Publications

trophic calculations reveal the mechanism of population-level variation in mercury concentrations between marine ecosystems: case studies of two polar seabirds.	the incorporation of quantitative trophic level analysis in ecotoxicological studies provides explanatory power to identify the factors, trophic or environmental, driving population-level variation in mercury exposure at large geographic scales. in the antarctic marine ecosystem, mercury concentrations and stable isotope values in adélie penguins (pygoscelis adeliae) were compared between the antarctic peninsula and the ross sea. correcting tissue δ(15)n values for baseline δ(15)n values reveale ...	2013	23993395
increase in penguin populations during the little ice age in the ross sea, antarctica.	penguins are an important seabird species in antarctica and are sensitive to climate and environmental changes. previous studies indicated that penguin populations increased when the climate became warmer and decreased when it became colder in the maritime antarctic. here we determined organic markers in a sediment profile collected at cape bird, ross island, high antarctic, and reconstructed the history of adélie penguin colonies at this location over the past 700 years. the region transformed ...	2013	23969993
diatom-specific highly branched isoprenoids as biomarkers in antarctic consumers.	the structure, functioning and dynamics of polar marine ecosystems are strongly influenced by the extent of sea ice. ice algae and pelagic phytoplankton represent the primary sources of nutrition for higher trophic-level organisms in seasonally ice-covered areas, but their relative contributions to polar marine consumers remain largely unexplored. here, we investigated the potential of diatom-specific lipid markers and highly branched isoprenoids (hbis) for estimating the importance of these two ...	2013	23418580
penguin tissue as a proxy for relative krill abundance in east antarctica during the holocene.	antarctic krill (euphausia superba) is a key component of the southern ocean food web. it supports a large number of upper trophic-level predators, and is also a major fishery resource. understanding changes in krill abundance has long been a priority for research and conservation in the southern ocean. in this study, we performed stable isotope analyses on ancient adélie penguin tissues and inferred relative krill abundance during the holocene epoch from paleodiets of adélie penguin (pygoscelis ...	2013	24076768
metabolic alkalosis due to feeding chicks in breeding adélie penguins pygoscelis adeliae under natural conditions.	prolonged abnormal vomiting causes metabolic alkalosis. many seabirds are known to feed their chicks by regurgitation. we hypothesized that metabolic alkalosis occurs in seabirds even under natural conditions during the breeding season. adélie penguins pygoscelis adeliae feed their chicks by regurgitating food for 50-60 d until the chicks fledge. in this study, the concentrations of cl(-), hco(3)(-), na+, k+, ph, and pco2 in the blood of breeding adélie penguins were measured throughout the chic ...	2013	19302032
penguin eggshell membranes reflect homogeneity of mercury in the marine food web surrounding the antarctic peninsula.	remote regions such as the antarctic have become increasingly important for investigations into far-reaching anthropogenic impacts on the environment, most recently in regard to the global mercury cycle. spatial patterns of mercury availability in four regions of the antarctic peninsula were investigated using three species of sympatrically breeding pygoscelis penguins as biomonitors. eggshells with intact membranes from adélie, gentoo, and chinstrap penguins were collected at 24 breeding coloni ...	2012	23069932
spatially integrated assessment reveals widespread changes in penguin populations on the antarctic peninsula.	as important marine mesopredators and sensitive indicators of antarctic ecosystem change, penguins have been a major focus of long-term biological research in the antarctic. however, the vast majority of such studies have been constrained by logistics and relate mostly to the temporal dynamics of individual breeding populations from which regional trends have been inferred, often without regard for the complex spatial heterogeneity of population processes and the underlying environmental conditi ...	2012	22834377
adélie penguins and temperature changes in antarctica: a long-term view.	during the summer months, adélie penguins represent the dominant biomass of terrestrial antarctica. literally millions of individuals nest in ice-free areas around the coast of the continent. hence, these modern populations of adélie penguins have often been championed as an ideal biological indicator of ecological and environmental changes that we currently face. in addition, adélie penguins show an extraordinary record of sub-fossil remains, dating back to the late pleistocene. at this time, t ...	2012	22691195
wanted: dead or alive? isotopic analysis (δ13c and δ15n) of pygoscelis penguin chick tissues supports opportunistic sampling.	physiological stress and starvation have been shown to affect δ(13)c and δ(15)n isotope values and, given that animals often die from starvation, the cause of death may be an important factor to consider in stable isotope analyses of opportunistically collected samples.	2012	22302487
exogenous corticosterone and nest abandonment: a study in a long-lived bird, the adélie penguin.	breeding individuals enter an emergency life-history stage when their body reserves reach a minimum threshold. consequently, they redirect current activity toward survival, leading to egg abandonment in birds. corticosterone (cort) is known to promote this stage. how and to what extent cort triggers egg abandonment when breeding is associated with prolonged fasting, however, requires further investigation. we manipulated free-living male adélie penguins with cort-pellets before their laying peri ...	2011	21763694
adélie penguin survival: age structure, temporal variability and environmental influences.	the driving factors of survival, a key demographic process, have been particularly challenging to study, especially for winter migratory species such as the adélie penguin (pygoscelis adeliae). while winter environmental conditions clearly influence antarctic seabird survival, it has been unclear to which environmental features they are most likely to respond. here, we examine the influence of environmental fluctuations, broad climatic conditions and the success of the breeding season prior to w ...	2011	21691857
environmental influences on adelie penguin breeding schedules, endocrinology, and chick survival.	to understand how the social and physical environment influences behaviour, reproduction and survival, studies of underlying hormonal processes are crucial; in particular, interactions between stress and reproductive responses may have critical influences on breeding schedules. several authors have examined the timing of breeding in relation to environmental stimuli, while others have independently described endocrine profiles. however, few studies have simultaneously measured endocrine profiles ...	2011	21624370
