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Tracey L Rogers - One of the best experts on this subject based on the ideXlab platform.
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trace element analysis in the serum and hair of antarctic leopard Seal hydrurga leptonyx and Weddell Seal leptonychotes Weddellii
Science of The Total Environment, 2008Co-Authors: Rachael Gray, P J Canfield, Tracey L RogersAbstract:Leopard Seal, Hydrurga leptonyx, and Weddell Seal, Leptonychotes Weddellii, occupy an upper trophic level within the Antarctic ecosystem and are useful indicator species in the Southern Ocean of trace element concentrations. Reference values for the concentration of 19 trace elements were determined in the serum and hair of leopard and Weddell Seals sampled in Eastern Antarctica. These reference values can be used as 'baseline' levels for monitoring trace element concentrations in these species. Greater trace element concentrations were determined in hair compared to serum, indicating different time scales of trace element accumulation in these samples. For the majority of trace elements, except for Se in the leopard Seal samples and Cr in the Weddell Seal samples, significant regression relationships for trace element concentrations in hair and serum were not elucidated. Significant differences were determined in the concentrations of seven out of 15 elements with hair type, moult and new, in the leopard Seal; concentrations in moult hair were determined to be greater than in new hair for all elements except Zn. Hair analysis was determined to be useful for monitoring exposure to trace elements and when collected off the ice from moulting Seals, hair can be employed as a non-invasive sample for trace element analysis in leopard and Weddell Seals.
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trace element analysis in the serum and hair of antarctic leopard Seal hydrurga leptonyx and Weddell Seal leptonychotes Weddellii
Science of The Total Environment, 2008Co-Authors: Rachael Gray, P J Canfield, Tracey L RogersAbstract:Leopard Seal, Hydrurga leptonyx, and Weddell Seal, Leptonychotes Weddellii, occupy an upper trophic level within the Antarctic ecosystem and are useful indicator species in the Southern Ocean of trace element concentrations. Reference values for the concentration of 19 trace elements were determined in the serum and hair of leopard and Weddell Seals sampled in Eastern Antarctica. These reference values can be used as 'baseline' levels for monitoring trace element concentrations in these species. Greater trace element concentrations were determined in hair compared to serum, indicating different time scales of trace element accumulation in these samples. For the majority of trace elements, except for Se in the leopard Seal samples and Cr in the Weddell Seal samples, significant regression relationships for trace element concentrations in hair and serum were not elucidated. Significant differences were determined in the concentrations of seven out of 15 elements with hair type, moult and new, in the leopard Seal; concentrations in moult hair were determined to be greater than in new hair for all elements except Zn. Hair analysis was determined to be useful for monitoring exposure to trace elements and when collected off the ice from moulting Seals, hair can be employed as a non-invasive sample for trace element analysis in leopard and Weddell Seals.
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vocal individuality of in air Weddell Seal leptonychotes Weddellii pup primary calls
Marine Mammal Science, 2006Co-Authors: Kym Collins, John M Terhune, Tracey L Rogers, Kathryn E Wheatley, Robert HarcourtAbstract:As a result of selective pressures faced during lactation, vocal recognition may play a crucial role in maintaining the phocid mother–pup bond during the period of dependence. To investigate this possibility, we examined whether Weddell Seal (Leptonychotes Weddellii) pups produce individually distinctive “primary” calls. One temporal, nine fundamental frequency features, and two spectral characteristics were measured. A discriminant function analysis (DFA) of 15 Vestfold Hills pups correctly classified 52% of calls, while the cross-validation procedure classified 29% of calls to the correct pup. A second DFA of 10 known-age McMurdo Sound pups correctly classified 44% of “test” calls. For novel calls, the probabilities of attaining such classification rates by chance are low. The relationship between age and call stereotypy indicated that pups 2 wk and older may be more vocally distinctive. Overall, findings suggest that Weddell Seal pup “primary” calls are moderately distinctive and only exhibit sufficient stereotypy to aid maternal recognition by approximately two weeks of age.
