Publications

too much of a good thing: sea ice extent may have forced emperor penguins into refugia during the last glacial maximum.	the relationship between population structure and demographic history is critical to understanding microevolution and for predicting the resilience of species to environmental change. using mitochondrial dna from extant colonies and radiocarbon-dated subfossils, we present the first microevolutionary analysis of emperor penguins (aptenodytes forsteri) and show their population trends throughout the last glacial maximum (lgm, 19.5-16 kya) and during the subsequent period of warming and sea ice re ...	2015	25728986
geochemical record of high emperor penguin populations during the little ice age at amanda bay, antarctica.	emperor penguins (aptenodytes forsteri) are sensitive to the antarctic climate change because they breed on the fast sea ice. studies of paleohistory for the emperor penguin are rare, due to the lack of archives on land. in this study, we obtained an emperor penguin ornithogenic sediment profile (pi) and performed geochronological, geochemical and stable isotope analyses on the sediments and feather remains. two radiocarbon dates of penguin feathers in pi indicate that emperor penguins colonized ...	2016	27261428
contrasting responses to a climate regime change by sympatric, ice-dependent predators.	models that predict changes in the abundance and distribution of fauna under future climate change scenarios often assume that ecological niche and habitat availability are the major determinants of species' responses to climate change. however, individual species may have very different capacities to adapt to environmental change, as determined by intrinsic factors such as their dispersal ability, genetic diversity, generation time and rate of evolution. these intrinsic factors are usually excl ...	2016	26975876
the complete mitochondrial genome sequence of emperor penguins (aptenodytes forsteri).	the emperor penguin (aptenodytes forsteri) is the largest living species of penguin. herein, we first reported the complete mitochondrial genome of emperor penguin. the mitochondrial genome is a circular molecule of 17 301 bp in length, consisting of 13 protein-coding genes, 22 trna genes, two rrna, and one control region. to verify the accuracy and the utility of new determined mitogenome sequences, we constructed the species phylogenetic tree of emperor penguin together with 10 other closely s ...	2016	26403091
diving physiology of seabirds and marine mammals: relevance, challenges and some solutions for field studies.	to fully understand how diving seabirds and marine mammals balance the potentially conflicting demands of holding their breath while living their lives underwater (and maintaining physiological homeostasis during exercise, feeding, growth, and reproduction), physiological studies must be conducted with animals in their natural environments. the purpose of this article is to review the importance of making physiological measurements on diving animals in field settings, while acknowledging the cha ...	2016	27421239
full circumpolar migration ensures evolutionary unity in the emperor penguin.	defining reliable demographic models is essential to understand the threats of ongoing environmental change. yet, in the most remote and threatened areas, models are often based on the survey of a single population, assuming stationarity and independence in population responses. this is the case for the emperor penguin aptenodytes forsteri, a flagship antarctic species that may be at high risk continent-wide before 2100. here, using genome-wide data from the whole antarctic continent, we reveal ...	2016	27296726
the influence of historical climate changes on southern ocean marine predator populations: a comparative analysis.	the southern ocean ecosystem is undergoing rapid physical and biological changes that are likely to have profound implications for higher-order predators. here, we compare the long-term, historical responses of southern ocean predators to climate change. we examine palaeoecological evidence for changes in the abundance and distribution of seabirds and marine mammals, and place these into context with palaeoclimate records in order to identify key environmental drivers associated with population ...	2016	26391440
legacy persistent organic pollutants including pbdes in the trophic web of the ross sea (antarctica).	the ecological features of the ross sea trophic web are peculiar and different from other polar food webs, with respect to the use of habitat and species interactions; due to its ecosystem integrity, it is the world's largest marine protected area, established in 2016. polar organisms are reported to bioaccumulate lipophilic contaminant, viz persistent organic pollutants (pops). legacy pops and flame retardants (polybrominated diphenyl ethers, pbdes) were studied in key species of the ross sea ( ...	2017	28732330
