Stable isotope analysis of ancient and modern gentoo penguin egg membrane and the krill surplus hypothesis in Antarctica

2013 ◽  
Vol 25 (2) ◽  
pp. 213-218 ◽  
Author(s):  
Steven D. Emslie ◽  
Michael J. Polito ◽  
William P. Patterson

AbstractThe ‘krill surplus’ hypothesis in Antarctica posits that the historic depletion of krill-eating whales and seals in the 18–20th centuries provided a surplus of krill in the Southern Ocean that benefited penguins. A previous study which examined stable isotopes in ancient and modern tissues of Adélie penguin (Pygoscelis adeliae) provides support for this hypothesis. Specifically, a significant decrease in δ13C and δ15N values occurred in modern versus ancient tissues from an apparent dietary shift from fish to krill associated with the purported krill surplus. Here, we present new data on gentoo penguin (Pygoscelis papua) tissues from active and abandoned colonies at three locations in the Antarctic Peninsula. We found an overall, but weak, decrease in modern versus fossil δ15N and δ13C values of gentoo penguin egg membrane with considerable variation across three breeding sites. Dietary mixing models suggest that shifts between fish and krill in gentoo penguins were likely not as strong as those previously observed in Adélie penguins. This weaker signal probably results from the greater reliance on fish in their diets, past and present, though we cannot rule out declines in primary productivity or other ecosystem shifts which also could account for declines in δ13C and δ15N values.

2019 ◽  
Vol 53 (6) ◽  
pp. 491-500
Author(s):  
V. M. Smagol ◽  
D. V. Pilipenko ◽  
A. O. Dzhulai

Abstract The research covers water area, island archipelagos and coastal line of the Antarctic Peninsula from 65°31ʹ S, 64°25ʹ W in the South to 65°03ʹ S, 63°53ʹ W in the North. There was time gap of 7 years between the researches (2011 and 2018), which allows to define tendencies in development of individual colonies and to make conclusion about success of existence of a given species. The work itself was carried out during the first half of January, that is in the time when the stage of brooding ends and the period of hatching starts. As of 2011, 12 nesting points of gentoo penguin (Pygoscelis papua) with total number of 8,342 pairs were found in the region under investigation. Till 2018, quantity of the colony grew to 14, with total number of 14,105 pairs. For seven years, quantity of nesting points of aelie penguin (Pygoscelis adeliae) almost did not change (4 colonies). Instead, total number of the species decreased somewhat: from 3559 pairsin 2011 to 3295 onesin 2018. Number of chinstrap penguin (Pygoscelis antarctica) in united stable locality for nesting also decreased from 26 pairsin 2011 to19 onesin 2018. Booth Island (65°04ʹ S, 64°02ʹ W) for chinstrap penguins and Green Island (65°19ʹ S, 64°09ʹ W) for gentoo penguins are the southern most points of nesting range of the species. Also, 7 colonies of antarctic shag (Phalacrocorax bransfieldensis) were revealed in the region under investigation. For seven years from 2011 to 2018 total number of the species in the region under investigation grew from 190 pairs to 299, and in most cases the antarctics shag forms settlements jointly with penguins.


Polar Record ◽  
1995 ◽  
Vol 31 (179) ◽  
pp. 409-418 ◽  
Author(s):  
Steven D. Emslie

ABSTRACTInvestigations on the age and taphonomy of modern and abandoned penguin rookeries were completed in the Antarctic Peninsula region, 1992–1994. Systematic collection and identification of bones from modern rookeries of Adélie (Pygoscelis adeliae), chinstrap (P. antarctica), and gentoo (P. papua) penguins indicate a bias in element preservation for humeri, furcula, femora, and tibiotarsi. More than 73% of the individuals represented by these elements are juveniles. Bones from abandoned rookeries show similar patterns that can help identify old breeding sites and the species that occupied them. Radiocarbon dates completed on 13 chinstrap and Adélie penguin bones, feathers, and eggshell fragments from five abandoned rookeries suggest that occupation of these sites occurred only during warm intervals of the Little Ice Age (AD 1500–1850). These data also provide information on the paleoecology and paleobiogeography of penguins in the Antarctic Peninsula region, which help explain modern distribution patterns and demography.


Polar Record ◽  
2016 ◽  
Vol 53 (1) ◽  
pp. 79-87 ◽  
Author(s):  
Solange Jara-Carrasco ◽  
Ricardo Barra ◽  
Winfred Espejo ◽  
José E. Celis ◽  
Daniel González-Acuña ◽  
...  

