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Ammonium Chemotaxis In Chlamydomonas Reinhardtii, Gabela Nelson

LSU Doctoral Dissertations

Analysis of ammonium chemotaxis in Chlamydomonas reinhardtii is largely hindered, compared to that of phototaxis, despite equal importance on flagellated microalgal physiology. A major contribution of this shortfall is the lack of proper assay method. We developed a simple Petri dish assay method in which light is homogenously exposed while patterns of the cellular migration are tracked with a function of time. Using the method, new findings were revealed. First, this research presented that a strain lacking the eyespot organelle required for light gradient-sensing exhibits similar chemotactic behavior compared to a wild-type strain, suggesting Chlamydomonas sense an ammonium gradient not …

Dynamics Of Co2 Consumption, And Biomass And Lipid Carbon Production During Photobioreactor Cultivation Of The Diatom Cyclotella, Altan Özkan

Turkish Journal of Botany

Understanding of CO₂ delivery and consumption dynamics in algal photobioreactors are critical to unravel microalgae?s full potential for bioproduct generation and carbon capture from flue gas streams. This study aims to expand our current understanding by cultivating the diatom Cyclotella under controlled process conditions of a bubble column photobioreactor and analyzing CO₂ consumption dynamics in real time using results from an online CO₂ sensor connected to the reactor exhaust. Two sets of experiments were conducted: they served to contrast the influence of silicon and nitrate (Si&N colimitation) and Si limitation, and the light availability, respectively. CO2 consumption …

Seasonal Starch Allocation In Starry Stonewort (Nitellopsis Obtusa) Harvested From Lake Koronis, Mn, And Development Of Non-Chemical Management Recommendations, Alyssa M. Haram

All Graduate Theses, Dissertations, and Other Capstone Projects

Starry stonewort (Nitellopsis obtusa) (Desvaux in Loiseleur) J. Groves is an invasive macro alga that can take over entire water columns and outcompete native species. Previous research has quantified seasonal life history and phenology but there is no research quantifying carbohydrate allocation which was the aim for Chapter II. Management efforts to control Nitellopsis obtusa have been limited to stressing the thalli and have not been able to directly target the reproductive bulbils on larger scales. Smaller scale efforts such as the use of hand pulling can be used but hand pulling is not realistic for larger infestations. Chapter III …

Exploring Secondary Metabolite Profiles Of Sloth Algae, Valerie Quach, Paige Smith

Honors Theses

In this experiment, we investigated the composition of the secondary metabolites in sloth algal cultures. Additionally, we investigated the effects of secondary metabolites in sloth algal cultures on insects. The three outlets of investigation include insect avoidance tests, sending samples to the Natural Center for Natural Products Research, and analyzing sequencing data with AntiSMASH to identify secondary metabolite biosynthetic gene clusters. While our data from the Drosophila fly tests were inconclusive, we found that our samples contain many different gene clusters for terpenes, NRPS, PKS, RiPPs, which are volatile compounds with a wide array of biosynthetic functions. This research can …

Review: Influence Of Meteorological Conditions And Algal Community Composition On Hypolimnetic Hypoxia, Ian P. Stone

Honors Projects

Hypoxia has been a central focus of research regarding water quality impairments throughout the world in the past century. The fresh and coastal marine waters affected by hypoxia are of great importance due to the ecosystem services and species habitat they provide, and because of the regional economic activity spurned by these waters in return. As such, a great deal of research effort has been devoted to elucidating the causes and ecological effects of hypoxia with the hopes of remediating the issue. The bulk of this effort has been directed at the role of anthropogenic allochthonous nutrient loading and algal …

Diverse Far-Red Light Utilization Strategies In Cyanobacteria And Algae, Benjamin Martin Wolf

Arts & Sciences Electronic Theses and Dissertations

In their natural environments, photosynthetic organisms are often exposed to widely varied light environments. Species adapted to shade light, often found growing in lower layers of photosynthetic biofilms, must survive on filtered light alone. Filtered light is highly enriched in far-red wavelengths, which are normally unavailable for photosynthetic energy production in most oxygenic phototrophs. To overcome light limitations in filtered light environments, some species of algae and cyanobacteria utilize specialized photosynthetic pigments and antenna systems to harvest these far-red wavelengths. By sampling the natural environment and using custom-built far-red light growth chambers, I have isolated several species of oxygenic phototrophs …

Landsat Collections Reveal Long-Term Algal Bloom Hot Spots Of Utah Lake, Rachel Shanae Tate

