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Oceanic very short-lived substances (VSLSs), such as bromoform (CHBr3), contribute to stratospheric halogen loading and, thus, to ozone depletion. However, the amount, timing, and region of bromine delivery to the stratosphere through one of the main entrance gates, the Indian summer monsoon circulation, are still uncertain. In this study, we created two bromoform emission inventories with monthly resolution for the tropical Indian Ocean and west Pacific based on new in situ bromoform measurements and novel ocean biogeochemistry modeling. The mass transport and atmospheric mixing ratios of bromoform were modeled for the year 2014 with the particle dispersion model FLEXPART driven by ERA-Interim reanalysis. We compare results between two emission scenarios: (1) monthly averaged and (2) annually averaged emissions. Both simulations reproduce the atmospheric distribution of bromoform from ship- and aircraft-based observations in the boundary layer and upper troposphere above the Indian Ocean reasonably well. Using monthly resolved emissions, the main oceanic source regions for the stratosphere include the Arabian Sea and Bay of Bengal in boreal summer and the tropical west Pacific Ocean in boreal winter. The main stratospheric injection in boreal summer occurs over the southern tip of India associated with the high local oceanic sources and strong convection of the summer monsoon. In boreal winter more bromoform is entrained over the west Pacific than over the Indian Ocean. The annually averaged stratospheric injection of bromoform is in the same range whether using monthly averaged or annually averaged emissions in our Lagrangian calculations. However, monthly averaged emissions result in the highest mixing ratios within the Asian monsoon anticyclone in boreal summer and above the central Indian Ocean in boreal winter, while annually averaged emissions display a maximum above the west Indian Ocean in boreal spring. In the Asian summer monsoon anticyclone bromoform atmospheric mixing ratios vary by up to 50 % between using monthly averaged and annually averaged oceanic emissions. Our results underline that the seasonal and regional stratospheric bromine injection from the tropical Indian Ocean and west Pacific critically depend on the seasonality and spatial distribution of the VSLS emissions.

Ants, like many other animals, use visual memory to follow extended routes through complex environments, but it is unknown how their small brains implement this capability. The mushroom body neuropils have been identified as a crucial memory circuit in the insect brain, but their function has mostly been explored for simple olfactory association tasks. We show that a spiking neural model of this circuit originally developed to describe fruitfly (Drosophila melanogaster) olfactory association, can also account for the ability of desert ants (Cataglyphis velox) to rapidly learn visual routes through complex natural environments. We further demonstrate that abstracting the key computational principles of this circuit, which include one-shot learning of sparse codes, enables the theoretical storage capacity of the ant mushroom body to be estimated at hundreds of independent images. Author Summary We propose a model based directly on insect neuroanatomy that is able to account for the route following capabilities of ants. We show this mushroom body circuit has the potential to store a large number of images, generated in a realistic simulation of an ant traversing a route, and to distinguish previously stored images from highly similar images generated when looking in the wrong direction. It can thus control successful recapitulation of routes under ecologically valid test conditions.

Endozoicomonas bacteria are generally beneficial symbionts of diverse marine invertebrates including reef-building corals, sponges, sea squirts, sea slugs, molluscs, and Bryozoans. In contrast, the recently reported Ca. Endozoicomonas cretensis was identified as a vertebrate pathogen, causing epitheliocystis in fish larvae resulting in massive mortality. Here, we described the Ca. E. cretensis draft genome, currently undergoing genome decay as evidenced by massive insertion sequence (IS element) expansion and pseudogene formation. Many of the insertion sequences are also predicted to carry outward-directed promoters, implying that they may be able to modulate the expression of neighbouring coding sequences (CDSs). Comparative genomic analysis has revealed many Ca. E. cretensis-specific CDSs, phage integration and novel gene families. Potential virulence related CDSs and machineries were identified in the genome, including secretion systems and related effector proteins, and systems related to biofilm formation and directed cell movement. Mucin degradation would be of importance to a fish pathogen, and many candidate CDSs associated with this pathway have been identified. The genome may reflect a bacterium in the process of changing niche from symbiont to pathogen, through expansion of virulence genes and some loss of metabolic capacity. Genome Biology and Evolution, 10 (6) ISSN:1759-6653

This report identifies transferable skills and competences relevant for early career researchers to gather during their doctoral training program and beyond, in order to increase their employability in multiple work sectors. A skills matrix and infographic (see Appendix) with nine different categories, containing a total of 66 transferable skills and competences, is presented. Advice on how to acquire and document these skills and competences is provided. Source at https://doi.org/10.5281/zenodo.1299178 More information at http://eurodoc.net/news/2018/press-release-eurodoc-report-on-transferable-skills-and-competences

Groundwater seepage leads to the formation of theater-headed valleys (THVs) in unconsolidated sediments. In bedrock, the role of groundwater in THV development remains disputed. Here, we integrate field and remote-sensing observations from Gnejna Valley (Maltese Islands) with numerical modeling to demonstrate that groundwater seepage can be the main driver of THV formation in jointed limestone overlying clays. The inferred erosion mechanisms entail (1) widening of joints and fractures by fluid pressure and dissolution and (2) creeping of an underlying clay layer, which lead to slope failure at the valley head and its upslope retreat. The latter is slower than the removal of the talus by creep and sliding on the valley bed. The location and width of THVs are controlled by the location of the master fault and the extent of the damage zone, respectively. The variability of seepage across the fault zone determines the shape of the valley head, with an exponential decrease in seepage away from the fault giving rise to a theater-shaped head that best matches that of Gnejna Valley. Our model may explain the formation of THVs by groundwater in jointed, strong-over-weak chemical sedimentary lithologies, particularly in arid terrestrial settings. peer-reviewed

Oceanic dissolved organic carbon (DOC) is an important carbon pool, similar in magnitude to atmospheric CO2, but the fate of its oldest forms is not well understood1, 2. Hot hydrothermal circulation may facilitate the degradation of otherwise un-reactive dissolved organic matter, playing an important role in the long-term global carbon cycle. The oldest, most recalcitrant forms of DOC, which make up most of oceanic DOC, can be recovered by solid-phase extraction. Here we present measurements of solid-phase extractable DOC from samples collected between 2009 and 2013 at seven vent sites in the Atlantic, Pacific and Southern oceans, along with magnesium concentrations, a conservative tracer of water circulation through hydrothermal systems. We find that magnesium and solid-phase extractable DOC concentrations are correlated, suggesting that solid-phase extractable DOC is almost entirely lost from solution through mineralization or deposition during circulation through hydrothermal vents with fluid temperatures of 212–401 °C. In laboratory experiments, where we heated samples to 380 °C for four days, we found a similar removal efficiency. We conclude that thermal degradation alone can account for the loss of solid-phase extractable DOC in natural hydrothermal systems, and that its maximum lifetime is constrained by the timescale of hydrothermal cycling, at about 40 million years3.