and community succession of the earliest life‐history stages in situ and on natural substrata. We tested the use of four different imaging systems, varying in costs from US$ 1400 to US$ 5440. While the most expensive SONY αRiv system provided the best visual output and ground resolution (up to 5 μm/pixel with a + 4 close‐up lens); regardless of systems, 3D models always had a ground resolution ≤23 μm/pixel and errors in planar measurements of submillimetre features were similar among systems. This level of resolution compares well with stereomicroscopy in the range of 5:1 to 10:1 magnification, while providing detailed 3D digital records through time. Using a coral reef example, we apply this approach to demonstrate how it can be used to monitor small reef areas (~300–600 cm2) through time, including the quantification of biophysical metrics such as cover of small facilitative and competitive organisms and microhabitat complexity. We further show that organisms as small 0.5 mm in size, such as 2‐month‐old coral settlers, can be located accurately within the 3D models and measured with a good level of confidence. This method can be readily applied to other benthic environments to elucidate drivers of early recruitment and recovery of benthic organisms following disturbance impacts at very fine scales, directly on natural substrata, to avoid biases inherent with laboratory‐based analyses of artificial surfaces.