Chernobyl nuclide record from a North Sea sediment trap

Mitochondrial, exosomal miR137-COX6A2 and gamma synchrony as biomarkers of parvalbumin interneurons, psychopathology, and neurocognition in schizophrenia

Early detection and intervention in schizophrenia requires mechanism-based biomarkers that capture neural circuitry dysfunction, allowing better patient stratification, monitoring of disease progression and treatment. In prefrontal cortex and blood of redox dysregulated mice (Gclm-KO ± GBR), oxidative stress induces miR-137 upregulation, leading to decreased COX6A2 and mitophagy markers (NIX, Fundc1, and LC3B) and to accumulation of damaged mitochondria, further exacerbating oxidative stress and parvalbumin interneurons (PVI) impairment. MitoQ, a mitochondria-targeted antioxidant, rescued all these processes. Translating to early psychosis patients (EPP), blood exosomal miR-137 increases and COX6A2 decreases, combined with mitophagy markers alterations, suggest that observations made centrally and peripherally in animal model were reflected in patients' blood. Higher exosomal miR-137 and lower COX6A2 levels were associated with a reduction of ASSR gamma oscillations in EEG. As ASSR requires proper PVI-related networks, alterations in miR-137/COX6A2 plasma exosome levels may represent a proxy marker of PVI cortical microcircuit impairment. EPP can be stratified in two subgroups: (a) a patients' group with mitochondrial dysfunction "Psy-D", having high miR-137 and low COX6A2 levels in exosomes, and (b) a "Psy-ND" subgroup with no/low mitochondrial impairment, including patients having miR-137 and COX6A2 levels in the range of controls. Psy-D patients exhibited more impaired ASSR responses in association with worse psychopathological status, neurocognitive performance, and global and social functioning, suggesting that impairment of PVI mitochondria leads to more severe disease profiles. This stratification would allow, with high selectivity and specificity, the selection of patients for treatments targeting brain mitochondria dysregulation and capture the clinical and functional efficacy of future clinical trials.

Radiocesium in Japan Sea associated with sinking particles from Fukushima Dai-ichi Nuclear Power Plant accident

This study examined the temporal variations in radiocesium concentration associated with sinking particles in the northeastern Japan Sea between September 2010 and July 2012. We analyzed sediment trap samples from this period after the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident in March 2011. Cesium-134 was detected in samples collected between May and July 2011 at a depth of 1100 m (4.2-11 mBq g-dry^-1) but not in other periods at 1100 m or deeper (3100 and 3500 m). These results confirmed the deposition of FDNPP-derived radiocesium on the surface water in the late April 2011, which rapidly sank with sinking particles to a depth of at least 1100 m, in the northeastern Japan Sea, about 40 days after the deposition in the North Pacific. If FDNPP-derived ¹³⁷Cs was excluded, no seasonal changes were detected in the ¹³⁷Cs activity concentration of the sinking particles, and the ¹³⁷Cs activity concentration of the particles increased with increasing depth. Judging from the concentration of ¹³⁷Cs of sinking particle and seasonal variation of total mass flux and organic matter content, the lithogenic particle seems to be important for radiocesium associated with sinking particles. These data also strongly suggest a difference in sinking features of particles between 2010-2011 and 2011-2012 deployments. Due to the existence of benthic front, shallow water (1100 m) and deep water (3500 m) are separated during 2010-2011 deployment, but in the winter of 2011-2012, this front disappeared and the particles in surface water seem to have sunk to the depth of 3100 m. The sinking velocity of the particles at 1100 m was estimated to be 33-62 m day^-1, with a mean sinking velocity of 43 m day^-1. These values were comparable to those estimated at depths shallower than 1000 m in the North Pacific after the FDNPP accident, or in the Mediterranean, North, and Black Seas after the Chernobyl accident.

Fukushima Daiichi-Derived Radionuclides in the Ocean: Transport, Fate, and Impacts

The events that followed the Tohoku earthquake and tsunami on March 11, 2011, included the loss of power and overheating at the Fukushima Daiichi nuclear power plants, which led to extensive releases of radioactive gases, volatiles, and liquids, particularly to the coastal ocean. The fate of these radionuclides depends in large part on their oceanic geochemistry, physical processes, and biological uptake. Whereas radioactivity on land can be resampled and its distribution mapped, releases to the marine environment are harder to characterize owing to variability in ocean currents and the general challenges of sampling at sea. Five years later, it is appropriate to review what happened in terms of the sources, transport, and fate of these radionuclides in the ocean. In addition to the oceanic behavior of these contaminants, this review considers the potential health effects and societal impacts.

Vertical and lateral transport of particulate radiocesium off Fukushima

Transport processes of particulate radiocesium were investigated using a sediment trap deployed at about 100 km east of the Fukushima Daiichi Nuclear Power Plant. A sediment trap was installed at 873 m depth of the station (119 m above the bottom), and time-series sampling of sinking particles was carried out from August, 2011 to June, 2013. The accident-derived radiocesium was detected from sinking particles over two years after the accident. Observed 137Cs flux was highest in September 2011 (98 mBq m(-2) day(-1): decay-corrected to March 11, 2011), and decreased over time with seasonal fluctuations. Particulate fluxes of radiocesium were mainly affected by two principal processes. One was the rapid sinking of radiocesium-bound particles (moderate mode). This mode was dominant especially in the early postaccident stage, and was presumed to establish the distribution of radiocesium in the offshore seabed. Another mode was observed in winter, and secondary transport of particles attributed to turbulence near the seabed increased fluxes of particulate radiocesium (turbulence mode). Although the latter process would not drastically change the distribution of sedimentary radiocesium in the short term, attention should be paid as this key process redistributing the accident-derived radiocesium may cumulatively affect the long-term distribution.

Sediment fluxes and the littoral drift along northeast Andhra Pradesh Coast, India: estimation by remote sensing

The littoral drift regime along the northeastern coast of India was investigated by analyzing coastal drift indicators and shoreline changes based on multitemporal satellite images. The study of offshore turbidity patterns and quantitative estimation of suspended sediments was undertaken to understand the magnitude and direction of movement of sediment fluxes. The study revealed that: (1) the character of coastal landforms and sedimentation processes indicate that the sediment transport is bidirectional and monsoon dependent; (2) multidate, multitemporal analysis of satellite images helps to show the nature of sediment transport along the coast. The dominant net sediment transport is in a NE direction along the eastern coast of India. Finally, this assessment demonstrates the potential of remote sensing technology in understanding the coastal morphometric changes, long-term sediment transport, shoreline changes, and offshore turbidity distribution pattern and the implications for the transport of sediment-associated pollutants.