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Biochemistry, Biophysics, and Structural Biology

2019

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Articles 1 - 25 of 25

Full-Text Articles in Marine Biology

Insight Into The Molecular Mechanisms For Microcystin Biodegradation In Lake Erie And Lake Taihu, Lauren E. Krausfeldt, Morgan M. Steffen, Robert M. Mckay, George S. Bullerjahn, Gregory L. Boyer, Steven W. Wilhelm Dec 2019

Insight Into The Molecular Mechanisms For Microcystin Biodegradation In Lake Erie And Lake Taihu, Lauren E. Krausfeldt, Morgan M. Steffen, Robert M. Mckay, George S. Bullerjahn, Gregory L. Boyer, Steven W. Wilhelm

Great Lakes Institute for Environmental Research Publications

Microcystins are potent hepatotoxins that are frequently detected in fresh water lakes plagued by toxic cyanobacteria. Microbial biodegradation has been referred to as the most important avenue for removal of microcystin from aquatic environments. The biochemical pathway most commonly associated with the degradation of microcystin is encoded by the mlrABCD (mlr) cassette. The ecological significance of this pathway remains unclear as no studies have examined the expression of these genes in natural environments. Six metatranscriptomes were generated from microcystin-producing Microcystis blooms and analyzed to assess the activity of this pathway in environmental samples. Seventy-eight samples were collected from Lake Erie, …


Comparative Brain Morphology Of The Greenland And Pacific Sleeper Sharks And Its Functional Implications, Kara E. Yopak, Bailey C. Mcmeans, Christopher G. Mull, Kirk W. Feindel, Kit M. Kovacs, Christian Lydersen, Aaron T. Fisk, Shaun P. Collin Dec 2019

Comparative Brain Morphology Of The Greenland And Pacific Sleeper Sharks And Its Functional Implications, Kara E. Yopak, Bailey C. Mcmeans, Christopher G. Mull, Kirk W. Feindel, Kit M. Kovacs, Christian Lydersen, Aaron T. Fisk, Shaun P. Collin

Great Lakes Institute for Environmental Research Publications

In cartilaginous fishes, variability in the size of the brain and its major regions is often associated with primary habitat and/or specific behavior patterns, which may allow for predictions on the relative importance of different sensory modalities. The Greenland (Somniosus microcephalus) and Pacific sleeper (S. pacificus) sharks are the only non-lamnid shark species found in the Arctic and are among the longest living vertebrates ever described. Despite a presumed visual impairment caused by the regular presence of parasitic ocular lesions, coupled with the fact that locomotory muscle power is often depressed at cold temperatures, these sharks remain capable of capturing …


High Concentrations Of Trimethylamines In Slime Glands Inhibit Skein Unraveling In Pacific Hagfish, Gaurav Jain, Marie Starksen, Kashika Singh, Christopher Hoang, Paul Yancey, Charlene Mccord, Douglas S. Fudge Nov 2019

High Concentrations Of Trimethylamines In Slime Glands Inhibit Skein Unraveling In Pacific Hagfish, Gaurav Jain, Marie Starksen, Kashika Singh, Christopher Hoang, Paul Yancey, Charlene Mccord, Douglas S. Fudge

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Hagfish defend themselves from fish predators by producing large volumes of gill-clogging slime when they are attacked. The slime consists of seawater and two major components that are ejected from the slime glands: mucus and threads. The threads are produced within specialized cells and packaged into intricately coiled bundles called skeins. Skeins are kept from unraveling via a protein adhesive that dissolves when the skeins are ejected from the slime glands. Previous work revealed that hagfish slime glands have high concentrations of methylamines including trimethylamine N-oxide (TMAO), trimethylglycine (betaine) and dimethylglycine (DMG); however, the function of these compounds in the …


The Influence Of Dynamic Environmental Interactions On Detection Efficiency Of Acoustic Transmitters In A Large, Deep, Freshwater Lake, Natalie V. Klinard, Edmund A. Halfyard, Jordan K. Matley, Aaron T. Fisk, Timothy B. Johnson Sep 2019

The Influence Of Dynamic Environmental Interactions On Detection Efficiency Of Acoustic Transmitters In A Large, Deep, Freshwater Lake, Natalie V. Klinard, Edmund A. Halfyard, Jordan K. Matley, Aaron T. Fisk, Timothy B. Johnson

