Agricultural University of Iceland

Linking meta‐omics and biogeochemistry approaches in soils has remained challenging. This study evaluates the use of an internal RNA extraction standard and its potential for making quantitative estimates of a given microbial community size (biomass) in soil metatranscriptomics. We evaluate commonly used laboratory protocols for RNA processing, metatranscriptomic sequencing and quantitative reverse transcription polymerase chain reaction (qRT‐PCR). Metatranscriptomic profiles from soil samples were generated using two library preparation protocols and prepared in triplicates. RNA extracted from pure cultures of Saccharolobus solfataricus was added to the samples as an internal nucleic acid extraction standard (NAEstd). RNA reads originating from NAEstd were identified with a 99.9% accuracy. A remarkable replication consistency between triplicates was seen (average Bray–Curtis dissimilarity 0.03 ± 0.02), in addition to a clear library preparation bias. Nevertheless, the between‐sample pattern was not affected by library type. Estimates of 16S rRNA transcript abundance derived from qRT‐PCR experiments, NAEstd and a previously published quantification method of metatranscriptomics (hereafter qMeTra) were compared with microbial biomass carbon (MBC) and nitrogen (MBN) extracts. The derived biomass estimates differed by orders of magnitude. While most estimates were significantly correlated with each other, no correlation was observed between NAEstd and MBC extracts. We discuss how simultaneous changes in community size and the soils nucleic acid retention strength might hamper accurate biomass estimation. Adding NAEstd has the potential to shed important light on nucleic acid retention in the substance matrix (e.g., soil) during extraction.

In the last decades, the rate of stillbirths in the Icelandic Dairy Cattle population has increased. Some of these stillbirths may be caused by recessive lethal mutations segregating in the population. These alleles can be identified by detecting homozygous haplotype deficiency (HHD) in genotyped animals. The aim of this study was to find genomic regions affecting stillbirth and fertility in the Icelandic Dairy Cattle population. We analysed genotypes from 20,557 animals with 35,481 autosomal markers. We identified HHD segments and estimated their effects on stillbirths and insemination failure, measured as non-return rates. We conducted genome-wide association studies (GWAS) for stillbirth and five fertility traits: interval from first to last inseminations, conception rate, number of inseminations, calving interval and infertility. While no GWAS association reached the genome-wide significance threshold, some of the top signals co-located with HHD haplotypes. A total of 19 haplotypes significantly either decreased fertility, or increased incidence of stillbirths, or both. Two HHD regions on BTA13: 43,577,221–59,026,521 and BTA8: 83,276,598–84,472,391 were associated with both lower fertility and higher incidence of stillbirths. We found no evidence of large structural variations in or around the HHD regions, suggesting that these signals are likely due to single loss-of-function mutation or small structural variations. Further research should focus on exploring these regions using whole genome sequence data.

Increasing energy demand propels the construction of river dams and reservoirs for hydropower, raising concerns about environmental and societal ramifications. Ecological effects like river fragmentation, habitat loss, biodiversity decline, and disruptions of biogeochemical cycles have been addressed for several decades. The impact of water impoundment on submerged soils, particularly carbon stocks, is of growing interest. Studies reveal both increases and decreases of carbon stocks in submerged soils, depending on factors such as substrate resilience, water level fluctuations, soil type and submergence duration. This study examines the effects of 24 years of water impoundment on properties of organic and mineral constituents in Andosols under the Blöndulón hydroelectric reservoir in Iceland´s highlands. Submerged soils show higher carbon stocks than reference soils but are depleted in pedogenic minerals ferrihydrite and allophane. Unlike reference soils, where carbon declines with depth, submerged soils display rather uniform carbon distribution. This is likely due to movement of organic material from upper to lower horizons, and carbon additions from decaying vegetation in the years after the impoundment. Importantly, the apparent carbon enrichment of the submerged soils raises concerns about its long-term stability. The depletion of pedogenic minerals ferrihydrite and allophane may render the carbon sensitive to oxidation in the coming decades, particularly when soils are exposed during water level fluctuations. In short, the carbon enrichment of the drowned soils may not be permanent. Assessments of the consequences of water level fluctuations or potential future dam removal need to take the vulnerability of the exposed soils into account and consider the risk of increased carbon emissions from these soils.

