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Root exudation, the export of low-molecular weight organic carbon (C) from living plant roots to soil, influences microbial activity, nutrient availability, and ecosystem feedbacks to climate change, but the magnitude of this C flux at ecosystem and global scales is largely unknown. Here, we synthesize in situ measurements of root exudation rates and couple those to estimates of fine root biomass to estimate global and biome-level root exudate C fluxes. We estimate a global root exudate flux of 13.4 (10.1–20.2) Pg C y−1, or about 9% (7–14%) of global annual gross primary productivity. We did not find differences in root mass-specific exudation rates among biomes, though total exudate fluxes are estimated to be greatest in grasslands owing to their high density of absorptive root biomass. Our synthesis highlights the global importance of root exudates in the terrestrial C cycle and identifies regions where more in situ measurements are needed to improve future estimates of root exudate C fluxes. [ABSTRACT FROM AUTHOR]

Mercury (Hg) is an environmental contaminant that can negatively impact the health of humans and wildlife. Albatrosses and large petrels show some of the highest levels of Hg contamination among birds, with potential repercussions for reproduction and survival. Here, body feather total Hg (THg) concentrations were determined in breeding adults of five species of albatrosses and large petrels in the foraging guild at South Georgia during the mid-2010s. We tested the effects of species, sex and trophic ecology (inferred from stable isotopes) on THg concentrations and compared our results with published values from past decades. Feather THg concentrations differed significantly among species (range: 1.9–49.6 µg g−1 dw), and were highest in wandering albatrosses Diomedea exulans, intermediate in black-browed albatrosses Thalassarche melanophris and northern giant petrels Macronectes halli, and lowest in southern giant petrels M. giganteus and white-chinned petrels Procellaria aequinoctialis. Females were more contaminated than males in all species, potentially due to differences in distributions and diet composition. Across species, THg concentrations were not correlated with feather δ13C or δ15N values, implying that species effects (e.g., breeding and moulting frequencies) may be more important than trophic effects in explaining feather THg concentrations in this foraging guild. Within species, the only significant correlation was between THg and δ13C in wandering albatrosses, which could reflect higher Hg exposure in subtropical waters. Comparisons with THg concentrations from past studies, which reflect contamination from 10 to > 60 years ago, revealed considerable annual variation and some evidence for increases over time for wandering and black-browed albatrosses since before 1950 and from the late 1980s, respectively. [ABSTRACT FROM AUTHOR]

Stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) were measured in feathers to compare the non-breeding distributions and habitat use of adult brown skuas Stercorarius antarcticus lönnbergi from high-latitude colonies at Esperanza/Hope Bay (Antarctic Peninsula, 63°S) and Signy Island (South Orkneys, 60°S), with those from Bird Island (South Georgia, 54°S), which have also been tracked previously using geolocators. Breeding colony, but not sex, had a significant effect on feather δ13C and δ15N values. Feather stable isotope data from South Georgia birds mostly corresponded to oceanic, mixed subtropical–subantarctic to subantarctic waters, which agrees with the tracking data, as did a subset of the birds from the two higher latitude populations. However, other individuals displayed feather stable isotope ratios that were consistent with continental shelf or shelf-slope waters, suggesting that unlike the vast majority of brown skuas from South Georgia, many birds from higher latitude colonies spend the non-breeding season on, or near, the Patagonian Shelf. These population-level differences may have implications for exposure to anthropogenic threats or have carryover effects on subsequent breeding behaviour or performance. [ABSTRACT FROM AUTHOR]

Knowledge of lampreys during their marine phase is limited, and for the southern hemisphere species was gleaned from their predators (albatrosses) in the 1970s. Taking advantage of new methodologies and long-term data on predator diet and distributions, we infer diverse aspects of lamprey distribution and ecology. DNA analyses indicated that albatrosses at South Georgia prey on Patagonian lamprey Geotria macrostoma, originating from Argentina. Their core pelagic distribution when free swimming appears to be the Antarctic Polar Frontal zone (APFZ), and not South Georgia waters as assumed previously. If so, the APFZ would be the first known hotspot in abundance of an anadromous lamprey in oceanic waters. We could not identify a teleost fish that would be a likely host. Instead, we infer that the lamprey may prey on baleen whales, based on comparison of stable isotope ratios in lamprey with candidate host species, timing of appearance in albatross diets coincident with whale migrations, and circumstantial evidence (unexplained scarring recorded during the whaling era). We suggest that the lamprey do not tolerate cold Antarctic waters, and detach from southerly-migrating whales at the thermal boundary of the APFZ, where they become accessible to albatrosses in surface waters. Given strong evidence that relative importance of prey in seabird diets reflects availability in foraging areas, the steep decrease in the annual consumption of lamprey by albatrosses at South Georgia from > 550 tonnes in 1975–1976 and 1986, to very low levels in most years since 2012, is likely to indicate a major population decrease. Despite our unconventional means of assessing the population trend, there is a compelling case for listing of Patagonian lamprey at least as Near threatened by the International Union for the Conservation of Nature, and an urgent need to better understand anthropogenic threats in Argentina. [ABSTRACT FROM AUTHOR]

From food- to analytical-grade products, the commercial exploitation of phycocyanin (PC) strongly depends on its degree of purity. In this study, we utilized a pilot-scale system (100 L working volume), based on serial tangential flow micro- and ultra-filtration (cut size 0.2 μm and 50 kDa, respectively) for the concentration and purification of PC extracted from a commercial strain of Arthrospira platensis. The process resulted in a PC recovery of around 54%, whilst the resulting solution had a concentration of 1.1 ± 0.2 mgPC mL−1, purity of 1 ± 0.2, and antioxidant activity of 84 ± 6 ppmascorbic-acid-equivalent. Various preservatives were evaluated in order to enhance the stability of aqueous PC solution at room temperature. The addition of 0.4% citric acid had no effect (half-life ~ 7 days), while the addition of 2.5% sodium chloride or 20% sucrose significantly increased half-life up to ~ 250 days. PC solutions underwent either spray- or freeze-drying, either with or without carrier (trehalose) addition. The obtained PC powders had up to twofold higher color values compared to a commercial sample. The spray-drying process negatively affected the purity and yield of the final product (10% and 50% less than freeze-drying, respectively). In summary, our results suggest that tangential flow filtration followed by freeze-drying has huge potential for the production of food-grade phycocyanin. [ABSTRACT FROM AUTHOR]

One mechanism proposed to explain high species diversity in tropical systems is strong negative conspecific density dependence (CDD), which reduces recruitment of juveniles in proximity to conspecific adult plants. Although evidence shows that plant-specific soil pathogens can drive negative CDD, trees also form key mutualisms with mycorrhizal fungi, which may counteract these effects. Across 43 large-scale forest plots worldwide, we tested whether ectomycorrhizal tree species exhibit weaker negative CDD than arbuscular mycorrhizal tree species. We further tested for conmycorrhizal density dependence (CMDD) to test for benefit from shared mutualists. We found that the strength of CDD varies systematically with mycorrhizal type, with ectomycorrhizal tree species exhibiting higher sapling densities with increasing adult densities than arbuscular mycorrhizal tree species. Moreover, we found evidence of positive CMDD for tree species of both mycorrhizal types. Collectively, these findings indicate that mycorrhizal interactions likely play a foundational role in global forest diversity patterns and structure. A global study suggests that mycorrhizal fungi play a key role in determining forest diversity patterns and community structure, with mycorrhizal tree type systematically mediating the strength of conspecific negative density dependence. [ABSTRACT FROM AUTHOR]