Theses and Dissertations

Harmful algal blooms (HABs) and nuisance algal blooms (NABs) are a worldwide phenomenon with implications for human health and safety. HABs occur when algae or bacteria grow in high enough densities to harm animals and humans. A primary component of harmful algal blooms is cyanobacteria, which are aquatic, photosynthesizing microorganisms that produce toxins at high concentrations. Cyanobacterial biomass has increased worldwide in recent decades, raising concern about the future of fresh- and marine-water systems in a changing climate. Understanding the patterns and conditions of past algal blooms can provide useful insights for managing future blooms. Remote sensing can enhance our …

Screening Of Crude Microalgal Extracts For Antimicrobial Activity, Patrick Matulich

Theses & Dissertations

Microbial biofilm associated infections are a significant threat to patients with medical devices and are partially responsible for the increased resistance seen in nosocomial infections. The biofilm chemical and physical properties restrict access of chemotherapeutic agents. Therefore, there is a need to enhance the antimicrobial effects of current chemotherapeutic agents. Microalgae live in competitive environments that include film-forming, opportunistic pathogens S. maltophilia and C. albicans. Extracts from 5 diverse species of microalgae were screened for antimicrobial enhancing effects against established biofilms with two different extraction solvents, 3:1 hexanes and isopropyl (HIPA) and 2-methyltetrahydrofuran (2-MTHF).

Three species, B. braunii, …

Distribution And Population Structure Of The Invasive Nitellopsis Obtusa (Desv. In Loisel.) J. Groves And Native Species Of Characeae In The Northeast U.S.A., Robin Sleith

Dissertations, Theses, and Capstone Projects

Freshwater ecosystems are some of the most biologically diverse environments on Earth. Billions of humans rely on functioning freshwater ecosystems for drinking water and many other services. These ecosystems are increasingly threatened by human impacts including nutrient pollution, invasive species, and climate change. Here I contribute four research chapters that investigate freshwater diversity and ecosystem threats using the Characeae, a family of freshwater green macroalgae, as a study system. Characeae are a diverse and ancient group with more than 500 extant species and a fossil history spanning at least 250 million years. These algae are macrophytes in freshwater ecosystems, and …

Engineered Nanoparticles Interact With Nutrients To Intensify Eutrophication In A Wetland Ecosystem Experiment, Marie Simonin, Benjamin P. Colman, Steven M. Anderson, Ryan S. King, Matthew T. Ruis, Astrid Avellan, Christina M. Bergemann, Brittany G. Perrotta, Nicholas K. Geitner, Mengchi Ho, Belen De La Barrera, Jason M. Unrine, Gregory V. Lowry, Curtis J. Richardson, Mark R. Wiesner, Emily S. Bernhardt

Plant and Soil Sciences Faculty Publications

Despite the rapid rise in diversity and quantities of engineered nanomaterials produced, the impacts of these emerging contaminants on the structure and function of ecosystems have received little attention from ecologists. Moreover, little is known about how manufactured nanomaterials may interact with nutrient pollution in altering ecosystem productivity, despite the recognition that eutrophication is the primary water quality issue in freshwater ecosystems worldwide. In this study, we asked two main questions: (1) To what extent do manufactured nanoparticles affect the biomass and productivity of primary producers in wetland ecosystems? (2) How are these impacts mediated by nutrient pollution? To address …

Biological Soil Crusts In A Northeastern Pine Barren: Composition And Ecological Effects, Jessica Gilbert

Honors Theses

Biological soil crusts (BSCs), otherwise known as cryptogamic soil crusts, biocrusts, or cyanobacterial crusts, are soil aggregations hosting diverse biotic communities. They are composed of cyanobacteria and algae, and generally have a covering of moss and/or lichen. BSCs are typically found in arid to semi-arid regions throughout the world, and are integral soil stabilizers, moisture retainers, and nitrogen fixers in these communities. Along with these factors, BSCs are able to impact germination and establishment of plants, either as an accompanying influence, or direct result of those listed above. BSCs have yet to be formally described in the inland northeastern United …

A Multidomain Enzyme, With Glycerol-3-Phosphate Dehydrogenase And Phosphatase Activities, Is Involved In A Chloroplastic Pathway For Glycerol Synthesis In Chlamydomonas Reinhardtii, Daniela Morales-Sánchez, Yeongho Kim, Ee Leng Terng, Laura Peterson, Heriberto D. Cerutti

