Geology topics

Natalie K. Karouna-Reiner

Publications and source records attributed to Natalie K. Karouna-Reiner.

3 recordsLinked to original sources

USGS2025

A short-term sublethal oral exposure to microcystin-LR disrupts cecal microbiome homeostasis in mallard

Introduction: The frequency of cyanobacterial blooms seems to have increased globally in recent decades due to human induced eutrophication and climate change. Cyanobacterial blooms can produce several groups of toxins, among which microcystin-LR (MC-LR) is one of the most abundant. Effects of MC-LR on avian microbiome have not been studied and studies in laboratory murines have been limited to metabarcoding of prokaryotes. Methods: Using RNA shotgun sequencing, we compared the richness and composition of metabolically active prokaryotes, expressed virulence factors, antimicrobial resistance genes, metabolic pathways, Gene Ontology terms, enzymes, and proteins in mallards (Anas platyrhynchos) that were orally exposed to a sublethal dose of MC-LR for one week and unexposed birds. Results: Richness and composition of all compared features did not differ between exposed and control birds and none were differentially expressed between exposure groups. However, richness and/or composition of all features except virulence factors and Carbohydrate Active enzymes had multiple-fold greater dispersion in exposed birds than in controls. This effect was especially pronounced in expressed metabolic (MetaCyc) pathways. Discussion: Our results suggest that MC-LR exposure had a stochastic (rather than deterministic) effect on cecal microbiota, especially its function. Observed disturbance of the microbiota homeostasis is consistent with the Anna Karenina Principle. This principle has been documented in a wide range of eukaryotes using primarily microbial community metabarcoding. Although stochastic disturbance of microbiota function has been hypothesized, our study seems to be the first to demonstrate this in an experimental study.

Wisconsin↗

USGS2016

Chesapeake Bay fish–osprey ( Pandion haliaetus ) food chain: Evaluation of contaminant exposure and genetic damage

From 2011 to 2013, a large-scale ecotoxicological study was conducted in several Chesapeake Bay (USA) tributaries (Susquehanna River and flats, the Back, Baltimore Harbor/Patapsco Rivers, Anacostia/ middle Potomac, Elizabeth and James Rivers) and Poplar Island as a mid-Bay reference site. Osprey ( Pandion haliaetus ) diet and the transfer of contaminants from fish to osprey eggs were evaluated. The most bioaccumulative compounds (biomagnification factor > 5) included p,p′ -dichlorodiphenyldichloroethylene (DDE), total polychlorinated biphenyls (PCBs), total polybrominated diphenyl ethers (PBDEs), and bromodiphenyl ether (BDE) congeners 47, 99, 100, and 154. This analysis suggested that alternative brominated flame retardants and other compounds (methoxytriclosan) are not appreciably biomagnifying. A multivariate analysis of similarity indicated that major differences in patterns among study sites were driven by PCB congeners 105, 128, 156, 170/190, and 189, and PBDE congeners 99 and 209. An integrative redundancy analysis showed that osprey eggs from Baltimore Harbor/Patapsco River and the Elizabeth River had high residues of PCBs and p,p ′-DDE, with PBDEs making a substantial contribution to overall halogenated contamination on the Susquehanna and Anacostia/middle Potomac Rivers. The redundancy analysis also suggested a potential relation between PBDE residues in osprey eggs and oxidative DNA damage in nestling blood samples. The results also indicate that there is no longer a discernible relation between halogenated contaminants in osprey eggs and their reproductive success in Chesapeake Bay. Osprey populations are thriving in much of the Chesapeake, with productivity rates exceeding those required to sustain a stable population.

Chesapeake Bay↗

USGS2013

Comparative embryotoxicity of a pentabrominated diphenyl ether mixture to common terns ( Sterna hirundo ) and American kestrels ( Falco sparverius )

Concentrations of polybrominated diphenyl ethers (PBDEs) in Forster’s tern ( Sterna forsteri ) eggs from San Francisco Bay have been reported to range up to 63 μg g −1 lipid weight. This value exceeds the lowest-observed-adverse-effect level (1.8 μg g −1 egg wet weight; ∼32 μg −1 lipid weight) reported in an embryotoxicity study with American kestrels ( Falco sparverius ). As a surrogate for Forster’s terns, common tern ( Sterna hirundo ) eggs were treated by air cell injection with corn oil vehicle (control) or a commercial penta-BDE formulation (DE-71) at nominal concentrations of 0.2, 2, and 20 μg g −1 egg. As a positive control, kestrel eggs received vehicle or 20 μg DE-71 g −1 egg. In terns, there were no effects of DE-71 on embryonic survival, and pipping or hatching success; however, treated eggs hatched later (0.44 d) than controls. Organ weights, organ-to-body weight ratios, and bone lengths did not differ, and histopathological observations were unremarkable. Several measures of hepatic oxidative stress in hatchling terns were not affected by DE-71, although there was some evidence of oxidative DNA damage (8-hydroxy-deoxyguanosine; 8-OH-dG). Although DE-71 did not impair pipping and hatching of kestrels, it did result in a delay in hatch, shorter humerus length, and reduced total thyroid weight. Concentrations of oxidized glutathione, reduced glutathione, thiobarbituric acid reactive substances, and 8-OH-dG in liver were greater in DE-71-treated kestrels compared to controls. Our findings suggest common tern embryos, and perhaps other tern species, are less sensitive to PBDEs than kestrel embryos.

San Francisco Bay;Poplar Island↗