Great Lakes Institute for Environmental Research Publications

Background: Acoustic telemetry is an increasingly common method used to address ecological questions about the movement, behaviour, and survival of freshwater and marine organisms. The variable performance of acoustic telemetry equipment and ability of receivers to detect signals from transmitters have been well studied in marine and coral reef environments to inform study design and improve data interpretation. Despite the growing use of acoustic telemetry in large, deep, freshwater systems, detection efficiency and range, particularly in relation to environmental variation, are poorly understood. We used an array of 90 69-kHz acoustic receivers and 8 sentinel range transmitters of varying power …


Metatranscriptomic Analyses Of Diel Metabolic Functions During A Microcystis Bloom In Western Lake Erie (United States), Emily J. Davenport, Michelle J. Neudeck, Paul G. Matson, George S. Bullerjahn, Timothy W. Davis, Steven W. Wilhelm, Maddie K. Denney, Lauren E. Krausfeldt, Joshua M.A. Stough, Kevin A. Meyer, Gregory J. Dick, Thomas H. Johengen, Erika Lindquist, Susannah G. Tringe, Robert Michael L. Mckay Sep 2019

Metatranscriptomic Analyses Of Diel Metabolic Functions During A Microcystis Bloom In Western Lake Erie (United States), Emily J. Davenport, Michelle J. Neudeck, Paul G. Matson, George S. Bullerjahn, Timothy W. Davis, Steven W. Wilhelm, Maddie K. Denney, Lauren E. Krausfeldt, Joshua M.A. Stough, Kevin A. Meyer, Gregory J. Dick, Thomas H. Johengen, Erika Lindquist, Susannah G. Tringe, Robert Michael L. Mckay

Great Lakes Institute for Environmental Research Publications

This study examined diel shifts in metabolic functions of Microcystis spp. during a 48-h Lagrangian survey of a toxin-producing cyanobacterial bloom in western Lake Erie in the aftermath of the 2014 Toledo Water Crisis. Transcripts mapped to the genomes of recently sequenced lower Great Lakes Microcystis isolates showed distinct patterns of gene expression between samples collected across day (10:00 h, 16:00 h) and night (22:00 h, 04:00 h). Daytime transcripts were enriched in functions related to Photosystem II (e.g., psbA), nitrogen and phosphate acquisition, cell division (ftsHZ), heat shock response (dnaK, groEL), and uptake of inorganic carbon (rbc, bicA). Genes …


Tracking Landscape-Scale Movements Of Snow Buntings And Weather-Driven Changes In Flock Composition During The Temperate Winter, Emily A. Mckinnon, Marie Pier Laplante, Oliver P. Love, Kevin C. Fraser, Stuart Mackenzie, François Vézina Sep 2019

Tracking Landscape-Scale Movements Of Snow Buntings And Weather-Driven Changes In Flock Composition During The Temperate Winter, Emily A. Mckinnon, Marie Pier Laplante, Oliver P. Love, Kevin C. Fraser, Stuart Mackenzie, François Vézina

Great Lakes Institute for Environmental Research Publications

Nomadic movements of migratory birds are difficult to study, as the scale is beyond the capabilities of hand-held telemetry (10 s of kms) but too fine-scale for long-range tracking devices like geolocators (50–100 km accuracy). Recent widespread installation of automated telemetry receiving stations allowed us, for the first time, to quantify and test predictions about within-winter movements of a presumed nomadic species, the Snow Bunting (Pletrophenax nivalis). We deployed coded radio-transmitters on 40 individual Snow Buntings during two winters (2015-16 and 2016-17) in southern Ontario, Canada, and tracked movements over a 300 by 300 km area with 69–77 active radio-receiving …


Trophic Upgrading And Mobilization Of Wax Esters In Microzooplankton, Keyana Roohani, Brad A. Haubrich, Kai-Lou Yue, Nigel D'Souza, Amanda Mantalbano, Tatiana Rynearson, Susanne Menden-Deuer, Christopher Reid Aug 2019

Trophic Upgrading And Mobilization Of Wax Esters In Microzooplankton, Keyana Roohani, Brad A. Haubrich, Kai-Lou Yue, Nigel D'Souza, Amanda Mantalbano, Tatiana Rynearson, Susanne Menden-Deuer, Christopher Reid