Purpose: Human tuberculosis is characterized by immunopathology that affects T-cell phenotype and functions. Previous studies found impaired T-cell response to phytohemagglutinin (PHA) in patients with acute tuberculosis. However, the influence of disease severity, affected T-cell subsets, and underlying mechanisms remain elusive. Methods: Here we investigated PHA-induced and antigen-specific T-cell effector cytokines in tuberculosis patients (n = 55) as well as in healthy asymptomatic contacts (n = 32) from Ghana. Effects of Mycobacterium (M.) tuberculosis sputum burden and treatment response were analyzed and compared during follow-up. Finally, cytokine characteristics of the aberrant plasma milieu in tuberculosis were analyzed as a potential cause for impaired PHA response. Results: PHA-induced IFN-γ expression was significantly lower in sputum-positive tuberculosis patients as compared to both, contacts and paucibacillary cases, and efficiently discriminated the study groups. T-cell responses to PHA increased significantly early during treatment and this was more pronounced in tuberculosis patients with rapid treatment response. Analysis of alternative cytokines revealed distinct patterns and IL-22, as well as IL-10, showed comparable expression to IFN-γ in response to PHA. Finally, we found that high IL-6 plasma levels were strongly associated with impaired IFN-γ and IL-22 response to PHA. Conclusion: We conclude that impaired T-cell response to PHA stimulation in acute tuberculosis patients (i) was potentially caused by the aberrant plasma milieu, (ii) affected differentially polarized T-cell subsets, (iii) normalized early during treatment. This study shed light on the mechanisms of impaired T-cell functions in tuberculosis and yielded promising biomarker candidates for diagnosis and monitoring of treatment response. [ABSTRACT FROM AUTHOR]

Plastic pollution is distributed patchily around the world's oceans. Likewise, marine organisms that are vulnerable to plastic ingestion or entanglement have uneven distributions. Understanding where wildlife encounters plastic is crucial for targeting research and mitigation. Oceanic seabirds, particularly petrels, frequently ingest plastic, are highly threatened, and cover vast distances during foraging and migration. However, the spatial overlap between petrels and plastics is poorly understood. Here we combine marine plastic density estimates with individual movement data for 7137 birds of 77 petrel species to estimate relative exposure risk. We identify high exposure risk areas in the Mediterranean and Black seas, and the northeast Pacific, northwest Pacific, South Atlantic and southwest Indian oceans. Plastic exposure risk varies greatly among species and populations, and between breeding and non-breeding seasons. Exposure risk is disproportionately high for Threatened species. Outside the Mediterranean and Black seas, exposure risk is highest in the high seas and Exclusive Economic Zones (EEZs) of the USA, Japan, and the UK. Birds generally had higher plastic exposure risk outside the EEZ of the country where they breed. We identify conservation and research priorities, and highlight that international collaboration is key to addressing the impacts of marine plastic on wide-ranging species. Petrels are wide-ranging, highly threatened seabirds that often ingest plastic. This study used tracking data for 7,137 petrels of 77 species to map global exposure risk and compare regions, species, and populations. The results show higher exposure risk for threatened species and stress the need for international cooperation to tackle marine litter. [ABSTRACT FROM AUTHOR]

Seabirds often spend time on the water in the vicinity of their breeding colonies at the start or end of foraging trips, which may be for bathing, social interaction, information transfer, or to reduce predation risk for small petrels that prefer to return to land in darkness. Although such behaviour (hereafter rafting) is common, there are few data on variation in its incidence or timing across species, or analyses of relationships with intrinsic or extrinsic factors such as breeding stage (reflecting central-place foraging constraints) or weather. Here, we use GPS and immersion data collected over multiple years at Bird Island, South Georgia, to investigate rafting behaviour of four albatross and one burrow-nesting petrel species. Nearly all tracked birds (89%) landed within 10 km of the colony at the start of foraging trips for ~ 30 min, whereas only 17% did so at the end, suggesting they likely use rafting mainly for plumage maintenance after extended breeding shifts on land. Rafting duration, distance and bearing from the colony varied markedly according to species, wind speeds and period of the day (daylight vs. darkness), which may reflect differences in foraging direction, time constraints, degree of plumage soiling, diel activity patterns, or the requirement for high wind speeds for efficient flight. Given that all the study populations are decreasing, and most individuals make extensive use of nearshore waters during the breeding season, effective marine spatial planning is required that eliminates or mitigates human risks around their colonies. [ABSTRACT FROM AUTHOR]

Forest stands dominated by ectomycorrhizal (ECM) associated trees often have more closed nitrogen (N) cycling than stands dominated by arbuscular mycorrhizal (AM) associated trees, with slower N mineralization in ECM stands thought to suppress inorganic N cycling. However, most estimates of N mineralization come from measurements of net processes, which can lead to an incomplete view of ecosystem N retention and loss. To explore the mechanisms driving mycorrhizal N cycling syndromes, we measured gross N production and assimilation rates and net and potential N flux rates in paired N addition (from NH4SO4 and NaNO3) and control plots within ECM and AM-dominated stands. We observed greater gross N mineralization and microbial ammonium assimilation in ECM compared to AM stands, suggesting that increased microbial N demand drove lower net N mineralization rates in ECM stands. We found lower nitrification rates in ECM compared to AM stands and no effect of N addition on nitrification in ECM stands. Therefore, the low soil pH or high C:N ratios found in those stands, not limited ammonium supply, may have suppressed nitrification. Finally, potential denitrification rates and nitrous oxide fluxes were lower in ECM compared to AM stands with no effect of N addition, suggesting that denitrification is controlled by the endogenous supply of nitrate from nitrification, not exogenous nitrate inputs. Overall, we conclude that N mineralization may not play a central role in forming mycorrhizal nutrient syndromes, and that acidic conditions in ECM stands may ultimately control nitrification and the potential for ecosystem N loss. [ABSTRACT FROM AUTHOR]

Background: Mycobacterium (M.) tuberculosis-caused immunopathology is characterized by aberrant expression of plasma cytokines in human tuberculosis. Disease severity and long-term anti-mycobacterial treatment are potentially influenced by immunopathology and normalization of plasma cytokine levels during therapy may indicate treatment efficacy and recovery. Study design and methods: In this study, we analyzed the concentrations of selected plasma cytokines (i.e., IL-6, IP-10, IL-10, IL-22, IFNγ, GM-CSF, IL-8) and M. tuberculosis sputum burden in patients with tuberculosis (n = 76). Cytokine levels were compared to healthy contacts (n = 40) and changes under treatment were monitored (i.e., 6 and 16 weeks after treatment start). According to differences in M. tuberculosis sputum burden and conversion, tuberculosis patients were classified as paucibacillary as well as 'rapid' or 'slow' treatment responders. A subgroup of tuberculosis patients had fatal disease courses. Results: Six of seven cytokines were significantly higher in tuberculosis patients as compared to contacts and four of these (i.e., IL-6, IP-10, IL-10, and IL-22) were detectable in the majority of tuberculosis patients. IL-6 showed the strongest discriminating capacity for tuberculosis disease and in combination with IL-10 concentrations efficiently classified paucibacillary tuberculosis cases as well as those with fatal disease outcome. In addition, IL-6 and IP-10 levels decreased significantly after 6 weeks of treatment and analyses of subgroups with differential treatment response showed delayed decline of IL-6 levels in slow treatment responders. Conclusions: Combinations of different plasma cytokine (namely, IL-6, IL-10, and IP-10) efficiently classified tuberculosis patients with differential mycobacterial burden and especially IL-6 qualified as a biomarker candidate for early treatment response. [ABSTRACT FROM AUTHOR]

