Geology topics

Tammy M. Summers

Publications and source records attributed to Tammy M. Summers.

4 recordsLinked to original sources

USGS2021

Species and population specific gene expression in blood transcriptomes of marine turtles

Background Transcriptomic data has demonstrated utility to advance the study of physiological diversity and organisms’ responses to environmental stressors. However, a lack of genomic resources and challenges associated with collecting high-quality RNA can limit its application for many wild populations. Minimally invasive blood sampling combined with de novo transcriptomic approaches has great potential to alleviate these barriers. Here, we advance these goals for marine turtles by generating high quality de novo blood transcriptome assemblies to characterize functional diversity and compare global transcriptional profiles between tissues, species, and foraging aggregations. Results We generated high quality blood transcriptome assemblies for hawksbill ( Eretmochelys imbricata ) , loggerhead ( Caretta caretta ), green ( Chelonia mydas ), and leatherback ( Dermochelys coriacea ) turtles. The functional diversity in assembled blood transcriptomes was comparable to those from more traditionally sampled tissues. A total of 31.3% of orthogroups identified were present in all four species, representing a core set of conserved genes expressed in blood and shared across marine turtle species. We observed strong species-specific expression of these genes, as well as distinct transcriptomic profiles between green turtle foraging aggregations that inhabit areas of greater or lesser anthropogenic disturbance. Conclusions Obtaining global gene expression data through non-lethal, minimally invasive sampling can greatly expand the applications of RNA-sequencing in protected long-lived species such as marine turtles. The distinct differences in gene expression signatures between species and foraging aggregations provide insight into the functional genomics underlying the diversity in this ancient vertebrate lineage. The transcriptomic resources generated here can be used in further studies examining the evolutionary ecology and anthropogenic impacts on marine turtles.

BMC Genomics↗

USGS2021

Sea turtles across the North Pacific are exposed to perfluoroalkyl substances

Perfluorinated alkyl substances (PFASs) are global, persistent, and toxic contaminants. We assessed PFAS concentrations in green ( Chelonia mydas ) and hawksbill ( Eretmochelys imbricata ) turtles from the North Pacific. Fifteen compounds were quantified via liquid chromatography tandem mass spectrometry from 62 green turtle and 6 hawksbill plasma samples from Hawai’i, Palmyra Atoll, and the Northern Marianas Islands. Plasma from 14 green turtles severely afflicted with fibropapillomatosis, and eggs from 12 Hawaiian hawksbill nests from 7 females were analyzed. Perfluorooctane sulfonate (PFOS) predominated in green turtle plasma; perfluorononanoic acid (PFNA) predominated in hawksbill tissues. Concentrations were greater in hawksbill than green turtle plasma (p < 0.05), related to trophic differences. Green turtle plasma PFOS concentrations were related to human populations from highest to lowest: Hawai’i, Marianas, Palmyra. Influence on fibropapillomatosis was not evident. PFASs were maternally transferred to hawksbill eggs, with decreasing concentrations with distance from airports and with clutch order from one female. A risk assessment of PFOS showed concern for immunosuppression in Kailua green turtles and alarming concern for hawksbill developmental toxicity. Perfluoroundecanoic (PFUnA) and perfluorotridecanoic (PFTriA) acid levels were correlated with reduced emergence success (p < 0.05). Studies to further examine PFAS effects on sea turtle development would be beneficial.

Hawaii↗

USGS2018

Human induced trauma and directed take inhibits sea turtle recovery in the Commonwealth of the Northern Mariana Islands

Sea turtle conservation is often hindered by the lack of reliable information on population status and threats due to sampling difficulties of these highly migratory reptiles that live in remote and data-poor locations. This paper summarizes more than a decade of stranding recoveries (live and dead turtles) on the islands of Saipan and Tinian, Commonwealth of the Northern Mariana Islands (CNMI), to obtain baseline information on the primary threats to sea turtles in the CNMI. Gross external examination and necropsy of dead turtles was used to infer primary cause of stranding of 89 sea turtles (92.1% green ( Chelonia mydas ), 5.6% hawksbill ( Eretmochelys imbricata ), 1.1% olive ridley ( Lepidochelys olivacea ), and 1% unknown). Of these stranding recoveries, 80.9% were juveniles, 15.7% were adults, and 3.4% were unknown. Trauma related to illegal human take was the primary cause of stranding and accounted for 79% of CNMI sea turtle injuries and mortalities. The remaining 21% of strandings were attributed to (in rank order): marine debris entanglement, shark bite, boat strike, emaciation, and infectious disease. This study provides the first comprehensive characterization of cause-specific sea turtle injury and mortality in CNMI, described within the unique socio-cultural and historical dynamics of the region. Culturally-relevant suggestions for management are provided that may help address the primary threat to CNMI sea turtles.

Commonwealth of the Northern Mariana Islands, Guam↗

USGS2015

Causes of mortality in green turtles from Hawaii and the insular Pacific exclusive of fibropapillomatosis

Fibropapillomatosis (FP) comprises a majority of green turtle stranding in Hawaii; however, green turtles in the Pacific are also susceptible to non-FP related causes of death. We present here necropsy findings from 230 free-ranging green turtles originating from Hawaii, the Mariana archipelago, Palmyra Atoll, American Samoa, and Johnston Atoll that died from non-FP related causes. Most turtles died from fishing-induced or boat strike trauma followed by infectious/inflammatory diseases, nutritional problems (mainly cachexia), and an array of physiologic problems. Infectious/inflammatory problems included bacterial diseases of the lungs, eyes, liver or intestines, spirorchid fluke infection, or polyarthritis of unknown origin. Likelihood of a successful diagnosis of cause of death was a function of post-mortem decomposition. Fibropapillomatosis was not seen in turtles submitted from outside Hawaii. The preponderance of anthropogenic causes of mortality offers some management opportunities to mitigate causes of death in these animals by, for example, implementing measures to decrease boating and fishing interactions.

Diseases of Aquatic Organisms↗