Diet of Cape petrel Daption capense during the post-hatching period at Laurie Island, South Orkney Islands, Antarctica

The diet of Cape petrel Daption capense was investigated at Laurie Island, South Orkney Islands (60°46^′S, 44°42^′W), Antarctica, in the period January–February 1996. Stomach contents of adults and regurgitate of chicks were sampled during the post-hatching period. The analysis showed that during the whole sampling period Antarctic krill and fish represented the predominant preys in terms of frequency of occurrence, forming nearly 35.8% and 64% by mass, respectively. The species Electrona antarctica was the most frequent fish prey. Amphipods were present in lower numbers and cephalopods were detected in the diet, but in a very small proportion. Diet composition in terms of frequency of occurrence, mass and number is compared with results of previous studies. Received: 27 September 1996 / Accepted: 22 February 1997     

Stable isotope ratios of Antarctic petrel (Thalassoica antarctica) and snow petrel (Pagodroma nivea) bone collagen

This study investigated the trophic hierarchy status of the Antarctic petrel (Thalassoica antarctica) and snow petrel (Pagodroma nivea) within the Southern Ocean food-web off Dronning Maud Land, Antarctica. During 1991/92 ten Antarctic petrel and ten snow petrel carcasses were collected from Jekselen (71°59S, 02°35W) and Robertskollen (71°28S, 03°15W) respectively, in the northern Ahlmannryggen, Dronning Maud Land. Collagen from the dense bone of the humeri of these carcasses was extracted and the stable carbon and nitrogen isotope ratios of these samples determined. The snow petrel bone collagen samples displayed a mean ¹³C value of –23.9±0.7 (range: –24.7 to –22.9; n=9) and a mean ¹⁵N value of 15.2±1.6 (range: 12.9 to 18.4; n=10). The corresponding values for Antarctic petrel bone collagen were –24.8±1.0 (range: –26.2 to –22.8; n=9) and 13.2±0.6 (range: 12.5 to 13.9; n=8) respectively. The difference between the species ¹³C values may indicate differences in their foraging habitat. It has previously been suggested that the snow petrel has a higher wing loading than other Procellariiforme species, making the snow petrel less adapted to pelagic foraging than related species and more likely to forage close to the sea ice edge. Algae growing under sea ice apparently can have comparatively high ¹³C values, possibly due to growing under carbon dioxide limited conditions. If so, animals foraging close to the sea ice edge might be expected to show higher ¹³C values in their body tissues than animals foraging farther out over the open ocean. However, the high ¹³C of snow petrel collagen is possibly more likely to be related to the correspondingly high ¹⁵N values found in this tissue, and hence caused by snow petrels including offal from high trophic level Antarctic mammals and birds in their diet.     

Hybridisation between South polar skua (Catharacta maccormicki) and Brown skua (C. antarctica lonnbergi) in the Antarctic Peninsula region

Hybridisation between South polar skua (C. maccormicki) and Brown skua (C. antarctica lonnbergi) in the area of the Antarctic Peninsula is known at least since the beginning of the last century but no survey has been done so far. This paper reviews information on the species composition of skua colonies of more than 10 pairs in the Antarctic Peninsula region, and the incidence of mixed pairs. Morphometrics, population size and breeding success were examined in detail at King George Island. The northward distribution of South polar skuas extended to King George Island (62°11′ S 59°00′ W), with a small outlying population on Signy Island (60°45′ S 45°36′ W), whereas Brown skuas did not breed further south than Anvers Island archipelago (64°46′ S 64°03′ W). The proportion of mixed pairs was highest at the northern end of the ∼500-km-wide hybrid zone. Body size distribution of sympatric skuas from King George Island is clearly bimodal but overlaps considerably and hybrids cannot be identified. Skua population sizes at Potter Peninsula/King George Island remained stable between 1994 and 2004. Numbers of mixed breeding pairs fluctuated more strongly than those of pure species pairs. Breeding success of Brown skuas varied the least.     

