Master\u27s Recital

List of performers and performances

Trophic Structure and Sources of Variation Influencing the Stable Isotope Signatures of Meso- and Bathypelagic Micronekton Fishes

To better understand spatiotemporal variation in the trophic structure of deep-pelagic species, we examined the isotope values of particulate organic matter (POM) (isotopic baseline) and seven deep-pelagic fishes with similar diet compositions but contrasting vertical distributions across mesoscale features in the Gulf of Mexico using stable isotope and amino acid compound-specific isotope analyses. Species examined included four migratory (Benthosema suborbitale, Lepidophanes guentheri, Melamphaes simus, Sigmops elongatus) and three non-migratory zooplanktivorous fishes (Argyropelecus hemigymnus, Cyclothone obscura, Sternoptyx pseudobscura). Isotopic values of POM increased with depth, with meso- and bathypelagic samples characterized by higher δ C and δ N values relative to epipelagic samples. Despite similar diet compositions, mean δ N values of fishes spanned 3.43‰ resulting in mean trophic position estimates among species varying by 1.09 trophic levels. Interspecific differences in δ N were driven by higher δ N values in the non-migratory and deepest dwelling C. obscura (10.61‰) and lower δ N values in the migratory and shallowest dwelling L. guentheri (7.18‰) and B. suborbitale (8.11‰). Similarly, fish δ N values were correlated with depth, with the lowest values occurring in the migratory L. guentheri and B. suborbitale and highest values occurring in the non-migratory C. obscura. Our data suggest that depth-related trends in fish δ N and δ N values are driven by shallower dwelling species feeding within epipelagic food webs supported by POM with lower δ N values, while deeper dwelling, non-migratory species increasingly use food webs at depth supported by POM with elevated δ N values. Horizontal isotopic variation was observed across a large mesoscale oceanographic feature (Loop Current), with POM, three migratory, and one non-migratory species characterized by higher δ C and lower δ N values in the anticyclonic Loop Current relative to surrounding water masses. Our results demonstrate that isotopic values of POM can vary significantly over relatively small horizontal and vertical scales and that baseline variation can be conserved in the signatures of higher-order consumers. By gaining a more thorough understanding of the sources contributing to isotopic variation of deep-pelagic fishes, this paper will inform the design and interpretation of future feeding studies in the pelagic realm and advances our knowledge of deep-pelagic food web structure. 13 15 15 15 15 15 15 15 15 15 15 13 15 sourceAA sourceA

Trophic Structure and Food Web Dynamics of Deep-Pelagic Micronekton in the Gulf of Mexico

The deep-pelagic ocean is the largest but least studied ecosystem on Earth. As natural resource extraction and fisheries expand into the deep pelagic, there is increased need for comprehensive, ecosystem-based management plans for deep-pelagic ecosystems. Detailed knowledge of food webs is critical to effective ecosystem management, as trophic interactions regulate animal populations and influence the resilience of ecosystems to perturbation. Additionally, effective management strategies require data regarding feeding relationships amongst taxa, estimates of trophic position, and descriptions of energy transfer, which are lacking for the deep-pelagic Gulf of Mexico. This dissertation describes the trophic structure of deep-pelagic micronekton, which represent crucial components of deep-pelagic ecosystems worldwide, with the goal to provide data critical to the development of ecosystem-based management plans in deep-pelagic ecosystems. The first study describes fine-scale spatiotemporal variation in micronekton trophic structure in the Gulf of Mexico and presents evidence suggesting that micronekton inhabiting different regions of the water column feed within food chains supported by two different size classes of sinking particulate organic matter. The second study examines the trophic dynamics of deep-pelagic predatory fishes by providing estimates of their trophic position and quantifying their use of particulate organic matter from differing regions of the water column. Results indicate that all species occupy trophic positions between the third and fourth trophic level and receive the majority of their carbon from primary production derived near the surface of the ocean. These species, which often do not vertically migrate, access epipelagic primary production by consuming vertically migrating micronekton which forage in the epipelagic at night. The last study reveals that body size, depth of occurrence, and proximity to major oceanographic features are important determinants of trophic structure within the deep-pelagic micronekton assemblage of the Gulf of Mexico. The emerging picture of deep-pelagic food webs is one of extreme interconnectedness, with animals inhabiting the deepest depths of the GoM connected to primary production and food resources in epipelagic waters. Taken together, the results of this research increase our understanding of deep-pelagic food webs and ecosystems and will be used to better inform the construction of deep-pelagic ecosystem-based management plans

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

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

A quantitative model of normal Caenorhabditis elegans embryogenesis and its disruption after stress

AbstractThe invariant lineage of Caenorhabditis elegans has powerful potential for quantifying developmental variability in normal and stressed embryos. Previous studies of division timing by automated lineage tracing suggested that variability in cell cycle timing is low in younger embryos, but manual lineage tracing of specific lineages suggested that variability may increase for later divisions. We developed improved automated lineage tracing methods that allowroutine lineage tracing through the last round of embryonic cell divisions and we applied these methods to trace the lineage of 18 wild-type embryos. Cell cycle lengths, division axes and cell positions are remarkably consistent among these embryos at all stages, with only slight increase in variability later in development. The resulting quantitative 4-dimensional model of embryogenesis provides a powerful reference dataset to identify defects in mutants or in embryos that have experienced environmental perturbations. We also traced the lineages of embryos imaged at higher temperatures to quantify the decay in developmental robustness under temperature stress. Developmental variability increases modestly at 25°C compared with 22°C and dramatically at 26°C, and we identify homeotic transformations in a subset of embryos grown at 26°C. The deep lineage tracing methods provide a powerful tool for analysis of normal development, gene expression and mutants and we provide a graphical user interface to allow other researchers to explore the average behavior of arbitrary cells in a reference embryo

