100 research outputs found

    How high school training for work in blue-collar communities helps manufacture workplace gender inequality.

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    In states in the Rust Belt and the Southeast, many high schools emphasize courses related to local blue-collar work in order to better prepare students for careers in local industries. In new research, April Sutton, Amanda Bosky and Chandra Muller find that such emphases are often at the expense of college-preparation courses, which in turn has a knock-on effect for female employment rates. Women who are raised in blue-collar communities, and thus who missed out on college preparation courses, face a much bigger wage gap than those who attended high-school elsewhere

    Abyssal Ambushers

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    Field researcher and passionate conservationist Dante Fenolio reports on the DEEPEND project taking place int hte waters of the Gulf of Mexico

    Hiding in Plain Sight: Elopomorph Larvae Are Important Contributors to Fish Biodiversity in a Low-Latitude Oceanic Ecosystem

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    Leptocephalus larvae of elopomorph fishes are a cryptic component of fish diversity in nearshore and oceanic habitats. However, identifying those leptocephali can be important in illuminating species richness in a region. Since the Deepwater Horizon oil spill in 2010, sampling of offshore fishes in the epi-, meso-, and upper bathypelagic depth strata of the northern Gulf of Mexico resulted in 8989 identifiable specimens of leptocephalus larvae or transforming juveniles, in 118 taxa representing 83 recognized and established species and an additional 35 distinctive leptocephalus morphotypes not yet linked to a known described species. Leptocephali account for ∟13% of the total species richness of fishes collected in the offshore region. A new morphotype of Muraenidae leptocephalus is also described. We compare this study with other leptocephalus diversity studies in the western Atlantic

    Vertical Distribution of Deep-Pelagic (0-3000 M) Fishes Over the Charlie-Gibbs Fracture Zone Region of the Northern Mid-Atlantic Ridge

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    Only a tiny fraction of the world’s largest volume of living space, the ocean’s midwater biome, has ever been sampled. As part of the International Census of Marine Life field project, MAR-ECO, a discrete-depth trawling survey was conducted in 2009 aboard the NOAA ship Henry B. Bigelow to examine pelagic assemblage structure and distribution over the Charlie-Gibbs Fracture Zone of the northern Mid-Atlantic Ridge. The bottom topography in this region ranges from 4500 m in the channel to 700-800 m on top of adjacent seamounts. Sampling was conducted at 11 stations from 0-3000 m using a Norwegian “Krill” trawl with five codends that opened and closed by a pre-programmed timer. Seventy-five species of fishes were collected, with a maximum species diversity and biomass being observed between 700-1900 m. Other key features observed were a strong diel migrating component and frequent captures of putative bathypelagic fishes, shrimps, and cephalopods in the epipelagic zone (0-200 m). The results of MAR-ECO sampling show patterns unlike those previously reported for open ocean ecosystems

    Deep-Sea Fishes of the Mid-Atlantic Ridge: Results of the 2009 Henry Bigelow Expedition

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    As part of an ongoing study of the northern Mid-Atlantic Ridge biodiversity and ecology (CoML field project MAR-ECO), a detailed survey of the pelagic and demersal fishes in the region of the Charlie-Gibbs Fracture Zone (~ 600 n.m. south of Greenland) was conducted. A total of 17181 pelagic fishes (92 spp., 35 families) were sampled from 0-3000+ m, with the Myctophidae the most species-rich. The bristlemouth Cyclothone microdon was by far the dominant species in numbers (82% of total), while the sawtooth eel Serrivomer beani dominated biomass (27%). A total of 441 deep-demersal fishes (28 spp., 13 families) were sampled from 1872-3527 m, with the Macrouridae and Alepocephalidae comprising half of species numbers. The abyssal halosaur Halosauropsis macrochir was most abundant, while the abyssal grenadier Coryphaenoides armatus contributed the most biomass. Remarkable among the pelagic fish data were routine shallow catches of bathypelagic fishes (see A.B. Cook et al., this volume), and among the demersal fishes were the large size of the individuals, above or near the maximum known for many species. The high species number relative to sample number portends the enhanced deep-sea biodiversity about abrupt topographic features, while the lack of asymptote of species number versus sampling effort underscores our incomplete inventory of this biodiversity

    The Vertical and Horizontal Distribution of Deep-Sea Crustaceans in the Order Euphausiacea in the Vicinity of the DeepWater Horizon Oil Spill

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    The vertical and horizontal distributions of Euphausiacea in the northern Gulf of Mexico (GOM), including the location of the Deepwater Horizon oil spill, were analyzed from 340 trawl samples collected between April and June 2011. This study is the first comprehensive survey of euphausiid distributions from depths deeper than 1000 m in the GOM and includes stratified sampling from five discrete depth ranges (0–200 m, 200–600 m, 600–1000 m, 1000–1200 m, and 1200–1500 m), and expands the depth ranges of 30 species. In addition, this study demonstrates significantly higher abundance and biomass of the euphausiid assemblage from slope vs. offshore stations, while the offshore assemblage was significantly more diverse. There is also some evidence for seasonality in reproduction amongst the seven species that had gravid females. Lastly, these data represent the first quantification of the euphausiid assemblage in the region heavily impacted by the Deepwater Horizon event, and as there are no pre-spill data, may serve as an impacted baseline against which to monitor changes in the euphausiid assemblage in the years following exposure to Deepwater Horizon oil and dispersants in the water column