Background Icelandic horses are valued for their additional gaits, but assessing lameness in this breed can be challenging. Pelvic (P) vertical movement asymmetries, differences (D) in minimum (min)/maximum (max) position, are used to quantify impact (PDmin) and push‐off (PDmax) hindlimb lameness during the trot, but no established parameters exist for detecting hindlimb lameness in other gaits. Objective To evaluate temporal stride parameters and upper‐body movement asymmetry after transient hindlimb lameness induction in walk, trot and tölt. Study Design In vivo experiment. Methods Eleven Icelandic horses were measured before and after hindlimb lameness was induced (sole pressure). Vertical movement asymmetry of Head (H)/Pelvis (HDmin/HDmax/PDmin/PDmax) and hip‐hike were measured during ridden walk, sitting trot and tölt as well as in‐hand walk and trot, using an inertial measurement unit system. Linear mixed models compared sound and lame conditions within each gait, and differences in estimated marginal means (mm) between conditions are presented, with significance set at p < 0.05. Results Lameness induction significantly increased PDmin asymmetry in all gaits except walk in‐hand: walk (PDminridden: 5.07), trot (PDminhand: 10.72, PDminridden: 9.85) and tölt (PDminridden: 4.88). However, PDmax increased only for trot in‐hand (PDmaxhand: 4.80). Hip‐hike increased on the lame limb side at trot (hip‐hikehand: 20.90, hip‐hikeridden: 10.81) and tölt (hip‐hikeridden: 4.28). Main Limitations Findings need verification in clinically lame Icelandic horses with varying diagnoses and lameness severity. Conclusion PDmin and hip‐hike appear to be effective parameters for detecting mild hoof‐associated hindlimb lameness in Icelandic horses when trotting in‐hand or ridden. At walk or tölt under saddle, only slight PDmin changes were observed, likely due to lower limb loading in those gaits and the pelvic minimum position associating with different loading stages throughout the stride cycle for walking and running gaits. These findings suggest trot is the preferred gait for assessing mild hindlimb lameness in Icelandic horses.

Herbivores are an integral part of Arctic terrestrial ecosystems, driving ecosystem functioning and sustaining local livelihoods. In the context of accelerated climate warming and land use changes, understanding how herbivores contribute to the resilience of Arctic socio-ecological systems is essential to guide sound decision-making and mitigation strategies. While research on Arctic herbivory has a long tradition, recent literature syntheses highlight important geographical, taxonomic, and environmental knowledge gaps on the impacts of herbivores across the region. At the same time, climate change and limited resources impose an urgent need to prioritize research and management efforts. We conducted a horizon scan within the Arctic herbivory research community to identify emerging scientific and management priorities for the next decade. From 288 responses received from 85 participants in two online surveys and an in-person workshop, we identified 8 scientific and 8 management priorities centred on (a) understanding and integrating fundamental ecological processes across multiple scales from individual herbivore–plant interactions up to regional and decadal scale vegetation and animal population effects; (b) evaluating climate change feedbacks; and (c) developing new research methods. Our analysis provides a strategic framework for broad, inclusive, interdisciplinary collaborations to optimise terrestrial herbivory research and sustainable management practices in a rapidly changing Arctic.