Thermoregulation in Antarctic fulmarine petrels

We measured resting metabolic rates at air temperatures between ca. −5 and 30 °C in snow petrels (Pagodroma nivea), cape petrels (Daption capense), Antarctic petrels (Thalassoica antarctica), and Antarctic fulmars (Fulmarus glacialoides). We measured seven age classes for each species: adults, and nestlings that were 3, 8, 15, 28, 35, and 42 days old. Basal metabolic rate (BMR) and thermal conductance (C) of adults averaged, respectively, 140% and 100% of values predicted allometrically for nonpasserine birds. Minimum metabolic rates of unfasted nestlings aged 15–42 days averaged, respectively, 97% and 98% of predicted adult BMR in Antarctic petrels and snow petrels, versus 119% and 126% of predicted in Antarctic fulmars and cape petrels. Nestlings of the southerly breeding snow petrel and Antarctic petrel were relatively well insulated compared with nestlings of other high-latitude seabirds. Adult lower critical temperature (T_lc) was inversely related to body mass and averaged 9 °C lower than predicted allometrically. As nestlings grew, their T_lc decreased with increasing body mass from ca. 14 to 22 °C (depending upon species) at 3 days of age, to −4 to 8 °C when nestlings attained peak mass. Nestling T_lc subsequently increased as body mass decreased during pre-fledging weight recession. Nestling T_lc was close to mean air temperature from the end of brooding until fledging in the three surface nesting species. Accepted: 12 July 2000     

Diet and prey consumption of Antarctic petrels Thalassoica antarctica at Svarthamaren, Dronning Maud Land, and at sea outside the colony

The diet of the Antarctic petrel Thalassoica antarctica was studied during two seasons at Svarthamaren, an inland colony in Dronning Maud Land, Antarctica, and in the pack ice off the coast of Svarthamaren. The most important food (wet mass) at Svarthamaren was crustaceans (67%), fish (29%) and squid (5%); however, individuals collected in the pack ice took mostly fish (87%). The prey composition and lengths of prey are comparable to what has been documented in other studies on this species. Estimates of food consumption by birds breeding at Svarthamaren (ca. 250,000 pairs) suggest that approximately 6500 tonnes of crustaceans, 2800 tonnes of fish and 435 tonnes of squid are consumed during the breeding season. The annual consumptions of these birds are estimated to be 34,100 tonnes of crustaceans, 14,700 tonnes of fish, and 2300 tonnes of squid. Satellite telemetry data indicate that Antarctic petrels from Svarthamaren may fly more than 3000 km during one foraging trip, and thus may cover a huge ocean area to obtain their prey. Received: 1 September 1997 / Accepted: 3 February 1998     

The persistence of the snow petrel (Pagodroma nivea) in Dronning Maud Land (Antarctica) for over 37,000?years

Two samples of snow petrel Pagodroma nivea mumiyo (solidified stomach oil) from Heimefrontfjella (74°34′36″S, 11°13′24″W) in Dronning Maud Land, Antarctica, were radiocarbon dated at 37,400 ± 1,500 and 3,120 ± 70 years old (dates are corrected for the ‘reservoir effect’). The age of the older sample provides further evidence that snow petrel colonies have existed in the mountain peaks of Dronning Maud Land since before the last glacial maximum (approx. 20,000–16,000 years ago). This finding also pushes back the estimated timing of establishment of snow petrel breeding colonies in this part of the continent by several thousand years. The variation in the accumulation rates of these two samples (1.6 and 35.2 mm per millennium, respectively) supports previous observations that mumiyo accumulation rates are highly variable and probably relate to site-specific factors affecting accumulation and degradation of the oil. Studies that help us understand historical bird population distributions in continental Antarctica can significantly aid the development and refinement of models that explain glacial advancement and retreat, the relationship between sea ice and population viability and, perhaps, predict species responses to future climate shifts.     

