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.

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.

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

Regional tourism at the farmers’ market: consumers’ preferences for local food products

2019 ◽  
Vol 13 (1) ◽  
pp. 37-54 ◽  
Author(s):  
Benjamin Garner ◽  
Cesar Ayala
Keyword(s):  
Geographic Area ◽  
Farmers Markets ◽  
Farmers Market ◽  
Content Type ◽  
Regional Food ◽  
The Usa ◽  
Regional Brand ◽  
Consumer Habits ◽  
Food Identity ◽  
Number Of Customers

Purpose The purpose of this paper is to examine farmers’ market consumer behavior through a regional food and culinary tourism lens to see the ways these festive and atmospheric markets can be used to develop a regional brand or identity surrounding food production. Design/methodology/approach This study was based on a survey of 270 participants in a farmers’ market in the USA. A combination of descriptive and statistical analyses was used to analyze consumer habits and spending. Findings The findings in this study suggest that while most of the customers live in a town where the market is located, a significant number of customers come from other locations, with some traveling significant distances, to participate in this market, particularly for the Saturday market. Many of the customers come to purchase organic and local foods. Research limitations/implications This work is limited, in that it is a case study at one farmers’ market in the USA, and the work is exploratory in nature. Practical implications This work has implications for market managers seeking to increase their consumer base. Markets that want to increase their reach would do well to promote their events to a wider geographic area. The results presented here showed that consumers are willing to drive upward of 40 miles to attend a high-quality market. Originality/value This work expands our conceptualization of farmers’ markets by suggesting that these markets have the potential to form the backbone of a region is food identity through the creation of a food destination.

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.

Use of stable-carbon and -nitrogen isotopes to assess weaning and fasting in female polar bears and their cubs

2001 ◽  
Vol 79 (3) ◽  
pp. 499-511 ◽  
Author(s):  
S C Polischuk ◽  
K A Hobson ◽  
M A Ramsay
Keyword(s):  
Stable Isotope ◽  
Trophic Level ◽  
Nitrogen Isotopes ◽  
Milk Proteins ◽  
Milk Lipid ◽  
Polar Bears ◽  
Stable Carbon ◽  
Stable Isotope Analyses ◽  
The Impact ◽  
Isotope Analyses

In some species, stable-isotope techniques can provide insights into dietary regimens where there are temporal shifts in trophic level or feeding frequency. We determined stable carbon (δ13C) and nitrogen (δ15N) isotope values for plasma and milk proteins and δ13C values for milk lipids from female polar bears (Ursus maritimus) and cubs to (i) ascertain whether cubs are at a higher trophic level than their mothers as a result of nursing and whether we can determine when weaning occurs, and (ii) determine the impact of seasonal fasting on δ13C and δ15N values. The plasma δ13C values for mothers and cubs were similar to milk-protein δ13C values and were significantly enriched in 13C compared with those for milk lipid. Plasma from cubs of the year (COYs) in spring, when milk was their only diet, was isotopically enriched in 15N by 1.0‰ over that of their mothers (δ15N = 21.5 ± 0.8‰ (mean ± SD) for cubs and 20.5 ± 0.5‰ for mothers) and depleted in 13C by 0.8 ‰ (δ13C = –19.6 ± 0.5‰ for cubs and –18.8 ± 0.8‰ for mothers). For bears who fasted between summer and fall (3–4 months), plasma became depleted in 13C by 0.5‰ and in 15N by 1‰. Plasma from females, who had fasted from summer to spring (7–8 months) and given birth to cubs, became enriched in 13C by 0.7‰ and in 15N by 2‰. By using stable-isotope analyses we were able to show that (i) young cubs were at a higher trophic level than their mother when milk was their only food source, and (ii) seasonal fasting influenced δ13C and δ15N values. However, we were not able to use stable-isotope analyses to determine the exact time of weaning.

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.

Nitrogen isotopes in tooth enamel record diet and trophic level enrichment: Results from a controlled feeding experiment

2020 ◽  
pp. 120047
Author(s):  
Jennifer N. Leichliter ◽  
Tina Lüdecke ◽  
Alan D. Foreman ◽  
Nicolas N. Duprey ◽  
Daniela E. Winkler ◽  
...  
Keyword(s):  
Trophic Level ◽  
Nitrogen Isotopes ◽  
Tooth Enamel ◽  
Feeding Experiment
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