109 research outputs found

    Abnormal returns, risk, and financial statement data: The case of the Iraqi invasion of Kuwait

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    This paper examines abnormal returns and changes in risk for transportation firms immediately around the Iraqi invasion of Kuwait. Further, it tests whether the variation in the abnormal returns can be explained cross-sectionally with standard financial and industry-descriptive variables. The results indicate that transportation firms suffered a −2.09% abnormal return and increases in unsystematic risk. The cross sectional regression explains 31% of the variation in the abnormal returns, with firm size, liquidity, leverage, percentage of sales to the Department of Defense, and dummy variables denoting firms producing recreational vehicles or owning oil-producing subsidiaries contributing significantly to the regression

    From the surface to the seafloor: How giant larvaceans transport microplastics into the deep sea.

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    Plastic waste is a pervasive feature of marine environments, yet little is empirically known about the biological and physical processes that transport plastics through marine ecosystems. To address this need, we conducted in situ feeding studies of microplastic particles (10 to 600 μm in diameter) with the giant larvacean Bathochordaeus stygius. Larvaceans are abundant components of global zooplankton assemblages, regularly build mucus "houses" to filter particulate matter from the surrounding water, and later abandon these structures when clogged. By conducting in situ feeding experiments with remotely operated vehicles, we show that giant larvaceans are able to filter a range of microplastic particles from the water column, ingest, and then package microplastics into their fecal pellets. Microplastics also readily affix to their houses, which have been shown to sink quickly to the seafloor and deliver pulses of carbon to benthic ecosystems. Thus, giant larvaceans can contribute to the vertical flux of microplastics through the rapid sinking of fecal pellets and discarded houses. Larvaceans, and potentially other abundant pelagic filter feeders, may thus comprise a novel biological transport mechanism delivering microplastics from surface waters, through the water column, and to the seafloor. Our findings necessitate the development of tools and sampling methodologies to quantify concentrations and identify environmental microplastics throughout the water column

    Description and Relationships of Chaetopterus pugaporcinus, an Unusual Pelagic Polychaete (Annelida, Chaetopteridae)

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    An extraordinary new species, Chaetopterus pugaporcinus, is described from eight specimens collected from deep mesopelagic waters off Monterey Bay, California, by remotely operated vehicles. All specimens exhibit a consistent combination of both adult and larval characteristics, leaving in question the maturity of the specimens. All specimens lack ciliated larval bands and the stout, modified chaetae (cutting spines) typically found in segment A4 of chaetopterids. If the specimens described here are larvae, they are remarkable for their size, which ranged from 10 to 21 mm total length, nearly twice the length of the largest polychaete larvae previously reported and 5 to 10 times larger than known chaetopterid larvae. Then too, their lack of segment addition prior to settlement would be atypical. If adult, they are particularly unusual in their habitat choice and body form. Morphology of the uncini and comparison to larval morphology indicated a close relationship to either Chaetopterus or Mesochaetopterus. However, the lack of cutting spines and typical adult morphology made it impossible to determine to what genus this species should be allied. Thus, we carried out the first molecular phylogenetic analysis of the Chaetopteridae in order to appropriately place and name the new species. Three partial genes were sequenced for 21 annelid species. The sequencing also provides the first molecular evidence that Chaetopterus variopedatus sensu Hartman (1959) is not a single cosmopolitan species. The question of C. pugaporcinus being a delayed larva or a genuine holopelagic chaetopterid is discussed

    Vampire squid reproductive strategy is unique among coleoid cephalopods

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    Coleoid cephalopods are thought to go through only one reproductive cycle in their life. We here report that vampire squid (Vampyroteuthis infernalis) show evidence of multiple reproductive cycles. Female vampire squid spawn their eggs, then return to a resting reproductive state, which is followed by the development of a new batch of eggs. This reproductive cycle is likely to be repeated more than twenty times. This combination of reproductive traits is different from that of any other extant coleoid cephalopod

