Organisms Commons^™

Eelgrass (Zostera Marina) Population Decline In Morro Bay, Ca: A Meta-Analysis Of Herbicide Application In San Luis Obispo County And Morro Bay Watershed, Tyler King Sinnott

Master's Theses

The endemic eelgrass (Zostera marina) community of Morro Bay Estuary, located on the central coast of California, has experienced an estimated decline of 95% in occupied area (reduction of 344 acres to 20 acres) from 2008 to 2017 for reasons that are not yet definitively clear. One possible driver of degradation that has yet to be investigated is the role of herbicides from agricultural fields in the watershed that feeds into the estuary. Thus, the primary research goal of this project was to better understand temporal and spatial trends of herbicide use within the context of San Luis …

Phantom Ocean, Real Impact: Natural Surf Sound Experiments Alter Foraging Activity And Habitat Use Across Taxa, Ryan N. Wardle

Master's Theses

A growing body of research focuses on how background sounds shape and alter critical elements of animals’ lives, such as foraging behavior, habitat use, and ecological interactions (Bradbury & Vehrencamp, 2011; Barber et al., 2010; Kight & Swaddle, 2011; Shannon et al., 2016). Much of this research has centered on the effects of anthropogenic noise (Dominoni et al., 2020; Francis & Barber, 2013; Ortega, 2012; Swaddle et al., 2015), but recent studies have also revealed that natural sound sources can influence animal behavior (Davidson et al., 2017; Le et al., 2019). Natural sounds, such as crashing surf, can create conditions …

A Biogeographical Assessment Of Arctic Marine Fungi, Bentley E. Simpson

Honors College

Marine fungi play a crucial role in recycling nutrients and channeling energy to higher trophic levels in the world oceans. Despite their critical role, their distributions and community composition, particularly in the Arctic, are largely unknown. This study reveals depth-related trends of abundance, diversity, and community composition of Arctic marine fungi through analysis of data obtained in the Tara Oceans expedition. With samples from surface (0-50 m), deep chlorophyll max (50-200 m), and mesopelagic (200-1000 m) depths, relative abundance, operational taxonomic unit (OTU) richness, and diversity were found to increase as a function of depth. Basidiomycota and Ascomycota were found …

Biogeography Of Biological Control: Spatial Variation In Agent-Host Interactions, Nathan Harms

LSU Doctoral Dissertations

Management of plant invasions using biological control has the potential to generate spatial patterns which reflect geographic or genetic variation in invader or control agents. Despite its rarity in practice, investigations into the biogeography of interacting species (i.e., plant invader and control agent) in the context of biological control can lend insights into species distribution-abundance patterns and provide predictions for spatial variation in control success. I explored spatial variability in biological control agent-plant interactions using two wetland weed study systems with large geographic distributions: flowering rush (Butomus umbellatus L.) and alligatorweed (Alternanthera philoxeroides (Mart.) Griseb). Through literature and …

Characterization Of The Physical And Chemical Effect Of Membrane Disruption And Protein Inhibiting Treatments On E. Coli, Khadijah Wright

Honors Undergraduate Theses

The increase in antibacterial resistance has placed the issue of microbial multi-drug resistance on a global stage (Gurunathan, 2019). This issue poses a threat to human and animal health as well as to the environment (Aslam et al., 2018). It affects not only the efficacy of treatment but also how those treatments are conducted (Friedman, Temkin, & Carmeli, 2016). As a result of this ongoing threat, new treatments that have potent effects on bacteria are necessary. One scientific response to this issue has been the development of multifunctional nanoparticles (NPs)(H. Wang et al., 2018). NPs have the ability to be …

Antifungal Defense Molecules From Bacterial Symbionts Of North American Trachymyrmex Ants, Georgia Scherer

CMC Senior Theses

Defensive symbioses, in which microbes provide molecular defenses for an animal host, hold great potential as untapped sources of therapeutically useful antibiotics. Fungus-growing ants use antifungal defenses from bacterial symbionts to suppress pathogenic fungi in their nests. Preliminary chemical investigations of symbiotic bacteria from this large family of ants have uncovered novel antifungal molecules with therapeutic potential, such as dentigerumycin and selvamicin.

In this study, the bacterial symbionts of North American Trachymyrmex fungus-growing ants are investigated for antifungal molecules. Plate-based bioassays using ecologically-relevant fungal pathogens confirmed that these bacteria have antifungal activity. In order to purify and identify the antifungal …