Bulk Biomass Research Articles

From macro to micro: Biomass-derived advanced carbon microtube assembly for sodium-ion batteries

Developing high-rate anode materials for sodium-ion batteries is important to fulfill the requirement of high-power energy storage applications. Amorphous carbon micro-tubes (CMTs) are favorable for fast Na-ion storage, for the open carbon framework provides sufficient electrode/electrolyte contact and the one-dimensional skeleton offers fast electron and ion diffusion pathways. Herein, N, Fe co-doped carbon micron-tubes (NF-CMTs) were synthesized for the high-rate anode by using bulk biomass as the precursor. The transformation from the macro-sized biomass to the micro-sized carbon tubes was endowed by pyrolysis using N and Fe as catalysts. The open carbon frameworks enable capacitive-controlled capacity contribution, while its N-Fe defects offer multiple active sites for fast Na-ion storage. A high-capacity contribution was demonstrated by the pseudo-capacitive mechanism so that the NF-CMTs performed a superior rate capability of 120 mAh g−1 at 2.0 A g−1. The NF-CMTs with stable micro-tube frameworks exhibited high cycling stability over 1200 cycles, which was much superior to the commercial hard carbon anode. This study provides a cost-effective approach to develop carbon micro-tubes from bulk biomass for high-power SIB anodes.

Membrane fouling, methane production and microbial community under fluidization of biocarrier with conductive surface in anaerobic fluidized bed membrane bioreactor for greywater treatment

A comparative study of organic removal efficiency, fouling control, and methane production from synthetic greywater was performed operating three anaerobic fluidized bed membrane bioreactors (AFMBRs). Granular activated carbon (GAC) particles, polyaniline-coated polyethylene terephthalate (PET) beads, and uncoated PET beads were added as scouring agent to control fouling through each AFMBR. The use of PET spherical beads coated with polyaniline as a fluidized medium improved both fouling reduction and methane production kinetics. Although the GAC particles showed the highest organic removal efficiency in AFMBR due to adsorption capability, their progressive fragmentation reduced the methanogenic population and accelerated fouling rate. Microbial activity was adversely affected when the bulk biomass was exposed to the surfactant in the synthetic greywater. Microbiome analysis showed that the methanogenic archaeal population in the GAC bulk biomass reduced significantly from 10 to 0.5%, which corroborates the decrease in methane production rate. The methanogens on the PET beads shifted gradually from acetoclastic Methanosaeta to hydrogenotrophic Methanospirillum presumably because of the detachment of the biofilm that suppressed the slow-growing Methanosaeta. In addition, the key exoelectrogenic microbes were related to Desulfovibrio and Geobacter, which may be associated with direct interspecies electron transfer with the methanogens.

Mock samples resolve biases in diversity estimates and quantitative interpretation of zooplankton metabarcoding data

Metabarcoding is a rapidly developing tool in marine zooplankton ecology, although most zooplankton surveys continue to rely on visual identification for monitoring purposes. We attempted to resolve some of the biases associated with metabarcoding by sequencing a 313-b.p. fragment of the COI gene in 34 “mock” samples from the North Sea which were pre-sorted to species level, with biomass and abundance estimates obtained for each species and taxonomic group. The samples were preserved either in 97% ethanol or dehydrated for 24 h in a drying oven at 65 °C (the routine way of preserving samples for dry weight measurements). The visual identification yielded a total of 59 unique holoplanktonic and 16 meroplanktonic species/taxa. Metabarcoding identified 86 holoplanktonic and 124 meroplanktonic species/taxa, which included all but 3 of the species identified visually as well as numerous species of hard-to-identify crustaceans, hydrozoan jellyfish, and larvae of benthic animals. On a sample-to-sample basis, typically 90–95% of visually registered species were recovered, but the number of false positives was also high. We demonstrate robust correlations of relative sequence abundances to relative biomass for most taxonomic groups and develop conversion factors for different taxa to account for sequencing biases. We then combine the adjusted sequencing data with a single bulk biomass measurement for the entire sample to produce a quantitative parameter akin to species biomass. When examined with multivariate statistics, this parameter, which we call BWSR (biomass-weighed sequence reads) showed very similar trends to species biomass and comparable patterns to species abundance, highlighting the potential of metabarcoding not only for biodiversity estimation and mapping of presence/absence of species but also for quantitative assessment of zooplankton communities.