exogenous corticosterone mimics a late fasting stage in captive adelie penguins (pygoscelis adeliae).	fasting is part of penguin's breeding constraints. during prolonged fasting, three metabolic phases occur successively. below a threshold in body reserves, birds enter phase iii (piii), which is characterized by hormonal and metabolic shifts. these changes are concomitant with egg abandonment in the wild and increased locomotor activity in captivity. because corticosterone (cort) enhances foraging activity, we investigated the variations of endogenous cort, and the effects of exogenous cort on t ...	2011	21346242
contrasting time trends of organic contaminants in antarctic pelagic and benthic food webs.	we demonstrate that pelagic antarctic seabirds show significant decreases in concentrations of some persistent organic pollutants. trends in adélie penguins and southern fulmars fit in a general pattern revealed by a broad literature review. downward trends are also visible in pelagic fish, contrasting sharply with steady or increasing concentrations in antarctic benthic organisms. transfer of contaminants between antarctic pelagic and benthic food webs is associated with seasonal sea-ice dynami ...	2011	20880557
concentration of trace elements in feathers of three antarctic penguins: geographical and interspecific differences.	antarctica is often considered as one of the last pristine regions, but it could be affected by pollution at global and local scale. concentrations of al, cr, mn, fe, ni, cu, zn, as, se, cd and pb were determinated by icp-ms in feathers (n = 207 individuals) of gentoo, chinstrap and adélie penguin collected in 8 locations throughout the antarctic peninsula (2006-2007). the highest levels of several elements were found in samples from king george island (8.08, 20.29 and 1.76 µg g(-1) dw for cr, c ...	2011	21764193
chlorinated biphenyls and pesticides in migrating and resident seabirds from east and west antarctica.	the unhatched eggs of the following seabirds were analyzed to quantify pcbs, hexachlorobenzene (hcb), +¦-, +¦-, +¦-, +¦-hexachlorocyclohexanes (hchs), o,p' and p,p' isomers of ddt, ddd and dde: resident ad+¿lie (pygoscelis ad+¿liae, adpe) and emperor (aptenodytes forsteri, empe) penguins, migrating snow petrel (pagodroma nivea, snpt) and south polar skua (catharacta maccormicki, spsk) from the ross sea (east antarctica); and migrating brown skua (catharacta antartica, brsk) and resident adpe fro ...	2011	21704375
comparing plasma and faecal measures of steroid hormones in adelie penguins pygoscelis adeliae.	physiological measurements of both stress and sex hormones are often used to estimate the consequences of natural or human-induced change in ecological studies of various animals. different methods of hormone measurement exist, potentially explaining variation in results across studies; methods should be cross-validated to ensure that they correlate. we directly compared faecal and plasma hormone measurements for the first time in a wild free-living species, the adelie penguin (pygoscelis adelia ...	2010	19609534
an antarctic hot spot for fungi at shackleton's historic hut on cape royds.	the historic expedition huts located in the ross sea region of the antarctic and the thousands of artifacts left behind by the early explorers represent important cultural heritage from the "heroic era" of polar exploration. the hut at cape royds built by ernest shackleton and members of the 1907-1908 british antarctic expedition has survived the extreme antarctic environment for over 100 years, but recent studies have shown many forms of deterioration are causing serious problems, and microbial ...	2010	20386896
survival differences and the effect of environmental instability on breeding dispersal in an adelie penguin meta-population.	high survival and breeding philopatry was previously confirmed for the adélie penguin (pygoscelis adeliae) during a period of stable environmental conditions. however, movements of breeding adults as a result of an unplanned natural experiment within a four-colony meta-population provided interesting insights into this species' population dynamics. we used multistate mark-recapture models to investigate apparent survival and dispersal of breeding birds in the southwestern ross sea during 12 bree ...	2010	20566874
lack of leptin activity in blood samples of adélie penguin and bar-tailed godwit.	unsuccessful attempts to identify the leptin gene in birds are well documented, despite the characterization of its receptor (lepr). since leptin and lepr have poor sequence conservation among vertebrates, we speculated that a functional assay should represent the best way to detect leptin in birds. using a leptin bioassay that is based on activation of the chicken lepr in cultured cells, blood samples from wild birds with extreme seasonal variation in voluntary food intake and fat deposition (a ...	2010	20675300
responding to climate change: adélie penguins confront astronomical and ocean boundaries.	long-distance migration enables many organisms to take advantage of lucrative breeding and feeding opportunities during summer at high latitudes and then to move to lower, more temperate latitudes for the remainder of the year. the latitudinal range of the adélie penguin (pygoscelis adeliae) spans approximately 22 degrees. penguins from northern colonies may not migrate, but due to the high latitude of ross island colonies, these penguins almost certainly undertake the longest migrations for the ...	2010	20715628
working less to gain more: when breeding quality relates to foraging efficiency.	in animal populations, a minority of individuals consistently achieves the highest breeding success and therefore contributes the most recruits to future generations. on average, foraging performance is important in determining breeding success at the population level, but evidence is scarce to show that more successful breeders (better breeders) forage differently than less successful ones (poorer breeders). to test this hypothesis, we used a 10-year, three-colony, individual-based longitudinal ...	2010	20715627
should i stay or should i go? hormonal control of nest abandonment in a long-lived bird, the adélie penguin.	according to life-history theory, long-lived birds should favor their survival over the current reproductive attempt, when breeding becomes too costly. in seabirds, incubation is often associated with spontaneous long-term fasting. below a threshold in body reserves, hormonal and metabolic shift characteristics of a switch from lipid to protein utilization (phase iii, piii) occur. these metabolic changes are paralleled by nest abandonment and stimulation of refeeding behavior. parental behavior ...	2010	20691185
ecophysiological response of adelie penguins facing an experimental increase in breeding constraints.	foraging strategies play a key role in breeding effort. little is known, however, about their connection with hormonal and nutritional states, especially when breeding constraints vary. here, we experimentally increased foraging costs and thus breeding constraints by handicapping adélie penguins (pygoscelis adeliae) with dummy devices representing 3-4% of the penguins' cross-sectional area. we examined food-related stress (via plasma corticosterone concentration) and nutritional state (via metab ...	2010	20008359
