scholarly journals Author Correction: Zinc isotopes from archaeological bones provide reliable trophic level information for marine mammals

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Jeremy McCormack ◽  
Paul Szpak ◽  
Nicolas Bourgon ◽  
Michael Richards ◽  
Corrie Hyland ◽  
...  
Keyword(s):  
Trophic Level ◽  
Marine Mammals ◽  
Zinc Isotopes ◽  
Level Information

scholarly journals Zinc isotopes from archaeological bones provide reliable tropic level information for marine mammals

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Jeremy McCormack ◽  
Paul Szpak ◽  
Nicolas Bourgon ◽  
Michael Richards ◽  
Corrie Hyland ◽  
...  
Keyword(s):  
Trophic Level ◽  
Marine Mammals ◽  
Nitrogen Isotopes ◽  
Geographic Area ◽  
Marine Ecology ◽  
Dietary Analysis ◽  
Regional Food ◽  
Zinc Isotopes ◽  
Level Information ◽  
Discrimination Factors

AbstractIn marine ecology, dietary interpretations of faunal assemblages often rely on nitrogen isotopes as the main or only applicable trophic level tracer. We investigate the geographic variability and trophic level isotopic discrimination factors of bone zinc 66Zn/64Zn ratios (δ66Zn value) and compared it to collagen nitrogen and carbon stable isotope (δ15N and δ13C) values. Focusing on ringed seals (Pusa hispida) and polar bears (Ursus maritimus) from multiple Arctic archaeological sites, we investigate trophic interactions between predator and prey over a broad geographic area. All proxies show variability among sites, influenced by the regional food web baselines. However, δ66Zn shows a significantly higher homogeneity among different sites. We observe a clear trophic spacing for δ15N and δ66Zn values in all locations, yet δ66Zn analysis allows a more direct dietary comparability between spatially and temporally distinct locations than what is possible by δ15N and δ13C analysis alone. When combining all three proxies, a more detailed and refined dietary analysis is possible.

scholarly journals Examining predator–prey body size, trophic level and body mass across marine and terrestrial mammals

2014 ◽  
Vol 281 (1797) ◽  
pp. 20142103 ◽  
Author(s):  
Marlee A. Tucker ◽  
Tracey L. Rogers
Keyword(s):  
Community Structure ◽  
Body Size ◽  
Body Mass ◽  
Marine Environment ◽  
Trophic Level ◽  
Marine Mammals ◽  
Trophic Position ◽  
Trophic Levels ◽  
Predator Prey ◽  
Terrestrial Mammals

Predator–prey relationships and trophic levels are indicators of community structure, and are important for monitoring ecosystem changes. Mammals colonized the marine environment on seven separate occasions, which resulted in differences in species' physiology, morphology and behaviour. It is likely that these changes have had a major effect upon predator–prey relationships and trophic position; however, the effect of environment is yet to be clarified. We compiled a dataset, based on the literature, to explore the relationship between body mass, trophic level and predator–prey ratio across terrestrial ( n = 51) and marine ( n = 56) mammals. We did not find the expected positive relationship between trophic level and body mass, but we did find that marine carnivores sit 1.3 trophic levels higher than terrestrial carnivores. Also, marine mammals are largely carnivorous and have significantly larger predator–prey ratios compared with their terrestrial counterparts. We propose that primary productivity, and its availability, is important for mammalian trophic structure and body size. Also, energy flow and community structure in the marine environment are influenced by differences in energy efficiency and increased food web stability. Enhancing our knowledge of feeding ecology in mammals has the potential to provide insights into the structure and functioning of marine and terrestrial communities.

Fireproof killer whales (Orcinus orca): flame-retardant chemicals and the conservation imperative in the charismatic icon of British Columbia, Canada

2006 ◽  
Vol 63 (1) ◽  
pp. 224-234 ◽  
Author(s):  
Peter S Ross
Keyword(s):  
British Columbia ◽  
Trophic Level ◽  
Polybrominated Diphenyl Ethers ◽  
Marine Mammals ◽  
Polychlorinated Biphenyl ◽  
High Trophic Level ◽  
Orcinus Orca ◽  
Weight Of Evidence ◽  
Older Individuals ◽  
Killer Whales