Herbivores contribute to nutrient cycling in tundra ecosystems through their waste (e.g., faeces, urine). However, their contribution might vary among species and over time during the growing season likely due to differences in body size, digestive physiology, and variations in diet composition and quality. Capturing fine-scale variability requires intensive sampling, but traditional wet-lab methods for measuring nutrient concentration and stoichiometry in animal faeces are prohibitively expensive. To address this challenge, we developed a low-cost alternative using Near-Infrared Reflectance Spectroscopy (NIRS). We calibrated a general model for the main Icelandic tundra herbivores (i.e., pink-footed goose, Anser brachyrynchus, reindeer, Rangifer tarandus and sheep, Ovis aries) to assess faecal nutrient concentrations (nitrogen, phosphorus, and carbon) and stoichiometry (C:N, C:P, N:P). This was achieved using a set of 191 fresh faecal samples scanned with NIRS and analysed by traditional wet-lab methods. The multispecies models explained between 76 and 91 % of variation between samples. We then applied the models to over 300 samples and assessed changes in faecal nutrient concentration, and stoichiometry of the three herbivores throughout the growing season.We found that faecal quality varied between herbivore species, with sheep and reindeer generally having more similar nutrient concentrations and stoichiometry than geese. Seasonality also affected faecal nutrient content, with a general decrease in N and P concentrations over the growing season and an increase in C:N and C:P ratios, especially in geese. Geese contributed disproportionately to the nutrient pools of Icelandic rangelands due to their high defecation rate and large population. These results provide important insights into how different herbivore species can influence the biogeochemistry of nutrient-limited tundra rangelands throughout the growing season, and a general model for faecal nutrient content of tundra herbivores.

Ecosystems are experiencing changing global patterns of mean annual precipitation (MAP) and enrichment with multiple nutrients that potentially colimit plant biomass production. In grasslands, mean aboveground plant biomass is closely related to MAP, but how this relationship changes after enrichment with multiple nutrients remains unclear. We hypothesized the global biomass–MAP relationship becomes steeper with an increasing number of added nutrients, with increases in steepness corresponding to the form of interaction among added nutrients and with increased mediation by changes in plant community diversity. We measured aboveground plant biomass production and species diversity in 71 grasslands on six continents representing the global span of grassland MAP, diversity, management, and soils. We fertilized all sites with nitrogen, phosphorus, and potassium with micronutrients in all combinations to identify which nutrients limited biomass at each site. As hypothesized, fertilizing with one, two, or three nutrients progressively steepened the global biomass–MAP relationship. The magnitude of the increase in steepness corresponded to whether sites were not limited by nitrogen or phosphorus, were limited by either one, or were colimited by both in additive, or synergistic forms. Unexpectedly, we found only weak evidence for mediation of biomass–MAP relationships by plant community diversity because relationships of species richness, evenness, and beta diversity to MAP and to biomass were weak or opposing. Site-level properties including baseline biomass production, soils, and management explained little variation in biomass–MAP relationships. These findings reveal multiple nutrient colimitation as a defining feature of the global grassland biomass–MAP relationship.

Arctic landscapes occupy a nexus of environmental change processes, globally significant soil carbon stores, wildlife populations, and subsistence-based human societies. In response to rapid climate warming, tundra ecosystems are experiencing widespread changes to vegetation and underlying permafrost, coupled with an array of ecological disturbances that are expected to intensify in the future. Declines in the extent of the cryosphere on land (permafrost and seasonal snow) and offshore (sea-ice) raise the question of whether and for how long warmer portions of the Low Arctic will fit established concepts of “what is Arctic,” given the influence the cryosphere has historically had on tundra ecosystem structure and function. The era of spaceborne observation of circumpolar tundra greenness, in the form of the Normalized Difference Vegetation Index (NDVI), has entered its fifth decade and provides foundational information concerning ecosystem conditions and responses to climatic trends, variability, ecological disturbance, and successional processes. Here we review the evolving story of Arctic greening, and synthesize long-term spaceborne records of NDVI, climatic data, field observations, and the knowledge base of Arctic residents to place the last four decades of Arctic environmental change in context, and establish expectations and research priorities for the coming decade. Greenness dynamics display high spatio-temporal variability, reflecting complex interactions of climatic warming and variability, landscape history, ecological disturbance, and other factors. Nonetheless, long-term increases in NDVI—commonly known as “the greening of the Arctic”—remain prominent across large areas in all available long-term spaceborne datasets and align with long-term shifts in vegetation structure documented in disparate Arctic regions. Common shifts reported from the Low Arctic, such as shrubification, generally portend declines in floristic diversity, and shifts in fauna that favor boreal forest species. Despite lingering uncertainties regarding trend attribution and sources of interannual variability, the sequence of record-high circumpolar tundra greenness values observed since 2020 provides strong evidence that Arctic tundra ecosystems have entered a state without historic precedent on timescales approaching a millennium.