foraging in an oxidative environment: relationship between delta13c values and oxidative status in adelie penguins.	the alternation of short/coastal and long/pelagic foraging trips has been proposed as a strategy for seabirds to reconcile self-feeding and parental care. both types of foraging trips may result in different foraging efforts and diet qualities, and consequently are likely to modify the oxidative status of seabirds. we examined the relationship between the oxidative status of adélie penguins and (i) the duration of their foraging trips and (ii) their plasma delta(13)c values reflecting their spat ...	2010	19955151
stable isotopes reveal holocene changes in the diet of adélie penguins in northern victoria land (ross sea, antarctica).	adélie penguin (pygoscelis adeliae) modern and fossil eggshells and guano samples collected from ornithogenic soils in terra nova bay (victoria land, ross sea) were processed for carbon and nitrogen isotopic ratios with the aim of detecting past penguin dietary changes. a detailed and greatly expanded adélie penguin dietary record dated back to 7,200 years bp has been reconstructed for the investigated area. our data indicate a significant dietary shift between fish and krill, with a gradual dec ...	2010	20886238
autonomous gliders reveal features of the water column associated with foraging by adelie penguins.	despite their strong dependence on the pelagic environment, seabirds and other top predators in polar marine ecosystems are generally studied during their reproductive phases in terrestrial environments. as a result, a significant portion of their life history is understudied which in turn has led to limited understanding. recent advances in autonomous underwater vehicle (auv) technologies have allowed satellite-tagged adélie penguins to guide auv surveys of the marine environment at the palmer ...	2010	21558258
isolation and characterization of macaroni penguin (eudyptes chrysolophus) microsatellite loci and their utility in other penguin species (spheniscidae, aves).	we report the characterization of 25 microsatellite loci isolated from the macaroni penguin (eudyptes chrysolophus). thirteen loci were arranged into four multiplex sets for future genetic studies of macaroni penguin populations. all 25 loci were tested separately in each of four other penguin species [adélie penguin (pygoscelis adeliae), chinstrap penguin (pygoscelis antarctica), gentoo penguin (pygoscelis papua) and king penguin (aptenodytes patagonicus)]. between eight and 12 loci were polymo ...	2009	21564950
high mitogenomic evolutionary rates and time dependency.	using entire modern and ancient mitochondrial genomes of adélie penguins (pygoscelis adeliae) that are up to 44000 years old, we show that the rates of evolution of the mitochondrial genome are two to six times greater than those estimated from phylogenetic comparisons. although the rate of evolution at constrained sites, including nonsynonymous positions and rnas, varies more than twofold with time (between shallow and deep nodes), the rate of evolution at synonymous sites remains the same. the ...	2009	19836098
contamination profiles of selected pcb congeners, chlorinated pesticides, pcdd/fs in antarctic fur seal pups and penguin eggs.	the aim of this study was to investigate levels of some major environmental contaminants, such as polychlorinated biphenyls (pcbs), polychlorinated dibenzo-p-dioxins and dibenzofurans (pcdd/fs) and organochlorine pesticides in antarctic samples. concentrations of some persistent organic pollutants (pops) were investigated in antarctic fur seal pups and eggs of three species of penguins. dichloro-diphenyl-trichloroethane (ddt) was the main pollutant, followed by pcbs; other organochlorine compoun ...	2009	19375148
modelling mitochondrial site polymorphisms to infer the number of segregating units and mutation rate.	we present a mathematical model of mitochondrial inheritance evolving under neutral evolution to interpret the heteroplasmies observed at some sites. a comparison of the levels of heteroplasmies transmitted from mother to her offspring allows us to estimate the number n(x) of inherited mitochondrial genomes (segregating units). the model demonstrates the necessity of accounting for both the multiplicity of an unknown number n(x), and the threshold , below which heteroplasmy cannot be detected re ...	2009	19324622
perfluorinated contaminants in fur seal pups and penguin eggs from south shetland, antarctica.	perfluorinated compounds (pfcs) have emerged as a new class of global environmental pollutants. in this study, the presence of perfluorochemicals (pfcs) in penguin eggs and antarctic fur seals was reported for the first time. tissue samples from antarctic fur seal pups and penguin eggs were collected during the 2003/04 breeding season. ten pfc contaminants were determined in seal and penguin samples. the pfc concentrations in seal liver were in the decreasing order, pfos>pfna>pfhpa>pfunda while ...	2009	19321191
effects of individual quality, reproductive success and environmental variability on survival of a long-lived seabird.	1. heterogeneity in individual quality (i.e. individuals having different performance levels that are consistent throughout life) can drive the demography of iteroparous species, but quality in the context of environmental variability has rarely been evaluated. 2. we investigated the demographic responses of a long-lived seabird, the adélie penguin (pygoscelis adeliae), to contrasting environmental conditions as a function of reproductive success, breeding quality (bq) and experience. a continuo ...	2009	19302318
the phylogeography of adelie penguin faecal flora.	the gut of animals changes quickly from a totally sterile environment before birth to a numerous and highly diverse microbial community shortly after birth. however, few studies have examined the source of the bacteria colonizing the gut. we used a genetic based approach to investigate the distribution and acquisition of faecal microbial communities by adelie penguins, pygoscelis adeliae, breeding in the ross sea region of antarctica by cloning a portion of the 16s rrna gene and by automated rib ...	2009	19040454
salmonella infections in antarctic fauna and island populations of wildlife exposed to human activities in coastal areas of australia.	salmonella infections in antarctic wildlife were first reported in 1970 and in a search for evidence linking isolations with exposure to human activities, a comparison was made of serovars reported from marine fauna in the antarctic region from 1982-2004 with those from marine mammals in the northern hemisphere. this revealed that 10 (83%) salmonella enterica serovars isolated from antarctic penguins and seals were classifiable in high-frequency (hf) quotients for serovars prevalent in humans an ...	2009	18789175
bacterial diversity associated with ornithogenic soil of the ross sea region, antarctica.	in the ross sea region of antarctica, ornithogenic soils form on land under adélie penguin rookeries. compared with mineral soils of the ross sea region, ornithogenic soils are generally high in microbial biomass, organic carbon, and total nitrogen and phosphorus, with high electrical conductivity and large variations in ph. the objective of this study was to assess the bacterial composition of ornithogenic soils from cape hallett and cape bird in the ross sea region using culture-independent me ...	2009	19190698
