Development and analytical characteristics of a quantitative real-time PCR assay for detection of spheniscid alphaherpesvirus 1 in penguins

Herpesviruses are associated with disease in many penguin species. Herpesvirus-associated lesions can cause significant morbidity and mortality in penguins and have been identified in African penguins (Spheniscus demersus), Humboldt penguins (Spheniscus humboldti), and a little blue penguin (Eudyptula minor) infected with spheniscid alphaherpesvirus 1 (SpAHV1). Further investigation is necessary to understand the impact of herpesviruses on penguin health, but there are no rapid, sensitive, and specific methods for detecting and quantifying herpesviral load. We therefore developed a quantitative real-time PCR (qPCR) assay for the detection of SpAHV1 in penguins. TaqMan primer-probes targeting the DNA polymerase gene were designed using a commercial software program. Inter- and intra-assay variability, dynamic range, limit of detection, and analytical specificity were assessed. We used our assay to analyze previously collected field samples from Punta San Juan, Peru, in which conventional consensus PCR had detected one SpAHV1-positive penguin sample. Our qPCR assay was highly specific for SpAHV1. It had a dynamic range of 107-101 target copies per reaction and performed with high efficiency and low intra- and inter-assay variability. Reaction efficiency was not impacted by penguin DNA from SpAHV1-negative tracheal swabs. We detected an additional field sample as positive with our newly developed qPCR assay, and although this likely represents detection of another infected penguin, the true disease status of this population is currently uncharacterized given that no gold-standard test exists for SpAHV1. Our qPCR assay may provide a valuable tool in the surveillance and characterization of SpAHV1 in penguins.

Optic nerve meningioma and cloacal adenocarcinoma in a Humboldt penguin

A 26-y-old, male, captive Humboldt penguin (Spheniscus humboldti) was euthanized following a 3.5-mo history of weakened elimination mechanics, recurrent tenesmus, intermittent hemorrhagic droppings, and a cloacal mass. Blepharospasm, of unknown cause, of the right eye was present for ~3 mo before euthanasia. Autopsy revealed a cloacal adenocarcinoma with localized coelomic carcinomatosis and distant metastases to the liver and lungs. On histopathology, a 2.6 × 1.2 × 0.5-mm, well-demarcated mass was found surrounding the right optic nerve, expanding the subdural space and wrapping the leptomeninges. The mass was composed of neoplastic spindle-to-polygonal cells consistent with a meningioma, meningothelial subtype. No evidence of neoplasia was found in the optic chiasm or brain, indicating a primary retrobulbar meningioma. Immunohistochemistry for cytokeratin AE1/AE3, vimentin, and S100 revealed robust and consistent immunoreactivity to vimentin, and weak and variable immunoreactivity to cytokeratin and S100, supporting the diagnosis. Meningiomas have been described only rarely in avian species, and we found no reports of optic nerve meningiomas in any avian species to date. The optic nerve meningioma in this case was considered a clinically incidental finding.

Microplastics in Seabird Feces from Coastal Areas of Central Chile

Pollution from plastic waste thrown into the ocean affects all levels of the food chain. Marine species of birds are affected by plastic particles of different sizes, especially the mesoplastics (1 to 10 mm) found in their digestive tract, which mainly cause obstructions. In the case of microplastics (1.000 µm to 1 mm), their presence in the digestive tract of these species has been widely reported. We studied fecal samples of the Dominican gull (Larus dominicanus) (n = 14), Magellanic penguins (Spheniscus magellanicus) (n = 8), and Humboldt penguin (Spheniscus humboldti) (n = 1) obtained from the Wildlife Rehabilitation Center of the Biobío region, Chile. Microfibers of various colors were present in the feces of Dominican gulls and Magellanic penguins, corresponding mainly in composition to polypropylene (PP) (83%) and rayon (77%). These results demonstrate that microplastic particles occur in the coastal environments of central Chile and suggest that they are probably circulating in the food chain.

Antarctic Penguin Biogeography Project: Database of abundance and distribution for the Adélie, chinstrap, gentoo, emperor, macaroni and king penguin south of 60 S

Background

The Antarctic Penguin Biogeography Project is an effort to collate all known information about the distribution and abundance of Antarctic penguins through time and to make such data available to the scientific and management community. The core data product involves a series of structured tables with information on known breeding sites and surveys conducted at those sites from the earliest days of Antarctic exploration through to the present. This database, which is continuously updated as new information becomes available, provides a unified and comprehensive repository of information on Antarctic penguin biogeography that contributes to a growing suite of applications of value to the Antarctic community. One such application is the Mapping Application for Antarctic Penguins and Projected Dynamics (MAPPPD; www.penguinmap.com), a browser-based search and visualisation tool designed primarily for policy-makers and other non-specialists, and mapppdr, an R package developed to assist the Antarctic science community. This dataset contains records of Pygoscelisadeliae, Pygoscelisantarctica, Pygoscelispapua, Eudypteschrysolophus, Aptenodytespatagonicus and Aptenodytesforsteri annual nest, adult and/or chick counts conducted during field expeditions or collected using remote sensing imagery, that were subsequently gathered by the Antarctic Penguin Biogeography Project from published and unpublished sources, at all known Antarctic penguin breeding colonies south of 60 S from 01-11-1892 to 12-02-2022-02-12.

New information

This dataset collates together all publicly available breeding colony abundance data (1979-2022) for Antarctic penguins in a single database with standardised notation and format. Colony locations have been adjusted as necessary using satellite imagery and each colony has been assigned a unique four-digit alphanumeric code to avoid confusion. These data include information previously published in a variety of print and online formats as well as additional survey data not previously published. Previously unpublished data derive primarily from recent surveys collected under the auspices of the Antarctic Site Inventory, Penguin Watch or by the Lynch Lab at Stony Brook University.

Microplastic Interactions and Possible Combined Biological Effects in Antarctic Marine Ecosystems

Antarctica and the Southern Ocean are the most remote regions on Earth, and their quite pristine environmental conditions are increasingly threatened by local scientific, tourism and fishing activities and long-range transport of persistent anthropogenic contaminants from lower latitudes. Plastic debris has become one of the most pervasive and ubiquitous synthetic wastes in the global environment, and even at some coastal Antarctic sites it is the most common and enduring evidence of past and recent human activities. Despite the growing scientific interest in the occurrence of microplastics (MPs) in the Antarctic environment, the lack of standardized methodologies for the collection, analysis and assessment of sample contamination in the field and in the lab does not allow us to establish their bioavailability and potential impact. Overall, most of the Southern Ocean appears to be little-affected by plastic contamination, with the exception of some coastal marine ecosystems impacted by wastewater from scientific stations and tourist vessels or by local fishing activities. Microplastics have been detected in sediments, benthic organisms, Antarctic krill and fish, but there is no clear evidence of their transfer to seabirds and marine mammals. Therefore, we suggest directing future research towards standardization of methodologies, focusing attention on nanoplastics (which probably represent the greatest biological risks) and considering the interactions of MPs with macro- and microalgae (especially sea-ice algae) and the formation of epiplastic communities. In coastal ecosystems directly impacted by human activities, the combined exposure to paint chips, metals, persistent organic pollutants (POPs), contaminants of emerging interest (CEI) and pathogenic microorganisms represents a potential danger for marine organisms. Moreover, the Southern Ocean is very sensitive to water acidification and has shown a remarkable decrease in sea-ice formation in recent years. These climate-related stresses could reduce the resilience of Antarctic marine organisms, increasing the impact of anthropogenic contaminants and pathogenic microorganisms.