Selection for performance in horse breeding benefits from precise genetic insights at a molecular level, but knowledge remains limited. This study used whole-genome sequences of 39 elite and non-elite Icelandic horses to identify candidate causal variants linked to previously identified haplotypes in the STAU2 and RELN genes affecting pace and other gaits. A frameshift variant in linkage disequilibrium with the previously identified haplotypes in the STAU2 gene (r² = 0.85) was identified within a predicted STAU2 transcript. This variant alters the amino acid sequence and introduces a premature stop codon but does not appear harmful or disease-causing and is potentially unique to equine biology. A large portion of the RELN haplotype overlapped with an H3K27me3 modification mark, suggesting a regulatory role of this region. Despite the small sample size, the RELN haplotype’s effects were validated for tölt, trot, and canter/gallop. Additionally, the RELN haplotype significantly influenced the age at which horses were presented for breeding field tests, indicating a potential role of the region in precocity and trainability. Functional experiments are needed to further investigate the regions’ influences on biological processes and their potential impact on horse performance.

Climatic feedbacks and ecosystem impacts related to dust in the Arctic include direct radiative forcing (absorption and scattering), indirect radiative forcing (via clouds and cryosphere), semi-direct effects of dust on meteorological parameters, effects on atmospheric chemistry, as well as impacts on terrestrial, marine, freshwater, and cryospheric ecosystems. This review discusses our recent understanding on dust emissions and their long-range transport routes, deposition, and ecosystem effects in the Arctic. Furthermore, it demonstrates feedback mechanisms and interactions between climate change, atmospheric dust, and Arctic ecosystems.

A novel bacterium, designated 19SA41, was isolated from the air of the Icelandic volcanic island Surtsey. Cells of strain 19SA41 are Gram-stain-negative, strictly aerobic, non-motile rods and form pale yellow-pigmented colonies. The strain grows at 4–30 °C (optimum, 22 °C), at pH 6–10 (optimum, pH 7.5) and with 0–4% NaCl (optimum, 0.5%). Phylogenetic analyses based on 16S rRNA gene sequences showed that 19SA41 belonged to the genus Flavobacterium and is most similar to Flavobacterium xinjiangense DSM 19743 T , with a sequence similarity of 96.52%. The new strain contained iso-C 15 : 0 (22%) and summed feature 3 (C 16∶1 ω6c/C 16∶1 ω7c) (20%) as the predominant fatty acids. The major respiratory quinone was menaquinone-6 (100%). The polar lipid profile consisted of phosphatidylethanolamine and several uncharacterized amino lipids, glycolipids and lipids. The genome of the new strain was 4.01 Mbp, and its G+C content was 33.2 mol%. Based on characterization and comparative results, using a polyphasic taxonomic approach, we propose that the new isolate represents a novel species of the genus Flavobacterium with the name Flavobacterium aerium sp. nov. The type strain is ISCaR-07695 T (=DSM 116640 T =UBOOC-M-3567 T ).

In this study, the impact of the varying environments, wet–cool (2017), dry–hot (2018), and fluctuating (2019), on two spring wheat genotypes, Diskett and Bumble, grown in field conditions in southern Sweden was studied. From harvested grains, polymeric gluten proteins were fractionated and collected using SE-HPLC and then analyzed with LC-MS/MS. Proteins and peptides identified through searches against the protein sequences ofTriticum aestivum (taxon 4565) from the UniProtKB database showed 7 high molecular weight glutenin subunits (HMW-GS) and 24 low molecular weight glutenin subunits (LMW-GS) with different enrichment levels for both genotypes. Glu-B1 for HMW-GS and Glu D3 and m- and s-types for LMW-GS were dominated in both genotypes, and a small proportion of α-, γ-, and ω-gliadins were also present. A minor variation in HMW-GS and LMW-GS compositions was observed between the years, while small amounts of heat shock proteins were identified under the “dry–hot” period for Diskett. In conclusion, Diskett showed more stable and climate-resistant protein patterns in the studied varying climate as compared to Bumble. The study highlights the use of proteomics and LC-MS/MS for differentiation of wheat genotypes, although it shows low sensitivity in measuring the diverse environment impact on the polymeric proteins.