corticosterone responses in birds: individual variation and repeatability in adelie penguins (pygoscelisadeliae) and other species, and the use of power analysis to determine sample sizes.	plasma corticosterone concentrations increase when birds experience a stressor, and in this study we quantified variation in corticosterone responses for the first time in a species of free-living bird. adelie penguins (pygoscelisadeliae) nesting at cape bird on ross island in antarctica were sampled on three occasions. penguins with relatively low or high corticosterone responses on the first occasion had consistently low or high responses, as previously found for great tits and chickens. a mod ...	2009	19351536
nonlinear effects of winter sea ice on the survival probabilities of adélie penguins.	the population dynamics of antarctic seabirds are influenced by variations in winter sea ice extent and persistence; however, the type of relationship differs according to the region and the demographic parameter considered. we used annual presence/absence data obtained from 1,138 individually marked birds to study the influence of environmental and individual characteristics on the survival of adélie penguins pygoscelis adeliae at edmonson point (ross sea, antarctica) between 1994 and 2005. abo ...	2009	19543920
arthrobacter psychrochitiniphilus sp. nov., a psychrotrophic bacterium isolated from antarctica.	a psychrotrophic arthrobacter strain, gp3(t), was isolated from adélie penguin guano from antarctica and characterized. the 16s rrna gene sequence of the novel strain showed the highest similarity (97.8 %) with that of arthrobacter psychrolactophilus b7(t). the novel strain showed a morphological change from rod to coccus. the growth temperature range of strain gp3(t) was 0-25 degrees c, with optimal growth at 20 degrees c. the strain grew over a salinity range of between 0 and 3 % (w/v) nacl an ...	2009	19625417
growing in antarctica, a challenge for white adipose tissue development in adelie penguin chicks (pygoscelis adeliae).	rapid growth is of crucial importance for adélie penguin chicks reared during the short antarctic summer. it partly depends on the rapid ontogenesis of fat stores that are virtually null at hatching but then develop considerably (x40) within a month to constitute both an isolative layer against cold and an energy store to fuel thermogenic and growth processes. the present study was aimed at identifying by rt-pcr the major transcriptional events that chronologically underlie the morphological tra ...	2008	18799630
mutation and evolutionary rates in adélie penguins from the antarctic.	precise estimations of molecular rates are fundamental to our understanding of the processes of evolution. in principle, mutation and evolutionary rates for neutral regions of the same species are expected to be equal. however, a number of recent studies have shown that mutation rates estimated from pedigree material are much faster than evolutionary rates measured over longer time periods. to resolve this apparent contradiction, we have examined the hypervariable region (hvr i) of the mitochond ...	2008	18833304
corticosterone responses to capture and restraint in emperor and adelie penguins in antarctica.	birds respond to capture, handling and restraint with increased secretion of corticosterone, a glucocorticoid hormone that helps birds adjust to stressful situations. hoods are reported to calm birds, but possible effects of hoods on corticosterone responses have not been reported for any bird. corticosterone responses to restraint in adelie penguins held by their legs with their head covered by a hood were markedly lower than responses of penguins restrained in a mesh bag inside a cardboard box ...	2008	18393566
liver and heart mitochondria obtained from adelie penguin (pygoscelis adeliae) offers high resistance to lipid peroxidation.	lipid peroxidation is generally thought to be a major mechanism of cell injury in aerobic organisms subjected to oxidative stress. all cellular membranes are especially vulnerable to oxidation due to their high concentration of polyunsaturated fatty acids. however, birds have special adaptations for preventing membrane damage caused by reactive oxygen species. this study examines fatty acid profiles and susceptibility to lipid peroxidation in liver and heart mitochondria obtained from adelie pen ...	2008	18637558
sea ice cover and its influence on adélie penguin reproductive performance.	the relationship between adélie penguins (pygoscelis adeliae) and ice is well established, with sea ice influencing penguin populations through a variety of processes operating at different spatial and temporal scales. to further explain the relationship between sea ice and adélie penguin reproductive performance, we investigated the relative importance of various measures of sea ice cover on breeding success at béchervaise island, east antarctica. our results show a clear distinction in the res ...	2008	18724720
melting glaciers: a probable source of ddt to the antarctic marine ecosystem.	persistent organic pollutants reach polar regions by long-range atmospheric transport and biomagnify through the food web accumulating in higher trophic level predators. we analyzed adélie penguin (pygoscelis adeliae) samples collected from 2004 to 2006 to evaluate current levels of sigmaddt (p,p'-ddt + p,p'-dde) in these birds, which are confined to antarctica. ratios of p,p'-ddt to p,p'-dde in adélie penguins have declined significantly since 1964 indicating current exposure to old rather than ...	2008	18589951
occurrence and diversity of the tetracycline resistance gene tet(m) in enteric bacteria of antarctic adelie penguins.		2008	18487230
bayesian inference of errors in ancient dna caused by postmortem degradation.	methods for extracting and amplifying sequences using ancient dna (adna) can be prone to errors caused by postmortem modifications of the dna strand. a new statistical method is developed for predicting errors in adna sequences caused by such processes. in addition to the canonical dna substitution model parameters, a discrete markov chain is used to describe nucleotide substitutions occurring via postmortem degradation of the adna sequences. a computer program, bypassr-degr, was developed imple ...	2008	18420593
corticosterone and foraging behavior in a diving seabird: the adélie penguin, pygoscelis adeliae.	because hormones mediate physiological or behavioral responses to intrinsic or extrinsic stimuli, they can help us understand how animals adapt their foraging decisions to energetic demands of reproduction. thus, the hormone corticosterone deserves specific attention because of its influence on metabolism, food intake and locomotor activities. we examined the relationships between baseline corticosterone levels and foraging behavior or mass gain at sea in a diving seabird, the adélie penguin, py ...	2008	18221738
mutational bias in penguin microsatellite dna.	analysis of nucleotide sequence variation at a microsatellite dna locus revealed extensive size homoplasy of alleles in adélie penguins (pygoscelis adeliae). variation in the flanking regions at this locus allowed discrimination between mechanisms proposed for length changes in microsatellite dna alleles. we further examined the structure of alleles for the same microsatellite dna locus across 11 additional species of penguin (spheniscidae) by mapping allele sequences onto an independent penguin ...	2008	15994417