Finite element modeling of biomass hopper flow

Hoppers are widely used biomass handling devices that channel bulk biomass from storage to subsequent handling equipment. Jenike’s longstanding approach, based on the Mohr-Coulomb model, has been successfully used to design hoppers handling cohesionless granular materials such as grains and other agricultural produces. However, designing a hopper to ensure reliable biomass flow is found to be challenging due to cohesion, irregular particle shape, and bulk material elastoplasticity. This study aims to address the biomass handling engineering challenge with alternative constitutive material models concerning the flow behavior of bulk solids. Finite element modeling is an approach that allows for implementation of different material models, whose underlying constitutive theories assist in investigating the origin and manifestation of bulk mechanical behavior of granular materials. This study focuses on the incipient gravity hopper flow of two types of biomass feedstocks, i.e., ground corn stover and Douglas fir wood. Three widely used constitutive material models, i.e., Mohr-Coulomb model, modified Cam-Clay model, and Drucker-Prager/Cap model, are implemented. Using the flow pattern represented by the volume of biomass exhibiting more than 7% of axial strain (Kamath and Puri, 1999), the finite element model predicts that the bulk corn stover particulate material forms an arch, which represents a hampered transition from the static state to the dynamic flow-state out of the hopper, whereas bulk Douglas fir wood particulate material develops a reliable mass flow pattern. A laboratory scale hopper was used to experimentally determine the biomass flow conditions, which were subsequently compared with the predicted onset of flow by a finite element model (FEM). The developed FEM was found to correctly predict the initiation of mass flow for the milled Douglas fir wood, whereas corn stover was predicted to establish a strong core flow suggesting an unreliable handling characteristic. This observation aligns with the reported poor handling of milled corn stover.

Bacterial physiology highlighted by the δ13C fractionation of bacteriohopanetetrol isomers

Lipid biomarkers, such as the various bacteriohopanetetrol (BHT) isomers studied here, are useful tools in tracing bacterially mediated nitrogen and carbon cycle processes affecting greenhouse gas emissions, including the anaerobic oxidation of ammonia. Three BHT isomers occur commonly in the environment. By gas chromatography, BHT-34S elutes first; it is produced by numerous bacteria. The two later eluting isomers are more constrained in their origin. The marine anammox bacteria ‘Ca. Scalindua’ is the only known producer of a BHT isomer of unknown stereochemistry (BHT-x), making BHT-x a diagnostic biomarker in anoxic marine settings. The BHT-34R isomer is produced by three freshwater aerobic heterotrophic producers (Frankia spp., Acetobacter pasteurianus, and Komagataeibacter xylinus), a freshwater serine-cycle (Type II) methanotroph (Methylocella palustris), and the freshwater anammox ‘Ca. Brocadia’, which makes the detection of freshwater anammox using BHT-34R more complicated. We investigated whether the source of BHT-34R in freshwater environments could be ascertained via its δ13C value. We used conventional on-column gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) (as opposed to high temperature GC-C-IRMS) to determine the δ13C composition of acetylated BHT isomers in cultured bacteria and bacterial enrichments. We combined these with bulk biomass and substrate δ13C compositions to establish carbon isotopic fractionation factors. The two anammox genera had large fractionation factors from dissolved inorganic carbon (DIC) to biomass (Δ13Cbiomass – DIC = –43.8 to –26.4 ‰) and to BHTs (Δ13CBHT – DIC = –53.8 to –38.2 ‰), which clearly distinguished them from the freshwater aerobic heterotrophic producers (Δ13Cbiomass – substrate = –2.3 to –0.1 ‰; Δ13CBHT – substrate = –12.8 to 5.2 ‰). Methylocella assimilated mainly carbon from DIC, rather than from methane, into its biomass and BHT, and previous work suggested this assimilation comes with relatively small fractionation. Thus, in peatlands, the BHT δ13C values of Methylocella would not reflect the low δ13C values of biogenic methane. Consequently, the presence of BHT-34R with low δ13C values relates to ‘Ca. Brocadia’ and presents a novel tool to trace anammox in freshwater environments.