Purpose: Degenerative cervical myelopathy (DCM) is the most common cause of adult spinal cord dysfunction worldwide. However, the current incidence of DCM is poorly understood. The Hospital Episode Statistics (HES) database contains details of all secondary care admissions across NHS hospitals in England. This study aimed to use HES data to characterise surgical activity for DCM in England. Methods: The HES database was interrogated for all cases of DCM between 2012 and 2019. DCM cases were identified from 5 ICD-10 codes. Age-stratified values were collected for 'Finished Consultant Episodes' (FCEs), which correspond to a patient's hospital admission under a lead clinician. Data was analysed to explore current annual activity and longitudinal change. Results: 34,903 FCEs with one or more of the five ICD-10 codes were identified, of which 18,733 (53.6%) were of working age (18–64 years). Mean incidence of DCM was 7.44 per 100,000 (SD ± 0.32). Overall incidence of DCM rose from 6.94 per 100,000 in 2012–2013 to 7.54 per 100,000 in 2018–2019. The highest incidence was seen in 2016–2017 (7.94 per 100,000). The median male number of FCEs per year (2919, IQR: 228) was consistently higher than the median female number of FCEs per year (2216, IQR: 326). The rates of both emergency admissions and planned admissions are rising. Conclusions: The incidence of hospitalisation for DCM in England is rising. Health care policymakers and providers must recognise the increasing burden of DCM and act to address both early diagnoses and access to treatment in future service provision plans. [ABSTRACT FROM AUTHOR]

Birds exhibit wide variation in their use of aquatic environments, on a spectrum from entirely terrestrial, through amphibious, to highly aquatic. Although there are limited empirical data on hearing sensitivity of birds underwater, mounting evidence indicates that diving birds detect and respond to sound underwater, suggesting that some modifications of the ear may assist foraging or other behaviors below the surface. In air, the tympanic middle ear acts as an impedance matcher that increases sound pressure and decreases sound vibration velocity between the outside air and the inner ear. Underwater, the impedance-matching task is reversed and the ear is exposed to high hydrostatic pressures. Using micro- and nano-CT (computerized tomography) scans of bird ears in 127 species across 26 taxonomic orders, we measured a suite of morphological traits of importance to aerial and aquatic hearing to test predictions relating to impedance-matching in birds with distinct aquatic lifestyles, while accounting for allometry and phylogeny. Birds that engage in underwater pursuit and deep diving showed the greatest differences in ear structure relative to terrestrial species. In these heavily modified ears, the size of the input areas of both the tympanic membrane and the columella footplate of the middle ear were reduced. Underwater pursuit and diving birds also typically had a shorter extrastapedius, a reduced cranial air volume and connectivity and several modifications in line with reversals of low-to-high impedance-matching. The results confirm adaptations of the middle ear to aquatic lifestyles in multiple independent bird lineages, likely facilitating hearing underwater and baroprotection, while potentially constraining the sensitivity of aerial hearing. [ABSTRACT FROM AUTHOR]

Conceptual and empirical advances in soil biogeochemistry have challenged long-held assumptions about the role of soil micro-organisms in soil organic carbon (SOC) dynamics; yet, rigorous tests of emerging concepts remain sparse. Recent hypotheses suggest that microbial necromass production links plant inputs to SOC accumulation, with high-quality (i.e., rapidly decomposing) plant litter promoting microbial carbon use efficiency, growth, and turnover leading to more mineral stabilization of necromass. We test this hypothesis experimentally and with observations across six eastern US forests, using stable isotopes to measure microbial traits and SOC dynamics. Here we show, in both studies, that microbial growth, efficiency, and turnover are negatively (not positively) related to mineral-associated SOC. In the experiment, stimulation of microbial growth by high-quality litter enhances SOC decomposition, offsetting the positive effect of litter quality on SOC stabilization. We suggest that microbial necromass production is not the primary driver of SOC persistence in temperate forests. Factors such as microbial necromass origin, alternative SOC formation pathways, priming effects, and soil abiotic properties can strongly decouple microbial growth, efficiency, and turnover from mineral-associated SOC. Mineral-associated soil carbon buildup is poorly explained by microbial necromass production (a common hypothesis). During litter decomposition, these processes are decoupled by priming effects and alternate soil carbon formation pathways [ABSTRACT FROM AUTHOR]

Morphological variation in biological structures may be driven by genetic and environmental factors, such as inter- and intraspecific competition for resources. In seabirds, although the bill is also involved in vocalization, olfaction, sexual selection and defence, the main drivers of high morphological plasticity in bill size and shape appear to relate primarily to diet and thus to niche differentiation. Here, we combined geometric morphometrics and comparisons of linear measurements as a precise tool for measuring shape variation in anatomical features, to investigate the differences among species and populations (island groups) in bill shape of three planktivorous petrels (Antarctic prion Pachyptila desolata, blue petrel Halobaena caerulea and thin-billed prion Pachyptila belcheri). Fieldwork was carried out in South Georgia (54° 0′ S, 38° 3′ W), Falkland (51° 42′ S, 57° 51′ W), Diego Ramírez (56° 31′ S, 68° 44′ W) and Kerguelen (49° 20′ S, 69° 20′ E) Islands, from 2010 to 2021. Results show that the bills of Antarctic prions were more robust and shorter, appropriate for filtering large amounts of small prey. Blue petrels and thin-billed prions had narrower and longer bills, effective for catching and tearing large single prey. Also, Antarctic prions and blue petrels from Kerguelen had longer and narrower bills than conspecifics from other colonies, which could potentially be explained by geographic variation in diet. In conclusion, prey availability and diversity appear to be important factors influencing variation in bill morphology. This study highlights the utility of geometric morphometrics for investigating bill shape variation in seabirds. Nevertheless, further studies are needed to better understand selective pressures leading to morphological variation of biological structures. [ABSTRACT FROM AUTHOR]

Interspecific introgression can occur between species that evolve rapidly within an adaptive radiation. Pachyptila petrels differ in bill size and are characterised by incomplete reproductive isolation, leading to interspecific gene flow. Salvin's prion (Pachyptila salvini), whose bill width is intermediate between broad-billed (P. vittata) and Antarctic (P. desolata) prions, evolved through homoploid hybrid speciation. MacGillivray's prion (P. macgillivrayi), known from a single population on St Paul (Indian Ocean), has a bill width intermediate between salvini and vittata and could also be the product of interspecies introgression or hybrid speciation. Recently, another prion population phenotypically similar to macgillivrayi was discovered on Gough (Atlantic Ocean), where it breeds 3 months later than vittata. The similarity in bill width between the medium-billed birds on Gough and macgillivrayi suggest that they could be closely related. In this study, we used genetic and morphological data to infer the phylogenetic position and evolutionary history of P. macgillivrayi and the Gough medium-billed prion relative other Pachyptila taxa, to determine whether species with medium bill widths evolved through common ancestry or convergence. We found that Gough medium-billed prions belong to the same evolutionary lineage as macgillivrayi, representing a new population of MacGillivray's prion that originated through a colonisation event from St Paul. We show that macgillivrayi's medium bill width evolved through divergence (genetic drift) and independently from that of salvini, which evolved through hybridisation (gene flow). This represents the independent convergence towards a similarly medium-billed phenotype. The newly discovered MacGillivray's prion population on Gough is of utmost conservation relevance, as the relict macgillivrayi population in the Indian Ocean is very small. [ABSTRACT FROM AUTHOR]

