Exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), an environmental endocrine disruptor and model AhR agonist, is linked to skeletal abnormalities, cardiac edema, stunted growth rate, altered metabolism, and neurobehavioral deficits. We have previously reported transgenerational reproductive outcomes of developmental TCDD exposure in adult zebrafish (Danio rerio), an NIH-validated model for developmental and generational toxicology. Using the same paradigm of sublethal TCDD exposure (50 pg/ml) at both 3 and 7 weeks post fertilization (wpf), we investigated several novel endpoints, including longitudinal morphometrics and anxiety-linked behavior, in fish exposed as juveniles. We also assessed developmental abnormalities and neurobehavior in their F1 larval offspring. TCDD exposure induced timepoint-dependent decreases in several craniofacial and trunk morphometrics across juvenile development. In early adulthood, however, only exposed males underwent a transient period of compensatory growth, ending between 7 and 12 months post fertilization (mpf). At 12 mpf, exposed adult fish of both sexes displayed increased exploratory behaviors in a novel tank test. The F1 offspring of parents exposed at both 3 and 7 wpf were hyperactive, but neurobehavioral outcomes diverged depending on parental exposure window. F1 exposure-lineage larvae had increased rates of edema and skeletal abnormalities, but fewer unhatched larvae compared to controls. Parent- and timepoint-specific effects of exposure on abnormality rate were also evaluated; these outcomes were considerably less severe. Our novel behavioral findings expand current knowledge of the long-term and intergenerational consequences of early-life TCDD exposure in a zebrafish model, in addition to delineating minor longitudinal morphometric changes in exposed fish and abnormalities in larval offspring.

In North America, terrestrial records of biodiversity and climate change that span Marine Oxygen Isotope Stage (MIS) 5 are rare. Where found, they provide insight into how the coupling of the ocean–atmosphere system is manifested in biotic and environmental records and how the biosphere responds to climate change. In 2010–2011, construction at Ziegler Reservoir near Snowmass Village, Colorado (USA) revealed a nearly continuous, lacustrine/wetland sedimentary sequence that preserved evidence of past plant communities between ~140 and 55 ka, including all of MIS 5. At an elevation of 2705 m, the Ziegler Reservoir fossil site also contained thousands of well-preserved bones of late Pleistocene megafauna, including mastodons, mammoths, ground sloths, horses, camels, deer, bison, black bear, coyotes, and bighorn sheep. In addition, the site contained more than 26,000 bones from at least 30 species of small animals including salamanders, otters, muskrats, minks, rabbits, beavers, frogs, lizards, snakes, fish, and birds. The combination of macro- and micro-vertebrates, invertebrates, terrestrial and aquatic plant macrofossils, a detailed pollen record, and a robust, directly dated stratigraphic framework shows that high-elevation ecosystems in the Rocky Mountains of Colorado are climatically sensitive and varied dramatically throughout MIS 5.

Magnetospheric substorms represent the episodic dissipation of energy stored in the geomagnetic tail that was previously extracted from the solar wind. This energy release produces activity throughout the entire magnetosphere-ionosphere system, and it results in a wide variety of phenomena such as auroral intensifications and the generation of new current systems. All of these phenomena involve the acceleration of particles, sometimes up to several MeV. In this paper we present a brief overview of substorm phenomenology. We then review some of the evidence for particle acceleration in Earth’s magnetosphere during substorms. Such in situ observations in this most accessible of all cosmic plasma domains may hold important clues to understanding acceleration processes in more distant astrophysical systems.

Subject headings: acceleration of particles — Earth — solar wind