Diet differences among age classes of Arctic seals: evidence from stable isotope and mercury biomarkers

Young, Brent G.; Loseto, Lisa L.; Ferguson, Steven H.

doi:10.1007/s00300-009-0693-3

Cited by 66 publications

(58 citation statements)

References 45 publications

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“…Fish populations in the Arctic are often older (due to low fishing pressure) and have slower growth rates compared with populations at lower latitudes and these factors contribute to enhanced Hg bioaccumulation. [210] Case studies of top-down trophic influences on biotic mercury levels Predators can exert a top-down influence on biotic Hg concentrations depending on their feeding ecology and diet preferences, [144,216,217] which relate to the animals' size, age, sex and reproductive status. These in turn influence energetic demands, social behaviour and habitat use (see Fig.…”

Section: Freshwater Food Websmentioning

confidence: 99%

The fate of mercury in Arctic terrestrial and aquatic ecosystems, a review

Douglas

Loseto²,

Macdonald³

et al. 2012

Environ. Chem.

119

147

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Environmental context. Mercury, in its methylated form, is a neurotoxin that biomagnifies in marine and terrestrial foodwebs leading to elevated levels in fish and fish-eating mammals worldwide, including at numerous Arctic locations. Elevated mercury concentrations in Arctic country foods present a significant exposure risk to Arctic people. We present a detailed review of the fate of mercury in Arctic terrestrial and marine ecosystems, taking into account the extreme seasonality of Arctic ecosystems and the unique processes associated with sea ice and Arctic hydrology.Abstract. This review is the result of a series of multidisciplinary meetings organised by the Arctic Monitoring and Assessment Programme as part of their 2011 Assessment 'Mercury in the Arctic'. This paper presents the state-of-the-art knowledge on the environmental fate of mercury following its entry into the Arctic by oceanic, atmospheric and terrestrial pathways. Our focus is on the movement, transformation and bioaccumulation of Hg in aquatic (marine and fresh water) and terrestrial ecosystems. The processes most relevant to biological Hg uptake and the potential risk associated with Hg exposure in wildlife are emphasised. We present discussions of the chemical transformations of newly deposited or transported Hg in marine, fresh water and terrestrial environments and of the movement of Hg from air, soil and water environmental compartments into food webs. Methylation, a key process controlling the fate of Hg in most ecosystems, and the role of trophic processes in controlling Hg in higher order animals are also included. Case studies on Eastern Beaufort Sea beluga (Delphinapterus leucas) and landlocked Arctic char (Salvelinus alpinus) are presented as examples of the relationship between ecosystem trophic processes and biologic Hg levels. We examine whether atmospheric mercury depletion events (AMDEs) contribute to increased Hg levels in Arctic biota and provide information on the links between organic carbon and Hg speciation, dynamics and bioavailability. Long-term sequestration of Hg into non-biological archives is also addressed. The review concludes by identifying major knowledge gaps in our understanding, including:(1) the rates of Hg entry into marine and terrestrial ecosystems and the rates of inorganic and MeHg uptake by Arctic microbial and algal communities; (2) the bioavailable fraction of AMDE-related Hg and its rate of accumulation by biota and (3) the fresh water and marine MeHg cycle in the Arctic, especially the marine MeHg cycle.

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Section: Freshwater Food Websmentioning

confidence: 99%

The fate of mercury in Arctic terrestrial and aquatic ecosystems, a review

Douglas

Loseto²,

Macdonald³

et al. 2012

Environ. Chem.

119

147

View full text Add to dashboard Cite

show abstract

“…In other areas, their migrations have been linked to advancing and retreating ice (e.g., Svalbard, Freitas et al, 2008a;Chukchi/Bering Seas, Crawford et al, 2011). Seasonal and age-specific prey preferences are known (�owry et al, 1980;Thiemann et al, 2008;Young et al, 2010), as are patterns of habitat use, which differ within and among populations (Freitas et al, 2008a;Crawford et al, 2011;Carroll et al, 2013). In the Western Arctic, the less experienced subadults (< 6 y) appear to rely most heavily on invertebrates (Smith, 1987;Smith and Harwood, 2001;authors' unpubl.…”

Section: Introductionmentioning

confidence: 99%

Seasonal Movements and Diving of Ringed Seals, <i>Pusa hispida</i>, in the Western Canadian Arctic, 1999–2001 and 2010–11