Biogenic volatile organic compounds (BVOCs) play critical roles in ecological and earth-system processes. Ecosystem BVOC models rarely include soil and litter fluxes and their accuracy is often challenged by BVOC dynamics during periods of rapid ecosystem change like spring leaf out. We measured BVOC concentrations within the air space of a mixed deciduous forest and used a hybrid Lagrangian/Eulerian canopy transport model to estimate BVOC flux from the forest floor, canopy, and whole ecosystem during spring. Canopy flux measurements were dominated by a large methanol source and small isoprene source during the leaf-out period, consistent with past measurements of leaf ontogeny and theory, and indicative of a BVOC flux situation rarely used in emissions model testing. The contribution of the forest floor to whole-ecosystem BVOC flux is conditional on the compound of interest and is often non-trivial. We created linear models of forest floor, canopy, and whole-ecosystem flux for each study compound and used information criteria-based model selection to find the simplest model with the best fit. Most published BVOC flux models do not include vapor pressure deficit (VPD), but it entered the best canopy, forest floor, and whole-ecosystem BVOC flux model more than any other study variable in the present study. Since VPD is predicted to increase in the future, future studies should investigate how it contributes to BVOC flux through biophysical mechanisms like evaporative demand, leaf temperature and stomatal function. [ABSTRACT FROM AUTHOR]

There is increasing evidence that plant roots and mycorrhizal fungi, whether living or dead, play a central role in soil carbon (C) cycling. Root–mycorrhizal–microbial interactions can both suppress and enhance litter decay, with the net result dependent upon belowground nutrient acquisition strategies and soil nutrient availability. We measured the net effect of living roots and mycorrhizal fungi on the decay of dead roots and fungal hyphae in a hardwood forest dominated by either sugar maple (Acer saccharum) or white oak (Quercus alba) trees. Root and fungal litter were allowed to decompose within root-ingrowth bags and root-exclusion cores. In conjunction with root effects on decay, we assessed foraging responses and root induced changes in soil moisture, nitrogen (N) availability and enzyme activity. After 1 year, maple root production increased, and mycorrhizal fungal colonization decreased in the presence of decaying litter. In addition, we found that actively foraging roots suppressed the decay of root litter (− 14%) more than fungal litter (− 3%), and suppression of root decay was stronger for oak (− 20%) than maple roots (− 8%). Suppressive effects of oak roots on decay were greatest when roots also reduced soil N availability, which corresponded with reductions in hydrolytic enzyme activity and enhanced oxidative enzyme activities. These findings further our understanding of context‐dependent drivers of root–mycorrhizal–microbial interactions and demonstrate that such interactions can play an underappreciated role in soil organic matter accumulation and turnover in temperate forests. [ABSTRACT FROM AUTHOR]

Microbial processes play a central role in controlling the availability of N in temperate forests. While bacteria, archaea, and fungi account for major inputs, transformations, and exports of N in soil, relationships between microbial community structure and N cycle fluxes have been difficult to detect and characterize. Several studies have reported differences in N cycling based on mycorrhizal type in temperate forests, but associated differences in N cycling genes underlying these fluxes are not well-understood. We explored how rates of soil N cycle fluxes vary across gradients of mycorrhizal abundance (hereafter "mycorrhizal gradients") at four temperate forest sites in Massachusetts and Indiana, USA. We paired measurements of N-fixation, net nitrification, and denitrification rates with gene abundance data for specific bacterial functional groups associated with each process. We find that the availability of NO3 and rates of N-fixation, net nitrification, and denitrification are reduced in stands dominated by trees associated with ECM fungi. On average, rates of N-fixation and denitrification in stands dominated by trees associated with arbuscular mycorrhizal fungi were more than double the corresponding rates in stands dominated by trees associated with ectomycorrhizal fungi. Despite the structuring of flux rates across the mycorrhizal gradients, we did not find concomitant shifts in the abundances of N-cycling bacterial genes, and gene abundances were not correlated with process rates. Given that AM-associating trees are replacing ECM-associating trees throughout much of the eastern US, our results suggest that shifts in mycorrhizal dominance may accelerate N cycling independent of changes in the relative abundance of N cycling bacteria, with consequences for forest productivity and N retention. [ABSTRACT FROM AUTHOR]

Northern Macronectes halli and southern giant petrels M. giganteus are opportunistic predators and the dominant avian scavengers in sub-Antarctic and Antarctic ecosystems. At South Georgia, there are globally important breeding populations of both species; however, no detailed diet study has been carried out at this site for > 35 years. Here, we analysed stomach contents of northern (n = 81) and southern giant petrel (n = 73) chicks at Bird Island, South Georgia (2014/15–2016/17). Specifically, we investigated: (1) interspecific and sexual dietary segregation; (2) diet changes within and among recent years; and (3) long-term diet changes since 1979/80–1980/81. Overall diet composition was similar between species, with penguins comprising approximately half the diet by mass. In both species (but more pronounced in southern giant petrels), prey delivered by female parents included higher proportions (by mass) of penguins and Antarctic krill Euphausia superba, and by male parents included more Antarctic fur seal Arctocephalus gazella carrion and seabirds other than penguins. Consumption of penguins increased, and of seal carrion declined, as chick-rearing progressed, mirroring the decreasing availability of the latter after the peak pupping period in December at South Georgia. Comparisons with data from 1979/80–1980/81 suggest some changes in giant petrel diets; however, these differences were no greater than the typical annual variation, and there were no clear links between diet and breeding allochrony or the differing population trends (more rapid increase in northern than southern giant petrels). The high diet diversity and ability of giant petrels to exploit both carrion and marine prey facilitates coexistence with other sympatric Procellariiformes and explains their favourable population status. [ABSTRACT FROM AUTHOR]

The wandering albatross, Diomedea exulans, is a globally threatened species breeding at a number of sites within the Southern Ocean. Across the South Georgia archipelago, there are differences in population trends even at closely located colonies. Between 1999 and 2018 the largest colony, at Bird Island, declined at 3.01% per annum, while in the Bay of Isles, the decline was 1.44% per annum. Using mean demographic rates from a 31-year study at Bird Island and an 11-year study of breeding success at Prion Island in the Bay of Isles in a VORTEX model, we show that differences in breeding success do not fully explain observed differences in population trends. Other potential contributing factors are differential use of foraging areas, with possible knock-on effects on adult body condition, provisioning rate and breeding success, or on bycatch rates of adults or immatures. [ABSTRACT FROM AUTHOR]

Forests provide myriad ecosystem services, many of which are vital to local and regional economies. Consequently, there is a need to better understand how predicted changes in climate will impact forest dynamics and the implications of such changes for society as a whole. Here we focus on the impacts of climate change on Indiana forests, which are representative of many secondary growth broadleaved forests in the greater Midwest region in terms of their land use history and current composition. We found that predicted changes in climate for the state—warmer and wetter winters/springs and hotter and potentially drier summers—will dramatically shape forest communities, resulting in new assemblages of trees and wildlife that differ from forest communities of the past or present. Overall, suitable habitat is expected to decline for 17–29% of tree species and increase for 43–52% of tree species in the state, depending on the region and climate scenario. Such changes have important consequences for wildlife that depend on certain tree species or have ranges with strong sensitivities to climate. Additionally, these changes will have potential economic impacts on Indiana industries that depend on forest resources and products (both timber and non-timber). Finally, we offer some practical suggestions on how management may minimize the extent of climate-induced ecological impacts and highlight a case study from a tree planting initiative currently underway in the Patoka River National Wildlife Refuge and Management Area. [ABSTRACT FROM AUTHOR]