Science and Technology Department Faculty Journal Articles

Heterotrophic protists play pivotal roles in aquatic ecosystems by transferring matter and energy, including lipids, from primary producers to higher trophic predators. Using Oxyrrhis marina as a model organism, changes to the non-saponifiable protist lipids were investigated under satiation and starvation conditions. During active feeding on the alga Cryptomonas sp., the O. marina hexane soluble non-saponifiable fraction lipid profile reflected its food source with the observed presence of long chain mono-unsaturated fatty alcohols up to C25:1. Evidence of trophic upgrading in O. marina was observed with long chain mono-unsaturated fatty alcohol accumulation of up to C35:1. To the best of …


Incidence And Prevalence Of Francisella Noatunensis Subsp. Orientalis (Fno) Pathogenic Infections In Feral Hawaiian Tilapia, Daquille Peppers Aug 2019

Incidence And Prevalence Of Francisella Noatunensis Subsp. Orientalis (Fno) Pathogenic Infections In Feral Hawaiian Tilapia, Daquille Peppers

Biology Theses

Aquaculture has become a major food source for many countries and continues to grow each year. However, many of the fishes that are farmed are susceptible to pathogenic infections such as Francisellosis, a bacterial infection that contributes to disease and high mortality rate in many populations of farmed and wild fish around the world. In 1994, feral and farmed populations of tilapia (e.g. Oreochromis mossambicus) on Oahu, Hawaii were found to be infected with a novel Francisellosis strain, Francisella noatunensis subsp. orientalis (Fno). To prevent the spread of this pathogen, the Hawaii Department of Aquaculture (HDOA) initiated …


Stable Isotopes Of Carbon Reveal Flexible Pairing Strategies In A Migratory Arctic Bird, Rolanda J. Steenweg, Pierre Legagneux, Glenn T. Crossin, H. Grant Gilchrist, T. Kurt Kyser, Oliver P. Love Jul 2019

Stable Isotopes Of Carbon Reveal Flexible Pairing Strategies In A Migratory Arctic Bird, Rolanda J. Steenweg, Pierre Legagneux, Glenn T. Crossin, H. Grant Gilchrist, T. Kurt Kyser, Oliver P. Love

Great Lakes Institute for Environmental Research Publications

Many birds change their partners every year and pairing may occur before arrival on the breeding grounds. Early pairing strategies can benefit mates by strengthening pair-bonds and increasing the rate of pre-breeding resource acquisition, leading to increased reproductive output and success, especially for migratory species breeding in seasonally-constrained environments like the Arctic. Despite the theorized and documented advantages of early pairing, we know rather little about pairing phenology in many species. Here, we test the use of a stable isotope (carbon δ13C) method to assign geographic origin of paired birds to examine pairing phenology in Arctic-breeding Common Eiders (Somateria mollissima …


Evolutionary Expansions And Neofunctionalization Of Ionotropic Glutamate Receptors In Cnidaria, Ellen G. Dow Jun 2019

Evolutionary Expansions And Neofunctionalization Of Ionotropic Glutamate Receptors In Cnidaria, Ellen G. Dow

FIU Electronic Theses and Dissertations

Reef ecosystems are composed of a variety of organisms, transient species of fish and invertebrates, microscopic bacteria and viruses, and structural organisms that build the living foundation, coral. Sessile cnidarians, corals and anemones, interpret dynamic environments of organisms and abiotic factors through a molecular interface. Recognition of foreign molecules occurs through innate immunity via receptors identifying conserved molecular patterns. Similarly, chemosensory receptors monitor the environment through specific ligands. Chemosensory receptors include ionotropic glutamate receptors (iGluRs), transmembrane ion channels involved in chemical sensing and neural signal transduction. Recently, an iGluR homolog was implicated in cnidarian immunological resistance to recurrent infections of …


The Effects Of Ultraviolet Light Exposure On The Activity Of Catalase In The Coelomocytes Of Sea Urchins Lytechinus Variegatus And Arbacia Punctulata, Kandis Arlinghaus Apr 2019

The Effects Of Ultraviolet Light Exposure On The Activity Of Catalase In The Coelomocytes Of Sea Urchins Lytechinus Variegatus And Arbacia Punctulata, Kandis Arlinghaus