the humboldt penguin (spheniscus humboldti) rete tibiotarsale - a supreme biological heat exchanger.	humans are unable to survive low temperature environments without custom designed clothing and support systems. in contrast, certain penguin species inhabit extremely cold climates without losing substantial energy to self-heating (emperor penguins ambient temperature plummets to as low as -45°c). penguins accomplish this task by relying on distinct anatomical, physiological and behavioral adaptations. one such adaptation is a blood vessel heat exchanger called the 'rete tibiotarsale' - an inter ...	2017	28558939
the challenges of detecting subtle population structure and its importance for the conservation of emperor penguins.	understanding the boundaries of breeding populations is of great importance for conservation efforts and estimates of extinction risk for threatened species. however, determining these boundaries can be difficult when population structure is subtle. emperor penguins are highly reliant on sea ice, and some populations may be in jeopardy as climate change alters sea-ice extent and quality. an understanding of emperor penguin population structure is therefore urgently needed. two previous studies h ...	2017	28488293
muscle energy stores and stroke rates of emperor penguins: implications for muscle metabolism and dive performance.	in diving birds and mammals, bradycardia and peripheral vasoconstriction potentially isolate muscle from the circulation. during complete ischemia, atp production is dependent on the size of the myoglobin oxygen (o(2)) store and the concentrations of phosphocreatine (pcr) and glycogen (gly). therefore, we measured pcr and gly concentrations in the primary underwater locomotory muscle of emperor penguin and modeled the depletion of muscle o(2) and those energy stores under conditions of complete ...	2017	22418705
integrated population modeling reveals the impact of climate on the survival of juvenile emperor penguins.	early-life demographic traits are poorly known, impeding our understanding of population processes and sensitivity to climate change. survival of immature individuals is a critical component of population dynamics and recruitment in particular. however, obtaining reliable estimates of juvenile survival (i.e., from independence to first year) remains challenging, as immatures are often difficult to observe and to monitor individually in the field. this is particularly acute for seabirds, in which ...	2017	27770507
night diving by some emperor penguins during the winter breeding period at cape washington.	all through the bird literature and feature films, there is much ado about dedicated emperor penguin males fasting for 115 days while they do all the incubation of the single egg. sometimes, they may not fast for so long. based on a winter visit to cape washington, we obtained evidence that some birds may feed before the egg is laid, and if they do, and some are males, then their fast is much less than 115 days. the consequence of a shorter fast for the male is a better chance of completing the ...	2018	29317482
emperor penguins break their fast with night-time snacks.		2018	31467434
phase transitions in huddling emperor penguins.	emperor penguins (aptenodytes forsteri) are highly adapted to the harsh conditions of the antarctic winter: they are able to fast for up to 134 days during breeding. to conserve energy, emperor penguins form tight groups (huddles), which is key for their reproductive success. the effect of different meteorological factors on the huddling behaviour, however, is not well understood. using time-lapse image recordings of an emperor penguin colony, we show that huddling can be described as a phase tr ...	2018	30416209
biophysical characterization of aptenodytes forsteri cytochrome p450 aromatase.	cytochrome p450 19 (cyp19, aromatase) catalyzes the conversion of androgens to estrogens in a sequence of three reactions that each depend on nadph and o2. aromatase is a phylogenetically-ancient enzyme and its breadth of expression in other species has highlighted distinct physiological functions. in songbirds, estrogen production is required for programming the neural circuits controlling song and in the determination of sex in fish and reptiles. this work describes the expression, purificatio ...	2018	29684698