Zooplankton Biomass in Ponds - Determination of Biovolume and Dry Weight

The aim of this study was to evaluate the possibility of using simple screening methods to determine zooplankton biomass in ponds. Among the applicable methods, we selected sedimentation determination of wet biomass and dry biomass determination. Of the 369 samples analysed, the median volumetric zooplankton biomass was 0.012 ml.l-1 and the median dry weight of the samples was 0.44 mg.l-1. There was a relatively close relationship between the volumetric biomass determination and the zooplankton dry weight determination, allowing only one of these methods to be used. Due to the variation of results over a wide range of values, it is more appropriate to use a logarithmic expression for the correlation. No statistically conclusive relationship was found between the zooplankton biomass determined and any of the other physico-chemical or production parameters. Nevertheless, it was possible to trace the influence of fish production, altitude and nutrient content (nitrogen and phosphorus) on the size of zooplankton biomass. The use of screening determination methods can be recommended especially for long-term monitoring of sites to get a quick overview of zooplankton biomass in ponds. It is clear from the above data that predicting the development of the zooplankton community in ponds is highly problematic. Standard determination of zooplankton biomass at regular intervals during the growing season is usually not realistic outside scientific studies due to its technical and time-consuming nature. Therefore, for long-term monitoring of the zooplankton community at a given site, it is advisable to use relatively quick and inexpensive methods of determining zooplankton biomass, such as bulk biomass or dry weight. Although these methods do not give a detailed picture of the species structure of zooplankton, they do give information on the size of the total zooplankton biomass. Together with the determination of basic physico-chemical parameters and especially chlorophyll-a, a fairly good inference can then be made on the development of plankton communities.

Activation of persulfate by graphene/biochar composites for phenol degradation: Performance and nonradical dominated reaction mechanism

Recently, metal-free carbon catalysts have attracted extensive attention in sulfate radical (SO4•−)-based advanced oxidation processes (SR-AOPs). In this paper, graphene/biochar composites (GBCs) were prepared by blending two-dimensional graphene and bulk biomass followed by pyrolysis, and were employed to activate persulfate (PS) to degrade phenol. The effects of different factors (e.g., graphene/biomass mass ratio, GBC dosing, phenol concentration, pH values, reaction temperature, and background substrates in water) on the removal of phenol and the mechanism in the GBC/PS system were investigated. The results showed that 100% removal of phenol can be achieved in the GBC0.6 (i.e., the mass ratio of 0.6%) /PS system within 30 min (kobs = 0.1634 min−1). GBC0.6/PS system also demonstrated various advantages of adapting to a broad pH range (3 ∼ 9), the lower activation energy of 12.13 kJ/mol, strong resistance to inorganic ions and natural organic matters, and higher tolerance to the background water matrices. The adsorption of phenol in the GBC0.6/PS system was related to the π-π * EDA interaction of phenol with GBC0.6, while the degradation mainly relied on the nonradical pathway (singlet oxygen (1O2) and electron transfer) and secondarily on the radical pathway, the role of aqueous SO4•− and hydroxyl radical (•OH) was negligible. Meanwhile, spectroscopic characterizations confirmed that the porous structure, defects, multilayer graphite structure, and carboxyl group (-COOH) of GBC0.6 were also involved in the removal of phenol. This study provides a new idea for the removal of micropollutants from the water environment by a novel green and environment-friendly metal-free carbon catalyst via persulfate activation.