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individual variation of in air female pup contact calls in Weddell Seals leptonychotes Weddellii
Behaviour, 2005Co-Authors: Kym Collins, John M Terhune, Tracey L Rogers, Kathryn E Wheatley, Paul Damien Mcgreevy, Robert HarcourtAbstract:Vocal recognition may function as a critical factor in maintaining the phocid mother-pup bond during lactation. For vocal recognition to function, the caller must produce individually distinct calls that are recognised by their intended recipient. Mother-pup vocal recognition has been studied extensively in colonial otariids and appears to be characteristic of this family. Although less numerous, empirical studies of phocid species have revealed a range of recognition abilities. This study investigated whether Weddell Seal (Leptonychotes Weddellii) females produce individually distinct 'pup contact' calls that function during natural pair reunions. Fifteen calls from each of nine females recorded in the Vestfold Hills, Antarctica were analysed. One temporal, nine fundamental frequency and five spectral characteristics were measured. Results of the cross-validated Discriminant Function Analysis revealed that mothers produce individually distinct calls with 56% of calls assigned to the correct individual. The probability of achieving this level of discrimination on novel data by chance alone is highly improbable. Analysis of eight mother-pup reunions recorded near McMurdo Sound, Antarctica further demonstrated that these 'pup contact' calls function during natural pair reunions. Behavioural analysis also revealed that pups were chiefly responsible for establishing and maintaining close contact throughout the reunion process. Our study therefore demonstrates that Weddell Seal females produce calls with sufficient stereotypy to allow pups to identify them during pair reunions, providing evidence of a functioning mother-pup vocal recognition system.
Joachim Plotz - One of the best experts on this subject based on the ideXlab platform.
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light and scanning electron microscopical study on antarctophthirus ogmorhini lice from the antarctic Seal leptonychotes Weddellii
Parasitology Research, 2002Co-Authors: Birgit Mehlhorn, Heinz Mehlhorn, Joachim PlotzAbstract:Adult lice (Antarctophthirus ogmorhini) from the Weddell Seal Leptonychotes Weddellii were investigated by means of light and scanning electron microscopy. We established that this species is characterized by several morphological peculiarities which enable it to survive the low temperatures of the Antarctic sea and the body depression which occurs during the deep (450 m) and long diving periods of the Seals. The main peculiarities are: (1) the cuticle of the ventral and lateral surfaces is much thinner than that of the dorsal surface, (2) the body has numerous stiff spines which are covered by a thick layer of the Seal's sebum that closely surrounds the body of the louse, (3) the whole body is covered by a close layer of leaf-like scales which are apparently able to trap air bubbles and thus to provide a small zone of air close to the surface of the cuticle.
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microscopic anatomy of the eye of the deep diving antarctic Weddell Seal leptonychotes Weddellii
Journal of Morphology, 2001Co-Authors: Ulrich Welsch, Sven Ramdohr, Bernd Riedelsheimer, Regina Eisert, Rudolf Hebel, Joachim PlotzAbstract:The microscopic anatomy of the eye of the Weddell Seal was studied with various light and electron microscopic methods with a view to correlating morphological findings with the biology of this Seal which is adapted to the extremes of the Antarctic environment and to extreme diving excursions into the lightless depths of the sea. In the retina an area centralis was found but no fovea centralis. The densely packed photoreceptors consist exclusively of highly differentiated rods, which in primates detect light at low intensity but have rather poor image discrimination. The ganglion cells are relatively scarce, suggesting a high degree of convergence of the light-sensitive cells on the ganglion cells. The pigment epithelium is almost devoid of pigment granules. The extensive tapetum lucidum is about 400–500 μm thick and is composed of about 30 layers of specialized cells. The cornea is 650 (center) to 800–900 (periphery) μm thick. Its structure and glycosaminoglycan histochemistry correspond to that of other mammals. The iridocorneal angle is unusually deep and pervaded by an elaborate trabecular meshwork, which together with a complex canal of Schlemm can be correlated with the ability to absorb large amounts of fluid. The ciliary muscle and its antagonist, the membrane of Bruch, are poorly developed, suggesting relatively poor abilities of accommodation. The combination of a well-developed tapetum lucidum, an unpigmented pigment epithelium, well-developed rods, and a high number of rods converging on only few ganglion cells is obviously an adaptation to an extreme light sensitivity, enabling the animals to make use of the little light available in the deep sea. J. Morphol. 248:165–174, 2001. © 2001 Wiley-Liss, Inc.