Undergraduate Theses

Many sea urchins play important ecological roles in their environments, and it is important to study the impacts of environmental stressors on their physiology. Ultraviolet radiation (UVR) exposure has significant negative impacts on marine organisms including an increase in reactive oxygen species (ROS). Oxidative damage by ROS at the cellular level can cause lipid peroxidation, DNA fragmentation, and even cell death that may result in inflammation or disease. To prevent this cellular damage, organisms generate enzymes, such as catalase, that breakdown ROS into harmless substances. Elevated catalase activities under UVB, a range of UVR from 280–315 nm, exposure have been …


Lingering Impacts Of Hurricane Hugo On Rhizophora Mangle (Red Mangrove) Population Genetics On St. John, Usvi, Paul Ax Bologna, James J. Campanella, Dena J. Restaino, Zachary A. Fetske, Matthew Lourenco, John V. Smalley Apr 2019

Lingering Impacts Of Hurricane Hugo On Rhizophora Mangle (Red Mangrove) Population Genetics On St. John, Usvi, Paul Ax Bologna, James J. Campanella, Dena J. Restaino, Zachary A. Fetske, Matthew Lourenco, John V. Smalley

Marine Biology and Coastal Sciences Faculty Scholarship and Creative Works

Stochastic events can have catastrophic effects on island populations through a series of genetic stressors from reduced population size. We investigated five populations of red mangrove (Rhizophora mangle) from St. John, USVI, an UNESCO Biosphere Reserve, which were impacted by Hurricane Hugo in 1989. Our goal was to determine diversity and to ascertain potential population bottlenecks two decades after the event. With the lowest observed heterozygosity, highest inbreeding coefficient, and evidence of a major bottleneck, our results demonstrated that the Great Lameshur mangroves, devastated by Hurricane Hugo, were the least diverse stand of trees. The other four populations from St. …


Transitions In Microbial Communities Along A 1600 Km Freshwater Trophic Gradient, Mark J. Rozmarynowycz, Benjamin F.N. Beall, George S. Bullerjahn, Gaston E. Small, Robert W. Sterner, Sandra S. Brovold, Nigel A. D'Souza, Susan B. Watson, Robert Michael L. Mckay Apr 2019

Transitions In Microbial Communities Along A 1600 Km Freshwater Trophic Gradient, Mark J. Rozmarynowycz, Benjamin F.N. Beall, George S. Bullerjahn, Gaston E. Small, Robert W. Sterner, Sandra S. Brovold, Nigel A. D'Souza, Susan B. Watson, Robert Michael L. Mckay

Great Lakes Institute for Environmental Research Publications

This study examined vertically-resolved patterns in microbial community structure across a freshwater trophic gradient extending 1600 km from the oligotrophic waters of Lake Superior to the eutrophic waters of Lake Erie, the most anthropogenically influenced of the Laurentian Great Lakes system. Planktonic bacterial communities clustered by Principal Coordinates Analysis (PCoA) on UniFrac distance matrices into four groups representing the epilimnion and hypolimnion of the upper Great Lakes (Lakes Superior and Huron), Lake Superior's northern bays (Nipigon and Black bays), and Lake Erie. The microbes within the upper Great Lakes hypolimnion were the most divergent of these groups with elevated abundance …


Scale Up Isolation Of Aaptamine For In Vivo Evaluation Indicates Its Neurobiological Activity Is Linked To The Delta Opioid Receptor, Nicole L. Mcintosh, Eptisam Lambo, Laura Millan-Lobo, Fei Li, Li He, Phillip Crews, Jennifer L. Whistler, Tyler Johnson Mar 2019

Scale Up Isolation Of Aaptamine For In Vivo Evaluation Indicates Its Neurobiological Activity Is Linked To The Delta Opioid Receptor, Nicole L. Mcintosh, Eptisam Lambo, Laura Millan-Lobo, Fei Li, Li He, Phillip Crews, Jennifer L. Whistler, Tyler Johnson

Tyler Johnson

Opioid receptors belong to the large superfamily of seven transmembrane-spanning (7TM) G protein-coupled receptors (GPCRs). As a class, GPCRs are of fundamental physiological importance mediating the actions of the majority of known neurotransmitters and hormones. The Mu, Delta, and Kappa (MOP, DOP, KOP) opioid receptors are particularly intriguing members of this receptor family as they are the targets involved in many neurobiological diseases such as addiction, pain, stress, anxiety, and depression. Recently we discovered that the aaptamine class of marine sponge derived natural products exhibit selective agonist activity in vitro for the DOP versus MOP receptor. Our findings may explain …