crozier's penguin: an object history of maritime and museum science.	in november 1843 john cassidy, curator in the belfast museum received, perhaps rather dolefully, a collection of bird skins. the museum was barely managing to cope with the constant flow of donations from the 'four quarters of the globe'. but the gift of bird skins could not be ignored. sent by captain francis crozier, recently returned from the british antarctic expedition, the bequest contained 150 species of southern ocean birds, including the remains of two immature 'great penguins'. taking ...	2018	29503030
a well-preserved partial scapula from japan and the reconstruction of the triosseal canal of plotopterids.	the discovery of a well-preserved cranial end of a plotopterid scapula from the early oligocene jinnobaru formation in southwestern japan has provided a fine example of its bone structure and has enabled the reconstruction of the triosseal canal (canalis triosseus) of the unique extinct penguin-like bird. it is believed that plotopterids performed penguin-like underwater propulsion using wings that were similar to those of penguins. until this discovery, the lack of well-preserved plotopterid sc ...	2018	30155348
comparative population genomics reveals key barriers to dispersal in southern ocean penguins.	the mechanisms that determine patterns of species dispersal are important factors in the production and maintenance of biodiversity. understanding these mechanisms helps to forecast the responses of species to environmental change. here, we used a comparative framework and genomewide data obtained through rad-seq to compare the patterns of connectivity among breeding colonies for five penguin species with shared ancestry, overlapping distributions and differing ecological niches, allowing an exa ...	2018	30308702
a buoyancy, balance and stability challenge to the hypothesis of a semi-aquatic spinosaurus stromer, 1915 (dinosauria: theropoda).	a recent interpretation of the fossil remains of the enigmatic, large predatory dinosaur spinosaurus aegyptiacus stromer 1915 proposed that it was specially adapted for a semi-aquatic mode of life-a first for any predatory dinosaur. to test some aspects of this suggestion, a three-dimensional, digital model of the animal that incorporates regional density variations, lungs and air sacs was generated, and the flotation potential of the model was investigated using specially written software. it w ...	2018	30128195
population response of an apex antarctic consumer to its prey and climate fluctuations.	a fundamental endeavor in population ecology is to identify the drivers of population dynamics. a few empirical studies included the effect of prey abundance when investigating simultaneously the effects of density-dependence and climate factors on marine top-predator population dynamics. our aim was to unravel the mechanisms forcing population dynamics of an apex consumer seabird, the south polar skua, using long-term climatic and population time series of the consumer and its prey in terre adé ...	2019	30116877
blood transcriptome resources of chinstrap (pygoscelis antarcticus) and gentoo (pygoscelis papua) penguins from the south shetland islands, antarctica.	the chinstrap (pygoscelis antarcticus) and gentoo (p. papua) penguins are distributed throughout antarctica and the sub-antarctic islands. in this study, high-quality de novo assemblies of blood transcriptomes from these penguins were generated using the illumina miseq platform. a total of 22.2 and 21.8 raw reads were obtained from chinstrap and gentoo penguins, respectively. these reads were assembled using the oases assembly platform and resulted in 26,036 and 21,854 contigs with n50 values of ...	2019	30929406
receding ice drove parallel expansions in southern ocean penguins.	climate shifts are key drivers of ecosystem change. despite the critical importance of antarctica and the southern ocean for global climate, the extent of climate-driven ecological change in this region remains controversial. in particular, the biological effects of changing sea ice conditions are poorly understood. we hypothesize that rapid postglacial reductions in sea ice drove biological shifts across multiple widespread southern ocean species. we test for demographic shifts driven by climat ...	2019	31843914
trace elements and persistent organic pollutants in chicks of 13 seabird species from antarctica to the subtropics.	seabirds from remote regions are mainly exposed to environmental contaminants from non-point contamination of their food webs. pre-fledging seabird chicks are fed by their parents with marine prey captured in the vicinity of breeding colonies. contaminant concentrations in tissues of pre-fledging chicks can thus be mostly related to local dietary sources, and have the potential to unravel spatial patterns of environmental contamination in marine ecosystems. here, mercury (hg), 13 other trace ele ...	2020	31711015