<Emphasis Type="Italic">Manayunkia speciosa</Emphasis> Leidy (Polychaeta: Sabellidae): introduction of this nonindigenous species in the Neotropical Region (Uruguay river,South America)

We report the migration of Manayunkia speciosa from its distribution in North America into the Neotropical Region (Argentina). We collected specimens from November 2007 to March 2009 in the lower Uruguay River-at 33° 5.01′S 58° 12′W, 33° 5.9′S 58°25.2′W from sediments reaching densities of 2,890 ind. m⁻², at a mean abundance of 350 ind. m⁻². Introductions of nonindigenous species, resulting intentionally or accidentally from anthropic activities, cause significant changes in ecosystems. In aquatic environments, polychaetes are a key invasive group that increases the geographical range of several species through human activities. M. speciosa may have reached the Río de la Plata Basin through a shipping vector and thereafter the Uruguay River by self-navigation.     

External nutrient inputs into terrestrial ecosystems of the Falkland Islands and the Maritime Antarctic region

Antarctic terrestrial ecosystems are nutrient-poor and depend for their functioning in part on external nutrients. However, little is known about the relative importance of various sources. We measured external mineral nutrient sources (wind blown material, precipitation and guano) at three locations, the cold temperate oceanic Falkland Islands (51°76′S), and the Maritime Antarctic Signy (60°71′S) and Anchorage Islands (67°61′S). These islands differ in the level of vegetation development through different environmental constraints and historical factors. Total mineral nitrogen input differed considerably between the islands. During the 3 month summer period it amounted to 18 mg N m⁻² on the Falkland Islands and 6 and 102 mg N m⁻² at Signy and Anchorage Islands, respectively. The high value for Anchorage was a result of guano deposition. By measuring stable isotopic composition (δ¹⁵N) of the different nitrogen sources and the dominant plant species, we investigated the relative utilisation of each source by the vegetation at each island. We conclude that external mineral nitrogen inputs to Antarctic terrestrial ecosystems show great spatial variability, with the local presence of bird (or other vertebrate) colonies being particularly significant.     

Antioxidant enzyme activity of filamentous fungi isolated from Livingston Island, Maritime Antarctica

From 18 soil samples taken in the vicinity of the permanent Bulgarian Antarctic base “St. Kliment Ohridski” (62°38′29″S, 60°21′53″W) on Livingston Island, 109 filamentous fungi were isolated on selective media. The most widespread fungal species were members of the genera Cladosporium, Geomyces, Penicillium and Aspergillus. Other species, already recorded in Antarctic environment, were also isolated: Lecanicillium muscarium, Epicoccum nigrum and Alternaria alternata. Thirty strains demonstrating good growth were screened for antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) that play an important role in the defense of aerobic organisms against oxidative stress, by converting reactive oxygen species into nontoxic molecules. Six of them showed high enzyme activity. The tested strains produced SOD with statistically significant higher activity at 15°C than at 30°C suggesting that this enzyme is cold-active. Such SOD could be useful in medicine and cosmetics. The best producer of cold-active SOD, Aspergillus glaucus 363, cultivated in bioreactors, demonstrated optimal growth temperature at 25°C and maximum enzyme activities at 25 and 30°C for SOD and CAT, respectively. The electrophoretical analysis showed that the fungus possesses Cu/Zn-SOD.     

Microorganisms in a high altitude Glacier Ice in Tibet

Eighty-one strains of viable microorganisms were recovered from 23 samples collected from Ice Core 3 of Malan Glacier (China, 91° 45.3′ E, 35° 48.4′ N) drilled at high altitude (5620 m). All the strains were prokaryotes—75 of bacteria (including spore-forming ones) and 6 of actinomycetes. The characteristic genera differ from those of Arctic and Antarctic ice, in which many fungi and algae are widely distributed; this shows an difference of environmental conditions between Tibet and polar regions. The variation in number and species ofBacillus in different ice core layers implied changes of environmental conditions in the past.     

