The aquatic cooling canal system associated with a nuclear reactor built in the early 1950s received accidental releases of radiocesium (137Cs) from the reactor between 1954 and 1964, resulting in ...the dispersion of ~8.2 × 1012 Bq of 137Cs into the associated canals and ponds. The primary purpose of this study was to document concentrations of 137Cs in littoral zone fish currently occupying components of the cooling canal system, 3 canals and 2 impoundments, to determine how concentrations varied among these various components. Secondarily, we examined for potential influence of weirs within the canal system on concentrations in fish as well as the potential relationship between fish species and body size and on 137Cs concentrations in fish. We collected samples of sediment, biofilm, and fish from each component of the R-Reactor cooling system and compared 137Cs among sites and species in individual sites. Concentrations of 137Cs in sediments, biofilms and mosquitofish varied significantly among sampling areas with higher concentrations in RCAN1, a canal segment that was the closest to the reactor and received reactor effluent for a longer period than other components. Comparisons among other components of the cooling system, and species comparisons relative to presumed trophic positions and fish length were not consistent. However, littoral zone fish in the cooling canal system continue to bioaccumulate 137Cs >50 years after the original releases of contamination.
•Fish in the shallow canals and ponds of a reactor cooling system were assayed for legacy 137Cs > 50 years post-release.•All fish monitored within the cooling system had measurable levels of 137Cs.•Fish in the canal closest to the reactor, which received reactor effluent for a longer period, had the highest 137Cs levels.•There was no support for biomagnification or size effects for 137Cs accumulation, likely due to a narrow range of fish sizes.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Microplastic pollution is of current public concern for global environmental healthand of relevance for aquaculture and fisheries. Microplastic ingestion has been shown tocause intestinal damage, ...microbiota dysbiosis, and disturbed lipid and energy metabolismin fish. However, these data resulted from exposures of adult fish at microplasticconcentrations 2-7 times higher than concentrations found in the environment. Todetermine the impact of microplastic ingestion on fish health at environmentally relevant,chronic, low doses of microplastic fibers, Oryzias latipes larvae and juveniles wereexposed to five concentrations of polyethylene (PE) fibers for 21 days through feed. Fishenergy intake, growth & condition and reproductive output were assessed to determine theoverall impact on fish health. To assess energy intake, gut integrity was evaluated at themolecular and cellular level. Relative gene expression of key digestive genes from guttissue was quantified using real time-quantitative polymerase chain reaction (RT-qPCR).An effect on digestive gene expression potentially effecting nutrient absorption andantioxidant production was indicated via a significant decrease of slc6a6 expression inlarvae exposed to the highest concentration. No significant molecular changes wereobserved in juvenile gut tissue. Gut morphology was analyzed using histomorphologicalobservations of the intestinal mucus layer and cell types. No significant impairment to gutepithelial layers was observed in larvae or juveniles. To assess growth & condition,Fulton’s condition factor, hepatosomatic index, and gonadosomatic index were measured.No differences were observed in larval or juvenile growth. To assess reproductive output,exposed fish were bred and fecundity, fertility and hatching rate were evaluated. Fecundityand fertility were not affected by consumption of microplastic fibers at theseconcentrations. However, hatching in the F1 offspring was delayed by 2-3 days uponenvironmentally relevant PE exposure of juvenile fish. Significantly delayed hatching canimpact overall offspring survivability and ultimately population recruitment. Comparisonsof different developmental stages allowed for identification of vulnerable developmentalstages for microplastic exposure; larvae were more susceptible to molecular changes dueto PE exposure; however, juveniles demonstrated organismal level effects via delayed egghatching. This study is one of the first to provide toxicological data on the risk of PE fiberingestion during development stages of fish. Results indicate no imminent threat to fishcondition at current measured environmental levels of microplastics; however, closemonitoring of vital spawning grounds for commercially important fishes is recommended.
Southern flounder skin pigmentation is a critical phenotypic characteristic for this species’ survival in the natural environment. Normal pigmentation allows rapid changes of color for concealment to ...capture prey and UV light protection. In contrast, highly visible hypopigmented pseudo-albinos exhibit a compromised immune system and are vulnerable to predation, sensitive to UV exposure, and likely have poor survival in the wild. Skin and brain tissue samples from normally pigmented and hypopigmented individuals were analyzed with next-generation RNA sequencing. A total of 1,589,613 transcripts were used to identify 952,825 genes to assemble a de novo transcriptome, with 99.43% of genes mapped to the assembly. Differential gene expression and gene enrichment analysis of contrasting tissues and phenotypes revealed that pseudo-albino individuals appeared more susceptible to environmental stress, UV light exposure, hypoxia, and osmotic stress. The pseudo-albinos’ restricted immune response showed upregulated genes linked to cancer development, signaling and response, skin tissue formation, regeneration, and healing. The data indicate that a modified skin collagen structure likely affects melanocyte differentiation and distribution, generating the pseudo-albino phenotype. In addition, the comparison of the brain transcriptome revealed changes in myelination and melanocyte stem cell activity, which may indicate modified brain function, reduced melanocyte migration, and impaired vision.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
We present a novel ensemble architecture for learning problem-solving techniques from a very small number of expert solutions and demonstrate its effectiveness in a complex real-world domain. The key ...feature of our “Generalized Integrated Learning Architecture” (GILA) is a set of heterogeneous independent learning and reasoning (ILR) components, coordinated by a central meta-reasoning executive (MRE). The ILRs are
weakly coupled
in the sense that all coordination during learning and performance happens through the MRE. Each ILR learns independently from a small number of expert demonstrations of a complex task. During performance, each ILR proposes partial solutions to subproblems posed by the MRE, which are then selected from and pieced together by the MRE to produce a complete solution. The heterogeneity of the learner-reasoners allows both learning and problem solving to be more effective because their abilities and biases are complementary and synergistic. We describe the application of this novel learning and problem solving architecture to the domain of airspace management, where multiple requests for the use of airspaces need to be deconflicted, reconciled, and managed automatically. Formal evaluations show that our system performs as well as or better than humans after learning from the same training data. Furthermore, GILA outperforms any individual ILR run in isolation, thus demonstrating the power of the ensemble architecture for learning and problem solving.
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