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histophysiology of the eye of the deep diving antarctic Weddell Seal leptonychotes Weddellii
EPIC3Journal of Morphology: 248 pp. 165-174, 2001Co-Authors: Ulrich Welsch, Sven Ramdohr, Bernd Riedelsheimer, Regina Eisert, Rudolf Hebel, Joachim PlotzAbstract:The microscopic anatomy of the eye of the Weddell Seal was studied with various light and electronmicroscopic methods with aview to correlating morphological findings with the biology of this Seal whichis adapted to the extremes of the Antarctic environment and to extreme diving excursions into the lightlessdepth of the sea. In the retina and area centralis was found but no fovea centralis. Thedensily packed photoreceptors consist exclusively of highly differenciated rods, which inprimates detect light at low intensity but have rather poor image discrimination.The ganglion cells are relatively scarce, suggesting a high degree of convergence of thelight-sensitive cells on the ganglion cells. The pigment epithelium is almost devoid ofpigment granules. The extensive tapetum lucidum is about 400-500 micrometer thickand is composed of about 30 layers of specialized cells. the cornea is 650 (center)to 800-900 (periphery) micrometer thick. Its structure and glucosaminoglycan histochemistrycorrespond to that of other mammals. The iridocorneal angle is unusually deep andpervaded by an elaborate trabecular meshwork, which together with a complex canalof Schlemm can be correlated with the ability to absorb large amounts of fluid. Theciliary muscle and its antagonist, the membrane of Bruch, are poorly developed., suggestingrelatively poor abilities of accomodation. The combination of a well-developed tapetumlucidum, and unpigmented pigment epithelium, well-developed rods, and a high number of rodconverging on only few ganglion cells is obviously an adaptation to an extreme lightsensitivity, enabling the animal to make use of the little light available in the deep sea.
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histological histochemical and ultrastructural investigations on the gastrointestinal system of antarctic Seals Weddell Seal leptonychotes Weddellii and crabeater Seal lobodon carcinophagus
Journal of Morphology, 1995Co-Authors: Udo Schumacher, Joachim Plotz, Peter Klein, Ulrich WelschAbstract:The morphology of the principal sections of the gastrointestinal system of two Antarctic Seals with different dietary habits, namely, the Weddell Seal (Leptonychotes Weddellii) and the crabeater Seal (Lobodon carcinophagus), has been investigated. Histologically examined by light microscopy, the tissue layers of the gastrointestinal tract of both Seals are almost identical to those observed in most other mammals and no major differences in principle organization could be found between the two Seal species. The ultrastructure of the gastric and intestinal epithelial cells has been examined and is also closely comparable to that of these cells in other mammals; however, Paneth cells have not been found in our material. In general, therefore, adaptations of the gastrointestinal tract to the aquatic environment or the diet are not obvious at the morphological levels of organization studied. Histochemical differences are found between the two closely related species; mucins of the surface epithelium in the stomach of Weddell Seals are highly sulfated, while those in the crabeater Seal are not. Mucous neck cells in Weddell Seals contain acid mucosubstances, while those of crabeater Seals contain neutral ones. Goblet cells in the small and large intestine in Weddell Seals contain both neutral and acid mucosubstances. Both mucin types are detected in the crabeater Seal; however, the mucins of the colon in the crabeater Seal are more highly sulfated than those in the Weddell Seal. The ratio of globet cells to enterocytes in the large intestine of crabeater Seals is higher than that in Weddell Seals. © 1995 Wiley-Liss, Inc.
Patricia Ronayne A De Ferrer - One of the best experts on this subject based on the ideXlab platform.
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variaciones de los niveles de grasa y proteina en la leche de la foca de Weddell leptonychotes Weddellii lesson 1826 en la isla laurie antartica estudio preliminar
Revista De Biologia Marina Y Oceanografia, 2008Co-Authors: Maria Elena Marquez, Alejandro R Carlini, A Baroni, Patricia Ronayne A De FerrerAbstract:The Weddell Seal (Leptonychotes Weddellii Lesson, 1826) has in common with other antarctic phocids, a lactation characterized by high rates of nutrients and ...
