Dataset Information

Temporal increase in organic mercury in an endangered pelagic seabird assessed by century-old museum specimens.

ABSTRACT: Methylmercury cycling in the Pacific Ocean has garnered significant attention in recent years, especially with regard to rising mercury emissions from Asia. Uncertainty exists concerning whether increases in anthropogenic emissions over time may have caused increased mercury bioaccumulation in the biota. To address this, we measured total mercury and, for a subset of samples, methylmercury (the bioaccumulated form of mercury) in museum feathers from an endangered seabird, the black-footed albatross (Phoebastria nigripes), spanning a 120-y period. We analyzed stable isotopes of nitrogen (?(15)N) and carbon (?(13)C) to control for temporal changes in trophic structure and diet. In post-1940 and -1990 feathers, we detected significantly higher mean methylmercury concentrations and higher proportions of samples exhibiting above deleterious threshold levels (? 40,000 ng · g(-1)) of methylmercury relative to prior time points, suggesting that mercury toxicity may undermine reproductive effort in the species. We also found higher levels of (presumably curator-mediated) inorganic mercury in older specimens of albatross as well as two nonpelagic species lacking historical exposure to bioavailable mercury, patterns suggesting that studies on bioaccumulation should measure methylmercury rather than total mercury when using museum collections. ?(15)N contributed substantially to models explaining the observed methylmercury variation. After simultaneously controlling for significant trends in ?(13)C over time and ?(15)N with methylmercury exposure, year remained a significant independent covariate with feather methylmercury levels among the albatrosses. These data show that remote seabird colonies in the Pacific basin exhibit temporal changes in methylmercury levels consistent with historical global and recent regional increases in anthropogenic emissions.

SUBMITTER: Vo AT

PROVIDER: S-EPMC3088636 | biostudies-literature | 2011 May

REPOSITORIES: biostudies-literature

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Temporal increase in organic mercury in an endangered pelagic seabird assessed by century-old museum specimens.

Vo Anh-Thu E AT Bank Michael S MS Shine James P JP Edwards Scott V SV

Proceedings of the National Academy of Sciences of the United States of America 20110418 18

Methylmercury cycling in the Pacific Ocean has garnered significant attention in recent years, especially with regard to rising mercury emissions from Asia. Uncertainty exists concerning whether increases in anthropogenic emissions over time may have caused increased mercury bioaccumulation in the biota. To address this, we measured total mercury and, for a subset of samples, methylmercury (the bioaccumulated form of mercury) in museum feathers from an endangered seabird, the black-footed albatr ...[more]

PMID: 21502496

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Project description:Sylvilagus floridanus Papillomavirus (SfPV) causes growth of large horn-like tumors on rabbits. SfPV was described in cottontail rabbits (probably Sylvilagus floridanus) from Kansas and Iowa by Richard Shope in 1933, and detected in S. audubonii in 2011. It is known almost exclusively from the US Midwest. We explored the University of Kansas Natural History Museum for historical museum specimens infected with SfPV, using molecular techniques, to assess if additional wild species host SfPV, and whether SfPV occurs throughout the host range, or just in the Midwest. Secondary aims were to detect distinct strains, and evidence for strain spatio-temporal specificity. We found 20 of 1395 rabbits in the KU collection SfPV symptomatic. Three of 17 lagomorph species (S. nuttallii, and the two known hosts) were symptomatic, while Brachylagus, Lepus and eight additional Sylvilagus species were not. 13 symptomatic individuals were positive by molecular testing, including the first S. nuttallii detection. Prevalence of symptomatic individuals was significantly higher in Sylvilagus (1.8%) than Lepus. Half of these specimens came from Kansas, though new molecular detections were obtained from Jalisco-Mexico's first-and Nebraska, Nevada, New Mexico, and Texas, USA. We document the oldest lab-confirmed case (Kansas, 1915), pre-dating Shope's first case. SfPV amplification was possible from 63.2% of symptomatic museum specimens. Using multiple methodologies, rolling circle amplification and, multiple isothermal displacement amplification in addition to PCR, greatly improved detection rates. Short sequences were obtained from six individuals for two genes. L1 gene sequences were identical to all previously detected sequences; E7 gene sequences, were more variable, yielding five distinct SfPV1 strains that differing by less than 2% from strains circulating in the Midwest and Mexico, between 1915 and 2005. Our results do not clarify whether strains are host species specific, though they are consistent with SfPV specificity to genus Sylvilagus.

Project description:BackgroundMuseum biological specimens provide a unique means of gathering ecological information that spans wide temporal ranges. Museum specimens can also provide information on the microbial communities that persist within the host specimen. Together, these provide researchers valuable opportunities to study long-term trends and mechanisms of microbial community change. The effects of decades-long museum preservation on host-microbial communities have not been systematically assessed. The University of Colorado's Museum of Natural History has densely sampled Oreohelix strigosa (Rocky Mountainsnail) for the past century; many are preserved in ethanol, which provides an excellent opportunity to explore how the microbiome changes across time in preservation.ResultsWe used 16S rRNA (ribosomal ribonucleic acid) gene amplicon sequencing to examine Oreohelix strigosa gut microbiomes from museum specimens across a 98-year range, as well as within short-term preservation treatments collected in 2018. Treatment groups included samples extracted fresh, without preservation; samples starved prior to extraction; and samples preserved for 1 month, 6 months, and 9 months. General microbiome composition was similar across all years. Sample groups belonging to specific years, or specific short-term treatments, showed unique associations with select bacterial taxa. Collection year was not a significant predictor of microbial richness, though unpreserved short-term treatments showed significantly higher richness than preserved treatments. While the year was a significant factor in microbiome composition, it did not explain much of the variation across samples. The location was a significant driver of community composition and explained more of the variability.ConclusionsThis study is the first to examine animal host-associated microbiome change across a period of nearly one century. Generally, geographic location was a greater factor in shaping gut microbiome composition, rather than a year collected. Consistent patterns across this temporal range indicate that historic specimens can answer many ecological questions surrounding the host-associated microbiome. Video Abstract.

Dataset Information

Temporal increase in organic mercury in an endangered pelagic seabird assessed by century-old museum specimens.

Publications

Temporal increase in organic mercury in an endangered pelagic seabird assessed by century-old museum specimens.

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