Evolutionary dynamics of the clade 2.3.4.4B H5N8 high-pathogenicity avian influenza outbreaks in coastal seabirds and other species in southern Africa from 2017 to 2019

From late 2017 to early 2018, clade 2.3.4.4B H5N8 highly pathogenic avian influenza (HPAI) viruses caused mass die-offs of thousands of coastal seabirds along the southern coastline of South Africa. Terns (Laridae) especially were affected, but high mortalities in critically endangered and threatened species like African Penguins (Spheniscus demersus) caused international concern and, exactly a year later, the disease recurred at a key African Penguin breeding site on Halifax Island, Namibia. Twenty-five clade 2.3.4.4B H5N8 HPAI viruses from coastal seabirds and a Jackal Buzzard (Buteo rufofuscus) were isolated and/or sequenced in this study. Phylogenetic analyses of the full viral genomes and time to the most recent common ancestor (tMRCA) analyses of the HA, NA, PB1 and PA genes determined that the South African coastal seabird viruses formed a monophyletic group nested within the South African genotype 4 viruses. This sub-lineage likely originated from a single introduction by terrestrial birds around October 2017. Only the HA and NA sequences were available for the Namibian penguin viruses, but the phylogenetic data confirmed that the South African coastal seabird viruses from 2017 to 2018 were the source and the most closely related South African virus was found in a gull. tMRCA analyses furthermore determined that the progenitors of the five genotypes implicated in the earlier 2017 South African outbreaks in wild birds and poultry were dated at between 2 and 4 months prior to the index cases. tMRCA and phylogenetic data also showed that the novel genotype 6 virus introduced to South Africa in 2018, and later also detected in Nigeria and Poland in 2019, most likely arose in late 2017 in West, Central or East Africa. We propose that it continued to circulate there, and that an unidentified reservoir was the source of both the South African outbreaks in early 2018 and in Nigeria in mid-2019.

Assessment of the Safety and Efficacy of an Oral Probiotic-Based Vaccine Against Aspergillus Infection in Captive-Bred Humboldt Penguins (Spheniscus humboldti)

Aspergillosis is a fungal infection caused mainly by Aspergillus fumigatus that often results in respiratory disease in birds. Aspergillosis is a major cause of morbidity and mortality in captive-bred penguin species. Currently, there is no registered vaccine to prevent aspergillosis. Recent research demonstrated that oral administration of gram-negative bacteria expressing high levels of galactose-α-1,3-galactose (α-Gal) modulates anti-α-Gal immunity and protects turkeys from clinical aspergillosis caused by experimental A. fumigatus infection. The role of anti-α-Gal immunity in penguins has not been studied. Here, we tested the distribution of α-1,3-galactosyltransferase (α1,3GT) genes in the fecal microbiome of Humboldt penguins (Spheniscus humboldti). The occurrence of natural anti-α-Gal antibodies (Abs) in sera and eggs of healthy Humboldt penguins was also assessed. A trial was then conducted to test whether oral administration of Escherichia coli Nissle, expressing high α-Gal levels, modulates anti-α-Gal immunity in a colony of Humboldt penguins. Animals in the vaccination and placebo groups were evaluated before the trial and followed for one year for aspergillosis detection using a diagnostic panel including computed tomography scans, capillary zone electrophoresis, 3-hydroxybutyrate levels, and anti-A. fumigatus Abs. Anti-α-Gal Abs were detected in sera (IgM and IgY) and eggs (IgY) of healthy penguins. Microbiota analysis and functional predictions revealed the presence of α1,3GT genes in the microbiota of Humboldt penguins and other penguin species. A strong decrease in anti-α-Gal IgM levels was observed in all animals in the placebo group three months after vaccination protocol. This decrease was not observed in E. coli Nissle-treated penguins. After the vaccination protocol, we found a positive correlation between anti-E. coli IgY and anti-α-Gal IgY in the E. coli Nissle group, suggesting a correlation between the presence of the bacteria and these Abs. During the study period, three penguins exhibited respiratory signs consistent with aspergillosis. Two were from the placebo group whose symptoms resolved with specific treatments, while a single vaccinated individual developed fatal respiratory aspergillosis eight months after the trial. We conclude that E. coli Nissle represents a safe potential probiotic with a protective effect against aspergillosis in Humboldt penguins that deserves to be further explored for therapeutic uses in these animals.

Marine Vertebrates Impact the Bacterial Community Composition and Food Webs of Antarctic Microbial Mats

The biological activity of marine vertebrates represents an input of nutrients for Antarctic terrestrial biota, with relevant consequences for the entire ecosystem. Even though microbial mats assemble most of the biological diversity of the non-marine Antarctica, the effects of the local macrofauna on these microecosystems remain understudied. Using 16S rRNA gene sequencing, 13C and 15N stable isotopes, and by characterizing the P and N-derived nutrient levels, we evaluated the effects of penguins and other marine vertebrates on four microbial mats located along the Antarctic Peninsula. Our results show that P concentrations, C/N and N/P ratios, and δ15N values of "penguin-impacted" microbial mats were significantly higher than values obtained for "macrofauna-free" sample. Nutrients derived from penguin colonies and other marine vertebrates altered the trophic interactions of communities within microbial mats, as well as the relative abundance and trophic position of meiofaunal groups. Twenty-nine bacterial families from eight different phyla significantly changed with the presence of penguins, with inorganic nitrogen (NH4 + and NO3 -) and δ15N appearing as key factors in driving bacterial community composition. An apparent change in richness, diversity, and dominance of prokaryotes was also related to penguin-derived nutrients, affecting N utilization strategies of microbial mats and relating oligotrophic systems to communities with a higher metabolic versatility. The interdisciplinary approach of this study makes these results advance our understanding of interactions and composition of communities inhabiting microbial mats from Antarctica, revealing how they are deeply associated with marine animals.