Long-lived and high trophic level marine mammals are vulnerable to accumulating often very high concentrations of persistent chemicals, including pesticides, industrial by-products, and flame retardants. In the case of killer whales (Orcinus orca), some of the older individuals currently frequenting the coastal waters of British Columbia (BC) were born during the First World War, well before the advent of widespread chemical manufacture and use. BC's killer whales are now among the most polychlorinated biphenyl (PCB) contaminated marine mammals in the world. While the "legacy" PCBs have largely been banned, polybrominated diphenyl ethers (PBDEs) have recently emerged as a major concern. The endocrine-disrupting nature of these two persistent fire retardants in biota spells trouble at the top of the food chain, with increasing evidence of effects on reproductive health, the immune system, and development in exposed mammals. The heavy contamination of BC's killer whales, coupled with their long life span and high trophic level, highlights the need for a "weight of evidence" approach in research, conservation planning, and regulatory decisions. Given the global nature of contaminant dispersion, such approaches can only be effective when carried out on both national and international scales.

Trophic relationships of albatrosses associated with squid and large-mesh drift-net fisheries in the North Pacific Ocean

1997 ◽  
Vol 75 (4) ◽  
pp. 549-562 ◽  
Author(s):  
Patrick Gould ◽  
Peggy Ostrom ◽  
William Walker
Keyword(s):  
Pacific Ocean ◽  
Trophic Level ◽  
North Pacific ◽  
Marine Mammals ◽  
North Pacific Ocean ◽  
Transitional Zone ◽  
Trophic Relationships ◽  
Commercial Fishing ◽  
The North ◽  
The North Pacific

The diets of Laysan (Diomedea immutabilis) and black-footed albatrosses (D. nigripes) killed in squid and large-mesh drift nets in the transitional zone of the North Pacific Ocean were investigated by examining the contents of the digestive tracts and determining δ13C and δ15N values in breast-muscle tissue. The results show that (i) the combined prey of the two species of albatross consists of over 46 species of marine organisms including coelenterates, arthropods, mollusks, fish, and marine mammals; (ii) both species supplement their traditional diets with food made available by commercial fishing operations (e.g., net-caught squid and offal); (iii) while obtained from drift nets, diets of nonbreeding Laysan and black-footed albatrosses are dominated by neon flying squid (Ommastrephes bartrami); (iv) in the absence of drift-net-related food, Laysan albatrosses feed most heavily on fish and black-footed albatrosses feed most heavily on squid; and (v) based on δ15N values, nonbreeding adult Laysan albatrosses from the transitional zone of the North Pacific Ocean and Laysan albatross nestlings fed by adults from Midway Island in the subtropical Pacific feed at one trophic level and one-third of a trophic level lower than black-footed albatrosses, respectively.

scholarly journals Spatial segregation and similar trophic-level diet among eastern Canadian Arctic/north-west Atlantic killer whales inferred from bulk and compound specific isotopic analysis

2013 ◽  
Vol 94 (6) ◽  
pp. 1343-1355 ◽  
Author(s):  
Cory J.D. Matthews ◽  
Steven H. Ferguson
Keyword(s):  
Trophic Level ◽  
Marine Mammals ◽  
Trophic Position ◽  
Canadian Arctic ◽  
Isotopic Analysis ◽  
Killer Whales ◽  
Dietary Specialization ◽  
North West ◽  
Isotopic Variation ◽  
Eastern Canadian Arctic

Killer whales in the Eastern Canadian Arctic (ECA) prey on narwhal, beluga, bowhead whales and seals, while further south in the north-west Atlantic (NWA), killer whales off the coast of Newfoundland and Labrador prey on both marine mammals and fish. Bulk and amino acid (AA) specific isotopic composition of dentinal collagen in teeth of 13 ECA/NWA killer whales were analysed to assess the degree, if any, of dietary specialization of killer whales across the region. Dentine was sampled from within annual growth layer groups (GLGs) to construct chronological profiles of stable nitrogen (δ15N) and carbon (δ13C) isotopic compositions for individual whales spanning 3–25 years. Interannual isotopic variation across GLGs was less than that among individuals, and median bulk δ15N values differed by up to 5‰ among individuals. Significant correlation between bulk δ15N values and baseline (source AA) δ15N values indicates much of the observed isotopic variation among individuals reflects foraging within isotopically distinct food webs, rather than diet differences. This interpretation is supported by consistent differences in bulk δ13C values between the two individuals with lowest source AA δ15N values and the remaining whales. After accounting for baseline isotopic variation, comparable δ15N values among individuals indicates similar trophic-level diet, although uncertainties in relative trophic 15N enrichment of individual AAs currently limits trophic position estimates for top consumers. Further research is required to clarify seasonal movement patterns and possible diet shifts of ECA/NWA killer whales to better define their role in marine ecosystems across the region.