Invasive species present a major conservation threat globally and nowhere are their affects more pronounced than in island ecosystems. Determining how native island populations respond demographically to invasive species can provide information to mitigate the negative effects of invasive species. Using 20 years of mark-recapture data from three sympatric species of albatrosses (black-browed Thalassarche melanophris, grey-headed T. chrysostoma, and light-mantled albatrosses Phoebetria palpebrata), we quantified the influence of invasive European rabbits Oryctolagus cuniculus and extreme weather patterns on breeding probability and success. Temporal variability in rabbit density explained 33–76% of the variability in breeding probability for all three species, with severe decreases in breeding probability observed after a lag period following highest rabbit numbers. For black-browed albatrosses, the combination of extreme rainfall and high rabbit density explained 33% of total trait variability and dramatically reduced breeding success. We showed that invasive rabbits and extreme weather events reduce reproductive output in albatrosses and that eliminating rabbits had a positive effect on albatross reproduction. This illustrates how active animal management at a local breeding site can result in positive population outcomes even for wide ranging animals like albatrosses where influencing vital rates during their at-sea migrations is more challenging. [ABSTRACT FROM AUTHOR]

Prions Pachyptila are the most abundant seabirds in the Southern Ocean and comprise two main groups: those with and without bill lamellae to filter zooplankton. With few exceptions, each breeding location supports at most one species from each of these groups. However, Gough Island supports two morphologically very similar, filter-feeding species: broad-billed P. vittata and MacGillivray's prions P. macgillivrayi. To understand how these two species co-occur in sympatry, we compared the foraging ranges, habitat selectivity, trophic segregation and moult schedules of these species using combined geolocation-immersion loggers. After breeding, both species showed a well-defined westward migration prior to moulting. Moult lasted 11–19 weeks and was significantly longer in MacGillivray's than broad-billed prions. Moulting birds occurred in specific areas within the Argentine Basin, with little overlap between the two species. Habitat analysis revealed species-specific preferences, in particular sea surface temperature. Activity patterns also differed; MacGillivray's prions spent more time in flight, which indicates a more active foraging strategy, relying less on filter feeding. Stable isotope ratios (δ15N) in flight feathers were greater in MacGillivray's prion, which is consistent with its less specialized bill morphology resulting in feeding at a higher trophic level. Inter-specific spatial segregation was observed for most of the tracking period, in large part because broad-billed prions breed roughly 3 months earlier than MacGillivray's prions. At Tristan da Cunha, 250 km farther north, where only broad-billed prions breed, they departed, moulted and returned significantly later (15–17 days) than conspecifics from Gough Island, providing evidence for character displacement in sympatry with MacGillivray's prion. [ABSTRACT FROM AUTHOR]

Diet analyses can reveal important changes in seabird foraging ecology and, by inference, resource availability and predator–prey dynamics within the wider marine ecosystem. Here, we analysed stomach contents of 1544 grey-headed albatross Thalassarche chrysostoma (GHA) and black-browed albatross T. melanophris (BBA) chicks from Bird Island, South Georgia. We describe dietary shifts (1996–2017), and link those to annual prey availability indices and breeding success. Annual variability in diet was high, and long-term trends in the main components were broadly similar in both albatrosses. Fish consumption (by mass) generally increased over time. Mackerel icefish Champsocephalus gunnari occurrence increased in GHA diets, but was unrelated to local densities derived from fisheries/research cruises. Cephalopod consumption declined until the early 2000s, then plateaued, and the occurrence of the ommastrephid squid Martialia hyadesi declined over time in both albatrosses. In BBAs, Antarctic krill Euphausia superba consumption decreased over time. Conversely, Antarctic krill consumption by GHAs increased until the early 2000s, decreased until the mid-2010s, and increased again in 2017. Antarctic krill consumption was unrelated to local densities based on acoustic surveys, and did not correlate with breeding success. Remotely sensed chlorophyll-a within core foraging areas showed a positive relationship with Antarctic krill in GHA diets, but a negative relationship with M. hyadesi occurrence in both albatross diets. Dietary shifts had consequences for GHA breeding success, which was negatively related to the importance of the cranchiid Galiteuthis glacialis and positively related to M. hyadesi importance. These results highlight the complex mechanisms linking prey availability, diet and breeding success in albatrosses. [ABSTRACT FROM AUTHOR]

The long-distance quantum transfer between electron-spin qubits in semiconductors is important for realising large-scale quantum computing circuits. Electron-spin to photon-polarisation conversion is a promising technology for achieving free-space or fibre-coupled quantum transfer. In this work, using only regular lithography techniques on a conventional 15 nm GaAs quantum well, we demonstrate acoustically-driven generation of single photons from single electrons, without the need for a self-assembled quantum dot. In this device, a single electron is carried in a potential minimum of a surface acoustic wave (SAW) and is transported to a region of holes to form an exciton. The exciton then decays and creates a single optical photon within 100 ps. This SAW-driven electroluminescence, without optimisation, yields photon antibunching with g(2)(0) = 0.39 ± 0.05 in the single-electron limit (g(2)(0) = 0.63 ± 0.03 in the raw histogram). Our work marks the first step towards electron-to-photon (spin-to-polarisation) qubit conversion for scaleable quantum computing architectures. Electron-spin to photon-polarisation conversion is a promising technology for achieving free-space or fibre coupled quantum transfer. Here, the authors demonstrate acoustically-driven single photons from single electrons, without the need for self-assembled quantum dots, using a SAW-driven lateral n-i-p junction. [ABSTRACT FROM AUTHOR]

Information on the status of giant petrels breeding at South Georgia was previously based on studies at a small number of the archipelago's breeding sites. Here, we report the results of the first complete archipelago-wide survey of breeding northern Macronectes halli and southern M. giganteus giant petrels in the austral summers 2005/2006 and 2006/2007. We estimate that 15,398 pairs of northern and 8803 pairs of southern giant petrels bred at South Georgia. These are the largest and second largest populations at any island group, representing 71.0% and 17.3%, respectively, of updated global estimates of 21,682 pairs of northern and 50,819 pairs of southern giant petrels. A comparison of counts at locations surveyed in both 1986/1987–1987/1988 and 2005/2006–2006/2007 indicated increases of 74% and 27% in northern and southern giant petrels, respectively, over the intervening 18–20 years. The greater increase in northern giant petrels was likely influenced by the recovery of the Antarctic fur seal Arctocephalus gazella population at South Georgia, which provides an abundant but transient food resource (carrion). Due to allochrony, this provides greater benefits to northern giant petrels. The large, and increasing, population of king penguins Aptenodytes patagonicus at South Georgia also provides a potentially valuable food resource. The flexible and opportunistic foraging behaviour of giant petrels has contributed to their positive population trends. Other, more specialised, seabirds such as albatrosses have declined at South Georgia in recent decades mainly because of problems at sea, compounded by greater predation pressure from the increasing populations of giant petrels. [ABSTRACT FROM AUTHOR]

Illex argentinus is an ecologically and economically important species, assumed to be restricted to the Patagonian Shelf and around the subtropical convergence. Beaks found in diet samples from black-browed albatrosses Thalassarche melanophris during chick rearing initially suggested that it may also inhabit Antarctic waters until it was appreciated that I. argentinus is used as fishing bait by commercial longliners within albatrosses foraging areas. Here, we applied a new methodology involving stable isotope analysis (δ13C and δ15N) in two regions [tip of the rostrum (juvenile) and wing (adult)] of lower beaks obtained from diet samples of black-browed albatrosses breeding at Bird Island (South Georgia). The aims were to (1) assess if I. argentinus could inhabit Antarctic waters somewhere in the life cycle (2) determine the trophic ecology of I. argentinus, and (3) discuss possible migration patterns of I. argentinus and whether its distribution may change in the future. Values of δ13C (proxy for habitat) were − 18.4 ± 0.7‰ and − 17.1 ± 0.4‰ during the juvenile and adult life stages, respectively, indicating a northwards ontogenetic shift, and that this species exclusively inhabits waters north of the Antarctic Polar Front. Values of δ15N was lower in juveniles (+5.9 ± 1.1‰) than adults (+8.4 ± 1.3‰), indicating an increase of one trophic level throughout the squid's life, suggesting a diet shift from zooplankton to fish and squid. Based on predicted effects of climate change, the distribution of I. argentinus may become more restricted as the northern limit moves southwards because of warming ocean temperature. [ABSTRACT FROM AUTHOR]