Mercury Levels in Feathers of Penguins from the Antarctic Peninsula Area: Geographical and Inter-Specific Differences

Polar regions, symbols of wilderness, have been identified as potential sinks of mercury coming from natural and anthropogenic sources at lower latitudes. Changes in ice coverage currently occurring in some areas such as the Antarctic Peninsula could enhance these phenomena and their impacts on local biota. As long-lived species at the top of food chains, seabirds are particularly sensitive to this highly toxic metal with the capacity to be biomagnified. Specifically, their feathers can be useful for Hg monitoring since they mainly accumulate its most toxic and persistent form, methyl-Hg. To that end, feathers of gentoo (Pygoscelis papua), chinstrap (P. antarcticus), and Adélie penguins (P. adeliae) (n = 108) were collected by passive sampling in seven different locations throughout the Antarctic Peninsula area and analyzed by ICP-MS after microwave-digestion. More than 93% of the samples showed detectable Hg levels (range: 6.3–12,529.8 ng g⁻¹ dry weight), and the highest ones were found in the feathers of chinstrap penguins from King George Island. Hg bioconcentration and biomagnification seem to be occurring in the Antarctic food web, giving rise to high but non-toxic Hg levels in penguins, similar to those previously found in Arctic seabirds.

Effects of Diesel, Heavy Metals and Plastics Pollution on Penguins in Antarctica: A Review

Simple Summary

Antarctica is contaminated by anthropogenic pollution. Due to the persistent low temperatures, the toxic impacts of pollution to the environment can be extensive. The severity of the effects varies according to the animal species, chemical type and level of exposure. Penguins are at major risk as they are the most prominent group of animals in Antarctica. This review highlights the background of penguins in Antarctica, the anthropogenic pollution and cases, as well as the toxic effects of diesel, heavy metals and microplastics toward penguins. A bibliometric analysis is also included.

Abstract

Antarctica is a relatively pristine continent that attracts scientists and tourists alike. However, the risk of environmental pollution in Antarctica is increasing with the increase in the number of visitors. Recently, there has been a surge in interest regarding diesel, heavy metals and microplastics pollution. Contamination from these pollutants poses risks to the environment and the health of organisms inhabiting the continent. Penguins are one of the most prominent and widely distributed animals in Antarctica and are at major risk due to pollution. Even on a small scale, the impacts of pollution toward penguin populations are extensive. This review discusses the background of penguins in Antarctica, the anthropogenic pollution and cases, as well as the impacts of diesel, heavy metals and microplastics toxicities on penguins. The trends of the literature for the emerging risks of these pollutants are also reviewed through a bibliometric approach and network mapping analysis. A sum of 27 articles are analyzed on the effects of varying pollutants on penguins in Antarctica from 2000 to 2020 using the VOSviewer bibliometric software, Microsoft Excel and Tableau Public. Research articles collected from the Scopus database are evaluated for the most applicable research themes according to the bibliometric indicators (articles, geography distribution, annual production, integrated subject areas, key source journals and keyword or term interactions). Although bibliometric studies on the present research theme are not frequent, our results are sub-optimal due to the small number of search query matches from the Scopus database. As a result, our findings offer only a fragmentary comprehension of the topics in question. Nevertheless, this review provides valuable inputs regarding prospective research avenues for researchers to pursue in the future.

Molecular epidemiology of aspergillosis in Magellanic penguins and susceptibility patterns of clinical isolates

Aspergillus section Fumigati is reported in up to 99% of aspergillosis cases in penguins. So far, no data regarding molecular epidemiology and azole resistance are available for A. fumigatus isolates collected from Magellanic penguins. The aim of this work was to perform molecular identification of Aspergillus section Fumigati at species level, to genotype those isolates using microsatellite markers, to evaluate the in vitro susceptibility patterns of A. fumigatus sensu stricto, and to characterize the cyp51A gene in clinical A. fumigatus strains isolated from Magellanic penguins with proven aspergillosis. All 34 isolates included in the study were identified as A. fumigatus sensu stricto. Analyzing the genetic diversity of the isolates of A. fumigatus sensu stricto, we identified two possible outbreaks in the rehabilitation center and we also observed the maintenance of clonal strains through the years. One A. fumigatus sensu stricto isolate was resistant to posaconazole, but the mutations found in the cyp51A gene of this isolate have not been described as conferring phenotypic resistance, suggesting that other mechanisms of resistance could be involved in the resistance of this isolate. With this study we were able to understand the molecular diversity of Aspergillus fumigatus isolates collected from Magellanic penguins, to characterize them and to associate them with the described global population of Aspergillus fumigatus.

Evolved increases in hemoglobin-oxygen affinity and the Bohr effect coincided with the aquatic specialization of penguins

In diving birds like penguins, physiologic considerations suggest that increased hemoglobin (Hb)-O₂ affinity may improve pulmonary O₂ extraction and enhance dive capacity. We integrated experimental tests on whole-blood and native Hbs of penguins with protein engineering experiments on reconstructed ancestral Hbs. The experiments involving ancestral protein resurrection enabled us to test for evolved changes in Hb function in the stem lineage of penguins after divergence from their closest nondiving relatives. We demonstrate that penguins evolved an increased Hb-O₂ affinity in conjunction with a greatly augmented Bohr effect (i.e., reduction in Hb-O₂ affinity at low pH) that should maximize pulmonary O₂ extraction without compromising O₂ delivery at systemic capillaries.

Dive capacities of air-breathing vertebrates are dictated by onboard O₂ stores, suggesting that physiologic specialization of diving birds such as penguins may have involved adaptive changes in convective O₂ transport. It has been hypothesized that increased hemoglobin (Hb)-O₂ affinity improves pulmonary O₂ extraction and enhances the capacity for breath-hold diving. To investigate evolved changes in Hb function associated with the aquatic specialization of penguins, we integrated comparative measurements of whole-blood and purified native Hb with protein engineering experiments based on site-directed mutagenesis. We reconstructed and resurrected ancestral Hb representing the common ancestor of penguins and the more ancient ancestor shared by penguins and their closest nondiving relatives (order Procellariiformes, which includes albatrosses, shearwaters, petrels, and storm petrels). These two ancestors bracket the phylogenetic interval in which penguin-specific changes in Hb function would have evolved. The experiments revealed that penguins evolved a derived increase in Hb-O₂ affinity and a greatly augmented Bohr effect (i.e., reduced Hb-O₂ affinity at low pH). Although an increased Hb-O₂ affinity reduces the gradient for O₂ diffusion from systemic capillaries to metabolizing cells, this can be compensated by a concomitant enhancement of the Bohr effect, thereby promoting O₂ unloading in acidified tissues. We suggest that the evolved increase in Hb-O₂ affinity in combination with the augmented Bohr effect maximizes both O₂ extraction from the lungs and O₂ unloading from the blood, allowing penguins to fully utilize their onboard O₂ stores and maximize underwater foraging time.