crevasse fall in the antarctic: a patient's perspective.	as a veterinarian working on an adélie penguin research program, i was to spend six months on an island off the coast of mawson station in the australian antarctic territory. during a field training exercise on my third day at mawson, i fell into a crevasse with my four-wheel-drive quad bike and was crushed between the bike and the crevasse wall six metres below the rim. i had hypothermia and abdominal injuries, and underwent two emergency surgical procedures at mawson station. sixteen days afte ...	2007	11379493
penguin colonies as secondary sources of contamination with persistent organic pollutants.	although long-range atmospheric transport has been described as the predominant mechanism for exposing polar regions to persistent organic pollutants (pops), recent studies have suggested that bird activity can also contribute substantially to contaminant levels in some environments. however, because the species so far reported have all been migratory, it has not been demonstrated conclusively whether locally elevated contamination represents transport from lower latitudes by the migrating birds ...	2007	17671662
divergent responses of pygoscelis penguins reveal a common environmental driver.	the responses of predators to environmental variability in the antarctic peninsula region have exhibited divergent patterns owing to variation in the geographic settings of colonies and predator life-history strategies. five breeding colonies of pygoscelis penguins from king george island and livingston island, south shetland islands, antarctica, were examined to (1) compare the responses of sympatric congeners to recent changes in their antarctic ecosystem and (2) assess underlying causes for s ...	2007	17566778
marine pelagic ecosystems: the west antarctic peninsula.	the marine ecosystem of the west antarctic peninsula (wap) extends from the bellingshausen sea to the northern tip of the peninsula and from the mostly glaciated coast across the continental shelf to the shelf break in the west. the glacially sculpted coastline along the peninsula is highly convoluted and characterized by deep embayments that are often interconnected by channels that facilitate transport of heat and nutrients into the shelf domain. the ecosystem is divided into three subregions, ...	2007	17405208
abrupt recent shift in delta 13c and delta 15n values in adélie penguin eggshell in antarctica.	stable isotope values of carbon (delta13c) and nitrogen (delta15n) in blood, feathers, eggshell, and bone have been used in seabird studies since the 1980s, providing a valuable source of information on diet, foraging patterns, and migratory behavior in these birds. these techniques can also be applied to fossil material when preservation of bone and other tissues is sufficient. excavations of abandoned adélie penguin (pygoscelis adeliae) colonies in antarctica often provide well preserved remai ...	2007	17620620
polybrominated diphenyl ethers, polychlorinated dibenzo-dioxins, -furans, and -biphenyls in three species of antarctic penguins.	fish-eating seabirds are recognized to be at risk of accumulating toxic contaminants due to their high position in the trophic web and to their low ability to metabolize xenobiotic compounds. penguins are widely distributed in antarctica and represent an important fraction of the antarctic biomass. they feed mainly on krill and, depending on krill availability, also on fish. it has been reported that predators may be a sink for volatile and toxic chemicals and this may pose a serious environment ...	2007	17993226
genetic diversity in populations of gentoo penguins (pygoscelis papua).	rapd analysis was used to examine the extent of genetic polymorphism in two populations of gentoo penguin (pygoscelis papua) from antarctic islands (petermann and livingston). the chosen two of three 10 mer oligonucleotide primers accordingly to preliminary results showed different levels of polymorphism in gentoo penguins at petermann island (from 23.53 to 42.86%) and livingston island (from 52.94 to 57.14%). nei's similarity coefficients were in range from 0.5606 (when gentoo genome profiles w ...	2006	16865990
outbreaks of avian cholera in hope bay, antarctica.	during austral summers 1999-2000 and 2000-01, two outbreaks of avian cholera occurred in the hope bay area (63 degrees 24's, 56 degrees 59'w), located on the tip of the antarctic peninsula. eighty-six dead birds were found: five kelp gulls (larus dominicanus), 36 skuas (stercorarius sp.), and 45 adelie penguins (pygoscelis adeliae). the carcasses were studied using clinical, pathological, and microbiological criteria. water samples from ponds where birds were settled and samples from 90 healthy ...	2006	16870848
corticosterone in relation to body mass in adelie penguins (pygoscelis adeliae) affected by unusual sea ice conditions at ross island, antarctica.	penguins naturally fast each year during breeding and again whilst moulting, and may lose more than 40% of body mass during a fast. fasting in emperor (aptenodytes forsteri) and king (aptenodytes patagonicus) penguins has been divided into three phases, with phase iii characterised by an increased rate of body mass loss, increased plasma corticosterone concentrations, and a change in behaviour leading to abandonment of the breeding attempt and return to sea to feed. initial corticosterone concen ...	2006	16876799
competition among penguins and cetaceans reveals trophic cascades in the western ross sea, antarctica.	an apparent trophic cascade that appears during summer in the western ross sea, antarctica, explains why the antarctic silverfish (pleuragramma antarcticum) there becomes cannibalistic; its principal prey, crystal krill (euphausia crystallorophias) becomes scarce; and the diatom community is minimally grazed compared to adjacent areas. the krill is the major grazer of diatoms. on the basis of fieldwork at ross island, we suggest that the cascade results from foraging by unusually numerous adélie ...	2006	16937647
characterization of cyp1a enzyme in adélie penguin liver.	as cyp1a enzymes are induced by certain contaminants, their induction pattern has been used as a biomarker for exposure of certain pollutants. ethoxyresorufin o-deethylase (erod) activities are widely used in environmental assessments of polychlorinated biphenyls in many wildlife species. the erod activity, a typical probe for cyp1a enzyme was studied in liver microsomes prepared from adélie penguins (pygoscelis adeliae) (n=10). penguin liver microsomes (0.5 mg/ml) were incubated with the substr ...	2006	16949883
occurrence of organochlorine pesticides (ocps) and their enantiomeric signatures, and concentrations of polybrominated diphenyl ethers (pbdes) in the adélie penguin food web, antarctica.	concentrations and enantiomeric signatures of organochlorine pesticides were determined in antarctic krill, emerald rockcod and adélie penguin from the ross sea, antarctica. hcb and ddts were prevalent contaminants in penguin eggs. the highest concentrations of sigmahchs (1.35 +/- 0.72 ng/g) were found in the rockcod muscle, where gamma-hch (1.23 +/- 0.67 ng/g) was the principal isomer. the ratio gamma-hch/alpha-hch was evaluated. enantioselective gas chromatography was used for the evaluation o ...	2006	16183185