Integrating Genome-Resolved Metagenomics with Trait-Based Process Modeling to Determine Biokinetics of Distinct Nitrifying Communities within Activated Sludge.

Conventional bioprocess models for wastewater treatment are based on aggregated bulk biomass concentrations and do not incorporate microbial physiological diversity. Such a broad aggregation of microbial functional groups can fail to predict ecosystem dynamics when high levels of physiological diversity exist within trophic guilds. For instance, functional diversity among nitrite-oxidizing bacteria (NOB) can obfuscate engineering strategies for their out-selection in activated sludge (AS), which is desirable to promote energy-efficient nitrogen removal. Here, we hypothesized that different NOB populations within AS can have different physiological traits that drive process performance, which we tested by estimating biokinetic growth parameters using a combination of highly replicated respirometry, genome-resolved metagenomics, and process modeling. A lab-scale AS reactor subjected to a selective pressure for over 90 days experienced resilience of NOB activity. We recovered three coexisting Nitrospira population genomes belonging to two sublineages, which exhibited distinct growth strategies and underwent a compositional shift following the selective pressure. A trait-based process model calibrated at the NOB genus level better predicted nitrite accumulation than a conventional process model calibrated at the NOB guild level. This work demonstrates that trait-based modeling can be leveraged to improve our prediction, control, and design of functionally diverse microbiomes driving key environmental biotechnologies.

Biomass conversion into recyclable strong materials

We review the conversion of waste biomass into recyclable materials using different methods of materials treatment such as thermal, mechanical and chemical processes. Renewable and sustainable biomaterials are increasingly becoming alternatives for synthetic strong materials, e.g. composites. The type of treatment of biomaterial will determine the form to which the biomass is converted and its subsequent applications. It is anticipated that the transformation will produce materials that have superior qualities, properties and characteristics. These include biopolymer materials such as cellulose and hemicellulose, which have all been obtained as products of treatment and extraction from plant materials such as lignocellulose. The main reason for inefficient biomass conversion has been found to be poor manipulation of composite properties during biomass treatment process. The treatment processes are expected to facilitate dehydration, dehydrogenation, deoxygenation and decarboxylation of the bulk biomass materials to target the formation of new compounds that may be used to make strong materials. Significance: This work demonstrates that plant material, as a solid-state biomass material for strong structural applications such as in biocomposites, is affected by factors that include the alignment of fibres, orientation of fibres, and mass density distribution. However, biocomposite materials have been found to be non-toxic, corrosionresistant, low-cost, and renewable. They are preferred because the materials possess high thermal stability, are biodegradable and recyclable, and have high biocompatibility, performance, strength, water-resistance, specific surface area and aspect ratio to qualify them for applications including biobricks for construction, slabs for paving, vehicle internal components, ultra-high temperature aerospace ceramics, and energy storage devices.

Vapor Phase Terpenes Mitigate Oxidative Degradation of Cannabis sativa Inflorescence Cannabinoid Content in an Accelerated Stability Study.