Field measurement of net photosynthesis of mosses at Langhovde,East Antarctica

Net photosynthesis and dark respiration (CO₂ flux) of Antarctic mosses were measured at Langhovde, East Antarctica, from 9 to 17 January 1988. Moss blocks were taken from communities in the Yukidori Valley (69°14′30″S, 39°46′00″E) at Langhovde. Each block was composed ofCeratodon purpureus andBryum pseudotriquetrum, orB. pseudotriquetrum. The upper part of the block was used to measure net photosynthesis and dark respiration. The net photosynthesis of each sample was measured in the field for one or three days with two infrared CO₂ gas analyzers and an assimilation chamber. The relationships of net photosynthetic rate and dark respiration rate, to the water content of the sample, the intensity of solar radiation and the moss temperature were estimated from the field data. The maximum rate of net photosynthesis was about 4 μmol CO₂ m⁻²s⁻¹ at saturating radiation intensity and at optimum temperature, about 10°C. Environmental features of moss habitats in the Yukidori Valley are discussed in relation to these results.     

First census of breeding seabirds between Cap Bienvenue (Terre Adélie) and Moyes Islands (King George V Land), Antarctica: new records for Antarctic seabird populations

Breeding population sizes of penguins, fulmarine etrels and skuas were estimated for the first time on a major part of the Terre Adélie coast and a section of the King George V Land coast during the 1997/1998 austral summer. We counted 106,400 breeding pairs and 12,400 Adélie penguin (Pygoscelis adeliae) chicks by direct counts, and 6960 breeding pairs from aerial photographs. Minimum breeding populations for other species are (direct counts): Antarctic fulmar (Fulmarus glacialoides) 6861 pairs, Antarctic petrel (Thalassoica antarctica) 4574 pairs, cape petrel (Daption capense) 194 pairs, snow petrel (Pagodroma nivea) 767 pairs, south polar skua (Catharacta maccormicki) 129 pairs and subantarctic skua (Catharacta lonnbergi) 1 breeding bird. We discovered 29 new seabird breeding locations in King George V Land, including 6 Antarctic fulmar, 4 Antarctic petrel, 3 cape petrel, 6 snow petrel and 10 south polar skua colonies. The largest colonies found contained up to 4205 breeding pairs of Antarctic fulmars. Population sizes of all species obtained in this study are higher than those found during previous partial surveys. Although these differences are in great part due to differences in survey methods, they also reflect real population changes. Our minimum population sizes obtained for a small portion of the Antarctic coast (<2%) suggest an underestimation of the estimated world breeding populations for several species of Antarctic seabirds. Accepted: 28 August 1998     

Vagrant Antarctic fur seals at Gough Island in 2009

The Antarctic fur seal Arctocephalus gazella at Gough Island (40°20′S, 09°54′W) in the South Atlantic Ocean, first seen in October/November 2005, was recorded again in September–October 2009. Up to three different individual Antarctic fur seals were sighted on a single day, on a particular beach. A total of seven different individuals were recorded over a 3-week period, well before the onset of the breeding (pupping) season of the resident population of Subantarctic fur seals A. tropicalis. Positively identified individuals were all male, mostly subadult and lean. Only a fraction (~20%) of the available beaches was searched, and it is unknown if the Antarctic fur seals were still present at Gough Island during the austral summer breeding season of southern fur seals.     

