Jesús Benzal

Geographic variation in the immunoglobulin levels in pygoscelid penguins

Antarctic organisms, including penguins, are susceptible to parasites and pathogens. Effects of infestation could differ in different locations along a geographical gradient from north to south consistent with conditions that affect the prevalence and virulence of parasites and pathogens. The immune system, including immunoglobulins as the main component of the humoral immune response, is the major way by which organisms confront infestation. We investigated the variation in immunoglobulin levels in three species of antarctic penguins (Pygoscelis antarctica, Pygoscelis papua, and Pygoscelis adeliae) along a geographical gradient from King George Island (62°15′S) to Avian Island (67°46′S). We found that immunoglobulin levels increased northwards in all the three species. This could indicate a higher impact of parasites and/or pathogens relative to the existing gradient in temperatures along this coast. Changing temperatures, consistent with global climate change, could be altering the ecology of parasite or pathogen infestation within the biota of northern Antarctica. We have also found marginal differences in immunoglobulin levels between sexes in both chinstrap and gentoo penguins.

Pollution and physiological variability in gentoo penguins at two rookeries with different levels of human visitation.

Abstract Human activity and specifically tourism has been increasing in Antarctica over the last few years. Few studies have examined the indirect effects of human visits on Antarctic penguin rookeries. This work aims to study the differences between a highly visited (Hannah Point) and a rarely visited (Devils Point, Byers Peninsula) gentoo penguin rookery on Livingston Island. Our results suggest that potential indirect effects of human impact are observed in gentoo penguins at Hannah Point, a colony heavily visited by tourists. Penguins at Hannah Point showed a higher presence of heavy metals such as Pb and Ni and a higher number of erythrocytic nuclear abnormalities than penguins at Devils Point. Immunological parameters showed different results depending on whether we consider the cellular response - the number of lymphocytes being higher in penguins from Hannah Point - or the humoral response - the level of immunoglobulins being higher in penguins from Devils Point. Measurements of corticosterone levels in feathers and heterophil/lymphocyte (H/L) ratio in blood showed lower levels in the heavily visited rookery than in the rarely visited rookery. Finally, we did not detect Campylobacter jejuni, a bacteria potentially transmitted by humans in either of the populations and we did not find any difference in the prevalence of Campylobacter lari between the populations.

Gastrointestinal parasites in Chinstrap Penguins from Deception Island, South Shetlands, Antarctica

Knowledge about parasites of Antarctic birds is fragmented and scarce. The aim of this work is to contribute to the knowledge of gastrointestinal parasites of the Chinstrap Penguin (Pygoscelis antarctica) from Deception Island (South Shetlands, Antarctica). Gastrointestinal tracts of 64 fresh dead individuals (61 chicks and three adults) were collected from December 2006 to February 2009 and examined for macroparasites. Three adult parasite species were found: two Cestoda species (Parorchites zederi and Tetrabothrius pauliani) and one Nematoda species (Stegophorus macronectes). Also, immature acanthocephalans (Corynosoma sp.) were found in one penguin. The low parasite richness observed could be related to the stenophagic and pelagic diet of the host species. False negatives were found in coprological studies.

Seabird ticks (Ixodes uriae) distribution along the Antarctic Peninsula

The distribution of the tick Ixodes uriae is studied in the South Shetlands and different locations along the Antarctic Peninsula. Ticks were found beneath stones close to penguin rookeries of chinstrap, gentoo and adelie penguin, although no individuals were found parasitized. Our results showed that ticks are not distributed evenly along the Antarctic Peninsula being more common and abundant in the northern part with relative abundances of ticks ranging from 1 to 57 individuals per stone and from 2 to 26% of the stone inspected. Ticks are probably absent in the south.

Population variability in heat shock proteins among three Antarctic penguin species

Heat shock proteins (HSPs) are synthesised under stressful conditions such as exposure to elevated temperatures, contamination, free radicals, UV light or pathophysiological states resulting from parasites and/or pathogens. HSPs function to protect cells by means of modulation of protein folding. In Antarctica, these proteins have been studied in such organisms as protozoa and fishes, without attention to geographical variation. We studied the variation of HSP70 and HSP60 levels in Gentoo, Adelie and Chinstrap penguins among different populations along the Antarctic Peninsula from King George Island (62°15′S) to Avian Island (67°46′S). Our results show that the northern population of Gentoo penguin showed higher levels of HSP70 and HSP60 than the southern population. High temperature, human impact and immunity as a proxy for parasites and diseases in northern locations could explain such variation. Adelie penguin only showed significant geographical variation in HSP70, increasing north to south, a pattern perhaps related to increased UV radiation and decreased temperatures from north to south. Chinstrap penguin shows no population differences in the variation in neither HSP70 nor HSP60, although HSP70 showed marginally significant differences. Sexual differences in the level of these proteins are also discussed.