Introduction: As Cannabis sativa L. (Cannabaceae) ages, inflorescence phytochemicals are susceptible to oxidative degradation. Reduction of Δ9-tetrahydrocannabinol (Δ9-THC) content has the potential to impact the reliability and accuracy of dosing. Advances that improve cannabinoid stability during storage would have an important impact in medical cannabis markets. Reported here is the use of C. sativa terpenes with antioxidant properties that improve inflorescence cannabinoid stability. Materials and Methods: Killer Kush inflorescence samples were stored in a temperature-controlled environment, in opaque jars. To accelerate the rate of oxidate degradation, samples were stored with the oxidizing agent hydrogen peroxide. Vapor phase terpenes were added to inflorescence packaging. Two terpene blends and three different dosage amounts were evaluated. Inflorescence stability samples were prepared in triplicate for each sample type. Cannabinoid content was quantitatively assessed after 24, 81, and 127 days of storage using high-performance liquid chromatography. Terpene content was assessed using headspace gas chromatography mass spectrometry. Results from inflorescence stored with and without external terpenes were compared by analysis of variance (ANOVA) data processing. Results: After 127 days of storage, inflorescence in the accelerated study experienced a loss of 18.0% and 34.3% total Δ9-THC content for samples stored with and without external terpenes, respectively. The differences in cannabinoid content were found to be statistically significant at all timepoints using ANOVA processing. In the nonaccelerated study, only one of the six sample types investigated had a statistically significant greater total Δ9-THC content than control at all timepoints. Nevertheless, a dose-dependent relationship between the amount of external terpenes added to inflorescence and the preservation of total Δ9-THC content was observed. Discussion: In the accelerated study, exogenous terpenes reduced the degradation of inflorescence cannabinoid content by 47.4%. This represents the first reported addition of terpene antioxidants to inflorescence packaging for cannabinoid preservation. Of note, the antioxidants used in this system can be obtained from C. sativa. This is advantageous from a toxicological perspective as inhaling synthetic antioxidants presents unknown and unpredictable risks. When fully developed, the novel system has applications for inflorescence packaged for individual sale, as well as long-term storage of bulk biomass.

Anaerobic single-cell dispensing facilitates the cultivation of human gut bacteria.

Cultivation via classical agar plate (CAP) approaches is widely used to study microbial communities, but they are time-consuming. An alternative approach is the application of single-cell dispensing (SCD), which allows high-throughput, label-free sorting of microscopic particles. We aimed to develop a new anaerobic SCD workflow to cultivate human gut bacteria and compared it with CAP using faecal communities on three rich culture media. We found that the SCD approach significantly decreased the experimental time to obtain pure cultures from 17± 4 to 5± 0 days, while the isolate diversity and relative abundance coverage were comparable for both approaches. We further tested the total captured fraction by sequencing the sorted bacteria directly after growth as bulk biomass from 2400 dispensed single cells without downstream identification of individual strains. In this approach, the cultured fraction increased from 35.2% to 52.2% for SCD, highlighting the potential for deeper cultivation projects from single samples. SCD-based cultivation also captured species not detected by sequencing (16± 5 per sample, including seven novel taxa). From this work, 82 human gut bacterial species across five phyla (Actinobacteriota, Bacteroidota, Desulfobacterota, Firmicutes and Proteobacteria) and 24 families were obtained, including the first cultured member of 11 novel genera and 10 novel species that were fully characterized taxonomically.

Review on Self-Heating of Biomass Materials: Understanding and Description

Storage of bulk biomass materials is essential along the feedstock supply chain of bioenergy production. The self-heating accompanying biomass storage has hazardous consequences. With the increasing biomass utilization for bioenergy production, the risk and economic and environmental concerns about biomass storage have been attracting extensive research attention aimed at understanding the processes of heat generation, evaluating the propensity of a material to self-heating and spontaneous ignition, describing and predicting the self-heating process and consequences in biomass storage, and developing strategies and technologies for storage management. The advances in the understanding and description of heat generation processes including water-associated physical processes, microbiological degradation processes, and chemical oxidative processes during the self-heating in biomass storage are reviewed, with the focus on understanding the processes and their underlying mechanisms, reaction kinetics, and heats of reaction through experimental studies and description of heat generation and self-heating processes through kinetic analyses and modeling. This review highlights the need to improve the mechanistic model description of the self-heating processes and associated material changes and product formation, which demand a better understanding and description of microbial degradation and chemical oxidation through experimental study.