Abundance And Species Diversity Hotspots Of Tracked Marine Predators Across The North American Arctic, David J. Yurkowski, Marie Auger-Méthé, Mark L. Mallory, Sarah N.P. Wong, Grant Gilchrist, Andrew E. Derocher, Evan Richardson, Nicholas J. Lunn, Nigel E. Hussey, Marianne Marcoux, Ron R. Togunov, Aaron T. Fisk, Lois A. Harwood, Rune Dietz, Aqqalu Rosing-Asvid, Erik W. Born, Anders Mosbech, Jérôme Fort, David Grémillet, Lisa Loseto Mar 2019

Abundance And Species Diversity Hotspots Of Tracked Marine Predators Across The North American Arctic, David J. Yurkowski, Marie Auger-Méthé, Mark L. Mallory, Sarah N.P. Wong, Grant Gilchrist, Andrew E. Derocher, Evan Richardson, Nicholas J. Lunn, Nigel E. Hussey, Marianne Marcoux, Ron R. Togunov, Aaron T. Fisk, Lois A. Harwood, Rune Dietz, Aqqalu Rosing-Asvid, Erik W. Born, Anders Mosbech, Jérôme Fort, David Grémillet, Lisa Loseto

Great Lakes Institute for Environmental Research Publications

Aim: Climate change is altering marine ecosystems worldwide and is most pronounced in the Arctic. Economic development is increasing leading to more disturbances and pressures on Arctic wildlife. Identifying areas that support higher levels of predator abundance and biodiversity is important for the implementation of targeted conservation measures across the Arctic. Location: Primarily Canadian Arctic marine waters but also parts of the United States, Greenland and Russia. Methods: We compiled the largest data set of existing telemetry data for marine predators in the North American Arctic consisting of 1,283 individuals from 21 species. Data were arranged into four species groups: …


Plasma Mammalian Leptin Analogue Predicts Reproductive Phenology, But Not Reproductive Output In A Capital-Income Breeding Seaduck, Holly L. Hennin, Pierre Legagneux, H. Grant Gilchrist, Joël Bêty, John P. Mcmurtry, Oliver P. Love Feb 2019

Plasma Mammalian Leptin Analogue Predicts Reproductive Phenology, But Not Reproductive Output In A Capital-Income Breeding Seaduck, Holly L. Hennin, Pierre Legagneux, H. Grant Gilchrist, Joël Bêty, John P. Mcmurtry, Oliver P. Love

Great Lakes Institute for Environmental Research Publications

To invest in energetically demanding life history stages, individuals require a substantial amount of resources. Physiological traits, particularly those related to energetics, can be useful for examining variation in life history decisions and trade-offs because they result from individual responses to environmental variation. Leptin is a protein hormone found in mammals that is proportional to the amount of endogenous fat stores within an individual. Recently, researchers have confirmed that a mammalian leptin analogue (MLA), based on the mammalian sequence of leptin, is present with associated receptors and proteins in avian species, with an inhibitory effect on foraging and body mass …


Biogeochemical Characterization Of Metal Behavior From Novel Mussel Shell Bioreactor Sludge Residues, Sara C. Butler, James Pope, Subba Rao Chaganti, Daniel D. Heath, Christopher G. Weisener Jan 2019

Biogeochemical Characterization Of Metal Behavior From Novel Mussel Shell Bioreactor Sludge Residues, Sara C. Butler, James Pope, Subba Rao Chaganti, Daniel D. Heath, Christopher G. Weisener

Great Lakes Institute for Environmental Research Publications

Acid mine drainage (AMD) remediation commonly produces byproducts which must be stored or utilized to reduce the risk of further contamination. A mussel shell bioreactor has been implemented at a coal mine in New Zealand, which is an effective remediation option, although an accumulated sludge layer decreased efficiency which was then removed and requires storage. To understand associated risks related to storage or use of the AMD sludge material, a laboratory mesocosm study investigated the physio-chemical and biological influence in two conditions: anoxic storage (burial deep within a waste rock dump) or exposure to oxic environments (use of sludge on …


