Turtles of the Igapó: Their Ecology and Susceptibility to Mercury Uptake

Schneider, Larissa; Vogt, Richard C.

doi:10.1007/978-3-319-90122-0_11

Cited by 4 publications

(5 citation statements)

References 24 publications

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“…lower pH) and the elevated rates of decomposition of submerged organic matter increases mercury methylation by bacteria (Regnell and Watras, 2019). Methylmercury (methylHg) is an extremely toxic contaminant that can be highly damaging to people (Budnik and Casteleyn, 2019; Ceccatelli et al, 2010) and aquatic organisms including turtles (Barraza et al, 2021; Di Marzio et al, 2019; Green et al, 2010; Hopkins et al, 2013; Schneider and Vogt, 2018; Slimani et al, 2018). Patterns of mercury contamination have been intensely studied around dams (Budnik and Casteleyn, 2019; Millera Ferriz et al, 2021; Pestana et al, 2019; Wang et al, 2004).…”

Section: Discussionmentioning

confidence: 99%

“…In various regions around the world many communities have the tradition of consuming turtle eggs and meat as a source of protein or for medicinal use (Dudgeon, 2019; Green et al, 2010; Pezzuti et al, 2010; Winemiller et al, 2016). Freshwater turtles absorb methylmercury through their digestive system as the organic forms of mercury are soluble in fats, oils, lipids and remain bound to proteins in all the tissues of the organism (Green et al, 2010; Schneider and Vogt, 2018). This was shown in the lower Xingu river basin in Brazil where concentrations of 0.06 mg/kg of Hg were found, mostly in the livers of the yellow-spotted river turtle [ Podocnemis unifilis (Souza-Araujo et al, 2015)].…”

Section: Discussionmentioning

confidence: 99%

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Impacts of dams on freshwater turtles: a global review to identify conservation solutions

Bárcenas-García

Michalski

Morgan

et al. 2021

Preprint

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Dams create many impacts on freshwater ecosystems and biodiversity. Freshwater turtles are at direct and indirect risk due to changes caused by damming including the loss of terrestrial and aquatic nesting and feeding habitats, changes to resource availability and reduced dispersal. We reviewed the global scientific literature that evaluated the impact of dams on freshwater turtles, and carried out additional searches of literature published in seventeen languages for studies evaluating actions to mitigate the impact of dams. The search produced 43 published articles documenting dam impacts on 29 freshwater turtle species from seven families (Chelidae, Chelydridae, Emydidae, Geoemydidae, Kinosternidae, Podocnemididae and Trionychidae) in 13 countries. More than a third of studies (41.9%, n = 18) focused on nine North American species of the Emydidae. Few studies were found from Europe and Asia and none from Africa. The number of studies, life-history stage studied and threat status differed significantly between temperate and tropical latitudes. Most studies were from temperate latitudes, where studies focused more on adults and less threatened species compared with tropical latitudes. Studies evaluated dam impacts as barriers and changes to water flow and quality, but no studies were found that assessed turtles and changes to land cover or mercury caused by dams. More than half of the studies (59%, n = 24) suggested actions to help mitigate dam impacts. Yet, only four studies on three temperate and one tropical species documented the effect of interventions (dam removal, flow management, artificial pond maintenance and community-based action). These findings demonstrate a lack of documented evidence evaluating dam impacts on freshwater turtles particularly in tropical regions. This lack of evidence reinforces the importance of strengthening and maintaining robust long-term studies of freshwater turtles needed to develop effective conservation actions for this group of vertebrates.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Impacts of dams on freshwater turtles: a global review to identify conservation solutions

Bárcenas-García

Michalski

Morgan

et al. 2021

Preprint

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“…As bioaccumulation of Hg in turtles is known to be influenced by age (Schneider et al, 2013;Schneider and Vogt, 2018), the effects of carapace length (measured as CCL and used as a proxy for age) on Hg concentrations of turtles between the two rookeries was examined using an independent-sample two-tailed t-test. Mercury concentration was used as the dependent variable, and CCL as the independent variable.…”

Section: Statisticsmentioning

confidence: 99%

First Assessment of Mercury (Hg) Concentrations in Skin and Carapace of Flatback Turtles (Natator depressus) (Garman) From Western Australia

Schneider

Tucker²,

Vincent

et al. 2022

Front. Environ. Sci.