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variaciones de los niveles de grasa y proteina en la leche de la foca de Weddell leptonychotes Weddellii lesson 1826 en la isla laurie antartica estudio preliminar variations of fat and protein levels in the Weddell Seal leptonychotes Weddellii lesso
2008Co-Authors: Maria Elena Marquez, Alejandro R Carlini, A Baroni, Patricia Ronayne A De FerrerAbstract:The Weddell Seal (Leptonychotes Weddellii Lesson, 1826) has in common with other antarctic phocids, a lactation characterized by high rates of nutrients and energy transfer. The study of the variations in the milk composition contributes to the knowledge about this particular model of lactation and allows the acquisition of basic information for veterinary medical studies. The present study shows the preliminary results of the analyses of the variations in milk fat and protein levels from four females sampled sequentially along lactation at Laurie Island, South Orkney Islands during the 2002 breeding season. Important inter individual variations were observed among the sampled females, but a similar pattern along time which showed: a) an increasing trend for fat levels during the first half of the lactation period (13.04 to 61.25 g 100 g -1 ), and then maintaining high values (41.21 to 48.88 g 100 g -1 ) from this point until the end of suckling, and b) total protein levels fluctuated within a narrow range (8.10 to 11.74 g 100 g -1 ) along the period. Fat and protein values are similar to those reported for other phocids, allowing for the rapid growth and the formation of the blubber to protect the pup and assure its survival.
Rachael Gray - One of the best experts on this subject based on the ideXlab platform.
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trace element analysis in the serum and hair of antarctic leopard Seal hydrurga leptonyx and Weddell Seal leptonychotes Weddellii
Science of The Total Environment, 2008Co-Authors: Rachael Gray, P J Canfield, Tracey L RogersAbstract:Leopard Seal, Hydrurga leptonyx, and Weddell Seal, Leptonychotes Weddellii, occupy an upper trophic level within the Antarctic ecosystem and are useful indicator species in the Southern Ocean of trace element concentrations. Reference values for the concentration of 19 trace elements were determined in the serum and hair of leopard and Weddell Seals sampled in Eastern Antarctica. These reference values can be used as 'baseline' levels for monitoring trace element concentrations in these species. Greater trace element concentrations were determined in hair compared to serum, indicating different time scales of trace element accumulation in these samples. For the majority of trace elements, except for Se in the leopard Seal samples and Cr in the Weddell Seal samples, significant regression relationships for trace element concentrations in hair and serum were not elucidated. Significant differences were determined in the concentrations of seven out of 15 elements with hair type, moult and new, in the leopard Seal; concentrations in moult hair were determined to be greater than in new hair for all elements except Zn. Hair analysis was determined to be useful for monitoring exposure to trace elements and when collected off the ice from moulting Seals, hair can be employed as a non-invasive sample for trace element analysis in leopard and Weddell Seals.
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trace element analysis in the serum and hair of antarctic leopard Seal hydrurga leptonyx and Weddell Seal leptonychotes Weddellii
Science of The Total Environment, 2008Co-Authors: Rachael Gray, P J Canfield, Tracey L RogersAbstract:Leopard Seal, Hydrurga leptonyx, and Weddell Seal, Leptonychotes Weddellii, occupy an upper trophic level within the Antarctic ecosystem and are useful indicator species in the Southern Ocean of trace element concentrations. Reference values for the concentration of 19 trace elements were determined in the serum and hair of leopard and Weddell Seals sampled in Eastern Antarctica. These reference values can be used as 'baseline' levels for monitoring trace element concentrations in these species. Greater trace element concentrations were determined in hair compared to serum, indicating different time scales of trace element accumulation in these samples. For the majority of trace elements, except for Se in the leopard Seal samples and Cr in the Weddell Seal samples, significant regression relationships for trace element concentrations in hair and serum were not elucidated. Significant differences were determined in the concentrations of seven out of 15 elements with hair type, moult and new, in the leopard Seal; concentrations in moult hair were determined to be greater than in new hair for all elements except Zn. Hair analysis was determined to be useful for monitoring exposure to trace elements and when collected off the ice from moulting Seals, hair can be employed as a non-invasive sample for trace element analysis in leopard and Weddell Seals.