The Vehicle, Spring 2005

Table of Contents The Remnants of YouKaty Dwigginspage 5 Sunrise, Early Spring, with CigaretteMario Podeschipage 6-7 I\u27m Not the Butterfly, I\u27m the KnifeAllison Staulcuppage 8 AcceptanceHeather Lucaspage 9 WordsKaty Dwigginspage 10 Thank YouA.T. Shootpage 11 72 Beats ofA.T. Shootpage 12 I Think We Hang Out Too MuchAllison Staulcuppage 13 StorageA.T. Shootpage 14 Plum PerfectKaty Dwigginspage 15 Last MinuteMeghan Moralespage 16 Last Monday\u27s SummersaultKelly Richardspage 17 A Peaceful MomentStaci Lucepage 18-19 The SaviorKaty Dwigginspage 20 IslandsDanielle Hookepage 21 My Nalgene: A SonnetJesse Wygonikpage 22 Unwanted ChildKaty Dwigginspage 23 My Pain or YoursAllison Staulcuppage 24 TimmyKelly Richardspage 25-30https://thekeep.eiu.edu/vehicle/1083/thumbnail.jp

The Vehicle, Spring 2005

Table of Contents The Remnants of YouKaty Dwigginspage 5 Sunrise, Early Spring, with CigaretteMario Podeschipage 6-7 I\u27m Not the Butterfly, I\u27m the KnifeAllison Staulcuppage 8 AcceptanceHeather Lucaspage 9 WordsKaty Dwigginspage 10 Thank YouA.T. Shootpage 11 72 Beats ofA.T. Shootpage 12 I Think We Hang Out Too MuchAllison Staulcuppage 13 StorageA.T. Shootpage 14 Plum PerfectKaty Dwigginspage 15 Last MinuteMeghan Moralespage 16 Last Monday\u27s SummersaultKelly Richardspage 17 A Peaceful MomentStaci Lucepage 18-19 The SaviorKaty Dwigginspage 20 IslandsDanielle Hookepage 21 My Nalgene: A SonnetJesse Wygonikpage 22 Unwanted ChildKaty Dwigginspage 23 My Pain or YoursAllison Staulcuppage 24 TimmyKelly Richardspage 25-30https://thekeep.eiu.edu/vehicle/1083/thumbnail.jp

Exploring the Effects of Incorporating Egg Powder Containing Phospholipase α2 Antibody on Ground Striploin Shelf-Life

Lipid oxidation in beef may be enhanced by the hydrolysis of phospholipids by phospholipaseα2 (PLA2) during postmortem storage. Anti-phospholipaseα2 (aPLA2) is an antibody that can inhibit PLA2 activity. Past research has shown that aPLA2 can be mass-produced in the form of egg powder (EP) from hens immunized against PLA2. Therefore, the present study aimed to determine the effects of incorporating different levels of EP containing aPLA2 into ground striploin (GS) to assess its ability to extend beef shelf-life. Ten striploins were collected from 10 USDA Choice beef carcasses. Each striploin was ground and equally divided into 4 batches, and each batch was mixed with 0%, 0.4%, 0.8%, or 1.6% dried EP containing aPLA2. Each treatment batch was further divided into 3 smaller batches and subjected to retail display (0, 4, or 7d). Color descriptors, pH, proximate analysis, lipid oxidation, antioxidant capacity, and phospholipid and fatty acid (FA) profiles were measured. Percent visual discoloration and instrumental color measurements of GS were unaffected by aPLA2 EP treatments (P>0.05). The 1.6% treatment GS had a higher relative percentage of phosphatidylcholine compared with those from the 0% treatment (P<0.05), but the lack of lysophosphatidylcholine generation in the GS from any treatment reflects a lack of detectable level of PLA2 activity. Moreover, the addition of EP in GS increased the relative percentage of FA 11-18:1, 18:2, 20:1, and 22:6 (P<0.05). As a result, there was more lipid oxidation for GS from the 1.6% treatment compared with those from the 0% treatment (P<0.05), but GS from the 0.8% treatment showed higher antioxidant activity than those from the 0% treatment (P<0.05). In this study, the addition of EP containing aPLA2 did not demonstrate any effect to extend shelf-life when incorporated into GS

The Application of Novel Research Technologies by the Deep Pelagic Nekton Dynamics of the Gulf of Mexico (DEEPEND) Consortium

The deep waters of the open ocean represent a major frontier in exploration and scientific understanding. However, modern technological and computational tools are making the deep ocean more accessible than ever before by facilitating increasingly sophisticated studies of deep ocean ecosystems. Here, we describe some of the cutting-edge technologies that have been employed by the Deep Pelagic Nekton Dynamics of the Gulf of Mexico (DEEPEND; www.deependconsortium.org) Consortium to study the biodiverse fauna and dynamic physical-chemical environment of the offshore Gulf of Mexico (GoM) from 0 to 1,500 m