ABSTRACTPersistent organic pollutants (POPs) and their effects on Antarctic seabirds by using excreta as a non-destructive biomonitoring tool have received little consideration. Here we determine the levels of polychlorinated biphenyls (PCBs) and some organochlorine pesticides such as dichlorodiphenyltrichloroethanes (DDTs), hexachlorobencene (HCB), heptachlor, and endrin aldehyde in penguin excreta. Animal exposure to these environmental contaminants was determined through porphyrins in penguin droppings. Stool samples of Adélie penguin (Pygoscelis adeliae), chinstrap penguin (Pygoscelis antarctica) and gentoo penguin (Pygoscelis papua) were collected on two locations of the Antarctic Peninsula area: Base O´Higgins (Antarctic Peninsula) and Ardley Island (King George Island). Despite POPs have been banned more than three decades ago, the levels (ng g−1ww) of PCBs (1.45-2.35), DDTs (1.33-1.76), HCB (0.51-1.70), endrin (0.48-0.71) and heptachlor (0.97-2.40) showed that these pollutants are still present in Antarctica. Porphyrin levels in excreta (4.6-6.7 nmol g−1dw) were significantly correlated to POPs, indicating certain chemical exposure on penguin colonies that inhabit the Antarctic Peninsula area. The levels of heptachlor found in penguin guano may be affecting some biota in terrestrial sites next to nesting places. Further studies and better understanding of POPs impact on animal performance in Antarctic biota are recommended.


Polar Biology ◽  
2021 ◽  
Vol 44 (3) ◽  
pp. 621-629
Author(s):  
Mayuka Uchida ◽  
Ippei Suzuki ◽  
Keizo Ito ◽  
Mayumi Ishizuka ◽  
Yoshinori Ikenaka ◽  
...  

AbstractAntarctic minke whales (Balaenoptera bonaerensis) are migratory capital breeders that experience intensive summer feeding on Antarctic krill (Euphausia superba) in the Southern Ocean and winter breeding at lower latitudes, but their prey outside of the Antarctic is unknown. Stable isotope analyses were conducted on δ13C and δ15N from the baleen plates of ten pregnant Antarctic minke whales to understand the growth rate of the baleen plate and their diet in lower latitudes. Two to three oscillations along the length of the edge of the baleen plate were observed in δ15N, and the annual growth rate was estimated to be 75.2 ± 20.4 mm, with a small amplitude (0.97 ± 0.21 ‰). Bayesian stable isotope mixing models were used to understand the dominant prey that contributed to the isotopic component of the baleen plate using Antarctic krill from the stomach contents and reported values of Antarctic coastal krill (Euphausia crystallorophias), Antarctic silver fish (Pleuragramma antarcticum), Australian krill spp., and Australian pelagic fish spp.. The models showed that the diet composition of the most recent three records from the base of the baleen plates (model 1) and the highest δ15N values in each baleen plate (model 2) were predominantly Antarctic krill, with a contribution rate of approximately 80%. The rates were approximately 10% for Antarctic coastal krill and less than 2.0% for the two Australian prey groups in both models. These results suggest that pregnant Antarctic minke whales did not feed on enough prey outside of the Antarctic to change the stable isotope values in their baleen plates.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Robert S. Feranec ◽  
John P. Hart

Abstract Freshwater and marine fish have been important components of human diets for millennia. The Great Lakes of North America, their tributaries and smaller regional freshwater bodies are important Native American fisheries. The ethnohistorical record, zooarchaeological remains, and isotopic values on human bone and tooth collagen indicate the importance of fish in fourteenth- through seventeenth-century ancestral Wendat diets in southern Ontario, which is bordered by three of the Great Lakes. Maize (Zea mays ssp. mays) was the primary grain of Native American agricultural systems in the centuries prior to and following sustained European presence. Here we report new Bayesian dietary mixing models using previously published δ13C and δ15N values on ancestral Wendat bone and tooth collagen and tooth enamel. The results confirm previous estimates from δ13C values that ancestral Wendat diets included high proportions of maize but indicate much higher proportions of fish than has previously been recognized. The results also suggest that terrestrial animals contributed less to ancestral Wendat diets than is typically interpreted based on zooarchaeological records.