Age-Related Differences in the Gastrointestinal Microbiota of Chinstrap Penguins (Pygoscelis antarctica)

The gastrointestinal tract microbiota is known to play very important roles in the well being of animals. It is a complex community composed by hundreds of microbial species interacting closely among them and with their host, that is, a microbial ecosystem. The development of high throughput sequencing techniques allows studying the diversity of such communities in a realistic way and considerable work has been carried out in mammals and some birds such as chickens. Wild birds have received less attention and in particular, in the case of penguins, only a few individuals of five species have been examined with molecular techniques. We collected cloacal samples from Chinstrap penguins in the Vapour Col rookery in Deception Island, Antarctica, and carried out pyrosequencing of the V1-V3 region of the 16S rDNA in samples from 53 individuals, 27 adults and 26 chicks. This provided the first description of the Chinstrap penguin gastrointestinal tract microbiota and the most extensive in any penguin species. Firmicutes, Bacteoridetes, Proteobacteria, Fusobacteria, Actinobacteria, and Tenericutes were the main components. There were large differences between chicks and adults. The former had more Firmicutes and the latter more Bacteroidetes and Proteobacteria. In addition, adults had richer and more diverse bacterial communities than chicks. These differences were also observed between parents and their offspring. On the other hand, nests explained differences in bacterial communities only among chicks. We suggest that environmental factors have a higher importance than genetic factors in the microbiota composition of chicks. The results also showed surprisingly large differences in community composition with other Antarctic penguins including the congeneric Adélie and Gentoo penguins.

Distribution of metals and trace elements in adult and juvenile penguins from the Antarctic Peninsula area

The presence of metals in the Antarctic environment is principally a natural phenomenon caused by geochemical characteristics of the region, although some anthropogenic activities can increase these natural levels. Antarctic penguins present several of the characteristics of useful sentinels of pollution in Antarctica such as they are long-lived species situated at the top of food web. The concentrations of Al, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Cd, and Pb were determined by inductively coupled plasma–mass spectrometry in samples of liver, kidney, muscle, bone, feather, and stomach contents of gentoo, chinstrap, and Adélie penguin (12 adults, five juveniles) from carcasses of naturally dead individuals collected opportunistically in the Antarctic Peninsula area. The obtained results showed that accumulation and magnification of several elements can be occurring, so that Cd and Se reached levels potentially toxic in some specimens. The presence of human activities seems to be increasing the presence of toxic metals such as Mn, Cr, Ni, or Pb in penguins.

Monitoring trace elements in Antarctic penguin chicks from South Shetland Islands, Antarctica

UNLABELLED The concentration of human activities in the near-shore ecosystems from the northern Antarctic Peninsula area can cause an increasing bioavailability of pollutants for the vulnerable Antarctic biota. Penguin chicks can reflect this potential impact in the rookeries during the breeding season. They also can reflect biomagnification phenomena since they are on the top of the Antarctic food chain. The concentrations of Al, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Cd and Pb were measured by ICP-MS in samples of liver, kidney, muscle, bone, feather and stomach content of gentoo, chinstrap and Adélie penguin chicks (n=15 individuals) collected opportunistically in the Islands of King George and Deception (South Shetland Islands, Antarctica). The detected levels of some trace elements were not as low as it could be expected in the isolated Antarctic region. Penguin chicks can be useful indicators of trace elements abundance in the study areas. CAPSULE Carcasses of Antarctic penguin chicks were used to evaluate the bioavailability of trace elements in the Islands of King George and Deception.

First record of Babesia sp. in Antarctic penguins

This is the first reported case of Babesia sp. in Antarctic penguins, specifically a population of Chinstrap penguins (Pygoscelis antarctica) in the Vapour Col penguin rookery in Deception Island, South Shetlands, Antarctica. We collected peripheral blood from 50 adult and 30 chick Chinstrap penguins. Examination of the samples by microscopy showed intraerythrocytic forms morphologically similar to other avian Babesia species in 12 Chinstrap penguin adults and seven chicks. The estimated parasitaemias ranged from 0.25×10(-2)% to 0.75×10(-2)%. Despite the low number of parasites found in blood smears, semi-nested PCR assays yielded a 274 bp fragment in 12 of the 19 positive blood samples found by microscopy. Sequencing revealed that the fragment was 97% similar to Babesia sp. 18S rRNA from Australian Little Penguins (Eudyptula minor) confirming presence of the parasite. Parasite prevalence estimated by microscopy in adults and chicks was higher (24% vs. 23.3%, respectively) than found by semi-nested PCR (16% vs. 13.3% respectively). Although sampled penguins were apparently healthy, the effect of Babesia infection in these penguins is unknown. The identification of Babesia sp. in Antarctic penguins is an important finding. Ixodes uriae, as the only tick species present in the Antarctic Peninsula, is the key to understanding the natural history of this parasite. Future work should address the transmission dynamics and pathogenicity of Babesia sp. in Chinstrap penguin as well as in other penguin species, such as Gentoo penguin (Pygoscelis papua) and Adélie penguin (Pygoscelis adeliae), present within the tick distribution range in the Antarctic Peninsula.

Morphological, molecular and phylogenetic analyses of the spirurid nematode Stegophorus macronectes (Johnston & Mawson, 1942).

Stegophorus macronectes (Johnston & Mawson, 1942) is a gastrointestinal parasite found in Antarctic seabirds. The original description of the species, which was based only on females, is poor and fragmented with some unclear diagnostic characters. This study provides new morphometric and molecular data on this previously poorly described parasite. Nuclear rDNA sequences (18S, 5.8S, 28S and internal transcribed spacer (ITS) regions) were isolated from S. macronectes specimens collected from the chinstrap penguin Pygoscelis antarctica Forster on Deception Island, Antarctica. Using 18S rDNA sequences, phylogenetic analyses (maximum likelihood, maximum parsimony and Bayesian inference) of the order Spirurida were performed to determine the phylogenetic location of this species. Primer pairs of the ITS regions were designed for genus-level identification of specimens, regardless of their cycle, as an alternative to coprological methods. The utility of this molecular method for identification of morphologically altered specimens is also discussed.