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Mercury pollution in the surface ocean has more than doubled over the past century. Within oceanic food webs, sea turtles have life history characteristics that make them especially vulnerable to mercury (Hg) accumulation. In this study we investigated Hg concentrations in the skin and carapace of nesting flatback turtles (Natator depressus) from two rookeries in Western Australia. A total of 50 skin samples and 52 carapace samples were collected from nesting turtles at Thevenard Island, and 23 skin and 28 carapace samples from nesting turtles at Eighty Mile Beach. We tested the influence of turtle size on Hg concentrations, hypothesising that larger and likely older adult turtles would exhibit higher concentrations due to more prolonged exposure to Hg. We compared the rookeries, hypothesising that the turtles from the southern rookery (Thevenard Island) were more likely to forage and reside in the Pilbara region closer to industrial mining activity and loading ports (potential exposure to higher environmental Hg concentrations) with turtles from the northern rookery (Eighty Mile Beach) more likely to reside and feed in the remote Kimberley. Turtles from the Eighty Mile Beach rookery had significantly higher skin Hg concentrations (x̄ = 19.4 ± 4.8 ng/g) than turtles from Thevenard Island (x̄ = 15.2 ± 5.8 ng/g). There was no significant difference in carapace Hg concentrations in turtles between Eighty Mile Beach (x̄ = 48.4 ± 21.8 ng/g) and Thevenard Island (x̄ = 41.3 ± 16.5 ng/g). Turtle size did not explain Hg concentrations in skin samples from Eighty Mile Beach and Thevenard Island, but turtle size explained 43.1% of Hg concentrations in the carapace of turtles from Eighty Mile Beach and 44.2% from Thevenard Island. Mercury concentrations in the flatback turtles sampled in this study are relatively low compared to other sea turtles worldwide, likely a result of the generally low concentrations of Hg in the Australian environment. Although we predicted that mining activities would influence flatback turtle Hg bioaccumulations, our data did not support this effect. This may be a result of foraging ground overlap between the two rookeries, or the predominant wind direction carrying atmospheric Hg inland rather than seaward. This is the first Hg study in skin and carapace of flatback turtles and represents a baseline to compare Hg contamination in Australia’s surrounding oceans.

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“…; Gravena et al, 2014Gravena et al, , 2015, and restricts, but does not prevent, the movement of the Giant South American River Turtle, Podocnemis expansa (Pearse et al, 2006). The largest of the Amazonian turtles, P. expansa, routinely swims hundreds of kilometers (>200 km to nesting beaches and >400 km to feeding areas; Pearse et al, 2006;Schneider & Vogt, 2018). However, mostly due to their reproductive behavior, population genetic structure evolved only between subbasins of the Amazonas River, even between locations separated by <410 km (Pearse et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

Riverscape features determining the genetic structure of the Yellow‐Spotted Amazon River Turtle (Podocnemis unifilis) in Brazilian Amazonia

Agostini,

Machado,

Ritter

et al. 2024

Biotropica

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Landscape characteristics can influence gene flow depending on the species ability to disperse. This imposes different levels of resistance to movement, determining the genetic structure and diversity of populations. Waterfalls and rapids in the Amazon basin have been suggested as contributing factors to the diversification and genetic structure of freshwater species, including turtles. Thus, along some main rivers of the Brazilian Amazon: Juruá, Madeira, Amazonas, Trombetas, Tapajós, Xingu, Tocantins, and Araguaia, we evaluated the spatial distribution of genetic diversity and characterized the population structure of Podocnemis unifilis, a widely distributed and endangered Amazonian turtle, using the mitochondrial DNA control region. We tested for isolation by geographic distance and by resistance models through an integrative approach using genetic, geographic, and ecological data, comparing these matrices with genetic distance. We found heterogeneous levels of genetic diversity and no spatial patterns. Results supported the isolation by resistance hypothesis, where the movement of individuals was influenced by freshwater, vegetational, climatological, and geomorphological variables, explaining the genetic distance of P. unifilis. Rapids and waterfalls impose greater resistance although they are barriers with different levels of permeability to the P. unifilis gene flow. Thus, the idiosyncrasies of each sub‐basin must be considered in the interpretation of the patterns found in assessing phylogeographic history.Abstract in Portuguese is available with online material.

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Turtles of the Igapó: Their Ecology and Susceptibility to Mercury Uptake

Cited by 4 publications

References 24 publications

Impacts of dams on freshwater turtles: a global review to identify conservation solutions

Impacts of dams on freshwater turtles: a global review to identify conservation solutions

First Assessment of Mercury (Hg) Concentrations in Skin and Carapace of Flatback Turtles (Natator depressus) (Garman) From Western Australia

Riverscape features determining the genetic structure of the Yellow‐Spotted Amazon River Turtle (Podocnemis unifilis) in Brazilian Amazonia

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