1982 ◽  
Vol 3 ◽  
pp. 344
Author(s):  
Ye. Korotkevich ◽  
V.N. Petrov ◽  
N.I. Barkov ◽  
V.Ya. Lipenkov

The ice core from the 1 415 m Vostok bore hole has been studied. It was found that the ice-grain size increases with depth in the upper 700 m, a sharp gradient change occurring in the 300 to 400 m range. The grain cross-section area at depths of 100, 200, 300, 400, 500, 600, and 700 m was 1.1, 2.0, 1.5, 1.9, 2.6, and 3.3 mm2 respectively. Since grain size is a function of age, and is determined by initial size and growth rate, the latter being exponentially related to ice temperature, an attempt was made to interpret the obtained data in terms of palaeoclimatology. Calculations show that the upper part of the ice sheet (down to 300 m depth) formed during the past 12 ka, and grew under temperatures higher than those at which the lower part of the ice formed, that is ice at 300 to 700 m depth. This conclusion was confirmed by the results of oxygen isotope analysis. The air content of ice at depths 100 to 650, 650 to 850, 850 to 1 100, and 1 100 to 1 400 m reduced to normal conditions was 65, 70, 75, and 70 mm3 g−1 respectively. Calculations suggest that 3 to 30 ka BP the ice-sheet elevation at Vostok station was close to the present one, while 30 to 40, 40 to 55, and 55 to 75 ka BP it was 500, 1 000, and 500 m lower than at present, respectively.


2005 ◽  
Vol 17 (1) ◽  
pp. 11-16 ◽  
Author(s):  
RENBIN ZHU ◽  
LIGUANG SUN ◽  
XUEBIN YIN ◽  
ZHOUQING XIE ◽  
XIAODONG LIU

Gentoo penguin Pygoscelis papua is an important component of the Antarctic marine ecosystem. In this paper, we use an indirect approach, a geochemical method combining with 137Cs and 210Pb CRS mode dating, to study the dynamics of the gentoo population and colony on Barton Peninsula, King George Island, in the maritime Antarctic. Five sediment profiles were sampled in the zone between the gentoo penguin colony and tundra vegetation on this peninsula and the sediment sequence and typical elements from penguin guano were analysed. Results showed that the levels for typical elements display a dramatic change at around 5 cm depth, indicating the strong impact of penguin guano. The sediments below 5 cm showed lower concentrations in these elements, suggesting that these sediments had received little impact from penguin guano. By Q-mode factor analysis, a method for decomposing multiple factors, we found that over the past sixty years the gentoo colony showed a rapid enlargement and the tundra vegetation had been destroyed. Possible factors responsible for the enlargement of the penguin colony are tentatively discussed.


2010 ◽  
Vol 88 (2) ◽  
pp. 186-194 ◽  
Author(s):  
C. E. McParland ◽  
C. A. Paszkowski ◽  
J. L. Newbrey

Dietary overlap between waterbirds and fish in many freshwater systems can lead to competition for food resources and changes in the trophic position of top predators. We used stable isotope analysis of carbon and nitrogen from egg tissues to document differences in the trophic position of breeding Red-necked Grebes ( Podiceps grisegena (Boddaert, 1783)) on wetlands with and without fish in the Aspen Parkland of Alberta, Canada. Grebes occupied higher trophic levels in the presence of fish than in their absence, suggesting that small-bodied fish in Aspen Parkland food webs may lengthen food chains in which grebes are top predators. A mixed diet of invertebrates and fishes may be adaptive for grebes in this highly variable ecosystem where fish colonize wetlands in wet years and are extirpated in dry years. Carbon analyses indicated that female grebes likely obtained resources for egg production from breeding sites and not from wintering areas, as eggs had similar δ13C values to wetland primary producers, invertebrates, and fishes.


2013 ◽  
Vol 16 (1) ◽  
pp. 137-166 ◽  
Author(s):  
Gisela Grupe ◽  
Claus von Carnap-Bornheim ◽  
Cornelia Becker

Viking Haithabu and its successor, the medieval town of Schleswig, were important international trade centres. Human skeletal finds spanning a period of approximately 400 years represent the bodily relics of the former inhabitants, who witnessed the rise and fall of these trade centres. Analysis of δ13C and δ15N from bone collagen was performed to reconstruct and detect changes in dietary preferences over time. A comparison with the respective isotopic data obtained from a large archaeofaunal sample resulted in a classic ‘mixing muddle’ that could only be deciphered using isotope mass balance mixing models applied on an individual basis. It was found that the overall subsistence economy shifted over time from a focus on fishing to one based predominantly on farming. The move to utilizing a new main source of protein did not impair overall protein supply. In addition, changing living conditions experienced by the inhabitants of Schleswig may have led to a change in infant nursing strategy.


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