Effects of salinity and temperature on Deschampsia antarctica

Deschampsia antarctica is one of two species of vascular plants native to Antarctica. Populations of D. antarctica have become established on recently exposed glacial forelands on the Antarctic Peninsula and these plants may rely upon nutrient inputs from hauled out mammals, seabirds and sea spray. However, not much is known about the ability of these plants to tolerate salinity stress. We examined the effects of salinity and temperature on growth, reproduction, chlorophyll fluorescence and water relations of D. antarctica. In addition, we analysed concentrations of free proline in leaves and roots as previous studies have found large increases in the concentration of this amino acid in response to environmental stress. The growth chamber experiment was a 3 × 3 (temperature × salinity) complete factorial. Plants were grown at three temperature regimes: 7°/7°C, 12°/7°C, and 20°/7°C day/night and three salinity levels: <0.02 decismen per metre (dS m⁻¹; “low salinity”), 2.5 dS m⁻¹ (“medium salinity”), and 5.0 dS m⁻¹ (“high salinity”) for 66 days. Warmer temperatures improved leaf and tiller production as well as leaf and root length, which is consistent with previous findings on this species. Salinity reduced final root length by 6 and 13% in the medium and high-salinity treatments, respectively. Plants growing in medium and high-salinity treatments had xylem pressures that were more negative and higher free-proline concentrations, suggesting that proline may act as an osmoregulant in D. antarctica.     

Detection, differentiation, and abundance estimation of penguin species by high-resolution satellite imagery

Due to its high spatial resolution, broad spatial coverage, and cost-effectiveness, commercial satellite imagery is rapidly becoming a key component of biological monitoring in the Antarctic. While considerable success in surveying emperor penguins (Aptenodytes forsteri) has been facilitated by their large size and the visual simplicity of their habitat, there has been considerably less progress in mapping colonies on the Antarctic Peninsula and associated sub-Antarctic islands where smaller penguin species breed on topographically complex terrain composed of mixed substrates. Here, we demonstrate that Adélie penguin (Pygoscelis adeliae), chinstrap penguin (P. antarcticus), gentoo penguin (P. papua), and macaroni penguin (Eudyptes chrysolophus) colonies can be detected by high-resolution (2-m multispectral, 40–50-cm panchromatic) satellite imagery and that under ideal conditions, such imagery is capable of distinguishing among groups of species where they breed contiguously. To demonstrate the potential for satellite imagery to estimate penguin population abundance, we use satellite imagery of Paulet Island (63°35′S, 55°47′W) to estimate a site-wide population of 115,673 (99,222–127,203) breeding pairs of Adélie penguins.     

Distribution and abundance of Wilson’s storm petrels Oceanites oceanicus at two locations in East Antarctica: testing habitat selection models

Over the last decades, Antarctic seabird populations have been studied as bioindicators of the variability in the Southern Ocean marine ecosystem. Little information is available on the distribution and abundance of Wilson’s storm petrel (Oceanites oceanicus) in East Antarctica although the bioindicator value of this species has been investigated. Regional surveys were conducted at two coastal locations, Casey (66°S, 110°E) and Mawson (67°S, 62°E), to locate Wilson’s storm petrel nests using systematic searches in sites selected with a balanced random sampling design. Conducted in ice-free areas of similar size, searches located 553 Wilson’s storm petrel nests at Mawson and 630 at Casey. Comparable densities were observed between locations but regional estimates suggest that Wilson’s storm petrels are more abundant at Casey. Habitat preferences of Wilson’s storm petrels were investigated using resource selection functions based on Generalized Additive and Linear Models (GAMs and GLMs), which allow their ecological niche to be graphically and quantitatively described. The orientation of nests in relation to the prevailing winds was identified as a determinant of nest distribution at both locations. However, selected rock substrate types differed between Mawson and Casey. Snow was confirmed to constrain the spatial distribution of nests, especially at Casey where snow precipitations and accumulation are more common in summer, confirming the results of previous temporal surveys focusing on breeding success. At the southern edge of its geographic distribution, the Wilson’s storm petrel may be subject to more obvious climate related habitat changes in East Antarctica. Such models may provide valuable information to detect the potential effect of climate variations on this species and others, in the context of a broad Antarctic ecosystem monitoring.     