Plasmodium matutinum Transmitted by Culex pipiens as a Cause of Avian Malaria in Captive African Penguins (Spheniscus demersus) in Italy

Avian malaria is a parasitic disease of birds caused by protozoa belonging to the genus Plasmodium, within the order Haemosporida. Penguins are considered particularly susceptible, and outbreaks in captive populations can lead to high mortality. We used a multidisciplinary approach to investigate the death due to avian malaria, occurred between 2015 and 2019, in eight African penguins (Spheniscus demersus) kept in two Italian zoos located in central Italy, and situated about 30 km apart. We also provided information about the presence and circulation of Plasmodium spp. in mosquitoes in central Italy by sampling mosquitoes in both zoos where penguin mortalities occurred. In the eight dead penguins, gross and histopathological lesions were consistent with those previously observed by other authors in avian malaria outbreaks. Organs from dead penguins and mosquitoes collected in both zoos were tested for avian malaria parasites by using a PCR assay targeting the partial mitochondrial conserved region of the cytochrome b gene. Identification at species level was performed by sequencing analysis. Plasmodium matutinum was detected in both dead penguins and in mosquitoes (Culex pipiens), while Plasmodium vaughani in Culex pipiens only. Parasites were not found in any of the PCR tested Aedes albopictus samples. Based on our phylogenetic analysis, we detected three previously characterized lineages: Plasmodium matutinum LINN1 and AFTRU5, P. vaughani SYAT05. In Culex pipiens we also identified two novel lineages, CXPIP32 (inferred morphospecies Plasmodium matutinum) and CXPIP33 (inferred morphospecies P. vaughani). Significantly, LINN1 and AFTRU5 were found to be associated to penguin deaths, although only LINN1 was detected both in penguins (along the years of the study) and in Culex pipiens, while AFTRU5 was detected in a single penguin dead in 2017. In conclusion, in our study Plasmodium matutinum was found to cause avian malaria in captive penguins kept in Europe, with Culex pipiens being its most probable vector. Our results are in agreement with previous studies suggesting that Culex pipiens is one of the main vectors of Plasmodium spp. in Europe and the Northern Hemisphere. Zoos maintaining captive penguins in temperate areas where Culex pipiens is abundant should be well aware of the risks of avian malaria, and should put every effort to prevent outbreaks, in particular during the periods when the number of vectors is higher.

Avian orthoavulavirus 1 (Newcastle Disease virus) antibodies in five penguin species, Antarctic peninsula and Southern Patagonia

Avian orthoavulavirus 1 (AOaV-1) causes Newcastle disease, one of the most important and contagious infections in poultry, where migratory birds can play a key role as a reservoir. Seven hundred and seven serum samples were collected from five penguin species (King, Magellanic, Gentoo, Chinstrap and Adelie penguins) in the Antarctic and Sub-Antarctic zones. Using a competitive ELISA to detect antibodies against AOaV-1, we identified positive individuals in all penguin species. The Magellanic penguin showed the highest seropositivity rate (30.3%), suggesting it could be a natural reservoir of this virus. At the Antarctic zones, Chinstrap penguin showed the highest occurrence (7.5%). Interesting, positive sera was only obtained in Sub-Antarctic and Northern zones at the Antarctic peninsula, no seroreactivity was observed in Southern locations. Further studies are needed to establish the role of these penguin species in the epidemiology of the AOaV-1 and determine the effects of this virus in these populations.

The skull of the Miocene Spheniscus urbinai (Aves, Sphenisciformes): osteology, brain morphology, and the cranial pneumatic systems

Spheniscus urbinai represents one of four extinct Spheniscus species from the Cenozoic of southern South America, known from several poorly described diversely complete skulls and postcranial elements. Here, we present a review of the cranial osteology of all known specimens (collected in Argentina, Chile, and Peru), including a paleoneurological analysis using CT scans, and an exploration of its cranial pneumaticity compared to other extinct and living seabirds. Our results show that among Spheniscus species, S. urbinai exhibits slightly greater cranial pneumaticity than the living species. Additionally, we confirm previous findings which indicate that the marked reduction of cranial pneumaticity-which is characteristic of living penguins-occurred early during the Eocene (as observed in the Antarctic penguin MLP 12-I-20-1, but not in the coeval Anthropornis).

Implications of Foraging and Interspecies Interactions of Birds for Carriage of Escherichia coli Strains Resistant to Critically Important Antimicrobials

Globally, gulls have been associated with carriage of high levels of Escherichia coli strains resistant to critically important antimicrobials (CIAs), a major concern, as these antimicrobials are the sole alternative or one among only a few alternatives available to treat severe life-threatening infections in humans. Previous studies of Australian silver gulls demonstrated high levels of resistance to CIAs, particularly fluoroquinolone and extended-spectrum cephalosporins, among E. coli strains (carriage at 24% and 22%, respectively). This study aimed to identify and characterize strains from four distinct bird species inhabiting a common coastal environment, determine the frequency of carriage of CIA-resistant E. coli strains, and examine if these resistant clones and their resistance-encoding mobile genetic elements (MGEs) could be transmitted between species. CIA-resistant E. coli was detected in silver gulls (53%), little penguins (11%), and feral pigeons (10%), but not in bridled terns. In total, 37 different sequence types (STs) were identified, including clinically significant human-associated lineages, such as ST131, ST95, ST648, ST69, ST540, ST93, ST450, and ST10. Five main mobile genetic elements associated with bla _CTX-M-positive E. coli strains isolated from three bird species were detected. Examination of clonal lineages and MGEs provided indirect evidence of transfer of resistance between bird species. The carriage of CIA-resistant E. coli by gulls and pigeons with proximity to humans, and in some instances food-producing animals, increases the likelihood of further bidirectional dissemination.IMPORTANCE It has been shown that 20% of Australian silver gulls carry drug-resistant Escherichia coli strains of anthropogenic origin associated with severe diseases, such as sepsis and urinary tract infections, in humans. To further characterize the dynamics of drug-resistant E. coli in wildlife populations, we investigated the carriage of critically important antimicrobial (CIA) drug-resistant E. coli in four bird species in a common environment. Our results indicated that gulls, pigeons, and penguins carried drug-resistant E. coli strains, and analysis of mobile genetic elements associated with resistance genes indicated interspecies resistance transfer. Terns, representing a bird species that forages on natural food sources at sea and distant from humans, did not test positive for drug-resistant E. coli This study demonstrates carriage of CIA-resistant bacteria in multiple bird species living in areas commonly inhabited by humans and provides further evidence for a leapfrog effect of resistance in wildlife, facilitated by feeding habits.