Center for Plant Science Innovation: Faculty and Staff Publications

Understanding the unique features of algal metabolism may be necessary to realize the full potential of algae as feedstock for the production of biofuels and biomaterials. Under nitrogen deprivation, the green alga C. reinhardtii showed substantial triacylglycerol (TAG) accumulation and up-regulation of a gene, GPD2, encoding a multidomain enzyme with a putative phosphoserine phosphatase (PSP) motif fused to glycerol-3-phosphate dehydrogenase (GPD) domains. Canonical GPD enzymes catalyze the synthesis of glycerol-3-phosphate (G3P) by reduction of dihydroxyacetone phosphate (DHAP). G3P forms the backbone of TAGs and membrane glycerolipids and it can be dephosphorylated to yield glycerol, an osmotic stabilizer and compatible …

Lipid Content And Biomass Analysis In Autotrophic And Heterotrophic Algal Species, Addie M. Lauder, Daniel P. Jones, Thomas E. Walker, Todd Allen

Montview Journal of Research & Scholarship

Biofuels are a form of renewable energy derived from living matter, typically plants. The push for biofuels began in order to decrease the amount of carbon dioxide (CO2) released into the atmosphere, as biofuels are essentially carbon neutral. The idea is the same amount of CO2 the plants took in to perform photosynthesis will then be released in the burning of the biofuels. Algae is an excellent source of biofuels because it grows quickly and is versatile in terms of the type of fuel it can produce. The two most common mechanisms for algae growth are heterotrophic or photoautotrophic. Heterotrophically …

Influence Of Water Hardness On Accumulation And Effects Of Silver In The Green Alga, Raphidocelis Subcapitata, Aarya Venkat, Adriana L. Amerson, Gretchen K. Bielmyer-Fraser

Georgia Journal of Science

Metal pollution from anthropogenic sources can pose a threat to aquatic systems. Silver is released into the environment from various industrial processes. In excess, silver can accumulate and cause adverse effects in aquatic organisms, particularly those in lower trophic levels, such as phytoplankton. Water chemistry parameters, such as hardness, have been shown to modify toxicity of metals because divalent cations compete with the metal for binding sites on the biological membrane. The objective of this study was to assess population growth and silver accumulation in the green alga, Raphidocelis subcapitata, after silver exposure in waters of varying hardness for 7 …

Production And Harvest Of Microalgae In Wastewater Raceways With Resource Recycling, Alexander Colin Roberts

Master's Theses

Microalgae can be grown on municipal wastewater media to both treat the wastewater and produce feedstock for algae biofuel production. However the reliability of treatment must be demonstrated, as well as high areal algae productivity on recycled wastewater media and efficient sedimentation harvesting. This processes was studied at pilot scale in the present research.

A pilot facility was operated with nine CO₂-supplemented raceway ponds, each with a 33-m² surface area and a 0.3-m depth, continuously from March 6, 2013 through September 24, 2014. The ponds were operated as three sets of triplicates with two sets continuously fed …

Inferring Plastid Metabolic Pathways Within The Nonphotosynthetic Free-Living Green Algal Genus Polytomella, Sara Asmail

Electronic Thesis and Dissertation Repository

The advent of photosynthesis facilitated the evolution of aerobic life on Earth. However, species such as Prototheca wickerhamii and Plasmodium falciparum, among many others, have lost photosynthesis and opted for a free-living/parasitic lifestyle. Despite this loss, these species have retained the plastid for its metabolic pathways, without which they would die. Polytomella is a nonphotosynthetic free-living alga, closely related to the photosynthetic model organism Chlamydomonas reinhardtii, and has been shown to lack a plastid genome. I set out to determine Polytomella plastid metabolic pathways using bioinformatics to look for mRNA and DNA homologous sequences matching pathway enzymes in model organisms. …

Chemical Oxygen Demand Reduction Using The Algae Dunaliella Primolecta And Chlorella Vulgaris, Angeles L. Mora, Alejandro Hernandez, Alejandro Calderón-Urrea

STAR Program Research Presentations

Farm industry wastewater is characterized by high organic materials and by high chemical oxygen demand (COD). Farms with large livestock and poultry operations can be a major source of wastewater thus a major concern for effective environmental and industrial management. Effective environmental and industrial management are high in cost therefor biofuels produced from plants have a potential of replacing a portion of fossil fuel consumption with a renewable efficient alternative. Due to California’s water crisis in the recent years, it is questioned if a biological treatment system that uses algal growth to create renewable energy in the form of biodiesel …

Size-Fractionated Relationships Between Phytoplankton Production And Biomass, Luke Auman Bassett

Senior Theses

Phytoplankton are the autotrophic foundation of almost all marine ecosystems.