The rapid climatic and environmental changes observed in the Arctic and across the globe in general call for reliable model projections. In recent years our understanding of ongoing and future changes through ecosystem modelling has increased tremendously. Yet, most ecosystem models do not consider many of the feedback loops at play in natural ecosystems. Particularly those influenced by biota, beyond vegetation and to some extent microbes, are often neglected. As a first step towards a better integration of biotic influences into ecosystem models, we provide a broad overview of the various ways biota may influence feedback loops between the high-latitude biosphere and the atmosphere. We focus specifically on three key feedback loops between tundra and atmosphere (carbon dynamics, albedo and permafrost thaw) and the influences of three key ecosystem compartments (vegetation, decomposers and herbivores) on these. The influences of biota on ecosystem feedback loops are multifaceted and may appear patchy in both space and time. However, biota may still play important roles in modulating ecosystem feedback loops, and by including these dynamics into ecosystem models, magnitude, accuracy and credibility of model projections are likely to improve.

Background Scrapie is an infectious prion disease in sheep. Selective breeding for resistant genotypes of the prion protein gene ( PRNP ) is an effective way to prevent scrapie outbreaks. Genotyping all selection candidates in a population is expensive but existing pedigree records can help infer the probabilities of genotypes in relatives of genotyped animals. Results We used linear models to predict allele content for the various PRNP alleles found in Icelandic sheep and compiled the available estimates of relative scrapie susceptibility (RSS) associated with PRNP genotypes from the literature. Using the predicted allele content and the genotypic RSS we calculated estimated breeding values (EBV) for RSS. We tested the predictions on simulated data under different scenarios that varied in the proportion of genotyped sheep, genotyping strategy, pedigree recording accuracy, genotyping error rates and assumed heritability of allele content. Prediction of allele content for rare alleles was less successful than for alleles with moderate frequencies. The accuracy of allele content and RSS EBV predictions was not affected by the assumed heritability, but the dispersion of prediction was affected. In a scenario where 40% of rams were genotyped and no errors in genotyping or recorded pedigree, the accuracy of RSS EBV for ungenotyped selection candidates was 0.49. If only 20% of rams were genotyped, or rams and ewes were genotyped randomly, or there were 10% pedigree errors, or there were 2% genotyping errors, the accuracy decreased by 0.07, 0.08, 0.03 and 0.04, respectively. With empirical data, the accuracy of RSS EBV for ungenotyped sheep was 0.46–0.65. Conclusions A linear model for predicting allele content for the PRNP gene, combined with estimates of relative susceptibility associated with PRNP genotypes, can provide RSS EBV for scrapie resistance for ungenotyped selection candidates with accuracy up to 0.65. These RSS EBV can complement selection strategies based on PRNP genotypes, especially in populations where resistant genotypes are rare.

In the last decades, the rate of stillbirths in the Icelandic Dairy Cattle population has increased. Some of these stillbirths may be caused by recessive lethal mutations segregating in the population. These alleles can be identified by detecting homozygous haplotype deficiency (HHD) in genotyped animals. The aim of this study was to find genomic regions affecting stillbirth and fertility in the Icelandic Dairy Cattle population. We analysed genotypes from 20,557 animals with 35,481 autosomal markers. We identified HHD segments and estimated their effects on stillbirths and insemination failure, measured as non-return rates. We conducted genome-wide association studies (GWAS) for stillbirth and five fertility traits: interval from first to last inseminations, conception rate, number of inseminations, calving interval and infertility. While no GWAS association reached the genome-wide significance threshold, some of the top signals co-located with HHD haplotypes. A total of 19 haplotypes significantly either decreased fertility, or increased incidence of stillbirths, or both. Two HHD regions on BTA13: 43,577,221 − 59,026,521 and BTA8: 83,276,598 − 84,472,391 were associated with both lower fertility and higher incidence of stillbirths. We found no evidence of large structural variations in or around the HHD regions, suggesting that these signals are likely due to single loss-of-function mutation or small structural variations. Further research should focus on exploring these regions using whole genome sequence data.