energetics, growth, and body composition of adélie penguin chicks, pygoscelis adeliae.	adélie penguins are very abundant in antarctica and constitute a large biomass of predatory consumers in the antarctic ecosystem. adélies eat almost exclusively krill (euphausia spp.), and to determine krill requirements by adélies, information on energetics is needed, including energy intake of the chicks. i measured energy use and growth in adélie penguin chicks, using both field and laboratory techniques. field metabolic rate was quite variable, but mass-specific rates were not correlated wit ...	2006	9231397
microevolution and mega-icebergs in the antarctic.	microevolution is regarded as changes in the frequencies of genes in populations over time. ancient dna technology now provides an opportunity to demonstrate evolution over a geological time frame and to possibly identify the causal factors in any such evolutionary event. using nine nuclear microsatellite dna loci, we genotyped an ancient population of adélie penguins (pygoscelis adeliae) aged approximately 6,000 years b.p. subfossil bones from this population were excavated by using an accurate ...	2005	16275908
ancient dna enables timing of the pleistocene origin and holocene expansion of two adélie penguin lineages in antarctica.	the timing of divergent events in history is one of the central goals of contemporary evolutionary biology. such studies are however dependent on accurate evolutionary rates. recent developments in ancient dna analysis enable the estimation of more accurate evolutionary rates and therefore more accurate timing of divergence events. consequently, this leads to a better understanding of changes in populations through time. we use an evolutionary rate calculated from ancient dna of adélie penguins ...	2004	14595092
ontogeny of hepatic microsomal 3-hydroxylation of quinine in adélie penguins.	ontogeny of hepatic cytochrome p450 (cyp) content and of quinine 3-hydroxylation, a biomarker of human cyp3a activity, was investigated in adélie penguins (pygoscelis adeliae) by comparing liver microsomes from chicks aged 13-28 days (n=10) with those from adults. the total cyp content in chick microsomes was significantly lower than in adults and correlated with the age of the chicks (r=0.894, p<0.001). kinetic parameters (mean+/-s.d.) for quinine 3-hydroxylation in chick microsomes were lower ...	2004	15313446
bacterial diversity in adélie penguin, pygoscelis adeliae, guano: molecular and morpho-physiological approaches.	the total number of bacteria and culturable bacteria in adélie penguin (pygoscelis adeliae) guano was determined during 42 days of decomposition in a location adjacent to the rookery in admiralty bay, king george island, antarctica. of the culturable bacteria, 72 randomly selected colonies were described using 49 morpho-physiological tests, 27 of which were subsequently considered significant in characterizing and differentiating the isolates. on the basis of the nucleotide sequence of a fragmen ...	2004	19712357
foraging by deep-diving birds is not constrained by an aerobic diving limit: a model of avian depth-dependent diving metabolic rate.	the theoretical aerobic diving limit (tadl) specifies the duration of a dive after which oxygen reserves available for diving are depleted. the tadl has been calculated by dividing the available oxygen stores by the diving metabolic rate (dmr). contrary to diving mammals, most diving birds examined to date exceed the tadl by a large margin. this discrepancy between observation and theory has engendered two alternative explanations suggesting that dive duration is extended either anaerobically or ...	2004	15026973
fluoride content in bones of adelie penguins and environmental media in antarctica.	fluoride (f) distribution and its effects (fluorosis) were investigated in antarctica. droppings (l) excreta selected of aquatic birds, lake water, soil and moss (polytrichum alpinum) showed a high f concentration. although bones of adelie penguin (pygiscelis adeliae) and skua (catharacta maccormicki) showed exceptionally very high f concentration in the range of 832 to 7187 mg kg(-1), their radiographs did not show any evidence of skeletal fluorosis. the possible reason and geochemical aspects ...	2003	14740990
adélie penguins and environmental change.		2003	12702857
development of a highly sensitive screen for influenza a in guano and its application in the search for ancient rna preserved under antarctic adelie penguin colonies.	we have developed a reverse transcriptase polymerase chain reaction (rt-pcr)-based assay to detect influenza a in guano samples as part of our program to investigate ancient viral rna from under antarctic adelie penguin (pygoscelis adeliae) colonies. of five extraction protocols tested (rneasy, gtc trizol, gtc silica, rnaid, and agpc), agpc proved to be the most consistent and sensitive to low concentrations of influenza, but further purification with commercial viral nucleic acid spin filter sy ...	2003	14575142
rates of evolution in ancient dna from adélie penguins.	well-preserved subfossil bones of adélie penguins, pygoscelis adeliae, underlie existing and abandoned nesting colonies in antarctica. these bones, dating back to more than 7000 years before the present, harbor some of the best-preserved ancient dna yet discovered. from 96 radiocarbon-aged bones, we report large numbers of mitochondrial haplotypes, some of which appear to be extinct, given the 380 living birds sampled. we demonstrate dna sequence evolution through time and estimate the rate of e ...	2002	11910113
assumption and elimination of trace elements in adélie penguins from antarctica: a preliminary study.	the concentration and distribution of some trace elements were determined in stomach contents, excreta and feathers of adélie penguins (pygoscelis adeliae) breeding at edmonson point (terra nova bay-antarctica). in these materials obtained by non-destructive methods, concentrations of mercury, cadmium and lead measured were used to establish natural levels of these metals in the penguins' diet. an intake-excretion hypothesis was formulated.	2002	12408585
buoyancy and maximal diving depth in penguins: do they control inhaling air volume?	using a newly developed data logger to measure acceleration, we demonstrate that free-ranging king and adélie penguins only beat their flippers substantially during the first part of descent or when they were presumed to be chasing prey at the bottom of dives. flipper beating stopped during the latter part of ascent: at 29+/-9 % (mean +/- s.d.) of dive depth (mean dive depth=136.8+/-145.1 m, n=425 dives) in king penguins, and at 52+/-20 % of dive depth (mean dive depth=72.9+/-70.5 m, n=664 dives ...	2002	11948196
a dna-based method for identification of krill species and its application to analysing the diet of marine vertebrate predators.	accurate identification of species that are consumed by vertebrate predators is necessary for understanding marine food webs. morphological methods for identifying prey components after consumption often fail to make accurate identifications of invertebrates because prey morphology becomes damaged during capture, ingestion and digestion. another disadvantage of morphological methods for prey identification is that they often involve sampling procedures that are disruptive for the predator, such ...	2002	12453250