The flow of energy through an ecosystem is largely dependent how productivity moves through organisms of various sizes. For this reason, numerous studies have set out to quantify the respective contributions of these size-fractions to biomass and rates of primary production. This is done through field measurements of production or through mathematic models that infer production contributions from the easier field measured contributions to biomass. However, the accuracy of this method has been called into question. Can contributions to biomass really be used to accurately interpret contributions to production?

The …

Studying The Effects Of Theraflu On The Growth Of Selenastrum Capricornutum, Hannah Gray Boren

Honors Theses

Algae contribute to self-purification of streams and rivers and are necessary as food for fish and as components of aquatic food webs (1). However, too much or too little algae may create or be indicative of a problem. If nutrients are present in large amounts, algae growth may become excessive, resulting in algal “blooms.” These algal blooms can change the chemistry of the water, making it toxic to other aquatic occupants, including fish, birds, animals, and other plants (1). On the other hand, if nutrients in the water are limiting or are exhausted, algae growth is inhibited, which results in …

Priming In The Microbial Landscape: Periphytic Algal Stimulation Of Litter-Associated Microbial Decomposers, Kevin A. Kuehn, Steven N. Francoeur, Robert H. Findlay, Robert K. Neely

Faculty Publications

Microbial communities associated with submerged detritus in aquatic ecosystems often comprise a diverse mixture of autotrophic and heterotrophic microbes, including algae, bacteria, protozoa, and fungi. Recent studies have documented increased rates of plant litter mass loss when periphytic algae are present. We conducted laboratory and field experiments to assess potential metabolic interactions between natural autotrophic and heterotrophic microbial communities inhabiting submerged decaying plant litter of Typha angustifolia and Schoenoplectus acutus. In the field, submerged plant litter was either exposed to natural sunlight or placed under experimental canopies that manipulated light availability and growth of periphytic algae. Litter was collected …

Phycodnaviruses: A Peek At Genetic Diversity, David Dunigan, Lisa Fitzgerald, James L. Van Etten

David D Dunigan Ph. D.

The family Phycodnaviridae encompasses a diverse collection of large icosahedral, dsDNA viruses infecting algae. These viruses have genomes ranging from 160 to 560 kb. The family consists of six genera based initially on host range and supported by sequence comparisons. The family is monophyletic with branches for each genus, but the phycodnaviruses have evolutionary roots that connect with several other families of large DNA viruses, referred to as the nucleocytoplasmic large DNA viruses (NCLDV). The genomes of members in three genera in the Phycodnaviridae have recently been sequenced and the purpose of this manuscript is to summarize these data. The …

The Characterization Of Algae Grown On Nutrient Removal Systems And Evaluation Of Potential Uses For The Resulting Biomass, Kristin Hampel

Dissertations

Eutrophication resulting from excess nutrient loads is a major environmental issue that affects surface water quality and causes surplus primary production, thereby reducing dissolved oxygen concentrations. A method for managing nutrients in surface waters involves absorption of excess nutrients by deliberately cultivating benthic algal turf biomass, then harvesting it for a variety of uses, including biofuels, soil amendments, or feed supplements, thus coupling nutrient removal to additional economic drivers.

The goals of this work are to (1) evaluate the composition of algal biomass grown to remove surface water nutrients, (2) compare biomass grown at different geographic locations and in dissimilar …

Studies On Nitrogen And Silicon Deficiency In Microalgal Lipid Production, Curtis Adams

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Microalgae are single celled plants that inhabit aquatic and terrestrial environments across the planet. Many species are oleaginous, which means they are capable of producing oils, similar to many higher plants we are familiar with like canola, safflower and coconut. Different from higher plants, however, algae have simple structures that allow them to grow at very high rates. Due to these characteristics—oil production and rapid growth rates—algae are considered a promising future source of oil. Algal oils could be useful for production of food for people, feed for animals, biodiesel, detergents, and many other applications.

Algae have not been heavily …

La Serreta Endokarst (Se Spain): A Sustainable Value?, Antonia D. Asencio, Teodoro Espinosa

International Journal of Speleology

La Serreta endokarst (SE Spain), which UNESCO declared a World Heritage Site in 1998, was considered a sanctuary with cave art and one of the most important archaeological sites in the Mediterranean region for both the remains it hosts and the spectacular karstic landscape at the site.