Behavioural And Morphological Changes In Fish Exposed To Ecologically Relevant Boat Noises, Megan F. Mickle, Christopher M. Harris, Oliver P. Love, Dennis M. Higgs Jan 2019

Behavioural And Morphological Changes In Fish Exposed To Ecologically Relevant Boat Noises, Megan F. Mickle, Christopher M. Harris, Oliver P. Love, Dennis M. Higgs

Great Lakes Institute for Environmental Research Publications

There is increasing concern about the effect of underwater noise on fish due to rising levels of anthropogenic noise. We performed experiments on the black bullhead (Ameiurus melas), a species with known hearing specializations and located within the Laurentian Great Lakes where there is considerable commercial and recreational boat traffic. We tested and compared physiology (baseline cortisol), behaviour (activity, sheltering), and morphology (ciliary bundles of hair cells) of bullhead to boat noise. At 140 dB re 1 μPa (−54.84 dB re 1 m·s−2), we saw clear behavioural effects in terms of both activity and sheltering levels despite no obvious morphological …


Baseline Corticosterone Does Not Reflect Iridescent Plumage Traits In Female Tree Swallows, Keneth Sarpong, Christine L. Madliger, Christopher M. Harris, Oliver P. Love, Stéphanie M. Doucet, Pierre Paul Bitton Jan 2019

Baseline Corticosterone Does Not Reflect Iridescent Plumage Traits In Female Tree Swallows, Keneth Sarpong, Christine L. Madliger, Christopher M. Harris, Oliver P. Love, Stéphanie M. Doucet, Pierre Paul Bitton

Great Lakes Institute for Environmental Research Publications

The production of high quality secondary sexual traits can be constrained by trade-offs in the allocation of energy and nutrients with other metabolic activities, and is mediated by physiological processes. In birds, the factors influencing male plumage quality have been well studied; however, factors affecting female plumage quality are poorly understood. Furthermore, it remains uncertain which physiological traits mediate the relationship between body condition and ornaments. In this three-year study of after-second-year female tree swallows (Tachycineta bicolor), we investigated (1) the relationship between baseline corticosterone near the end of the brood-rearing period (CORTBR) and feather colour characteristics (hue, saturation, brightness) …


Monarch Butterfly Conservation Through The Social Lens: Eliciting Public Preferences For Management Strategies Across Transboundary Nations, Rodrigo Solis-Sosa, Christina A.D. Semeniuk, Sergio Fernandez-Lozada, Kornelia Dabrowska, Sean Cox, Wolfgang Haider Jan 2019

Monarch Butterfly Conservation Through The Social Lens: Eliciting Public Preferences For Management Strategies Across Transboundary Nations, Rodrigo Solis-Sosa, Christina A.D. Semeniuk, Sergio Fernandez-Lozada, Kornelia Dabrowska, Sean Cox, Wolfgang Haider

Great Lakes Institute for Environmental Research Publications

The monarch butterfly (Danaus plexippus), an iconic species that migrates annually across North America, has steeply declined in numbers over the past decade. Across the species’ range, public, private, and non-profit organizations aim to reverse the monarch decline by engaging in conservation activities such as habitat restoration, larvae monitoring, and butterfly tagging. Urban residents can actively participate in these activities, yet their contribution can also be realized as an electorate body able to influence the design of conservation programs according to their interests. Little is known, however about their preferences toward the objectives and design of international monarch conservation policies. …


Responses Of Phytoplankton Assemblages To Iron Availability And Mixing Water Masses During The Spring Bloom In The Oyashio Region, Nw Pacific, T. Isada, A. Hattori-Saito, H. Saito, Y. Kondo, J. Nishioka, K. Kuma, H. Hattori, R. M.L. Mckay, K. Suzuki Jan 2019

Responses Of Phytoplankton Assemblages To Iron Availability And Mixing Water Masses During The Spring Bloom In The Oyashio Region, Nw Pacific, T. Isada, A. Hattori-Saito, H. Saito, Y. Kondo, J. Nishioka, K. Kuma, H. Hattori, R. M.L. Mckay, K. Suzuki