Increases in carbon (C) inputs can augment soil organic matter (SOM), or reduce SOM by accelerating decomposition. Thus, there is a need to understand how and why ecosystems differ in their sensitivity to C inputs. Invasive plants that invade wide-ranging habitats, accumulate biomass rapidly, and contribute copious amounts of C to soil can be ideal for addressing this gap. We quantified the effects of the invasive C4 grass, Microstegium vimineum, on SOM in three temperate forests across plots varying in their relative abundance of arbuscular mycorrhizal (AM) versus ectomycorrhizal (ECM) trees. We hypothesized that invasion would differentially affect SOM along the mycorrhizal gradient owing to recognized patterns in nitrogen availability (AM > ECM) and the proportion of unprotected SOM (ECM > AM). Across all sites, M. vimineum was associated with lower particulate organic matter (POM) in ECM-dominated plots, consistent with our hypothesis that invader-derived C inputs should stimulate decomposers to acquire nitrogen from unprotected SOM in soils with low nitrogen availability. However, the pattern of lower POM in the ECM-dominated soils was offset by greater mineral-associated organic matter (MAOM)—and isotopic data suggest this was largely driven by native- rather than invader-derived SOM—implying an invasion-associated transfer of native-derived POM into MAOM. Our results demonstrate a context-dependent shift in the form of SOM in a system with presumably enhanced C inputs. This finding suggests a need to look beyond changes in total SOM stocks, as intrinsic SOM changes could lead to important long-term feedbacks on invasion or priming effects. [ABSTRACT FROM AUTHOR]

Despite their importance in ecosystems, population sizes and trends are unknown for many seabirds, including in the Antarctic. Here we report on the first comprehensive survey of south polar skuas Stercorarius maccormicki and Antarctic shags Leucocarbo bransfieldensis in Ryder Bay, and collate previous count data. In austral summer 2017/18, totals of 259 skuas at club sites and 978 occupied skua territories were counted in 2.3 km2 of suitable habitat at Rothera Point and adjacent islands. Based on the mean nearest neighbour distance (23.2 m), skua nest densities were comparable with colonies elsewhere. Long-term monitoring of skuas at Rothera Point indicated considerable annual variation and overall increases of 1.9 and 1.3% per annum, respectively, in breeding pairs from 1975/76 to 2017/18, and occupied territories from 1988/89 to 2017/18. In total, 405 pairs of Antarctic shags bred at two known and one newly discovered colony in 2017/18. Previous counts at the two known colonies indicated substantial annual variation and increases of 5.5 and 3.3% per annum, respectively, from 1985/86 to 2017/18 and 1989/90 to 2017/18. Factors leading to overall increases in both species, and the intermittent seasons of near-complete failure to breed, are unclear, but likely to reflect impacts of environmental change on their marine prey or sea ice. The breeding populations of south polar skuas and Antarctic shags in Ryder Bay represent 10.3 and 3.5%, respectively, of revised global estimates of 9500 and 11,684 breeding pairs. We recommend that the breeding colonies be included as important bird areas (IBAs) and within the Antarctic Specially Protected Area (ASPA) system, and provision made to conserve foraging areas at sea. [ABSTRACT FROM AUTHOR]

Alemtuzumab is a humanized anti-CD52 monoclonal antibody approved in more than 65 countries for the treatment of relapsing-remitting multiple sclerosis (RRMS). Compared with subcutaneous interferon-beta-1a, alemtuzumab significantly reduced clinical disease activity and the rate of brain volume loss, and improved disability outcomes in patients with active RRMS who were either treatment naive (CARE-MS I study) or who had an inadequate response (≥ 1 relapse after ≥ 6 months of treatment) to prior therapy (CARE-MS II study). Adverse events (AEs) associated with alemtuzumab include infusion-associated reactions, infections, and autoimmunity. The most commonly reported autoimmune AEs observed with alemtuzumab involve the thyroid gland, followed by immune thrombocytopenia and nephropathies. A monitoring program was designed and implemented to facilitate the early detection of autoimmune events to ensure timely and adequate management. The aim of this article is to provide physicians (including neurologists, general practitioners, endocrinologists, hematologists, and nephrologists who may be less familiar with the symptoms and treatment of autoimmune events), with practical real-world recommendations for the monitoring and management of autoimmunity associated with alemtuzumab treatment. [ABSTRACT FROM AUTHOR]

We present the first detailed data on the distribution and migration patterns of four pelagic seabird species in the Eastern Indian Ocean—the Lesser Noddy (Anous tenuirostris melanops), Brown Noddy (Anous stolidus), Wedge-tailed Shearwater (Ardenna pacifica) and Bridled Tern (Onychoprion anaethetus) breeding at the Houtman Abrolhos and the Wedge-tailed Shearwater breeding at Varanus Island, Western Australia—tracked using geolocators during their respective non-breeding periods. Lesser Noddies remained largely in the general vicinity or slightly to the south of the colony in their non-breeding season (February-September). Brown Noddies spent their non-breeding period (March-August) in the Northwest Shelf area of Western Australia, around 950 km north of the colony. In contrast, Bridled Terns and most Wedge-tailed Shearwaters undertook extensive non-breeding migrations. Wedge-tailed Shearwaters occupied waters adjacent or to the north of their nesting sites or migrated 4200 km northwest into the equatorial central Indian Ocean near the Ninety East Ridge during the non-breeding season (late April to mid-November). These same areas were used during the sabbatical summer by Wedge-tailed Shearwaters that had deferred breeding. Bridled Terns spent their non-breeding period (April-September) in the Celebes Sea, 3800 km north of the Houtman Abrolhos. The results are discussed in the context of potential marine threats to the different species during the non-breeding period. [ABSTRACT FROM AUTHOR]

Fed-batch method has shown a great promise in debottlenecking the high-solid enzymatic hydrolysis for the commercialization of cellulosic biosugar conversion for biofuel/biochemical production. To further improve enzymatic hydrolysis efficiency at high solid loading, fed-batch methods of green liquor-pretreated hardwood were performed to evaluate their effects on sugar recovery by comparing with one-stage batch method in this study. Among all the explored conditions, the fed-batch at 15% consistency gave higher sugar recovery on green liquor-pretreated hardwood compared to that of one-stage batch. By using general linear model analysis, the percentage of enzymatic sugar recovery in fed-batch consistency method (increasing consistency from the initial 10.7 to 15% at intervals of 24 and 48 h) was higher than that of batch hydrolysis at higher density of 15% consistency. Under that best fed-batch condition, the total sugar recovery of pretreated hardwood in enzymatic hydrolysate reached approximately 48.41% at Cellic® enzyme loading of 5 filter-paper unit (FPU)/g and 58.83% at Cellic® enzyme loading of 10 FPU/g with a hydrolysis time of 96 h. [ABSTRACT FROM AUTHOR]