Identification and Distribution of Novel Cressdnaviruses and Circular molecules in Four Penguin Species in South Georgia and the Antarctic Peninsula

There is growing interest in uncovering the viral diversity present in wild animal species. The remote Antarctic region is home to a wealth of uncovered microbial diversity, some of which is associated with its megafauna, including penguin species, the dominant avian biota. Penguins interface with a number of other biota in their roles as marine mesopredators and several species overlap in their ranges and habitats. To characterize the circular single-stranded viruses related to those in the phylum Cressdnaviricota from these environmental sentinel species, cloacal swabs (n = 95) were obtained from King Penguins in South Georgia, and congeneric Adélie Penguins, Chinstrap Penguins, and Gentoo Penguins across the South Shetland Islands and Antarctic Peninsula. Using a combination of high-throughput sequencing, abutting primers-based PCR recovery of circular genomic elements, cloning, and Sanger sequencing, we detected 97 novel sequences comprising 40 ssDNA viral genomes and 57 viral-like circular molecules from 45 individual penguins. We present their detection patterns, with Chinstrap Penguins harboring the highest number of new sequences. The novel Antarctic viruses identified appear to be host-specific, while one circular molecule was shared between sympatric Chinstrap and Gentoo Penguins. We also report viral genotype sharing between three adult-chick pairs, one in each Pygoscelid species. Sequence similarity network approaches coupled with Maximum likelihood phylogenies of the clusters indicate the 40 novel viral genomes do not fall within any known viral families and likely fall within the recently established phylum Cressdnaviricota based on their replication-associated protein sequences. Similarly, 83 capsid protein sequences encoded by the viruses or viral-like circular molecules identified in this study do not cluster with any of those encoded by classified viral groups. Further research is warranted to expand knowledge of the Antarctic virome and would help elucidate the importance of viral-like molecules in vertebrate host evolution.

Identification of Circovirus Genome in a Chinstrap Penguin (Pygoscelis antarcticus) and Adélie Penguin (Pygoscelis adeliae) on the Antarctic Peninsula

Circoviruses infect a variety of animal species and have small (~1.8–2.2 kb) circular single-stranded DNA genomes. Recently a penguin circovirus (PenCV) was identified associated with an Adélie Penguin (Pygoscelis adeliae) with feather disorder and in the cloacal swabs of three asymptomatic Adélie Penguins at Cape Crozier, Antarctica. A total of 75 cloacal swab samples obtained from adults and chicks of three species of penguin (genus: Pygoscelis) from seven Antarctic breeding colonies (South Shetland Islands and Western Antarctic Peninsula) in the 2015−2016 breeding season were screened for PenCV. We identified new variants of PenCV in one Adélie Penguin and one Chinstrap Penguin (Pygoscelis antarcticus) from Port Charcot, Booth Island, Western Antarctic Peninsula, a site home to all three species of Pygoscelid penguins. These two PenCV genomes (length of 1986 nucleotides) share > 99% genome-wide nucleotide identity with each other and share ~87% genome-wide nucleotide identity with the PenCV sequences described from Adélie Penguins at Cape Crozier ~4400 km away in East Antarctica. We did not find any evidence of recombination among PenCV sequences. This is the first report of PenCV in Chinstrap Penguins and the first detection outside of Ross Island, East Antarctica. Given the limited knowledge on Antarctic animal viral diversity, future samples from Antarctic wildlife should be screened for these and other viruses to determine the prevalence and potential impact of viral infections.

Gentoo penguins (Pygoscelis papua) react to underwater sounds

Marine mammals and diving birds face several physiological challenges under water, affecting their thermoregulation and locomotion as well as their sensory systems. Therefore, marine mammals have modified ears for improved underwater hearing. Underwater hearing in birds has been studied in a few species, but for the record-holding divers, such as penguins, there are no detailed data. We played underwater noise bursts to gentoo penguins (Pygoscelis papua) in a large tank at received sound pressure levels between 100 and 120 dB re 1 µPa RMS. The penguins showed a graded reaction to the noise bursts, ranging from no reactions at 100 dB to strong reactions in more than 60% of the playbacks at 120 dB re 1 µPa. The responses were always directed away from the sound source. The fact that penguins can detect and react to underwater stimuli may indicate that they make use of sound stimuli for orientation and prey detection during dives. Further, it suggests that penguins may be sensitive to anthropogenic noise, like many species of marine mammals.

Avian Influenza H5N8 Outbreak in African Penguins (Spheniscus demersus), Namibia, 2019

In January 2019, high mortalities were reported among African Penguins (Spheniscus demersus) in a breeding colony on Halifax Island, Namibia, Africa. Analysis of samples by reverse transcription quantitative PCR indicated the presence of highly pathogenic avian influenza (HPAI) subtype H5N8. Sequence analysis of the hemagglutinin and neuraminidase genes confirmed the presence of the virus in the birds and its high similarity to HPAI subtype H5N8 identified in South Africa in 2017. There have been no previous reports of HPAI H5N8 in Namibia.

Pingu virus: A new picornavirus in penguins from Antarctica

Picornaviridae family comprises single-stranded, positive-sense RNA viruses distributed into forty-seven genera. Picornaviruses have a broad host range and geographic distribution in all continents. In this study, we applied a high-throughput sequencing approach to examine the presence of picornaviruses in penguins from King George Island, Antarctica. We discovered and characterized a novel picornavirus from cloacal swab samples of gentoo penguins (Pygoscelis papua), which we tentatively named Pingu virus. Also, using RT-PCR we detected this virus in 12.9 per cent of cloacal swabs derived from P. papua, but not in samples from adélie penguins (Pygoscelis adeliae) or chinstrap penguins (Pygoscelis antarcticus). Attempts to isolate the virus in a chicken cell line and in embryonated chicken eggs were unsuccessful. Our results expand the viral diversity, host range, and geographical distribution of the Picornaviridae.

Training penguins to interact with enrichment devices for lasting effects

The modern zoo has brought about two major advances in the behavioral welfare of their exhibited animals: (a) The use of environmental enrichment to promote naturalistic behaviors and (b) the use of training to improve voluntary husbandry care. Whereas training itself has been talked about as an effective enrichment strategy, little has been done to combine training procedures with enrichment. Typically, enrichment is treated as a trial and error process, where potential enrichment items or procedures are cycled through until successful enrichment is found. The use of shaping or other training techniques has seldom been documented to increase engagement with possible enrichment items or procedures. The following study examined the possibility of combining training and enrichment to produce continued interactions with enrichment devices. Two species of penguin, Magellanic and southern rockhopper penguins, were studied. Two measures were taken: Time spent swimming and contact with enrichment devices. The enrichment devices could be manipulated by placing fish within and hanging out of each device. During baseline sessions, no hits to either device were observed. During training sessions, several hits were recorded when fish were in the devices and overall swimming time increased during these conditions. When baseline was reintroduced without fish in the devices, contact with the enrichment devices rapidly declined and swimming time for the rockhopper penguins decreased. When the devices were reintroduced with fish but without training, the greatest number of enrichment device contacts and the highest percentage of time spent swimming were observed for the rockhopper penguins.