    Trophic Ecology of Meso- and Bathypelagic Predatory Fishes in the Gulf of Mexico

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    The trophic ecology of eight circumglobal meso- and bathypelagic fishes (Anoplogaster cornuta, Chauliodus sloani, Coccorella atlantica, Gigantura chuni, G. indica, Omosudis lowii, Photostomias guernei, and Stomias affinis) with contrasting vertical migration habits (vertical migrators vs. non-migrators) were examined using stable isotope analysis (SIA). Mean δ13C values of these predators were similar among species, ranging from –18.17 to –18.99 ‰, suggesting that all species are supported by a similar carbon source. This finding was supported by mixing-model analysis; all of these deep-living predators received the majority (\u3e73%) of their carbon from epipelagic food resources. Mean δ15N values of the predators ranged from 9.18 to 11.13 ‰, resulting in trophic position estimates between the third and fourth trophic level, although significant shifts in δ15N with increasing body size suggest that some of these species undergo ontogenetic shifts in trophic position. Bayesian standard ellipses, used to estimate isotopic niche areas, differed in size among species, with those occupying the highest relative trophic positions possessing the largest isotopic niches. These results, which provide the first trophic descriptions using dietary tracers for several of these species, offer insight into the trophic structure of deep-sea ecosystems and will help inform the construction of ecosystem-based models

    Diel Variation in the Vertical Distribution of Deep-Water Scattering Layers in the Gulf of Mexico

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    Sound scattering layers (SSLs) are important components of oceanic ecosystems with ubiquitous distribution throughout the world\u27s oceans. This vertical movement is an important mechanism for exchanging organic matter from the surface to the deep ocean, as many of the organisms comprising SSLs serve as prey resources for linking the lower trophic levels to larger predators. Variations in abundance and taxonomic composition of mesopelagic organisms were quantified using repeated discrete net sampling and acoustics over a 30-h survey, performed during 26–27 June 2011 at single site (27°28’51”N and 88°27’54”W) in the northern Gulf of Mexico. We acoustically classified the mesopelagic SSL into four broad taxonomic categories, crustacean and small non-swimbladdered fish (CSNSBF), large non-swimbladdered fish (LNSBF), swimbladdered fish (SBF) and unclassified and we quantified the abundance of mesopelagic organisms over three discrete depth intervals; epipelagic (0–200 m); upper mesopelagic (200–600 m) and lower mesopelagic (600–1000 m). Irrespective of the acoustic categories at dusk part of the acoustic energy redistributed from the mesopelagic into the upper epipelagic (shallower than 100 m) remaining however below the thermocline depth. At night higher variability in species composition was observed between 100 and 200 m suggested that a redistribution of organisms may also occur within the upper portion of the water column. Along the upper mesopelagic backscatter spectra from CSNSBF migrated between 400 and 460 m while spectra from the other categories moved to shallower depths (300 and 350 m), resulting in habitat separation from CSNSBF. Relatively small vertical changes in both acoustic backscatter and center of mass metrics of the deep mesopelagic were observed for CNSBF and LNSBF suggesting that these animals may be tightly connected to deeper (below 1000 m) mesopelagic habitats, and do not routinely migrate into the epipelagic

    Deep-Pelagic (0-3000 m) Fish Assemblage Structure over the Mid-Atlantic Ridge Relative to the North Atlantic Subpolar Front

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    Only a tiny fraction of the world\u27s largest volume of living space, the ocean\u27s mid-water region, has ever been sampled. It is one of the least understood areas on earth, so as part of the International Census of Marine Life field project, MAR-ECO, a discrete-depth trawling survey was conducted in 2009 aboard the NOAA ship Henry Bigelow to examine pelagic assemblage structure and distribution over the Charlie-Gibbs Fracture Zone (CGFZ) of the northern Mid-Atlantic Ridge. The survey consisted of 11 stations divided into two transects, one northwest and one southeast of the CGFZ, which roughly coincides with the Subpolar Front. Sampling was conducted from 0-3000 m using a Norwegian Krill trawl with five codends that opened and closed by a preprogrammed timer. Seventy-five species of fish (29 families, 14 orders) were collected. Maximum species diversity was observed between 700-1900 m. Other key features observed were a strong diel migrating component and frequent captures of putative bathypelagic fishes in the epipelagic zone (0-200 m). Fish assemblage structure and distribution will be discussed as a function of physical oceanographic features. The results of this expedition have increased our knowledge about oceanic community structure in association with mid-ocean ridge systems and mesoscale circulation patterns
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