To coincide with the 40th anniversary of its discovery, the La Serreta cave-chasm was adapted for public use with the intention of showing visitors the remains, which date back to prehistoric times. The solution included attempts to minimize contact with the valuables in the cave in order to alter the existing remains as …

Applicability Of Pigment Compounds For Reducing Light Stress In Bentgrass, Gregory Keith Bartley

Masters Theses

Chlorinated copper phthalocyanine (Signature) and pulverized cells of Chlorella vulgaris (Chlorella) were evaluated in a controlled environment for their ability to act as photoprotectants under supraoptimal levels of ultraviolet (UV) and photosynthetically active radiation (PAR) when applied to plant leaves. Plant pigment changes were documented using High Performance Liquid Chromatography following 1 week of exposure to supraoptimal light in two separate experiments incorporating UV (106.6 μmol m-2 s-1) and PAR (760.6 μmol m-2 s-1) over a 12h photoperiod. Supraoptimal levels of UV and PAR light were found to cause significant reductions in Agrostis palustris chlorophyll and carotenoid leaf pigment levels. …

Genetic Engineering Of Dunaliella: Potential For Improved Biofuel Production, Alison Wirshing

Honors Theses and Capstones

Biodiesel produced from algal lipids is a promising source of renewable energy. Reasons for using algae, as opposed to vascular plants, are numerous. Oleaginous algae do not require fertile land or fresh water to grow, and therefore do not compete with food crop resources. Algae have short generation times and higher growth rates than larger vascular plants allowing for synthesis and accumulation of large quantities of neutral lipids, about 20-50% of the dry cell weight, in a short period of time. The efficiency of biodiesel production from oleaginous algae could be improved by using transgenic (genetically engineered) algae. The goal …

New Records For The Freshwater Algae Of Turkey (Tigris Basin), Tülay Özer, İlkay Açikgöz Erkaya, Abel Udo Udoh, Aydin Akbulut, Kazim Yildiz, Bülent Şen

Turkish Journal of Botany

Samples were collected from different habitats (plankton, epipelon, epiphyton, and epilithon) at 20 stations situated on rivers and dam systems in the Tigris Basin between December 2004 and November 2005. Twenty-five new records were identified for the Turkish freshwater algae. They belong to the following divisions: 3 to Cyanobacteria, 1 to Rhodophya, 1 to Euglenozoa, 2 to Myzozoa, 1 to Ochrophyta, 9 to Chlorophyta, and 8 to Charophyta.

Geologic Composition Influences Distribution Of Microbiotic Crusts In The Mojave And Colorado Deserts At The Regional Scale, Rebecca E. Drenovsky, Nicole Pietrasiak, Jeffrey R. Johansen

Biology

Abiotic and biotic factors influencing distribution of microbiotic crusts within hot deserts, such as the Mojave and Colorado Deserts, are poorly known. Our objective was to examine microbiotic crust distribution with reference to soil and parent material characteristics as well as plant functional groups in wilderness areas of Joshua Tree National Park (JTNP). A total of 75 sites were visually assessed for crust abundance and plant community composition; soil physical and chemical factors also were measured. Microbiotic crusts of JTNP, in particular lichen and moss crusts, were not as well-developed or as widely distributed as in other arid regions of …

The Diatoms Of Asartepe Dam Lake (Ankara), With Environmental And Some Physicochemical Properties, Tahi̇r Atici, Emi̇ne Olcay Obali

Turkish Journal of Botany

The shoreline benthic diatoms of Asartepe Dam Lake were identified from different habitats (epipelic, epiphytic, and epilithic) at 7 sampling stations between April 2003 and June 2004. In the investigation, a total of 93 taxa were identified. Of those, Cymbella affinis Kütz., Navicula radiosa Kütz., Ulnaria ulna (Nitzsch) Compère, Pinnularia borealis Ehrenb., Amphora ovalis (Kütz.) Kütz., Cyclotella ocellata Pant. and Nitzschia dissipata (Kütz.) Grunow were observed and abundant at all stations. Some physical and chemical water quality parameters were measured and correlated with biological parameters.

New Records For The Freshwater Algae Of Turkey, Tülay Baykal, Aydin Akbulut, İlkay Açikgöz, Abel U. Udoh, Kazim Yildiz, Bülent Şen

Turkish Journal of Botany

Algae samples were collected from important dam lakes and running waters of the Lower Euphrates Basin. Eighteen new records of Turkish freshwater algae were identified. Among these new records, 5 belong to Cyanophyta, 10 to Chlorophyta, 1 to Xanthophyta, and 2 to Bacillariophyta.