Transmission electron microscope analysis of virus-like particles in the freshwater lakes of Signy Island, Antarctica

Water samples from a range of fresh-water Antarctic lakes on Signy Island (South Orkney Islands: 60°45′S, 45 °38′W) were examined for the presence of virus-like particles (VLPs) during the 1998/1999 field season. It was discovered that VLPs were ubiquitous, morphologically diverse and abundant, with high concentrations ranging from 4.9 × 10⁶ ml⁻¹ to 3.1 × 10⁷ ml⁻¹. Likely hosts include bacteria, cyanobacteria and eukaryotic algae. In addition, an unusually large virus morphotype was observed with a head diameter 370 × 330 nm and a tail 1.3 μm long. Accepted: 15 May 2000     

The anatomical characters related to the brooding behavior of two Antarctic species of <Emphasis Type="Italic">Mysella</Emphasis> Angas, 1877 (Bivalvia,Galeommatoidea, Lasaeidae), with direct and indirect evidences of ovoviviparity

Brood protection is a common feature of marine bivalves from higher latitudes. In this study the pallial organs of the Antarctic bivalves, Mysella charcoti (Lamy, 1906) and M. narchii Passos & Domaneschi, 2006 were investigated with respect to anatomical characters related to brooding. Both species are simultaneous hermaphrodites and their eggs contain a large amount of yolk. The number of broods ranges from 16 to 30 in M. narchii and 7–27 in M. charcoti, and ovoviviparity was observed for both. Their ctenidia differ in structure, those of M. charcoti being simpler. In M. narchii there is a large elasticity of the tissue of the marginal food grooves of ctenidia, and cilia are much more abundant on the ctenidial abfrontal surface and on the visceral mass epithelium than in M. charcoti. Anatomical characters of M. charcoti can be considered derived when compared to those of M. narchii. In conclusion, detailed anatomical characters related to brooding may be useful in future systematic studies of Antarctic Bivalvia.     

<Emphasis Type="Italic">Asthenes dorbignyi</Emphasis> (Passeriformes: Furnariidae) host of <Emphasis Type="Italic">Argas neghmei</Emphasis> (Acari: Argasidae)

Argas neghmei Kohls & Hoogstraal is a Neotropical tick species parasite of poultry and man in the arid western of the southern cone of America in Argentina and Chile. Males, females and nymphs of an argasid were collected from 20 to 22 of June, 2007 in nests of Creamy-breasted Canastero, Asthenes dorbignyi (Reinchenbach) (Passeriformes: Furnariidae) at about 7 km S of La Poma (24°46′S, 66°12′W) and a male tick at 24°48′S, 66°10′W on Nov 27, 2008, Salta province, Argentina. Scanning electron microscope micrographies and sequences of 16S rDNA confirmed that the ticks found were A. neghmei. Development in breeding areas of A. dorbignyi is probably a source of infestation for animal premises and houses. However, the role of other unknown wild birds may also contribute to the invasion of A. neghmei in chicken houses or residences.     

Catecholamine release in heat-stressed Antarctic fish causes proton extrusion by the red cells

Two species of Antarctic fish were stressed by moving them from seawater at −1 °C to seawater at 10 °C and holding them for a period of 10 min. The active cryopelagic species Pagothenia borchgrevinki maintained heart rate while in the benthic species Trematomus bernacchii there was an increase in heart rate. Blood pressure did not change in either species. Both species released catecholamines into the circulation as a consequence of the stress. P. borchgrevinki released the greater amounts, having mean plasma concentrations of 177 ± 54 nmol · l⁻¹ noradrenaline and 263 ± 131 nmol · l⁻¹ adrenaline at 10 min. Plasma noradrenaline concentrations rose to 47 ± 14 nmol · l⁻¹ and adrenaline to 73 ± 28 nmol · l⁻¹ in T. bernacchii. Blood from P. borchgrevinki was tonometered in the presence of isoprenaline. A fall in extracellular pH suggests the presence of a Na⁺/H⁺ antiporter on the red cell membrane, the first demonstration of this in an Antarctic fish. Treatment with the β-adrenergic antagonist drug sotalol inhibited swelling of red blood cells taken from temperature-stressed P. borchgrevinki, suggesting that the antiporter responds to endogenous catecholamines. Accepted: 22 January 1998