Great Lakes Institute for Environmental Research Publications

Spring phytoplankton blooms play a major role in the carbon biogeochemical cycle of the Oyashio region, western subarctic Pacific, where the seasonal biological drawdown effect on seawater pCO 2 is one of the greatest among the world's oceans. However, the bloom often terminates before depleting macronutrients, and the initiation and magnitude of the bloom is heterogeneous. We conducted a high resolution taxonomic and physiological assessment of phytoplankton in relation to the different physicochemical water masses of Coastal Oyashio Water (COW), Oyashio water (OYW), and modified Kuroshio water (MKW) in the Oyashio region from April to June 2007. Massive diatom blooms …


Ammonium Recycling Supports Toxic Planktothrix Blooms In Sandusky Bay, Lake Erie: Evidence From Stable Isotope And Metatranscriptome Data, Justyna J. Hampel, Mark J. Mccarthy, Michelle Neudeck, George S. Bullerjahn, Robert Michael L. Mckay, Silvia E. Newell Jan 2019

Ammonium Recycling Supports Toxic Planktothrix Blooms In Sandusky Bay, Lake Erie: Evidence From Stable Isotope And Metatranscriptome Data, Justyna J. Hampel, Mark J. Mccarthy, Michelle Neudeck, George S. Bullerjahn, Robert Michael L. Mckay, Silvia E. Newell

Great Lakes Institute for Environmental Research Publications

Sandusky Bay, Lake Erie, receives high nutrient loadings (nitrogen and phosphorus) from the Sandusky River, which drains an agricultural watershed. Eutrophication and cyanobacterial harmful algal blooms (cyanoHABs) persist throughout summer. Planktothrix agardhii is the dominant bloom-forming species and the main producer of microcystins in Sandusky Bay. Non-N2 fixing cyanobacteria, such as Planktothrix and Microcystis, thrive on chemically reduced forms of nitrogen, such as ammonium (NH4+) and urea. Ammonium regeneration and potential uptake rates and total microbial community demand for NH4+ were quantified in Sandusky Bay. Potential NH4+ uptake rates in the light increased from June to August at all stations. …


Effects Of Aquatic Acidification On Calcium Uptake In White River Shrimp Litopenaeus Setiferus Gills, Maria-Flora Jacobs Jan 2019

Effects Of Aquatic Acidification On Calcium Uptake In White River Shrimp Litopenaeus Setiferus Gills, Maria-Flora Jacobs

UNF Graduate Theses and Dissertations

Previous research regarding aquatic acidification has examined the protonation of the carbonate and does not consider calcium to be a limiting factor. This is the first study to suggest that pH may affect the uptake of calcium in crustacean gills. This project describes ion transport mechanisms present in the cell membranes of white river shrimp Litopenaeus setiferus gill epithelium, and the effects of pH on the uptake of calcium by these means. Partially purified membrane vesicles (PPMV) of shrimp gills were prepared through a homogenization process that has been used previously to define ion transport in crab and lobster gill …


Development Of A Biomarker Panel For Identifying Stressed Marine Mammals, Laura Pujade Jan 2019

Development Of A Biomarker Panel For Identifying Stressed Marine Mammals, Laura Pujade

University of the Pacific Theses and Dissertations

Increasing anthropogenic disturbance in marine ecosystems such as fishing, oil-drilling, and noise pollution can have detrimental effects on the reproduction and survival of apex predators such as marine mammals. Stress activates the hypothalamic-pituitary-adrenal (HPA) axis, resulting in increased circulating glucocorticoid (GCs) hormones, which alter expression of target genes encoding metabolic enzymes and other mediators of stress. Prolonged HPA axis stimulation may increase catabolism of nutrient stores and suppress immune and reproductive functions, impacting the fitness of marine mammals. GCs measurements are used to identify wild animals experiencing stress. However, these measurements may not be sensitive enough to distinguish between an …


Island Invasion: The Silent Crisis In Hawaii, Sophia Janssen Jan 2019

Island Invasion: The Silent Crisis In Hawaii, Sophia Janssen

Pomona Senior Theses

Keeping out invasive species may, upon first review, seem like a trivial environmental cry from ecologists and deep environmentalists; a belated wish to return to an undeveloped world where nature was pristine. However invasive species create problems that impact all of us and can have far more severe consequences than changing a stunning landscape. These problems are heightened in islands like Hawaii, where the fragile ecosystems have developed over centuries of evolution and adaptation. The introduction of a disease-carrying mosquito can put the people of Hawaii at risk to many vector-born illnesses and create an epidemic, taking human life. The …