Novel penguin Avian avulaviruses 17, 18 and 19 are widely distributed in the Antarctic Peninsula

Three novel Avian avulavirus species were discovered and isolated during 2017 from Gentoo penguins (Pygoscelis papua) at Kopaitic island in the Northwestern region of the Antarctic Peninsula. The viruses were officially named as Avian avulavirus 17 (AAV17), Avian avulavirus 18 (AAV18) and Avian avulavirus 19 (AAV19), collectively referred to as penguin avulaviruses (PAVs). To determine whether these viruses are capable of infecting the three species of Pygoscelis spp. penguins (Gentoo, Adelie and Chinstrap) and assess its geographical distribution, serum samples were collected from seven locations across the Antarctic Peninsula and Southern Shetland Islands. The samples were tested by Hemagglutination inhibition assay using reference viruses for AAV17, AAV18 and AAV19. A total of 498 sera were tested, and 40 were positive for antibodies against AAV17, 20 for AAV18 and 45 for AAV19. Positive sera were obtained for the penguin's species for each virus; however, antibodies against AAV18 were not identified in Adelie penguins. Positive penguins were identified in all regions studied. Positive locations include Ardley Island and Cape Shirreff at Livingston Island (Southern Shetland Region); Anvers Island, Doumer Island and Paradise Bay in the Central Western region; and Avian Island at Southwestern region of the Antarctic Peninsula. The lowest occurrence was observed at the Southwestern region at Lagotellerie Island, where all samples were negative. On the other hand, Cape Shirreff and Paradise Bay showed the highest antibody titres. Field samples did not evidence cross-reactivity between viruses, and detection was significantly higher for AAV19 and lower for AAV18. This is the first serologic study on the prevalence of the novel Avian avulaviruses including different locations in the white continent. The results indicate that these novel viruses can infect the three Pygoscelis spp. penguins, which extend across large distances of the Antarctic Peninsula.

Can a Terrestrial Ectoparasite Disperse with Its Marine Host?

One of the most extreme examples of parasite adaptation comes from terrestrial ectoparasites exploiting marine hosts. Despite the ubiquity of such ectoparasitism and its ecological and evolutionary importance, investigations of the responses of ectoparasites to conditions encountered on their hosts are rare. In the case of penguins and their ticks, current understanding suggests that ticks freely parasitize their hosts on land but are incapable of surviving extended oceanic journeys. We examined this conjecture by assessing the physiological capacity of little penguin ticks to endure at-sea foraging and dispersal events of their hosts. Survival in penguins ticks was not significantly compromised by exposure to depths commonly associated with host dives (40 and 60 m), repeated seawater exposure relevant to the most common (30 s) and longest (120 s) recorded host dives, or extended (48 h) exposure to seawater. Mean (±SD) closed-phase durations in adult and nymphal ticks exhibiting discontinuous gas exchange ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mn>339</mml:mn><mml:mo>±</mml:mo><mml:mn>237</mml:mn></mml:mrow></mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mn>240</mml:mn><mml:mo>±</mml:mo><mml:mn>295</mml:mn></mml:mrow></mml:math> s, respectively) exceeded that of the maximum recorded host dive duration (120 s). Normoxic-anoxic-normoxic respirometry also confirmed spiracle closure. Mean metabolic rates ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mn>0.354</mml:mn><mml:mo>±</mml:mo><mml:mn>0.220</mml:mn></mml:mrow></mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mn>4.853</mml:mn><mml:mo>±</mml:mo><mml:mn>4.930</mml:mn></mml:mrow></mml:math> μL/h at 25°C for unfed and fed adult females, respectively) were significantly influenced by temperature; optimal and LT₅₀ temperatures for adult ticks and fed nymphal ticks were typically higher than swimming penguin body temperatures. These findings suggest that marine host dispersal is unlikely to present an insurmountable barrier to long-distance tick dispersal. Such dispersal has important implications for evolutionary theory, conservation, and epidemiology.

Identification of marine Important Bird and Biodiversity Areas for penguins around the South Shetland Islands and South Orkney Islands

AIM

To provide a method of analyzing penguin tracking data to identify priority at-sea areas for seabird conservation (marine IBAs), based on pre-existing approaches for flying seabirds but revised according to the specific ecology of Pygoscelis penguin species.

LOCATION

Waters around the Antarctic Peninsula, South Shetland, and South Orkney archipelagos (FAO Subareas 48.1 and 48.2).

METHODS

We made key improvements to the pre-existing protocol for identifying marine IBAs that include refining the track interpolation method and revision of parameters for the kernel analysis (smoothing factor and utilization distribution) using sensitivity tests. We applied the revised method to 24 datasets of tracking data on penguins (three species, seven colonies, and three different breeding stages-incubation, brood, and crèche).

RESULTS

We identified five new marine IBAs for seabirds in the study area, estimated to hold ca. 600,000 adult penguins.

MAIN CONCLUSIONS

The results demonstrate the efficacy of a new method for the designation of a network of marine IBAs in Antarctic waters for penguins based on tracking data, which can contribute to an evidence-based, precautionary, management framework for krill fisheries.

Application of different pharmacokinetic models to describe and predict pharmacokinetics of voriconazole in magellanic penguins following oral administration

Aspergillosis is a condition causing serious morbidity and mortality in captive penguins and other bird species. It can be treated with antifungal drugs, such as voriconazole. However, the pharmacokinetics of voriconazole are variable between different animal and bird species. Therefore, the pharmacokinetics of voriconazole were investigated in this study in Magellanic penguins. Pharmacokinetic models were constructed and applied to predict the pharmacokinetics of voriconazole during long-term treatment in Magellanic penguins, since the voriconazole treatment duration in chronic aspergillosis cases can last up to several months. Plasma voriconazole concentration-time data from adult Magellanic penguins (Spheniscus magellanicus; n = 15) following a single oral (PO) dose of either 2.5 mg/kg or 5 mg/kg in a herring in three separate study periods 7-12 months apart were collected. Mean plasma voriconazole concentrations were above the targeted MIC for Aspergillus fumigatus for 2 hr following a single 2.5 mg/kg voriconazole dose while the plasma concentrations exceeded the MIC for least 24 hr following a 5 mg/kg dose. Nonlinear mixed-effects modeling was used to fit two pharmacokinetic models, one with first-order and another with saturable elimination, to the single-dose data. Fits were good for both, as long as dose was included as a covariate for the first-order model so that clearance was lower and the half-life longer for animals receiving the 5 mg/kg dose. Although the single-dose data suggested saturated elimination at higher concentrations, the model with saturable elimination did not predict plasma voriconazole concentrations well for a clinical aspergillosis case receiving long-term treatment, possibly because of induction of metabolizing enzymes with chronic exposure. Pharmacokinetic models should accurately predict plasma drug concentrations for different dosage regimens in order to be applicable in the field. Future studies should focus on determining clearance at steady-state to be able to refine the pharmacokinetic models presented here and improve model performance for long-term oral voriconazole administration in Magellanic penguins.

