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Interdisciplinary Seminar: Ileana Fenwick & Tyler Souza
November 29, 2021 @ 12:20 pm - 1:20 pm
The UNC at Chapel Hill Department of Earth, Marine, and Environmental Sciences presents the interdisciplinary seminars of graduate students Ileana Fenwick & Tyler Souza. This event will be held on Monday, November 29th at 12:20 pm. This seminar will be held both in person and streamed online. The physical locations will be Room G201 on the ground floor of Murray Hall on campus UNC at Chapel Hill, NC. To view the event online join via Zoom Meeting ID 935 3703 8099.
Ileana Fenwick Interdisciplinary Seminar
Title: Improving our framework for sustaining human and marine communities impacted by ocean acidification (Fenwick)
Abstract: Increased global atmospheric carbon levels have significantly changed the carbonate chemistry of our world’s oceans. Reductions in ocean pH as a result have had cascading effects across ecosystems, the impacts of which have been the focal point of research questions across multiple trophic levels and systems as climate change and ocean acidification continue. Coastal marine ecosystems and the human communities that rely on them are especially vulnerable to interactions between anthropogenic induced stressors (e.g. pollution, coastal development, etc.) and ocean acidification. While these stressors often happen simultaneously and dynamically in nature, our methodology for approaching these effects and their implications within our research is lacking. Currently, our framework for evaluating these changes puts marine ecosystems and the valuable ecosystem services that sustain coastal communities at risk. It is pertinent our management and risk mediation efforts are well informed and interdisciplinary in nature to capture the nuances of these social-ecological systems. This work provides a summation of our current scientific understanding and the knowledge gaps in our approach to evaluating the finer scale and broader impacts of ocean acidification. Specifically, a multi-stressor interdisciplinary framework and action items for researchers, managers and stakeholders alike are presented to improve our assessments of these systems.
Tyler Souza Interdisciplinary Seminar
Title: From Fisheries to Forestry: How Human Activity Affects the Nitrogen Cycle in a Pacific Northwest Estuary (Souza)
Abstract: The estuaries of Oregon, and the Pacific Northwest more generally support one of the United States’ largest fishing industries and play an important ecological role in supporting healthy species populations. The Yaquina Estuary (Oregon) is used as a proxy to understand how these estuaries are responding to anthropogenically induced changes. In recent years, due to declining salmon populations and increased silviculture pressure, the primary source of bioavailable nitrogen to the estuary has shifted from decaying salmon carcasses to alder leaf litter from terrestrial runoff, leading to eutrophication concerns. To address these concerns, the extent and temporal variability of denitrification activity was measured in Yaquina Bay over a year using sediment cores collected approximately monthly. Denitrification rates in the estuary averaged 0.626 ± 0.141 mmol N m⁻² day⁻¹ and were not observed to have a direct relationship with water column nitrate concentrations. In fact, denitrification only removed an estimated 8.7% of the annual Yaquina River nitrate, likely a consequence of high river discharge and powerful tidal flushing. δ15N values were found to less than half that of similar estuaries that are currently experiencing eutrophication indicating that the estuary at present is not at threat of eutrophication.