Nitrogen limitation reduces the performance of target plant species in restored meadows

Restoring habitats degraded by intensive agriculture is challenging, and the resulting communities often have lower quality and host fewer species than reference ecosystems. To improve restoration outputs, we need to understand what limits both establishment and performance of target species in restored populations. In this study, we focused on grassland restoration with regional seeds and compared the performance of two target herbs, Betonica officinalis and Centaurea jacea, between restored and reference populations. We also measured plant functional traits and environmental characteristics to understand which parameters affect population performance. Individual plants of both species were smaller in restored populations, which indicates reduced performance. Leaves of plants from restored populations contained more δ15N and, in Betonica, also less nitrogen and higher C:N ratio, which suggests that the performance of the target species may be limited by nitrogen. Nitrogen limitation of all restored communities was further corroborated by the low N:P ratio of bulk biomass. In Centaurea, we also recorded massive herbivory damage in restored populations, which likely further reduced this species' performance in restored meadows. In summary, target plants in restored populations showed lower performance than conspecifics in reference sites, probably due to nutrient imbalance (low nitrogen availability) and excessive herbivory damage.

Experimental Studies of Structural and Technological Parameters of a Downdraft Gasifier Based on Plant Biomass

The relevance of the study is conditioned upon the need to develop and implement structural and technological solutions to improve the efficiency of the chemical and thermal conversion of biomass into combustible gas. Within the framework of the above, the authors of this paper have designed a downdraft gasifier running on plant biomass. The presented research links the heat quantity received from the utilisation of syngas produced during the gasifier operation cycle with the parameters of the gas blow regime and the physico-chemical properties of biomass. For an in-depth study of the influence of the gas blow regime on the yield and calorific value of syngas produced from biomass, the authors introduce the concept of the blow coverage quality coefficient. This coefficient describes the quality of the cross-section coverage of the gasification chamber neck with gas currents of the tuyere zone. The purpose of this study is to establish the influence of the blow coverage quality coefficient, the volume of blow gases and the void ratio of the bulk biomass layer on the heat quantity received from syngas produced during the gasifier operation cycle. A multi-factor experiment was planned and performed, which relates the dependent factor to variables, and the corresponding response surfaces were constructed. The research findings are that the maximum value of the heat quantity received from the utilisation of syngas produced during the one-hour gasifier operation cycle was 519 MJ. This value is achieved with 0.8 blow coverage quality coefficient and a blow gas volume of 47.4 m3/h and 46.75% void ratio of the bulk biomass layer. The measurement results are highly consistent with the calculated data. The coefficient of determination was R2=0.983. The practical value of this study is to substantiate the rational design and technological parameters of the downdraft biomass gasifier operation, which will increase the efficiency of biomass energy production. The findings presented in this study can be used both to design new gasifiers and to improve the efficiency of the available ones

High Carotenoid Mutants of Chlorella vulgaris Show Enhanced Biomass Yield under High Irradiance.

Microalgae represent a carbon-neutral source of bulk biomass, for extraction of high-value compounds and production of renewable fuels. Due to their high metabolic activity and reproduction rates, species of the genus Chlorella are highly productive when cultivated in photobioreactors. However, wild-type strains show biological limitations making algal bioproducts expensive compared to those extracted from other feedstocks. Such constraints include inhomogeneous light distribution due to high optical density of the culture, and photoinhibition of the surface-exposed cells. Thus, the domestication of algal strains for industry makes it increasingly important to select traits aimed at enhancing light-use efficiency while withstanding excess light stress. Carotenoids have a crucial role in protecting against photooxidative damage and, thus, represent a promising target for algal domestication. We applied chemical mutagenesis to Chlorella vulgaris and selected for enhanced tolerance to the carotenoid biosynthesis inhibitor norflurazon. The NFR (norflurazon-resistant) strains showed an increased carotenoid pool size and enhanced tolerance towards photooxidative stress. Growth under excess light revealed an improved carbon assimilation rate of NFR strains with respect to WT. We conclude that domestication of Chlorella vulgaris, by optimizing both carotenoid/chlorophyll ratio and resistance to photooxidative stress, boosted light-to-biomass conversion efficiency under high light conditions typical of photobioreactors. Comparison with strains previously reported for enhanced tolerance to singlet oxygen, reveals that ROS resistance in Chlorella is promoted by at least two independent mechanisms, only one of which is carotenoid-dependent.