    Prevalence of microplastics and anthropogenic debris within a deep-sea food web

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    Microplastic particles (\u3c5 mm) are ubiquitous throughout global marine ecosystems, including the deep sea. Ingestion of microplastics and other anthropogenic microparticles is reported in diverse marine taxa across trophic levels. Trophic transfer, or the movement of microplastics across trophic levels, is reported in laboratory studies but not yet widely measured in marine food webs. The Monterey Bay submarine canyon ecosystem contains a well-studied, known deep-sea food web in which to examine the trophic fate of microplastics. We measured microplastic abundance across 17 genera spanning approximately 5 trophic levels and a diversity of feeding behaviors. Samples were collected using remotely operated vehicles and oblique midwater trawls, and gut contents of all individuals examined (n = 157) were analyzed for microplastic abundance and other anthropogenic particles greater than 100 μm using stereo microscopy. Microparticles were analyzed with Raman spectroscopy to confirm material type. Anthropogenic particles were found in all genera examined, across crustacean, fish, mollusk, and gelatinous organisms, in amounts ranging from 0 to 24 particles per individual. There was no significant relationship between microplastic amount and fish trophic level, suggesting that the trophic transfer of microparticles is not occurring. Body size was positively correlated with microplastic abundance across all taxa. The fish genus Scomber sp. drove this relationship, suggesting higher microparticle abundance in mobile individuals with broad horizontal distributions. Future work should examine physiological pathways for microplastic transport within organisms (e.g. excretion, accumulation on gills, internal translocation of particles) and between organisms within shared habitats to more fully understand the fate of microplastics within aquatic food webs

    Feeding behavior of the ctenophore Thalassocalyce inconstans : revision of anatomy of the order Thalassocalycida

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    © 2009 The Authors. This article is distributed under the terms of the Creative Commons Attribution Noncommercial License. The definitive version was published in Marine Biology 156 (2009): 1049-1056, doi:10.1007/s00227-009-1149-6.Behavioral observations using a remotely operated vehicle (ROV) in the Gulf of California in March, 2003, provided insights into the vertical distribution, feeding and anatomy of the rare and delicate ctenophore Thalassocalyce inconstans. Additional archived ROV video records from the Monterey Bay Aquarium Research Institute of 288 sightings of T. inconstans and 2,437 individual observations of euphausiids in the Gulf of California and Monterey Canyon between 1989 and 2005 were examined to determine ctenophore and euphausiid prey depth distributions with respect to temperature and dissolved oxygen concentration [dO]. In the Gulf of California most ctenophores (96.9%) were above 350 m, the top of the oxygen minimum layer. In Monterey Canyon the ctenophores were more widely distributed throughout the water column, including the hypoxic zone, to depths as great as 3,500 m. Computer-aided behavioral analysis of two video records of the capture of euphausiids by T. inconstans showed that the ctenophore contracted its bell almost instantly (0.5 s), transforming its flattened, hemispherical resting shape into a closed bi-lobed globe in which seawater and prey were engulfed. Euphausiids entrapped within the globe displayed a previously undescribed escape response for krill (‘probing behavior’), in which they hovered and gently probed the inner surfaces of the globe with antennae without stimulating further contraction by the ctenophore. Such rapid bell contraction could be effected only by a peripheral sphincter muscle even though the presence of circumferential ring musculature was unknown for the Phylum Ctenophora. Thereafter, several live T. inconstans were collected by hand off Barbados and microscopic observations confirmed that assumption.Supported by the David and Lucile Packard Foundation and NOAA Grant #NA06OAR4600091

    Mesobot : An Autonomous Underwater Vehicle for Tracking and Sampling Midwater Targets

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    Mesobot, a new class of autonomous underwater vehicle, will address specific unmet needs for observing slow-moving targets in the midwater ocean. Mesobot will track targets such as zooplankton, fish, and descending particle aggregates using a control system based on stereo cameras and a combination of thrusters and a variable buoyancy system. The vehicle will also be able to collect biogeochemical and environmental DNA (eDNA) samples using a pumped filter sampler
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