scholarly journals Zinc Isotope Ratios as Indicators of Diet and Trophic Level in Arctic Marine Mammals

PLoS ONE ◽  
2016 ◽  
Vol 11 (3) ◽  
pp. e0152299 ◽  
Author(s):  
Klervia Jaouen ◽  
Paul Szpak ◽  
Michael P. Richards
Keyword(s):  
Trophic Level ◽  
Marine Mammals ◽  
Isotope Ratios ◽  
Zinc Isotope

Dietary biomagnification of organochlorine contaminants in Alaskan polar bears

2008 ◽  
Vol 86 (3) ◽  
pp. 177-191 ◽  
Author(s):  
T. W. Bentzen ◽  
E. H. Follmann ◽  
S. C. Amstrup ◽  
G. S. York ◽  
M. J. Wooller ◽  
...  
Keyword(s):  
Trophic Level ◽  
Marine Mammals ◽  
Trophic Status ◽  
Trophic Position ◽  
The Arctic ◽  
Polar Bears ◽  
Bowhead Whales ◽  
Organochlorine Contaminants ◽  
C Value ◽  
The Relationship

Concentrations of organochlorine contaminants in the adipose tissue of polar bears ( Ursus maritimus Phipps, 1774) vary throughout the Arctic. The range in concentrations has not been explained fully by bear age, sex, condition, location, or reproductive status. Dietary pathways expose polar bears to a variety of contaminant profiles and concentrations. Prey range from lower trophic level bowhead whales ( Balaena mysticetus L., 1758), one of the least contaminated marine mammals, to highly contaminated upper trophic level ringed seals ( Phoca hispida (Schreber, 1775)). We used δ15N and δ13C signatures to estimate the trophic status of 42 polar bears sampled along Alaska’s Beaufort Sea coast to determine the relationship between organochlorine concentration and trophic level. The δ15N values in the cellular portions of blood ranged from 18.2‰ to 20.7‰. We found strong positive relationships between concentrations of the most recalcitrant polychlorinated biphenyls (PCBs) and δ15N values in models incorporating age, lipid content, and δ13C value. Specifically these models accounted for 67% and 76% of the variation in PCB153 and oxychlordane concentration in male polar bears and 85% and 93% in females, respectively. These results are strong indicators of variation in diet and biomagnification of organochlorines among polar bears related to their sex, age, and trophic position.

Advantages of zinc isotopes as a new dietary proxy in marine ecology

2020 ◽  
Author(s):  
Jeremy McCormack ◽  
Paul Szpak ◽  
Nicolas Bourgon ◽  
Michael P. Richards ◽  
Corrie Hyland ◽  
...  
Keyword(s):  
Trophic Level ◽  
Nitrogen Isotopes ◽  
Geographic Area ◽  
Marine Ecology ◽  
Trophic Levels ◽  
Dietary Analysis ◽  
Regional Food ◽  
Zinc Isotopes ◽  
Faunal Assemblages ◽  
Discrimination Factors

Abstract In marine ecology, dietary interpretations of faunal assemblages often rely on nitrogen isotopes as the main or only applicable trophic level tracer. We investigate geographic variability and trophic level isotopic discrimination factors of a new tracer, bone 66Zn/64Zn ratios (δ66Zn value), and compared it to collagen nitrogen and carbon stable isotope (δ15N and δ13C) values. Focusing on ringed seals (Pusa hispida) and polar bears (Ursus maritimus) from multiple Arctic archaeological sites, we investigate trophic interactions between predator and prey over a broad geographic area. All proxies show variability among sites, influenced by the regional food web baselines. However, δ66Zn shows a significantly higher homogeneity among different sites. We observe a clear trophic spacing for δ15N and δ66Zn values in all locations, yet δ66Zn may more reliably record trophic levels between U. maritimus and prey species than δ15N. δ66Zn analysis allows a more direct dietary comparability between spatially and temporally distinct locations than what is possible by δ15N and δ13C analysis alone. When combining all three proxies a more detailed and refined dietary analysis is possible.

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