Supercritical Extraction of Biomass—A Green and Sustainable Method to Control the Pyrolysis Product Distribution

This research demonstrates that supercritical extraction of the biomass has a remarkable and complex influence on Scots pine tree fractions changing the surface concentration of water, lipids, and metals simultaneously. Surprisingly, this surface composition modification makes a considerable impact on the pyrolysis of the bulk biomass mechanism, leading to the alternation of the volatile and inorganic matter composition. The unique combination of time-of-flight secondary-ion mass spectrometry analysis and utilization of pyrolysis gas chromatography-mass spectrometry data on the thermal behavior of woody biomass demonstrates, for the first time, the extraordinary influence of surface adsorbed metals on the composition of pyrolysis products. ScCO2 could extract the surface metals in the form of fatty acid salts, demonstrating a sustainable and environmentally friendly pretreatment method for controlling the pyrolysis products.

A sequencing-free assay for foliose Ulva species identification, hybrid detection and bulk biomass characterisation

Sea Lettuce (Ulva spp. Ulvophyceae, Ulvaceae) has tremendous ecological and industrial impacts, from the negative effects of green tide events to the industrial production of food, feed, and value-added products. Due to the morphological similarities between Ulva species, their identification requires the use of “barcoding”, which relies on the sequencing of short fragments of DNA and the comparison of the obtained sequence to that of sequences present in public repositories. However, Sanger sequencing can be costly when hundreds of samples need to be analysed. In addition, “barcoding”, which uses Sanger sequencing, cannot be applied directly on bulk biomass, and requires independent assessment of the individuals within, which is often not possible in commercial products. Here, we describe a novel “sequencing-free” method for species identification of foliose Ulva species that by-passes the drawbacks associated with Sanger sequencing. The assay uses restriction digestion enzymes which target species-specific Single Nucleotide Polymorphisms (SNPs) present within the ITS1 sequence. Digestion of the ITS1 PCR product with two enzyme mixtures allows for the discrimination of the main foliose Ulva species, as well as U. compressa, which can have a foliose morphotype. Of the species tested, only U. pseudorotundata and U. arasakii show the same digestion pattern. Since those two Ulva species are allopatric, we expect this issue to be of limited impact for the users. In addition to species identification, we demonstrate that the assay can be used for hybrid detection, which can have interests for Ulva breeding and species delimitation. Importantly, the assay can be used to detect at once the different Ulva species present within a bulk of Ulva biomass, which could allow for traceability and characterisation of the purity of Ulva commercial products. This study provides a new quick and cost-effective method for foliose Ulva species identification that could readily be extended to other species.

Meta-models for rapid appraisal of the benefits of urban greening in the European context

Study regionThis study considers daily time series of 14 years of weather parameters (temperature, wind speed, rainfall, vapor pressure and radiation) for 671 functional urban areas (FUA) across Europe, from a latitude of 35° (Cyprus) to 65° (Finland). Study focusQuantification of urban greening effects usually requires relatively complex and integrated models. In this contribution, we apply well-established hydrological, biomass and energy balance equations to derive meta-models for the estimation of runoff reduction, urban surface heating and thermal protection of buildings, in order to quantify the effects of the greening of 1 m2 of impervious surface (e.g. roofs, sealed ground surfaces and underground parking lots). New hydrological insights for the regionWe propose empirical meta-models for the quick appraisal of urban greening benefits including: urban runoff reduction due to soil water retention and evapotranspiration, land surface temperature reduction, reduction of the indoor temperature beneath the greened surface, dry biomass growth. We show that the choice of vegetation growth parameters has a limited effect on the results, although the amount of produced bulk biomass obviously depends on vegetation type. The proposed meta-models can be applied for the assessment of urban greening benefits at the stage of policy evaluation, land planning and the programming of investments at regional or continental scale, before undertaking more detailed and site-specific calculations as required in the design phase.