latitudinal, sex and inter-specific differences in mercury and other trace metal concentrations in adélie and emperor penguins in the ross sea, antarctica.	we sought to determine mercury (hg) and other trace metal concentrations in adélie (pygoscelis adeliae) and emperor penguin (aptenodytes forsteri) breast feathers from the ross sea, antarctica, and relate those concentrations to the trophic position and the habitats in which each of these species forage. adélie penguin feathers from the southern ross sea colonies were higher in hg than those sampled further north in the ross sea, potentially due to greater exposure to local sources, such as volc ...	2020	32319892
a paradigm of thermal adaptation in penguins and elephants by tuning cold activation in trpm8.	to adapt to habitat temperature, vertebrates have developed sophisticated physiological and ecological mechanisms through evolution. transient receptor potential melastatin 8 (trpm8) serves as the primary sensor for cold. however, how cold activates trpm8 and how this sensor is tuned for thermal adaptation remain largely unknown. here we established a molecular framework of how cold is sensed in trpm8 with a combination of patch-clamp recording, unnatural amino acid imaging, and structural model ...	2020	32220960
chaotic emperor penguin optimised extreme learning machine for microarray cancer classification.	microarray technology plays a significant role in cancer classification, where a large number of genes and samples are simultaneously analysed. for the efficient analysis of the microarray data, there is a great demand for the development of intelligent techniques. in this article, the authors propose a novel hybrid technique employing fisher criterion, relieff, and extreme learning machine (elm) based on the principle of chaotic emperor penguin optimisation algorithm (cepo). epo is a recently d ...	2020	32196467
cameratransform: a python package for perspective corrections and image mapping.	camera images and video recordings are simple and non-invasive tools to investigate animals in their natural habitat. quantitative evaluations, however, often require an exact reconstruction of object positions, sizes, and distances in the image. here, we provide an open source software package to perform such calculations. our approach allows the user to correct for perspective distortion, transform images to "bird's-eye" view projections, or transform image-coordinates to real-world coordinate ...	2020	32864407
why the emperor penguin reigns where elephants shiver.	accurate sensing of the environmental temperature is crucial for the survival and wellbeing of organisms. in vertebrates, the cold- and menthol-activated ion channel trpm8 acts as the prime molecular sensor of cool temperatures. by comparing trpm8 in vertebrates with different habitat temperatures, from elephants to penguins, yang et al. identify key residues within the pore domain that determine the channel's cold sensitivity. strikingly, mice engineered to express penguin trpm8 show a remarkab ...	2020	32836018
the paris agreement objectives will likely halt future declines of emperor penguins.	the paris agreement is a multinational initiative to combat climate change by keeping a global temperature increase in this century to 2°c above preindustrial levels while pursuing efforts to limit the increase to 1.5°c. until recently, ensembles of coupled climate simulations producing temporal dynamics of climate en route to stable global mean temperature at 1.5 and 2°c above preindustrial levels were not available. hence, the few studies that have assessed the ecological impact of the paris a ...	2020	31696584
genetic factors for short life span associated with evolution of the loss of flight ability.	acquisition or loss of flying ability is evolutionarily linked with maximum life span (mls) in mammals and birds. although ecological factors, such as extrinsic mortality, may lead to either shortened or extended life spans through natural selection, mls is influenced by complex molecular and metabolic processes, and the genetic changes associated with flying ability that have led to either a longer or shorter mls are unknown. here, we examine the parallel evolution of flight in mammals and bird ...	2020	32607209
don: deep learning and optimization-based framework for detection of novel coronavirus disease using x-ray images.	in the hospital, a limited number of covid-19 test kits are available due to the spike in cases every day. for this reason, a rapid alternative diagnostic option should be introduced as an automated detection method to prevent covid-19 spreading among individuals. this article proposes multi-objective optimization and a deep-learning methodology for the detection of infected coronavirus patients with x-rays. j48 decision tree method classifies the deep characteristics of affected x-ray corona im ...	2021	33587262