Mercury concentrations in Atlantic bottlenose dolphins ( Tursiops truncatus ) inhabiting the Indian River Lagoon, Florida: Patterns of spatial and temporal distribution

Schaefer, Adam M.; Titcomb, Elizabeth Murdoch; Fair, Patricia A.; Stavros, Hui-Chen W.; Mazzoil, Marilyn; Bossart, Gregory D.; Reif, John S.

doi:10.1016/j.marpolbul.2015.05.007

Cited by 10 publications

(18 citation statements)

References 18 publications

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“…There was no statistically significant difference in ages between exposure groups ( P = 0.48), which is in agreement with a previous analysis of THg concentrations in IRL dolphins (Schaefer et al . , Table ) that found no statistically significant difference across age groups in either males or females. The difference between THg concentrations in males and females was also not statistically significant.…”

Section: Resultsmentioning

confidence: 85%

“…The clustering of individuals with high THg exposure shown in Figure who are routinely sighted in the northern IRL is consistent with a previous report which documented higher concentrations of THg in dolphins inhabiting the northern segments of the lagoon (Schaefer et al . ). These findings add to the evidence that concentrations of mercury in the IRL are not homogenous and that the social structure and feeding ecology of the population contributes to bioaccumulation of mercury through the food chain in local habitats.…”

Section: Discussionmentioning

confidence: 97%

“…No statistically significant differences were detected in the current analysis or the results previously reported by Schaefer et al . ().…”

Section: Methodsmentioning

confidence: 97%

“…, Schaefer et al . ) and are described briefly here. Total mercury concentration was determined in whole blood samples using combustion atomic absorption spectrometry (CAAS).…”

Section: Methodsmentioning

confidence: 99%

“…Concentrations of THg in liver, muscle, and kidney of deceased, stranded dolphins have been used as indicators of environmental contamination worldwide (Reif et al 2015). In the IRL, incorporation of photo-identification data to assign individuals to specific geographic segments demonstrated a north to south gradient in the concentrations of THg in blood (Schaefer et al 2015a). The explanation for this spatial distribution is unclear; the lack of local point sources of industrialization and mercury emissions suggests that global transport and atmospheric deposition is responsible for the bulk of the ecosystem burden in Florida.…”

mentioning

confidence: 99%

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Blood mercury concentrations in common bottlenose dolphins from the Indian River Lagoon, Florida: Patterns of social distribution

Titcomb

Reif

Fair³

et al. 2017

Marine Mammal Science

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Social network analysis has been shown to be effective in studying the social structure of cetacean populations. Common bottlenose dolphins (Tursiops truncatus) inhabiting the Indian River Lagoon (IRL), Florida, have among the highest concentrations of total mercury (THg) in blood reported worldwide. The purpose of this study was to examine the relationship between THg concentrations in IRL dolphins and their social affiliations. Whole blood samples from 98 dolphins with photo‐identification sighting histories were collected between 2003–2007 and 2010–2012. Dolphins were categorized into approximate tertiles of low (mean 199.7 μg/L), medium (mean 366.8 μg/L), and high (mean 990.5 μg/L) THg exposure. Social associations between individual dolphins were defined by the proportion of sightings documented with another known individual. Social network measures of individuals and associations between dyads were examined to determine differences among THg categories. Strong social affiliations of individuals within the highest category of THg were found (P = 0.04), suggesting shared exposures among dolphins foraging in specific areas of the estuary. Network measures of strength and affinity were significantly higher in the highest exposure category. This report used social network analysis as a novel way to examine patterns of exposure to an environmental contaminant in a cetacean population.

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Section: Resultsmentioning

confidence: 85%

Section: Discussionmentioning

confidence: 97%

“…No statistically significant differences were detected in the current analysis or the results previously reported by Schaefer et al . ().…”

Section: Methodsmentioning

confidence: 97%

“…, Schaefer et al . ) and are described briefly here. Total mercury concentration was determined in whole blood samples using combustion atomic absorption spectrometry (CAAS).…”

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

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Blood mercury concentrations in common bottlenose dolphins from the Indian River Lagoon, Florida: Patterns of social distribution

Titcomb

Reif

Fair³

et al. 2017

Marine Mammal Science

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Mercury accumulation, speciation, and temporal trends in Atlantic Stingrays (Hypanus sabinus)

2019

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Spatial variation in the accumulation of POPs and mercury in bottlenose dolphins of the Lower Florida Keys and the coastal Everglades (South Florida)

Kiszka

Heithaus

Scholl

et al. 2017

Environmental Pollution

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a b s t r a c tThe bottlenose dolphin (Tursiops truncatus) is an upper trophic level predator and the most common cetacean species found in nearshore waters of southern Florida, including the Lower Florida Keys (LFK) and the Florida Coastal Everglades (FCE). The objective of this study was to assess contamination levels of total mercury (T-Hg) in skin and persistent organic pollutants (PCBs, PBDEs, DDXs, HCHs, HCB, S PCDD/Fs and S DL-PCBs) in blubber samples of bottlenose dolphins from LFK (n ¼ 27) and FCE (n ¼ 24). PCBs were the major class of compounds found in bottlenose dolphin blubber and were higher in individuals from LFK (S 6 PCBs LFK males: 13,421 ± 7730 ng g À1 lipids, S 6 PCBs LFK females: 9683 ± 19,007 ng g À1 lipids)than from FCE (S 6 PCBs FCE males: 5638 ng g À1 ± 3627 lipids, S 6 PCBs FCE females: 1427 ± 908 ng g À1 lipids). These levels were lower than previously published data from the southeastern USA. The S DLPCBs were the most prevalent pollutants of dioxin and dioxin like compounds (S DL-PCBs LFK: 739 ng g À1 lipids, S DL-PCBs FCE: 183 ng g À1 lipids) since PCDD/F concentrations were low for both locations (mean 0.1 ng g À1 lipids for LFK and FCE dolphins). The toxicity equivalences of PCDD/Fs and DLPCBs expressed as TEQ in LFK and FCE dolphins is mainly expressed by DL-PCBs (81% LFK -65% FCE). T-Hg concentrations in skin were significantly higher in FCE (FCE median 9314 ng g À1 dw) compared to LFK dolphins (LFK median 2941 ng g À1 dw). These concentrations are the highest recorded in bottlenose dolphins in the southeastern USA, and may be explained, at least partially, by the biogeochemistry of the Everglades and mangrove sedimentary habitats that create favourable conditions for the retention of mercury and make it available at high concentrations for aquatic predators.

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Mercury concentrations in Atlantic bottlenose dolphins ( Tursiops truncatus ) inhabiting the Indian River Lagoon, Florida: Patterns of spatial and temporal distribution

Cited by 10 publications

References 18 publications

Blood mercury concentrations in common bottlenose dolphins from the Indian River Lagoon, Florida: Patterns of social distribution

Blood mercury concentrations in common bottlenose dolphins from the Indian River Lagoon, Florida: Patterns of social distribution

Mercury accumulation, speciation, and temporal trends in Atlantic Stingrays (Hypanus sabinus)

Spatial variation in the accumulation of POPs and mercury in bottlenose dolphins of the Lower Florida Keys and the coastal Everglades (South Florida)

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