Shane B Kanatous - One of the best experts on this subject based on the ideXlab platform.
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assessment of legacy and emerging persistent organic pollutants in Weddell Seal tissue leptonychotes Weddellii near mcmurdo sound antarctica
Science of The Total Environment, 2012Co-Authors: Stephen J Trumble, Eleanor M Robinson, Shawn R Noren, Sascha Usenko, Jay W Davis, Shane B KanatousAbstract:Muscle samples were collected from pup, juvenile and adult Weddell Seals (Leptonychotes Weddellii) near McMurdo Sound, Antarctica during the austral summer of 2006. Blubber samples were collected from juvenile and adult Seals. Samples were analyzed for emerging and legacy persistent organic pollutants (POPs) including current and historic-use organochlorine pesticides, polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs). Of the 41 target analytes, 28 contaminants were recovered from the Weddell Seal blubber, in this order of prevalence: p,p′-DDE, p,p′-DDT, trans-nonachlor, mirex, cis-nonachlor, PCB 153, PCB 138, dieldrin, heptachlor epoxide, nonachlor III, PCB 187, oxychlordane, cis-chlordane, PCB 118, PBDE 47, PCB 156, PCB 149, PCB 180, PCB 101, PCB 170, PCB 105, o,p′-DDT, PCB 99, trans-chlordane, PCB 157, PCB 167, PCB 189, and PCB 114. Fewer POPs were found in the muscle samples, but were similar in the order of prevalence to that of the blubber: p,p′-DDE, o,p′-DDT, trans-nonachlor, nonachlor III, oxychlordane, p,p′-DDT, dieldrin, mirex, cis-nonachlor, PCB 138, and PCB 105. Besides differences in toxicant concentrations reported between the muscle and blubber, we found differences in POP levels according to age class and suggest that differences in blubber storage and/or mobilization of lipids result in age class differences in POPs. To our knowledge, such ontogenetic associations are novel. Importantly, data from this study suggest that p,p′-DDT is becoming less prevalent temporally, resulting in an increased proportion of its metabolite p,p′-DDE in the tissues of this top predator. In addition, this study is among the first to identify a PBDE congener in Weddell Seals near the McMurdo Station. This may provide evidence of increased PBDE transport and encroachment in Antarctic wildlife.
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in the face of hypoxia myoglobin increases in response to hypoxic conditions and lipid supplementation in cultured Weddell Seal skeletal muscle cells
The Journal of Experimental Biology, 2012Co-Authors: Michael A De Miranda, Amber Schlater, Todd L Green, Shane B KanatousAbstract:SUMMARY A key cellular adaptation to diving in Weddell Seals is enhanced myoglobin concentrations in their skeletal muscles, which serve to store oxygen to sustain a lipid-based aerobic metabolism. The aim of this study was to determine whether Seal muscle cells are inherently adapted to possess the unique skeletal muscle adaptations to diving seen in the whole animal. We hypothesized that the Seal skeletal muscle cells would have enhanced concentrations of myoglobin de novo that would be greater than those from a C 2 C 12 skeletal muscle cell line and reflect the concentrations of myoglobin observed in previous studies. In addition we hypothesized that the Seal cells would respond to environmental hypoxia similarly to the C 2 C 12 cells in that citrate synthase activity and myoglobin would remain the same or decrease under hypoxia and lactate dehydrogenase activity would increase under hypoxia as previously reported. We further hypothesized that β-hydroxyacyl CoA dehydrogenase activity would increase in response to the increasing amounts of lipid supplemented to the culture medium. Our results show that myoglobin significantly increases in response to environmental hypoxia and lipids in the Weddell Seal cells, while appearing similar metabolically to the C 2 C 12 cells. The results of this study suggest the regulation of myoglobin expression is fundamentally different in Weddell Seal skeletal muscle cells when compared with a terrestrial mammalian cell line in that hypoxia and lipids initially prime the skeletal muscles for enhanced myoglobin expression. However, the cells need a secondary stimulus to further increase myoglobin to levels seen in the whole animal.