In this review, the multifaceted issue of food security is addressed, emphasizing the need for innovative and culturally appropriate solutions. Exploring insect livestock farming emerges as a potential remedy, offering a pathway to alleviate food insecurity and promote food sovereignty, particularly when integrated with social acceptability. Stakeholder engagement on both production and consumption fronts, coupled with sustained support, is vital for successful implementation. The expanding landscape of commercial insect farming in the West prompts questions about its broader scalability and equitable deployment, especially for vulnerable populations. Existing research gaps underscore the need for a coordinated effort across international, national, and legal frameworks to effectively integrate insect farming into existing agricultural systems. In this review, we have delved into the industrial-scale production processes of mealworms and black soldier flies (BSFs), known for their high protein content and organic waste conversion, covering small and industrial cultivation methods, offering insights into mealworm production life cycles, innovative rearing systems, and harvesting techniques. This review concludes with climate-specific recommendations for insect facilities, stressing the importance of sustainable practices, continuous research and development, effective market strategies and economic feasibilities in Iceland. In the context of escalating demand for sustainable protein sources, industrial-scale insect production emerges as a pivotal player in addressing global food security challenges.

Arctic biodiversity is under threat from both climate-induced environmental change and anthropogenic activity. However, the rapid rate of change and the challenging conditions for studying Arctic environments mean that many research questions must be answered before we can strategically allocate resources for management. Addressing threats to biodiversity in the Arctic is further complicated by the region's complex geopolitics, as eight countries claim jurisdiction over the area, with multiple local considerations such as Indigenous sovereignty and resource rights. Here, we identify research priorities to serve as a starting point for addressing the most pressing threats to Arctic biodiversity. We began by collecting pressing research questions about Arctic biodiversity, thematizing them as either threats or actions, and then categorizing them further into 18 groups. Then, drawing on cross-disciplinary and global expertise of professionals in Arctic science, management, and policy, we considered the barriers to answering these questions and proposed potential solutions that could be implemented if barriers were overcome. Overall, our horizon scan provides an expert assessment of threats (e.g., species’ responses to climate change) and actions (e.g., a lack of fundamental information regarding Arctic biodiversity) needing attention and is intended to guide future conservation action within the Arctic.

Maximum seasonal thaw depth, referred to as active layer thickness (ALT), is one of the key parameters used to monitor permafrost conditions. ALT maps based on interpolation of point measurements or derived from coarse or moderate spatial resolution satellite data often hide small‐scale spatial variations in thaw depth resulting from differences in surface characteristics and microtopography. To model and predict changes in hydrological and biogeochemical processes in permafrost areas accurately, high‐resolution remote sensing‐based estimations of ALT are needed. Therefore, we applied random forest (RF) regression on a set of topographical and spectral vegetation indices derived from optical unoccupied aerial systems data, Landsat 8 land surface temperature (LST) data, and field measurements to estimate thaw depths in palsas at three mires in north‐west Finland. We also analyzed differences in thaw depths between mires located at different elevations, between dome and plateau‐shaped palsas, and between different vegetation and surface cover classes. The RF models resulted in root mean square errors from 2.4 to 5.7 cm between predicted and observed thaw depths and the R ² values of 0.57–0.96. Height from the surrounding fen surface and LST were the most important variables in thaw depth models, although high‐accuracy results were also achieved without LST. The mean thaw depths did not differ between the sites with lowest and highest elevation, whereas the thaw depths were significantly deeper in dome‐shaped palsas compared to plateaus. The thaw depths were significantly different between vegetation cover classes only on plateau‐shaped palsas. The results indicate the high impact of the topography on the palsa thaw depth, thus highlighting the importance of accurate elevation models in spatial modeling of palsa ALT. The methodology presented in this study can be applied to other permafrost regions where field measurements of ALT are accompanied with high‐resolution topographical and multispectral data.