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Title: Integrated Modelling of Spatial and Temporal Heterogeneity in Trophic Shifts: A Bayesian Network Approach Based on Empirical Data Collection
Contributor(s): McDonald, Karlie (author); Ryder, Darren  (supervisor); Tighe, Matthew  (supervisor); Burns, Adrienne  (supervisor)orcid 
Conferred Date: 2015
Copyright Date: 2015
Thesis Restriction Date until: Access restricted until 2017-10-23
Open Access: No
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Abstract: The biogeochemical cycles of carbon (C), nitrogen (N) and phosphorus (P) have been significantly altered by anthropogenic nutrient enrichment in catchments. The concentrations of nutrients in aquatic systems are closely linked to complex interactions between catchment attributes that vary with space and time such as land use, rainfall, flow velocity, riparian vegetation and geology. In aquatic systems, a shift from a mesotrophic or oligotrophic state to a eutrophied trophic state occurs when nutrient concentrations exceed the assimilation capacity of the ecosystem, leading to increased rates of primary production and microbial processes. Trophic shifts can significantly alter ecosystem processes and threaten ecosystem services in freshwater and estuarine systems. The ratios of C, N, and P within aquatic systems can regulate primary production when one or more of these nutrients are present in concentrations below that required for the growth and accumulation of primary producers. Detecting and predicting trophic shifts is difficult as a result of high spatial and temporal heterogeneity in water column nutrient concentrations and insufficient information on the thresholds of, and interactions among the biophysical and chemical drivers of trophic shifts. This limited knowledge of threshold concentrations and stoichiometric ratios of nutrients, in addition to the drivers that regulate a shift to a eutrophied state limits the large scale application of efficient management strategies.
Publication Type: Thesis Doctoral
Fields of Research (FoR) 2008: 050206 Environmental Monitoring
060204 Freshwater Ecology
060205 Marine and Estuarine Ecology (incl Marine Ichthyology)
Fields of Research (FoR) 2020: 410599 Pollution and contamination not elsewhere classified
310304 Freshwater ecology
310305 Marine and estuarine ecology (incl. marine ichthyology)
Socio-Economic Objective (SEO) 2008: 960505 Ecosystem Assessment and Management of Forest and Woodlands Environments
961102 Physical and Chemical Conditions of Water in Coastal and Estuarine Environments
961103 Physical and Chemical Conditions of Water in Fresh, Ground and Surface Water Environments (excl. Urban and Industrial Use)
Socio-Economic Objective (SEO) 2020: 180301 Assessment and management of freshwater ecosystems
180205 Measurement and assessment of estuarine water quality
180306 Measurement and assessment of freshwater quality (incl. physical and chemical conditions of water)
Rights Statement: Copyright 2015 - Karlie McDonald
Open Access Embargo: 2017-10-23
HERDC Category Description: T2 Thesis - Doctorate by Research
Appears in Collections:School of Environmental and Rural Science
Thesis Doctoral

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