Review of the biology of the krill genusNyctiphanesG.O. Sars, 1883 (Euphausiacea: Euphausiidae): challenges for future research on environmental change

AbstractThe genus Nyctiphanes G.O. Sars, 1883 (Euphausiacea, Euphausiidae) includes four extant species. These species are a conspicuous component of trophic webs of coastal marine ecosystems due to their abundance, the formation of dense aggregations, swarms, and schools, fast growth, and high reproductive rates. They dominate the bulk biomass in eutrophic Eastern Boundaries System and subtropical mesotrophic habitats, with estimates of 30–40% of the total zooplankton biomass. Species of Nyctiphanes are efficient omnivores and conversely prey for a large number of zooplanktonic and nektonic species. We review current knowledge of the biogeography, reproductive biology, physiology, biochemistry, ecology, and parasitology of the four species of Nyctiphanes. Most published information on Nyctiphanes focuses on the two species from the Pacific Ocean, N. australis G.O. Sars, 1883 and N. simplex Hansen, 1911, and considerably less is known on the biology and ecology of N. couchii (Bell, 1853) and N. capensis Hansen, 1911 from the Atlantic Ocean. Knowledge on the biology and ecology of the species of Nyctiphanes is still behind what is currently known for species of krill, particularly compared to Euphausia Dana, 1850 and Thysanoessa Brandt, 1851, and new multi-focal studies on the effects that environmental variables have on reproductive aspects, survival, growth, and physiology are especially critical to address under future environmental change.

Monitoring of Nitrification in Chloraminated Drinking Water Distribution Systems With Microbiome Bioindicators Using Supervised Machine Learning.

Many drinking water utilities in the United States using chloramine as disinfectant treatment in their drinking water distribution systems (DWDS) have experienced nitrification episodes, which detrimentally impact the water quality. Identification of potential predictors of nitrification in DWDS may be used to optimize current nitrification monitoring plans and ultimately helps to safeguard drinking water and public health. In this study, we explored the water microbiome from a chloraminated DWDS simulator operated through successive operational schemes of stable and nitrification events and utilized the 16S rRNA gene dataset to generate high-resolution taxonomic profiles for bioindicator discovery. Analysis of the microbiome revealed both an enrichment and depletion of various bacterial populations associated with nitrification. A supervised machine learning approach (naïve Bayes classifier) trained with bioindicator profiles (membership and structure) were used to classify water samples. Performance of each model was examined using the area under the curve (AUC) from the receiver-operating characteristic (ROC) and precision-recall (PR) curves. The ROC- and PR-AUC gradually increased to 0.778 and 0.775 when genus-level membership (i.e., presence and absence) was used in the model and increased significantly using structure (i.e., distribution) dataset (AUCs = 1.000, p < 0.01). Community structure significantly improved the predictive ability of the model beyond that of membership only regardless of the type of data (sequence- or taxonomy-based model) we used to represent the microbiome. In comparison, an ATP-based model (bulk biomass) generated a lower AUCs of 0.477 and 0.553 (ROC and PR, respectively), which is equivalent to a random classification. A combination of eight bioindicators was able to correctly classify 85% of instances (nitrification or stable events) with an AUC of 0.825 (sensitivity: 0.729, specificity: 0.894) on a full-scale DWDS test set. Abiotic-based model using total Chlorine/NH2Cl and NH3 generated AUCs of 0.740 and 0.861 (ROC and PR, respectively), corresponding to a sensitivity of 0.250 and a specificity of 0.957. The AUCs increased to > 0.946 with the addition of NO2– concentration, which is indicative of nitrification in the DWDS. This research provides evidence of the feasibility of using bioindicators to predict operational failures in the system (e.g., nitrification).