Plant-soil feedbacks are known to play a central role in species co-existence, but conceptual frameworks for predicting their magnitude and direction are lacking. We ask whether co-occurring trees that associate with different types of mycorrhizal fungi, which are hypothesized to differ in terms of nutrient use and plant-soil feedbacks, differ in sapling establishment densities and probability of co-occurrence. Given that ectomycorrhizal (ECM) trees typically have fungal structures that protect roots from pathogens whereas arbuscular mycorrhizal (AM) trees do not, we hypothesized that ECM saplings would be clustered around ECM trees, while AM saplings would be suppressed near AM trees. Most previous studies have focused on seedlings, but here we examine whether the spatial signal is evident in later life stages. We measured the spatial associations of ~ 28,000 trees using point pattern analysis in a 25-ha old-growth forest where ECM trees comprised 72% of total basal area and 42% of the total stems, while AM trees comprised the remainder. Supporting our hypothesis, AM saplings were more inhibited by AM trees, while ECM saplings were more clustered around ECM trees. The spatial patterns of AM and ECM trees on saplings of the alternate mycorrhizal type were inhibited. To the extent that similar types of feedbacks occur for other AM and ECM trees, our results suggest that fundamental differences in the nature of local-scale biotic interactions between trees and their fungal symbionts may influence forest community assembly and ecosystem dynamics. [ABSTRACT FROM AUTHOR]

Financial performance of the P. patula × P. tecunumanii, P. greggii × P. tecunumanii, P. taeda × P. tecunumanii hybrids and their parental species was studied for South Africa. A model was developed for use in determining the profitability of a tree-breeding program (TBP) with pine hybrids in commercial plantations. Growth measurement data were collected in four, 12-year-old genetic trials on Mondi and Sappi land holdings in South Africa. Growth models developed for P. patula and P. taeda in South Africa were used to infer models for the other taxa and to calculate the optimal financial rotation age at discount rates of 6 and 8%. Financial data on pine plantations were collected from different sources in South Africa. Optimal rotation lengths in this study were found to be between 12 and 16 years for pulpwood and 17 years for sawtimber. The model output shows the net present value (NPV), the internal rate of return, and the minimum area that a tree grower has to plant every year in order to justify the investment in a TBP. A stochastic approach with Monte Carlo simulation showed that the sensitivity of NPV to uncertainty in the wood price was greater than that for the planting, harvesting, and transport costs. [ABSTRACT FROM AUTHOR]

Although fisheries discards are recognized as a key food source for many seabirds, there have been few thorough assessments of their importance relative to natural prey, and of their influence on the trophic structure of pelagic seabird communities during the non-breeding period. Competition for resources in Procellariiformes appears to be reduced mainly by avoiding spatial overlap, which is supposed to influence diet composition. However, artificial food sources provided by fisheries might relax niche partitioning, increasing trophic niche overlap. Using bycaught birds from pelagic longline fisheries, we combined the conventional diet and stable isotope analyses to assess the importance of fishing discards in the diet of eight species of Procellariiformes. Both methods revealed the high contribution of trawl discards to the non-breeding diet of three neritic species and a moderate contribution in several other species; discards from pelagic and demersal longline fisheries were considerably less important. There was a clear contrast in diets of neritic vs. oceanic species, which are closely related taxonomically, but segregate at sea. Niche partitioning was less clear among neritic species. They showed an unexpectedly high level of diet overlap, presumably related to the large volume of trawl discards available. This is the first study combining the conventional diet and stable isotope analyses to quantify the importance of fishery discards for a community of non-breeding seabirds, and demonstrates how the super-abundance of supplementary food generates high levels of overlap in diets and allows the coexistence of species. [ABSTRACT FROM AUTHOR]

South Georgia supports globally important populations of seabirds, including the wandering albatross Diomedea exulans, black-browed albatross Thalassarche melanophris and grey-headed albatross T. chrysostoma, currently classified by the world Conservation Union (IUCN) as vulnerable, near threatened and endangered, respectively. Surveys of these species at South Georgia were conducted during the incubation stage in November 2014 to January 2015, repeating previous surveys conducted in the 2003/2004 season. Numbers of wandering albatrosses breeding annually at South Georgia decreased by 18% (1.8% per year) from 1553 pairs in 2003/2004 to an estimated 1278 pairs in 2014/2015. Over the same period, black-browed and grey-headed albatrosses decreased by 19% (1.9% per year) and 43% (5% per year), respectively. These represent a continuation of negative trends at South Georgia since the 1970s and are in contrast to some populations elsewhere, which have shown signs of recent recovery. Given the importance of South Georgia for these species, the ongoing population declines, and in the case of grey-headed albatrosses, an acceleration of the decline is of major conservation concern. Incidental fisheries mortality (bycatch) is currently considered to be the main threat. Although seabird bycatch has been reduced to negligible levels in the fisheries operating around South Georgia, wider implementation of effective seabird bycatch mitigation measures is required to improve the conservation status of the South Georgia populations of wandering, black-browed and grey-headed albatrosses. In addition, more research is required to investigate the respective roles of bycatch and climate change in driving these population trends. [ABSTRACT FROM AUTHOR]

Given the potential role of telomeres as biomarkers of individual health and ageing, there is an increasing interest in studying telomere dynamics in a wider range of taxa in the fields of ecology and evolutionary biology. Measuring telomere length across the lifespan in wild animal systems is essential for testing these hypotheses, and may be aided by archived blood samples collected as part of longitudinal field studies. However, sample collection, storage, and DNA extraction methods may influence telomere length measurement, and it may, therefore, be difficult to balance consistency in sampling protocol with making the most of available samples. We used two complementary approaches to examine the impacts of sample storage method on measurements of relative telomere length (RTL) by qPCR, particularly focusing on FTA (Flinders Technology Associates) cards as a long-term storage solution. We used blood samples from wandering albatrosses collected over 14 years and stored in three different ways ( n = 179), and also blood samples from captive zebra finches ( n = 30) that were each stored using three different methods. Sample storage method influenced RTL in both studies, and samples on FTA cards had significantly shorter RTL measurements. There was no significant correlation between RTL measured in zebra finch blood on FTA cards and the same samples stored either as frozen whole blood or as extracted DNA. These results highlight the importance of consistency of sampling protocol, particularly in the context of long-term field studies, and suggest that FTA cards should not be used as a long-term storage solution to measure RTL without validation. [ABSTRACT FROM AUTHOR]

Trees possess myriad adaptations for coping with drought stress, but the extent to which their drought responses are influenced by interactions with soil microbes is poorly understood. To explore the role of microbes in mediating tree responses to drought stress, we exposed saplings of three species ( Acer saccharum, Liriodendron tulipifera, and Quercus alba) to a four week experimental drought in mesocosms. Half of the pots were inoculated with a live soil slurry (i.e., a microbial inoculum derived from soils beneath the canopies of mature A. saccharum, L. tulipifera or Q. alba stands), while the other half of the pots received a sterile soil slurry. Soil microbes ameliorated drought stress in L. tulipifera by minimizing reductions in leaf water potential and by reducing photosynthetic declines. In A. saccharum, soil microbes reduced drought stress by lessening declines in leaf water potential, though these changes did not buffer the trees from declining photosynthetic rates. In Q. alba, soil microbes had no effects on leaf physiological parameters during drought stress. In all species, microbes had no significant effects on dynamic C allocation during drought stress, suggesting that microbial effects on plant physiology were unrelated to source-sink dynamics. Collectively, our results suggest that soil microbes have the potential to alter key parameters that are used to diagnose drought sensitivity (i.e., isohydry or anisohydry). To the extent that our results reflect dynamics occurring in forests, a revised perspective on plant hydraulic strategies that considers root-microbe interactions may lead to improved predictions of forest vulnerability to drought. [ABSTRACT FROM AUTHOR]