Novel Avulaviruses in Penguins, Antarctica

We identified 3 novel and distinct avulaviruses from Gentoo penguins sampled in Antarctica. We isolated these viruses and sequenced their complete genomes; serologic assays demonstrated that the viruses do not have cross-reactivity between them. Our findings suggest that these 3 new viruses represent members of 3 novel avulavirus species.

Invader or resident? Ancient-DNA reveals rapid species turnover in New Zealand little penguins

The expansion of humans into previously unoccupied parts of the globe is thought to have driven the decline and extinction of numerous vertebrate species. In New Zealand, human settlement in the late thirteenth century AD led to the rapid demise of a distinctive vertebrate fauna, and also a number of 'turnover' events where extinct lineages were subsequently replaced by closely related taxa. The recent genetic detection of an Australian little penguin (Eudyptula novaehollandiae) in southeastern New Zealand may potentially represent an additional 'cryptic' invasion. Here we use ancient-DNA (aDNA) analysis and radiocarbon dating of pre-human, archaeological and historical Eudyptula remains to reveal that the arrival of E. novaehollandiae in New Zealand probably occurred between AD 1500 and 1900, following the anthropogenic decline of its sister taxon, the endemic Eudyptula minor. This rapid turnover event, revealed by aDNA, suggests that native species decline can be masked by invasive taxa, and highlights the potential for human-mediated biodiversity shifts.

FORCED MOLT IN FOUR JUVENILE YELLOW-EYED PENGUINS (MEGADYPTES ANTIPODES)

Penguins are dependent on waterproof plumage for survival. The molt in sub-Antarctic penguin species is a seasonal and catastrophic process during which the animals go through periods of fasting and high levels of stress. Their entire plumage is usually replaced in 3 wk. Attempts at consistent hormonal induction of molt in penguins have been unsuccessful. Four Yellow-eyed Penguins ( Megadyptes antipodes ) were referred for treatment at Wildbase, Massey University, Palmerston North, New Zealand, in late April 2014, following loss of waterproofing, feather breakage, increased body weight, pododermatitis, and damage to caudal feathers from hock sitting. Feather plucking of damaged areas to stimulate feather regrowth was attempted with poor results. Waiting 10-12 mo for a natural molt was not tenable. Catastrophic molt was induced by treatment with 10 g/kg of fresh beef thyroid gland orally once a day. The molt was complete in 18-26 d during which the animals regained full plumage and waterproofing after feather regrowth. The forced molt feathers had abnormal pigmentation but were of sufficient quality to allow release of the birds back to the wild.

Early diving behaviour in juvenile penguins: improvement or selection processes

The early life stage of long-lived species is critical to the viability of population, but is poorly understood. Longitudinal studies are needed to test whether juveniles are less efficient foragers than adults as has been hypothesized. We measured changes in the diving behaviour of 17 one-year-old king penguins Aptenodytes patagonicus at Crozet Islands (subantartic archipelago) during their first months at sea, using miniaturized tags that transmitted diving activity in real time. We also equipped five non-breeder adults with the same tags for comparison. The data on foraging performance revealed two groups of juveniles. The first group made shallower and shorter dives that may be indicative of early mortality while the second group progressively increased their diving depths and durations, and survived the first months at sea. This surviving group of juveniles required the same recovery durations as adults, but typically performed shallower and shorter dives. There is thereby a relationship between improved diving behaviour and survival in young penguins. This long period of improving diving performance in the juvenile life stage is potentially a critical period for the survival of deep avian divers and may have implications for their ability to adapt to environmental change.

Novel insights into early neuroanatomical evolution in penguins from the oldest described penguin brain endocast

Digital methodologies for rendering the gross morphology of the brain from X-ray computed tomography data have expanded our current understanding of the origin and evolution of avian neuroanatomy and provided new perspectives on the cognition and behavior of birds in deep time. However, fossil skulls germane to extracting digital endocasts from early stem members of extant avian lineages remain exceptionally rare. Data from early-diverging species of major avian subclades provide key information on ancestral morphologies in Aves and shifts in gross neuroanatomical structure that have occurred within those groups. Here we describe data on the gross morphology of the brain from a mid-to-late Paleocene penguin fossil from New Zealand. This most basal and geochronologically earliest-described endocast from the penguin clade indicates that described neuroanatomical features of early stem penguins, such as lower telencephalic lateral expansion, a relatively wider cerebellum, and lack of cerebellar folding, were present far earlier in penguin history than previously inferred. Limited dorsal expansion of the wulst in the new fossil is a feature seen in outgroup waterbird taxa such as Gaviidae (Loons) and diving Procellariiformes (Shearwaters, Diving Petrels, and allies), indicating that loss of flight may not drastically affect neuroanatomy in diving taxa. Wulst enlargement in the penguin lineage is first seen in the late Eocene, at least 25 million years after loss of flight and cooption of the flight stroke for aquatic diving. Similar to the origin of avian flight, major shifts in gross brain morphology follow, but do not appear to evolve quickly after, acquisition of a novel locomotor mode. Enlargement of the wulst shows a complex pattern across waterbirds, and may be linked to sensory modifications related to prey choice and foraging strategy.

Population structure and phylogeography of the Gentoo Penguin (Pygoscelis papua) across the Scotia Arc

Climate change, fisheries' pressure on penguin prey, and direct human disturbance of wildlife have all been implicated in causing large shifts in the abundance and distribution of penguins in the Southern Ocean. Without mark-recapture studies, understanding how colonies form and, by extension, how ranges shift is challenging. Genetic studies, particularly focused on newly established colonies, provide a snapshot of colonization and can reveal the extent to which shifts in abundance and occupancy result from changes in demographic rates (e.g., reproduction and survival) or migration among suitable patches of habitat. Here, we describe the population structure of a colonial seabird breeding across a large latitudinal range in the Southern Ocean. Using multilocus microsatellite genotype data from 510 Gentoo penguin (Pygoscelis papua) individuals from 14 colonies along the Scotia Arc and Antarctic Peninsula, together with mitochondrial DNA data, we find strong genetic differentiation between colonies north and south of the Polar Front, that coincides geographically with the taxonomic boundary separating the subspecies P. p. papua and P. p. ellsworthii. Using a discrete Bayesian phylogeographic approach, we show that southern Gentoos expanded from a possible glacial refuge in the center of their current range, colonizing regions to the north and south through rare, long-distance dispersal. Our findings show that this dispersal is important for new colony foundation and range expansion in a seabird species that ordinarily exhibits high levels of natal philopatry, though persistent oceanographic features serve as barriers to movement.

