Journey into Midnight: Population Dynamics, Vertical Distribution, and Trophic Ecology of Whalefishes (Cetomimidae) in the Bathypelagic Gulf of Mexico

Despite comprising the largest biome on Earth, the bathypelagic zone inhabitants represent a “black hole” in the understanding of deep-oceanic functioning due to physical and monetary limitations. The characteristics of the global bathypelagic realm create a limiting environment only inhabitable by specially adapted fauna. These include whalefishes (Stephanoberycoidei: Cetomimidae), which are a taxonomically and systematically challenging group of primarily bathypelagic fishes. Cetomimids were collected in the Gulf of Mexico using high-speed rope trawls and a multiple-opening-and-closing net system. Population dynamics were described using morphometric analysis. Vertical distributions, including diel variation, were described using a modified boxplot of abundance standardized by volume of filtered water. Finally, trophic ecology of male and larval Cetomimus/Gyrinomimus was described through gut-content analysis. In total, 493 Cetomimidae were collected, including six new records for the region (Cetomimus compunctus, C. picklei, Danacetichthys galathenus, Gyrinomimus bruuni, G. grahami, and male Cetomimus/Gyrinomimus TBD) and one new record for the Atlantic Ocean (C. compunctus). The assemblage is dominated by Cetostoma regani and Ditropichthys storeri and is highly skewed to favor adult females. Cetomimids were collected most often in the upper bathypelagic zone, including the smaller males and larvae. Asynchronous diel vertical migration is likely in C. regani and D. storeri and possible in species of Gyrinomimus. Specimen SL and depth of capture were not correlated. Male Cetomimus/Gyrinomimus primarily consume copepods although opportunistic feeding of larger crustacea including euphausiids and/or mysids is likely. Larvae gorge on copepods (in quantities reaching 1709) and may display a selective feeding strategy targeting swarming copepods

Ice front change of marine-terminating outlet glaciers in northwest and southeast Greenland during the 21st century

The increasingly negative mass balance of the Greenland ice sheet (GrIS) over the last ~25 years has been associated with enhanced surface melt and increased ice loss from marine-terminating outlet glaciers. Accelerated retreat during 2000–2010 was concentrated in the southeast and northwest sectors of the ice sheet; however, there was considerable spatial and temporal variability in the timing and magnitude of retreat both within and between these regions. This behaviour has yet to be quantified and compared for all glaciers in both regions. Furthermore, it is unclear whether retreat has continued after 2010 in the northwest, and whether the documented slowdown in the southeast post-2005 has been sustained. Here, we compare spatial and temporal patterns of frontal change in the northwest and southeast GrIS, for the period 2000–2015. Our results show near-ubiquitous retreat of outlet glaciers across both regions for the study period; however, the timing and magnitude of inter-annual frontal position change is largely asynchronous. We also find that since 2010, there is continued terminus retreat in the northwest, which contrasts with considerable inter-annual variability in the southeast. Analysis of the role of glacier-specific factors demonstrates that fjord and bed geometry are important controls on the timing and magnitude of glacier retreat

Soil–Air Mercury Flux near a Large Industrial Emission Source before and after Closure (Flin Flon, Manitoba, Canada)

Prior to its closure, the base-metal smelter in Flin Flon, Manitoba, Canada was one of the North America’s largest mercury (Hg) emission sources. Our project objective was to understand the exchange of Hg between the soil and the air before and after the smelter closure. Field and laboratory Hg flux measurements were conducted to identify the controlling variables and used for spatial and temporal scaling. Study results showed that deposition from the smelter resulted in the surrounding soil being enriched in Hg (up to 99 μg g^–1) as well as other metals. During the period of smelter operation, air concentrations were elevated (30 ± 19 ng m^–3), and the soil was a net Hg sink (daily flux: −3.8 ng m^–2 h^–1). Following the smelter closure, air Hg⁰ concentrations were reduced, and the soils had large emissions (daily flux: 108 ng m^–2 h^–1). The annual scaling of soil Hg emissions following the smelter closure indicated that the landscape impacted by smelter deposition emitted or re-emitted almost 100 kg per year. Elevated soil Hg concentrations and emissions are predicted to continue for hundreds of years before background concentrations are re-established. Overall, the results indicate that legacy Hg deposition will continue to cycle in the environment long after point-source reductions

H3B-8800, an orally available small-molecule splicing modulator, induces lethality in spliceosome-mutant cancers

Genomic analyses of cancer have identified recurrent point mutations in the RNA splicing factor-encoding genes SF3B1, U2AF1, and SRSF2 that confer an alteration of function(1-6). Cancer cells bearing these mutations are preferentially dependent on wild-type (WT) spliceosome function(7-11), but clinically relevant means to therapeutically target the spliceosome do not currently exist. Here we describe an orally available modulator of the SF3b complex, H3B-8800, which potently and preferentially kills spliceosome-mutant epithelial and hematologic tumor cells. These killing effects of H3B-8800 are due to its direct interaction with the SF3b complex, as evidenced by loss of H3B-8800 activity in drug-resistant cells bearing mutations in genes encoding SF3b components. Although H3B-8800 modulates WT and mutant spliceosome activity, the preferential killing of spliceosome-mutant cells is due to retention of short, GC-rich introns, which are enriched for genes encoding spliceosome components. These data demonstrate the therapeutic potential of splicing modulation in spliceosome-mutant cancers