polychloronaphthalenes and other dioxin-like compounds in arctic and antarctic marine food webs.	here we report accumulation patterns of polychlorinated naphthalenes (pcns), polychlorinated dibenzo-p-dioxins (pcdds), polychlorinated dibenzofurans (pcdfs), polychlorinated biphenyls (pcbs), and pesticides (hcb, p,p'dde) in polar organisms (polar bear from alaskan arctic and krill, sharp-spined notothen, crocodile icefish, antarctic silverfish, adélie penguin, south polar skua, and weddell seal from the ross sea, antarctica). pcns, found in most of the samples, ranged from 1.5 pg/g in krill to ...	2002	12214639
polychlorinated dibenzo-p-dioxins, dibenzofurans and polychlorinated biphenyls in polar bear, penguin and south polar skua.	concentrations of 2378-substituted polychlorinated dibenzo-p-dioxins (pcdds), dibenzofurans (dfs) and non- and mono-ortho-substituted polychlorinated biphenyls (dioxin-like pcbs) were measured in livers of polar bears from the alaskan arctic and in eggs of adelie penguin and south polar skua and weddell seal liver, fish and krill from antarctica. this is one of the first reports to document the concentrations of pcdds/dfs in polar bear livers from alaska, and in penguin and skua eggs from antarc ...	2002	12152823
physiological condition and reproductive consequences in adelie penguins.	animals must make "decisions" (e.g., when or whether to breed, the effort to put into a breeding episode) by integrating physiological, environmental and social inputs. this integration can be studied only in a field context. in adélie penguins (pygoscelis adeliae) reproduction is constrained by foraging ecology, mode of transport, and the extreme latitude at which they live. the decision whether to breed in a given year is influenced by body conditions. adélie penguins must fast for several wee ...	2002	21708696
gene flow on the ice: genetic differentiation among adélie penguin colonies around antarctica.	each summer adélie penguins breed in large disjunct colonies on ice-free areas around the antarctic continent. comprising > 10 million birds, this species represents a dominant feature of the antarctic ecosystem. the patchy distribution within a large geographical range, natal philopatry and a probable history of refugia, suggest that this species is likely to exhibit significant genetic differentiation within and among colonies. we present data from seven microsatellite dna loci for 442 individ ...	2001	11472533
a new technique for monitoring the behaviour of free-ranging adélie penguins.	measurement of the time allocation of penguins at sea has been a major goal of researchers in recent years. until now, however, no equipment has been available that would allow measurement of the aquatic and terrestrial behaviour of an antarctic penguin while it is commuting between the colony and the foraging grounds. a new motion detector, based on the measurement of acceleration, has been used here in addition to current methods of inferring behaviour using data loggers that monitor depth and ...	2001	11171350
cholangiocarcinoma with metastasis in a captive adelie penguin (pygoscelis adeliae).	a captive male adelie penguin (pygoscelis adeliae), wild caught in 1976, died unexpectedly. necropsy revealed cholangiocarcinoma with metastases to lung, pancreas, mesentery, and cloaca, the first known case of a penguin hepatic tumor.	2001	12785690
injuries to avian researchers at palmer station, antarctica from penguins, giant petrels, and skuas.	this paper describes 5 cases of injury to seabird researchers between 1996 and 1999 at palmer station, antarctica. the injuries were inflicted by 3 seabird species: the adelie penguin (pygoscelis adeliae); the southern giant petrel (macronectes giganteus); and the brown skua (catharacta lonnbergi). all injured parties were biologic researchers with previous field experience working under national science foundation research grants; all sought medical evaluation and treatment voluntarily. the nat ...	2000	10921359
prolactin and parental behavior in adélie penguins: effects of absence from nest, incubation length, and nest failure.	adélie penguin (pygoscelis adeliae) males and females, nesting in antarctica, alternate attendance at the nest with absences of many days to forage at sea. we investigated the importance of tactile input from egg and chicks on prolactin levels by observing nest attendance patterns and obtaining blood samples (1) during the first nest exchange of the incubation stage, (2) from birds whose incubation period was artificially increased or decreased by about 10 days, and (3) from birds whose nests ha ...	2000	11038289
strategic allocation of ejaculates by male adélie penguins.	sperm competition theory suggests that males should strategically allocate sperm to those females that will bring them the best possible genetic returns. although males of a number of species of insects and fishes have been shown to allocate sperm strategically, we provide, to our knowledge, the first evidence that an avian species is also capable of allocating ejaculates. male adélie penguins (pygoscelis adeliae) are more likely to transfer sperm during extra-pair copulations (epcs) than during ...	2000	11007330
a repeat complex in the mitochondrial control region of adélie penguins from antarctica.	we have determined the nucleotide sequence of the entire mitochondrial control region (cr) of the adélie penguin (pygoscelis adeliae) from antarctica. like in most other birds, this cr region is flanked by the gene nad6 and transfer (t)rna trne(uuc) at the 5' end and the gene rns and trnf(gaa) at the 3' end. sequence analysis shows that the adelie penguin cr contains many elements in common with other crs including the termination associated sequences (tas), conserved f, e, d, and c boxes, the c ...	2000	10984172
precise monitoring of porpoising behaviour of adélie penguins determined using acceleration data loggers.	a new method using acceleration data loggers enabled us to measure the porpoising behaviour of adélie penguins (pygoscelis adeliae), defined as a continuous rapid swimming with rhythmic serial leaps. previous hydrodynamic models suggested that leaping would be energetically cheaper when an animal swims continuously at depths of less than three maximum body diameters below the water surface. in the present study, free-ranging adélie penguins leapt at a mean speed of 2.8 m s(-)(1) above the predic ...	1999	10539960
sex steroid and corticosterone levels of adélie penguins (pygoscelis adeliae) during courtship and incubation.	plasma levels of sex steroids (progesterone, 17alpha-hydroxyprogesterone, total androgens, and estradiol) were measured at six stages from courtship to late incubation in adélie penguins. the pattern of change detected in the levels of plasma total androgens (males) and estradiol (females) was consistent with that found in many birds, with elevated levels during courtship (total androgens, 4 ng/ml; estradiol, 0.5 ng/ml) declining to low, stable levels during incubation. progesterone levels decli ...	1999	10094854
in vitro hepatic metabolism of a cyp3a-mediated drug, quinine, in adélie penguins.	very little is known about antarctic animals' ability to metabolise or detoxify xenobiotics. the activity of cytochromes p450 subfamily 3a (cyp3a) in adélie penguin liver was studied by incubating penguin liver microsomes with a human cyp3a substrate, quinine, and results were compared with those from human liver microsomes. the mean maximum rate of metabolism (vmax) for quinine in penguin livers was approximately five times less (160+/-72 versus 574+/-416 pmol/mg/min; p<0.01), and the mean km ( ...	1999	10661723