The Arctic is a highly seasonal environment with a harsh climate and extensive sea ice cover during the winter. Consequently, most Arctic-breeding seabirds migrate south to reach more benign environmental conditions. Knowledge of migration routes and wintering areas is integral for successful conservation of these globally important breeding populations. In this study, we deployed light-level geolocators on female common eiders Somateria mollissima breeding in Kongsfjorden, Svalbard, to track movements during the non-breeding season. We retrieved functioning loggers from 47 individual birds in 2009-2013 and mapped their migration routes and wintering areas. Thirty-six birds (77 %) wintered around the Icelandic coast and 11 (23 %) off the coasts of North Norway. Autumn migration took place between late August and late December, and spring migration from late March to late May. The migration (ca 1700 km to Iceland and 1300 km to North Norway) lasted for about 4 days in autumn and 3 days in spring. Later arrival resulted in later nest initiation, implying a carry-over effect of winter conditions on subsequent breeding. Birds that migrated to Norway departed later from Svalbard in autumn and consequently spent less time in the wintering area than individuals that migrated to Iceland. As just two countries, Iceland and Norway, appear to host all common eiders from Svalbard during the winter, the new information provided by this study on the core areas and timing of migration should provide the impetus for improved bilateral conservation management of this important Arctic breeding population of common eiders. [ABSTRACT FROM AUTHOR]

In this study, we investigate the numbers, productivity and territory distribution of the two species of skuas (brown Stercorarius lonnbergi and south polar Stercorarius maccormicki) breeding at Signy Island, South Orkneys, and compare the results with trends elsewhere. Comparison with previous counts indicates a biphasic increase in brown skuas at Signy Island; much faster from 1958/1959 to 1982/1983 (3.3 % per annum), than in subsequent years (0.4 % per annum from 1983/1984 to 2013/2014). Relative distribution of territories has changed little over time. The reduced rate of population growth in recent years was broadly coincident with a decrease in numbers of penguins (and therefore potential prey), which may also explain recent reductions in skua numbers at other Antarctic sites. As prey have become limiting, breeding success of brown skuas at Signy Island is now slightly lower than in the 1950s/early 1960s, but timing of breeding does not appear to have changed. Brown skuas at Signy Island may still have enough resources to start breeding, but as the season progresses and availability of resources declines, chick survival is reduced. South polar skuas have declined from ten pairs in 1982/1983 to one pair in 2013/2014, and mixed pairs have increased from one to three pairs. A review of the literature indicated that although population trend data are available for relatively few sites elsewhere in the subantarctic and Antarctic, numbers of brown skuas appear to be generally decreasing or stable, and of south polar skuas to be stable or increasing. [ABSTRACT FROM AUTHOR]

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The food and feeding ecology of albatrosses during the nonbreeding season is still poorly known, particularly with regard to the cephalopod component. This was studied in black-browed Thalassarche melanophris and grey-headed T. chrysostoma albatrosses by analysing boluses collected shortly after adults returned to colonies at Bird Island, South Georgia (54°S, 38°W), in 2009. Based on stable isotopic analyses of the lower beaks, we determined the habitat and trophic level (from δC and δN, respectively) of the most important cephalopods and assessed the relative importance of scavenging in terms of the albatrosses' feeding regimes. Based on lower rostral lengths (LRLs), the main cephalopod species in the diets of both albatrosses was Kondakovia longimana, by frequency of occurrence ( F > 90 %), number ( N > 40 %) and mass ( M > 80 %). The large estimated mass of many squid, including K. longimana, suggests that a high proportion (>80 % by mass) was scavenged, and that scavenging is much more important during the nonbreeding season than would be expected from breeding-season diets. The diversity of cephalopods consumed by nonbreeding birds in our study was similar to that recorded during previous breeding seasons, but included two new species [ Moroteuthis sp. B (Imber) and ? Mastigoteuthis A (Clarke)]. Based on similarities in LRL, δC and δN, the squid consumed may have been from the same oceanic populations or region, with the exception of Taonius sp. B (Voss) and K. longimana, which, based on significant differences in δN values, suggest that they may have originated from different stocks, indicating differences in the albatrosses' feeding regimes. [ABSTRACT FROM AUTHOR]

Studies of avian migration increasingly use stable isotope analysis to provide vital trophic and spatial markers. However, when interpreting differences in stable isotope values of feathers, many studies are forced to make assumptions about the timing of moult. A fundamental question remains about the consistency of these values within and between feathers from the same individual. In this study, we examine variation in carbon and nitrogen isotopes by sub-sampling feathers collected from the wings of adults of two small congeneric petrel species, the broad-billed Pachyptila vittata and Antarctic prion P. desolata. Broad-billed prion feather vane material was enriched in N compared to feather rachis material, but there was no detectable difference in δC. Comparison of multiple samples taken from Antarctic prion feathers indicated subtle difference in isotopes; rachis material was enriched in C compared to vane material, and there were differences along the length of the feather, with samples from the middle and tip of the feather depleted in N compared to those from the base. While the greatest proportion of model variance was explained by differences between feathers and individuals, the magnitude of these within-feather differences was up to 0.5 ‰ in δN and 0.8 ‰ in δC. We discuss the potential drivers of these differences, linking isotopic variation to individual-level dietary differences, movement patterns and temporal dietary shifts. A novel result is that within-feather differences in δC may be attributed to differences in keratin structure within feathers, suggesting further work is required to understand the role of different amino acids. Our results highlight the importance of multiple sampling regimes that consider both within- and between-feather variation in studies using stable isotopes. [ABSTRACT FROM AUTHOR]

The marine ecosystems of the Bering Sea and adjacent southern Chukchi Sea are experiencing rapid changes due to recent reductions in sea ice. Short-tailed shearwaters Puffinus tenuirostris visit this region in huge numbers between the boreal summer and autumn during non-breeding season, and represent one of the dominant top predators. To understand the implications for this species of ongoing environmental change in the Pacific sub-Arctic and Arctic seas, we tracked the migratory movements of 19 and 24 birds in 2010 and 2011, respectively, using light-level geolocators. In both years, tracked birds occupied the western (Okhotsk Sea and Kuril Islands) and eastern (southeast Bering Sea) North Pacific from May to July. In August-September of 2010, but not 2011, a substantial proportion (68 % of the tracked individuals in 2010 compared to 38 % in 2011) moved through the Bering Strait to feed in the Chukchi Sea. Based on the correlation with oceanographic variables, the probability of shearwater occurrence was highest in waters with sea surface temperatures (SSTs) of 8-10 °C over shallow depths. Furthermore, shearwaters spent more time flying when SST was warmer than 9 °C, suggesting increased search effort for prey. We hypothesized that the northward shift in the distribution of shearwaters may have been related to temperature-driven changes in the abundance of their dominant prey, krill (Euphausiacea), as the timing of krill spawning coincides with the seasonal increase in water temperature. Our results indicate a flexible response of foraging birds to ongoing changes in the sub-Arctic and Arctic ecosystems. [ABSTRACT FROM AUTHOR]

Waste wheat straw (WWS) is the waste product from feedstock preparation process in a straw pulp mill. It has a significant annual production rate and no commercial value has been explored on this material. In this study, waste wheat straw was pretreated using an autohydrolysis process followed by mechanical refining, and the pretreated materials were further enzymatically hydrolyzed to evaluate the total sugar recovery for bioethanol production. Results show that autohydrolysis at 170 °C for 40 min followed by 6000 revolution PFI refining provided the best result in this study, where a total sugar recovery (total sugars in autohydrolysis filtrate and enzymatic hydrolyzate over total carbohydrates on raw WWS) of 70 % at 4 filter paper unit per oven dry gram (FPU/OD g) substrate enzyme charge could be obtained. The economic evaluation of this biorefinery process indicates that cellulosic ethanol production from autohydrolysis of WWS is a very profitable business, with 28.4 % of internal rate of return can be achieved based on current ethanol wholesale price in China. [ABSTRACT FROM AUTHOR]