Browsing by Subject "Marine"

Environmental non-governmental organizations are now major players in environmental science and conservation. The largest now produce applied conservation science and work on local, national, and international scales and across scales to conserve marine and terrestrial ecosystems and connect local level environmental issues to international economic and political processes. However, despite the growing role of these organizations, there is still a lack of comprehensive examinations of their programs with a full analysis of programmatic design, structure, processes, and outcomes.

To fill this gap in both conservation practice and academic theory, I conducted a multi-scalar examination of Conservation International's Marine Management Area Science initiative. This $12.5 million initiative, lasting from 2005 until 2010 and funded by the Gordon and Betty Moore Foundation, had four main nodes of research and conservation work: Fiji, Belize, Eastern Tropical Pacific Seascape, and Brazil. Using non-governmental organization and science and technology studies literature as a theoretical framework, I endeavored to determine what factors affect how environmental non-governmental organizations manage the boundaries across multiple scales and between science and policy in international marine management area science initiatives. Drawing upon methodological approaches in multi-sited ethnography and participant action research, I conducted qualitative field research at each of the initiative's four main node sites and at Conservation International's headquarters, while simultaneously engaging with Conservation International so to return results back to the organization for adaptive management and learning.

My results are consistent with theoretical predictions and lend lessons learned to conservation practice. My research shows that managing the boundaries across scales and between science and policy in international marine management area science initiatives depends on how the program was initiated, the use of networks, partnerships, and coalitions, the level of programmatic participation, the degree of accountability and the ability to learn, the translation of scientific knowledge, and the assessment context. Future research on other environmental non-governmental organization programs has the potential to extend these findings.

Marine microalgae are photosynthetic microbes that are a potential source of fuels, animal feed, and other specialized products. Large scale cultivation of microalgae occurs in open, outdoor raceway ponds, which are exposed to the natural environment and these cultures quickly become a complex milieu of microbes. Microalgae interact with attached and free-floating bacteria found in their medium, with both positive and negative outcomes. To investigate the diversity and dynamics of microbes associated with these systems, samples were collected during multiple growth cycles of two biofuel-relevant microalgae strains, Desmodesmus sp. and Oocystis sp. in ~4,500 L outdoor raceway ponds. Microbiome community composition and diversity was dramatically different between ponds from the two algae and from the natural microbiome of the treated seawater used in pond medium. In spite of variable environments, the pond microbiomes were most similar to their inoculum PBR (photobioreactor) communities suggesting the importance of priority effects or environmental conditioning by the host algae. Ponds when both algae strains were grown were dominated by Rhodobacteraceae and Saprospiraceae while unhealthy microbiomes were dominated by Cytophagaceae and Puniceicoccaceae. Microbiome change was variable over time and resulted in different community structures at the time of algae harvest. Variation in the microbiome community structure was driven by the strain of algae grown, time, pond temperature and percent oxygen saturation. These results provide insight into this industrial ecology and are a foundation for future microbiome research to improve microalgae production.

As climate change continues to alter our global ecosystem, ecological disturbances will increase in both frequency and intensity. These ecological disturbances have been shown to significantly impact microbial communities, often altering composition and/or function. However, while disturbance events are commonly studied in host-associated and engineered systems, there has been relatively little research into the causes, persistence and population-level impacts of disturbance in the dynamic ocean. Furthermore, the research that has been performed on marine microbiome responses to perturbation has been limited to the a priori identification of disturbances, limiting the scope of current research to events considered disturbances from the researchers’ perspective (e.g. hurricanes, contamination, etc.). In this dissertation, I investigate ecological disturbances using a microbiome-centered approach focusing on the role of perturbation in shaping marine microbial assemblies. In my first chapter, I provide an overview of current and historical theoretical frameworks in disturbance ecology and discuss the potential limitations of these approaches. In my second chapter, I apply a microbiome-centered approach to identify disturbances in the coastal ocean. Using three years of observations from a coastal time series, we identified ten disturbance events based on the largest week-over-week changes in microbiome composition. These microbiome disturbances were not clearly linked to specific environmental changes and did not exhibit common responsive taxa. Further, a category 1 hurricane, the only event that would likely be classified a priori as an environmental disturbance, was not an outlier in microbiome composition, but did enhance a bloom in seasonally-abundant phytoplankton. Although large storms can have significant impacts on marine microbiomes, we propose that unmeasured disturbances may have large impacts on the microbiome and may only be detected from a microbial perspective. In my third chapter, I investigate a cyclonic, Gulf Stream frontal eddy as a potential spatial disturbance that can trap and transport microbial communities along this current. By parsing our samples based on microbial community composition, we were able to identify an eddy-specific microbiome even in highly dynamic frontal zones. Furthermore, the eddy microbiome was defined by a higher abundance of a specific high-light Prochlorococcus ASV that was also enriched in slope waters, suggesting that the eddy may harbor signatures of the nearshore community entrapped during eddy formation. Although the eddy microbiome is distinct from the Gulf Stream’s, especially in cyanobacteria (e.g. lower Trichodesmium and higher Prochlorococcus), it is most similar to the Gulf Stream, suggesting eddy microbiome assembly favors environmental filtering over historical contingencies. In my final chapter, I investigate the proximal drivers of hurricane-driven responses in coastal microbiomes using experimental incubations intended to mimic specific hurricane attributes. Coastal microbiomes experienced either a dilution, intended to mimic the initial dilution of the bacterioplankton community from extensive precipitation, or to a daily addition of dissolved organic matter (DOM) intended to mimic a hurricane-induced phytoplankton bloom. The dilution treatment, which represents a more immediate and stochastic effect of hurricane landfall, led to changes in several taxonomic groups, while the DOM treatment, which represents the more latent and deterministic phase of hurricane effects that peaks days to weeks after landfall induced a consistent change among a few taxa. Thus, manipulating specific hurricane-associated drivers can help to differentiate responses to different hurricane components. Together, my dissertation approaches disturbances in time, space and complexity from a microbiome-centered perspective. By broadening our concept of disturbance to include a microbiome-centered perspective, we can better identify how these events shape the microbiome. As global climate change and the associated increase in ecological disturbances i continues to alter our ecosystems, we must understand the full scope of these disturbance responses and the potential ramifications for critical biogeochemical cycles as we strive to predict and mitigate ecosystem changes.