Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 184 for “"Marine ecosystems"”.
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Microbial size spectra from diverse marine ecosystems
Characteristics of microbial size spectra (bacteria and phytoplankton) were examined in relation to changes in ecosystem productivity and environmental perturbations. Samples were obtained from productive coastal waters in Massachusetts and Cape Cod Bays, oligotrophic waters in the Sargasso Sea and …
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Microbal size spectra from diverse marine ecosystems
Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 1996.
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Understanding ocean iron dynamics and impacts on marine ecosystems
… human activities, which can significantly alter marine ecosystems. Thus, a comprehensive understanding of how the ocean Fe cycling operates and how it will respond to human perturbations is urgently needed. In this work, I first significantly improve the Fe parameterization in a global ocean …
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Defining the ecological and physiological traits of phytoplankton across marine ecosystems
Marine phytoplankton are central players in the global carbon cycle, responsible for nearly half of global primary production. The identification of the factors controlling phytoplankton ecology, physiology, and, ultimately, bloom dynamics has been a central problem in the field of biological …
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Air-sea Greenhouse Gases exchange in marine ecosystems: assessment and impacts
La investigación realizada en esta Tesis Doctoral se centra en ampliar y profundizar en el conocimiento sobre el intercambio de Gases de Efecto Invernadero (GEI), principalmente dióxido de carbono (CO2), pero también metano (CH4) y óxido nitroso (N2O), entre la atmósfera y el océano en diferentes …
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Tipping points, regime shifts and species interactions within shallow marine ecosystems
Understanding the response of ecosystems to perturbation is of great importance in a rapidly changing world. Research has shown that in response to pressures such as climate change or over exploitation, entire ecosystems can shift to alternative states, a phenomenon termed regime shifts, and in …
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Exploring the social, economic, and ecological dimensions of managing marine ecosystems
The degradation of marine and coastal ecosystems, compounded by the impacts of climate change, presents one of the greatest challenges to achieving a sustainable social-ecological future. Coastal marine ecosystems are essential for social-ecological resilience, providing vital services such as …
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DNA+eDNA: integration of traditional and emerging tools for monitoring marine ecosystems
… accurate species identification for evaluating marine biodiversity, ecological roles, and conservation needs. Traditional taxonomy often struggles with the identification of cryptic species, leading to the reliance on molecular methods such as DNA analysis. These techniques have improved species …
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Assessing the vulnerability of Antarctic marine ecosystems to invasive non-native species
… has been poorly connected to nearby temperate ecosystems due to physical and physiological barriers. Yet, Antarctica is experiencing significant environmental change and becoming increasingly exposed to ship-borne human activity that crosses the physical barriers. These factors may facilitate …
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Resilience in marine ecosystems: the effects of environmental and ecological context on ecosystem multistability
In recent times, disturbances in ecosystems due to anthropogenic and natural drivers have become increasingly prevalent. Many previous studies have tried to understand and quantify how these disturbances influence food web dynamics and ecosystem functioning and ultimately how this affects overall …
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Ecotoxicological assessment of galaxolide and tonalide as contaminants of emerging concern in marine ecosystems
… concentrations of HHCB and AHTN in the marine environments. In order to provide a more complete assessment on marine biota, empirical approach based on data of ecotoxicological assays was explored based on environmental risk assessment (ERA) scheme. In this case, it was intended to …
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A decision tree framework for assessing status of exploited marine ecosystems under changing environmental conditions
The removal of marine species through fishing has impacted marine ecosystems for thousands of years. The pressure of exploitation on marine ecosystems has now reached a point at which there is serious concern over ecosystem well-being on a global scale. There has, therefore, been a global move …
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An Integrated Modeling Study of Ocean Circulation, the Ocean Carbon Cycle, Marine Ecosystems, and Climate Change
… between ocean circulation, the carbon cycle, marine ecosystems, and climate change using an earth system model of intermediate complexity, ISAM-2.5D (Integrated Science Assessment Model). First, through the simulation of radiocarbon (in terms of Delta14C) it is demonstrated that the inclusion …
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Effects of anthropogenic and natural disturbance on sedimentary organic matter quantity, nutritional quality and degradation in river, lagoon, and coastal marine ecosystems
… habitats’ structure and biodiversity. Aquatic ecosystems, especially lagoons and marine coastal areas, appear to be more sensitive to anthropogenic and natural disturbances than terrestrial ones, whose ecological consequences are more tangible. Changes in the trophic status of aquatic …
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Marine Deoxygenation Predates the End-Triassic Mass Extinction Within the Equatorial Panthalassa and its Influence on Marine Ecosystems Before the Biotic Crisis
… Creek, Alaska in order track changes in the marine nitrogen cycle and redox across the upper Norian Stage of the Triassic through lower Hettangain Stage of the Jurassic (~215 to 198 million years ago). The geologic succession at Grotto Creek represents deeper water marine deposition in …
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CONNECTING TO THE MAURI OF THE MOANA: Using a community-based, intuitive and qualitative ecological monitoring process to connect with and consider the mauri of local marine ecosystems
… of the current state of health of local marine ecosystems can be informed by using a community-based, qualitative and intuitive approach to ecological monitoring, which is centred around the Māori ontological concept of mauri (life-force, vital energy). Internationally, and in Aotearoa …
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Birds of a Feather: Cultural and Ecological Relationships between the Unangax̂ and Seabirds in the Aleutian Islands, AK
This dissertation investigates how marine ecosystems and ancestral Unangax̂ communities in the Aleutian Islands of Alaska adapted to Holocene climate variability. Today, rapid warming in the Arctic/Subarctic is causing disruptions in marine ecosystems, threatening food webs and the economic and …
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Safeguarding the deep-Sea Marine ecosystem: a critical analysis of the legal framework governing the impacts of the upstream Petroleum Sector on the deep-sea marine ecosystems and coastal communities in South Africa
… environment, home to unique and diverse marine ecosystems. However, the increasing global demand for oil and gas has led to a surge in extraction activities in the deep ocean. These activities while essential for meeting energy demands, pose significant threats to the fragile deep-sea …
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South Africa's proposed new Marine Protected Area around the Prince Edward Islands: an analysis of legal obligations, options and opportunities
… management purposes as well as conservation of marine ecosystems and biodiversity in the area. As a first step the Minister announced that the current “no-fishing” zone would be extended from 8 to 12 nautical miles. This was done a few months later by means of an amendment to fishing regulations …
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