chlorinated hydrocarbons in the tissues of south polar skuas (catharacta maccormicki) and adélie penguins (pygoscelis adeliea) from ross sea, antarctica.	high rates of egg infertility and embryo death in a colony of south polar skuas breeding in the antarctic were similar to those in polluted north atlantic populations of the great skua. such loss could not be linked to factors such as organochlorine pollutants, as levels of dde and pcbs in the contents of skua eggs from the population were only a small fraction of those in polluted skua populations from the northern hemisphere. average eggshell thickness for skuas nesting on ross island has show ...	1997	15093368
feeding chases and food allocation in adelie penguins, pygoscelis adeliae	among penguins, well-developed feeding chases where chicks run after adults and beg for food are found only in the genera pygoscelisaptenodytesfeeding chases involving adult adelie penguins, with two chicks, compared to feeding chases involving those with one chick, were longer, occurred further from the breeding group and included more runs between each feed. feeding chases were more likely when chicks were close together, and which chick was fed was more likely to switch after a feeding chase. ...	1997	9398361
some observations on adelie penguin (pygoscelis adeliae) mortality in east antarctica.	the postmortem findings of an adult male adelie penguin found at magnetic island, east antarctica, demonstrating a premortem wound in addition to those consistent with an attack and scavenging by south polar skuas, are described. other causes of mortality are discussed.	1996	18645851
novel psychrobacter species from antarctic ornithogenic soils.	ornithogenic soil is derived from the deposition of the fecal matter of various species of birds and is a major source of nutrient input in the antarctic marine ecosystem. a significant proportion of microbiota of ornithogenic soil collected from an adélie penguin colony in eastern antarctica (vestfold hills ice-free zone) consisted of gram-negative, coccoid bacteria identified on the basis of their phospholipid ester-linked fatty acid and lipid class profiles as psychrobacter strains. phenotypi ...	1996	8863407
aspergillus spp. seropositivity in new zealand penguins.	one hundred-fifty yellow-eyed penguins (megadyptes antipodes) of 8 populations, 20 little blue penguins (eudyptula minor) of 2 populations, 9 rockhopper penguins (eudyptes chrysocome), and 5 adelie penguins (pygoscelis adeliae) from new zealand (nz) and antarctica (latitude range; 39 degrees 30' s - 77 degrees 13' s) were tested by indirect enzyme-linked immunosorbent assays (elisa) for fungal aspergillus spp. igg. one hundred-ten of 184 (60%) penguins were seropositive, and seroprevalence was r ...	1995	8587585
underwater swimming at low energetic cost by pygoscelid penguins	energetic requirements of under-water swimming in pygoscelid penguins were studied in antarctica, using respirometry together with a 21 m long swim canal and externally attached devices recording the swimming speed and dive duration of unrestrained animals. field measurements were compared with measurements of the hydrodynamic properties of an adelie penguin model in a circulating water tank. minimium transport costs during underwater swimming in adelie (pygoscelis adeliae), chinstrap (p. antarc ...	1994	9317354
mercury and major essential elements in seals, penguins, and other representative fauna of the antarctic.	concentrations of total hg and major essential elements, ca, mg, na, and k, were measured in the muscle, liver, and kidney of three species of seals, crabeater seal (lobodon carcinophagus), leopard seal (hydrurga leptonyx), and weddell seal (leptonychotes weddelli) collected in the antarctic. the muscle and liver of three species of penguins, i.e., gentoo penguin (pygoscelis papua), adelie penguin (p. adeliae), chinstrap penguin (p. antarctica), and other representative fauna were also analyzed ...	1993	8239712
evidence of ortho- and paramyxoviruses in fauna from antarctica.	serum antibodies to influenza a viruses and paramyxoviruses were detected in adelie penguin (pysoscelis adeliae) and antarctic skua (stercorarius skua maccormicki) sera in the ross sea dependency. an avian paramyxovirus was isolated from a penguin cloacal swab.	1993	8258855
[paracoccidioides brasiliensis, a new sample isolated from feces of a penguin (pygoscelis adeliae)].	the authors show the results obtained through the study of a paracoccidioides strain isolated from a penguin in the uruguaian antartide by gezuele et al. (1989). from the fecal mater it was isolated a fungus which was recently considered as a new species of the genus paracoccidioides--p. antarcticus. however, the mycological and immunochemical studies including the demonstration of the 43 kda glycoprotein by immunodiffusion test, sds-page and immunoelectrophoresis disclosed that such strain is s ...	1993	8278752
plasma melatonin in the adelie penguin (pygoscelis adeliae) under conditions daylight in antarctica.	circadian rhythms of melatonin secretion in birds are influenced by daylength and light intensity. daily patterns of melatonin secretion were examined in adelie penguins (pygoscelis adeliae) under natural continuous daylight at cape bird, antarctica (77 degrees s). although daylight is continuous during the antarctic summer there was a marked daily cycle of light intensity. however, there was no relationship between mean plasma melatonin levels and time of day in groups of 2-10 penguins sampled ...	1991	2056428
circadian rhythms of plasma melatonin in the adelie penguin (pygoscelis adeliae) in constant dim light and artificial photoperiods.	the response of plasma melatonin in adelie penguins (pygoscelis adeliae) to constant dim light and to light/dark cycles was measured to determine the capacity of the pineal gland to secrete melatonin after exposure to continuous daylight for 2 months. penguins were moved in mid-summer from the natural photoperiod to either constant dim light (n = 10), to a 12l:12d light/dark cycle (n = 5), or to a 12l:12d light/dark cycle with a 30 min light pulse (50-155 lux) on the third (n = 4) or sixth (n = ...	1991	1757886
the cost of a hot meal: facultative specific dynamic action may ensure temperature homeostasis in post-ingestive endotherms.	1. resting metabolic rate was determined in adelie penguins (pygoscelis adeliae) that had been fed warm and cold ingesta. 2. post-ingestion metabolic rate was found to be related to food temperature rather than to specific dynamic action. 3. calorimetric calculations indicate that up to 13% of adelie penguin daily energy expenditure may be used heating ingested food to body temperature. 4. heating food costs are predicted to be higher in endotherms living in cold regions and in species with low ...	1991	1682090
the ontogeny of oxygen consumption and ventilation in the adélie penguin, pygoscelis adeliae.	although both energy metabolism and ventilation parameters are highly size dependent in adult birds, the usual scaling relationships with mass do not hold in hatchlings or in growing chicks. in adélie penguins, three distinct behavioral phases during growth and development are reflected in the ontogeny of metabolism and ventilation. metabolic intensity increases in the nestling phase (age 0-11 days), stabilizes during the creche phase (14-40 days), and decreases in fledglings (40-55 days) and ad ...	1990	2080324