Molecular Epidemiology of Avian Malaria in Wild Breeding Colonies of Humboldt and Magellanic Penguins in South America

Avian malaria is a disease caused by species of the genera Haemoproteus, Leucocytozoon, and Plasmodium. It affects hundreds of bird species, causing varied clinical signs depending on the susceptibility of the host species. Although high mortality has been reported in captive penguins, limited epidemiological studies have been conducted in wild colonies, and isolated records of avian malaria have been reported mostly from individuals referred to rehabilitation centers. For this epidemiological study, we obtained blood samples from 501 adult Humboldt and 360 adult Magellanic penguins from 13 colonies throughout South America. To identify malaria parasitaemia, we amplified the mtDNA cytochrome b for all three parasite genera. Avian malaria was absent in most of the analyzed colonies, with exception of the Punta San Juan Humboldt penguin colony, in Peru, where we detected at least two new Haemoproteus lineages in three positive samples, resulting in a prevalence of 0.6% for the species. The low prevalence of avian malaria detected in wild penguins could be due to two possible causes: A low incidence, with high morbidity and mortality in wild penguins or alternatively, penguins sampled in the chronic stage of the disease (during which parasitaemia in peripheral blood samples is unlikely) would be detected as false negatives.

Extreme ecological response of a seabird community to unprecedented sea ice cover

Climate change has been predicted to reduce Antarctic sea ice but, instead, sea ice surrounding Antarctica has expanded over the past 30 years, albeit with contrasted regional changes. Here we report a recent extreme event in sea ice conditions in East Antarctica and investigate its consequences on a seabird community. In early 2014, the Dumont d'Urville Sea experienced the highest magnitude sea ice cover (76.8%) event on record (1982-2013: range 11.3-65.3%; mean±95% confidence interval: 27.7% (23.1-32.2%)). Catastrophic effects were detected in the breeding output of all sympatric seabird species, with a total failure for two species. These results provide a new view crucial to predictive models of species abundance and distribution as to how extreme sea ice events might impact an entire community of top predators in polar marine ecosystems in a context of expanding sea ice in eastern Antarctica.

Comparative osteohistology of Hesperornis with reference to pygoscelid penguins: the effects of climate and behaviour on avian bone microstructure

The broad biogeographic distribution of Hesperornis fossils in Late Cretaceous Western Interior Seaway deposits has prompted questions about whether they endured polar winters or migrated between mid- and high latitudes. Here, we compare microstructures of hesperornithiform long bones from Kansas and the Arctic to investigate whether migration or Late Cretaceous polar climate affected bone growth. We also examine modern penguin bones to determine how migration and climate may influence bone growth in birds with known behaviours. Histological analysis of hesperornithiform samples reveals continuous bone deposition throughout the cortex, plus an outer circumferential layer in adults. No cyclic growth marks, zonation or differences in vasculature are apparent in the Hesperornis specimens. Comparatively, migratory Adélie and chinstrap penguin bones show no zonation or changes in microstructure, suggesting that migration is not necessarily recorded in avian bone microstructure. Non-migratory gentoos show evidence of rapid bone growth possibly associated with increased chick growth rates in high-latitude populations and large body size. The absence of histological evidence for migration in extinct Hesperornis and extant pygoscelid penguins may reflect that these birds reached skeletal maturity before migration or overwintering. This underscores the challenges of using bone microstructure to infer the effects of behaviour and climate on avian growth.

Climate change and Southern Ocean ecosystems I: how changes in physical habitats directly affect marine biota

Antarctic and Southern Ocean (ASO) marine ecosystems have been changing for at least the last 30 years, including in response to increasing ocean temperatures and changes in the extent and seasonality of sea ice; the magnitude and direction of these changes differ between regions around Antarctica that could see populations of the same species changing differently in different regions. This article reviews current and expected changes in ASO physical habitats in response to climate change. It then reviews how these changes may impact the autecology of marine biota of this polar region: microbes, zooplankton, salps, Antarctic krill, fish, cephalopods, marine mammals, seabirds, and benthos. The general prognosis for ASO marine habitats is for an overall warming and freshening, strengthening of westerly winds, with a potential pole-ward movement of those winds and the frontal systems, and an increase in ocean eddy activity. Many habitat parameters will have regionally specific changes, particularly relating to sea ice characteristics and seasonal dynamics. Lower trophic levels are expected to move south as the ocean conditions in which they are currently found move pole-ward. For Antarctic krill and finfish, the latitudinal breadth of their range will depend on their tolerance of warming oceans and changes to productivity. Ocean acidification is a concern not only for calcifying organisms but also for crustaceans such as Antarctic krill; it is also likely to be the most important change in benthic habitats over the coming century. For marine mammals and birds, the expected changes primarily relate to their flexibility in moving to alternative locations for food and the energetic cost of longer or more complex foraging trips for those that are bound to breeding colonies. Few species are sufficiently well studied to make comprehensive species-specific vulnerability assessments possible. Priorities for future work are discussed.

Integrating oxidative ecology into conservation physiology

Ecologists have recently shown great interest in using physiological markers as indicators of the health of animal populations. In this context, the measurement of markers of oxidative balance, such as antioxidant defences and oxidative damage, may be a valuable tool. Indeed, at the individual level, antioxidant defences are positively associated with fertility and survival probability, while elevated oxidative damage during reproduction or growth may negatively affect recruitment and survival. Therefore, variation in oxidative balance is likely to influence demographic processes. This suggests that conservationists may be able to use oxidative markers to monitor population health. Yet, the connection between these markers and demographic parameters first needs to be established. We present here preliminary results obtained in colonies of breeding Gentoo (Pygoscelis papua) and Adélie penguins (Pygoscelis adeliae), showing that antioxidant defences strongly reflect population trends. However, population trend was not related to oxidative damage. This suggests that in the context of the emerging field of conservation physiology, antioxidant defences may represent a key parameter to monitor population health. We therefore exhort other research teams to assess the generality of this finding in other biological models, especially in species of conservation concern.

Multiple gene evidence for expansion of extant penguins out of Antarctica due to global cooling

Classic problems in historical biogeography are where did penguins originate, and why are such mobile birds restricted to the Southern Hemisphere? Competing hypotheses posit they arose in tropical-warm temperate waters, species-diverse cool temperate regions, or in Gondwanaland approximately 100 mya when it was further north. To test these hypotheses we constructed a strongly supported phylogeny of extant penguins from 5851 bp of mitochondrial and nuclear DNA. Using Bayesian inference of ancestral areas we show that an Antarctic origin of extant taxa is highly likely, and that more derived taxa occur in lower latitudes. Molecular dating estimated penguins originated about 71 million years ago in Gondwanaland when it was further south and cooler. Moreover, extant taxa are inferred to have originated in the Eocene, coincident with the extinction of the larger-bodied fossil taxa as global climate cooled. We hypothesize that, as Antarctica became ice-encrusted, modern penguins expanded via the circumpolar current to oceanic islands within the Antarctic Convergence, and later to the southern continents. Thus, global cooling has had a major impact on penguin evolution, as it has on vertebrates generally. Penguins only reached cooler tropical waters in the Galapagos about 4 mya, and have not crossed the equatorial thermal barrier.