Harwood¹,

Smith²,

Auld³

et al. 2015

ARCTIC

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ABSTRACT. Satellite-linked time-depth recorders were deployed on 17 ringed seals in early summer in 1999, 2000, and 2010, near the Inuvialuit community of Ulukhaktok, Northwest Territories, Canada. The main objective was to investigate movements and diving behaviour of ringed seals in the Prince Albert Sound (PAS) and eastern Amundsen Gulf (EAG) regions in relation to season, sex, and age-class. Tags performed well on 16 of 17 tagged seals, with average tracking periods of 256 d (SD 69, (61%), but they all traveled to distant zones, eight in total. During winter, all tagged adult females, five of seven adult males, and three of four subadults returned to PAS and EAG to occupy winter home ranges that were on average 15% of the size of the open water home range (mean winter ranges = 1299 km 2 for adult males, 3599 km 2 for adult females, and 30 499 km 2 for subadults). The mean size of the winter home ranges varied by as much as a factor of 10 among the three winters examined. Seal movements were most restricted during the winters with extensive fast ice (1999 -2000 and 2010 -11) and least restricted during the winter (2000 -01) when fast ice did not form in EAG. In winter, adult females made more long, deep dives than either adult males or subadults.

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“…An increase of Hg concentrations with age has been attributed to bioaccumulation as well as changes in diet over time. Juvenile seals usually have different diving and foraging behavior than adults resulting in a different diet comprised of a higher proportion of smaller fish (Lesage et al 2001;Young et al 2010). In the present study, d 15 N and d 13 C data indicated no significant difference (p = 0.43) in feeding ecology between pups (d 15 N = 16.31 ± 0.84 % and d 13 C = -14.54 ± 1.21 %), juveniles (d 15 N = 16.26 ± 0.89 % and d 13 C = -14.22 ± 0.66 %) and adults (d 15 N = 16.40 ± 0.85 % and d 13 C = -13.91 ± 1.38 %), possibly the result of a relatively small sample size for the juvenile and adult age classes.…”

Section: Age Versus Thg In Harbour Seal Hairmentioning

confidence: 99%

Mercury Accumulation in Harbour Seals from the Northeastern Pacific Ocean: The Role of Transplacental Transfer, Lactation, Age and Location

Noël

Jeffries

Lambourn

et al. 2015

Arch Environ Contam Toxicol

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Mercury (Hg) bioaccumulates in the aquatic food chain in the form of methylmercury, a compound well known for its neurotoxicity. We analyzed total mercury (THg) in hair collected from 209 harbour seals captured at 10 sites in British Columbia (Canada) and Washington State (USA) between 2003 and 2010. In addition, laser ablation inductively-coupled plasma mass spectrometry (LA-ICP-MS) allowed for a highly refined analysis of THg accumulation over time by examining nine whiskers taken from 4- to 6-week-old pups. We estimate that THg concentrations in pups increased sharply at a point corresponding to mid- to late gestation of their time in utero (4.7 ± 0.8 and 6.6 ± 1.3 µg/g dry weight (dw), respectively), and then again at the onset of nursing (8.1 ± 1.3 µg/g dw). These abrupt changes highlight the importance of both pre- and post-natal THg transfer from the mother to the growing fetus and the newborn pup. While THg levels varied among sites, hair analyses from seals collected at the same site demonstrated the influence of age in THg accumulation with pups (5.3 ± 0.3 µg/g) and juveniles (4.5 ± 0.5 µg/g) having lower levels than those in adults (8.3 ± 0.8 µg/g). Our results revealed that 33 % of the pups sampled (n = 167) had THg levels that surpassed a mammalian hair threshold for neurochemical alterations. This study suggests that Hg could represent a health concern to marine wildlife, especially as atmospheric emissions of this toxic element from human activities in the Pacific Rim and worldwide continue.

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Diet differences among age classes of Arctic seals: evidence from stable isotope and mercury biomarkers

Cited by 66 publications

References 45 publications

The fate of mercury in Arctic terrestrial and aquatic ecosystems, a review

The fate of mercury in Arctic terrestrial and aquatic ecosystems, a review

Seasonal Movements and Diving of Ringed Seals, <i>Pusa hispida</i>, in the Western Canadian Arctic, 1999–2001 and 2010–11

Mercury Accumulation in Harbour Seals from the Northeastern Pacific Ocean: The Role of Transplacental Transfer, Lactation, Age and Location

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