First place – graduate student podium

Sofia D’Ambrosio – PhD student in School of the Environment

Large variations in methane flux across the bottom boundary layer of a eutrophic lake

Methane (CH4) produced in anoxic sediments plays a significant role in the carbon and energy economy of many lakes and reservoirs. To reach the lake water column, CH4 released from sediments must cross the bottom boundary layer (BBL), the layer of water overlying the lakebed where currents are slowed by friction. BBL conditions, which often fluctuate hourly to daily with basin-wide internal waves (seiches), likely influence CH4 flux from sediments and thus the supply of CH4 to the lake carbon cycle. In this study, we measured CH4 fluxes across the BBL in a eutrophic lake with a novel in situ flux gradient approach adapted from marine applications. For 2-6 hour periods before and after the onset of summer stratification, we coupled estimates of CH4 fluxes across the BBL with simultaneous measurements of mixing, stratification, temperature, and oxygen. CH4 fluxes across the BBL increased from spring to summer as hypolimnetic hypoxia developed and stratification inhibited mixing out of the BBL and the hypolimnion. Additionally, seiche-induced shifts in BBL conditions corresponded with order-of-magnitude variations in CH4 fluxes within hours, with greater fluxes observed during intense BBL turbulence and lower fluxes observed during quiescent periods or episodic deliveries of dissolved oxygen. Our results are the first to demonstrate how the BBL exerts significant control on the spatiotemporal variability of CH4 fluxes from lake sediments, potentially regulating the supply of CH4 to the carbon cycle of many lentic systems.

First place – graduate student poster

Erin O’Rorke – medical student, College of Medicine

Safety of GalaFLEX in Prepectoral Breast Reconstruction

Background: Prepectoral implant-based breast reconstruction is gaining in popularity. Acellular dermal matrices (ADMs) are an integral part of prepectoral reconstruction. However, large quantities of ADM are required for total implant coverage and the cost of ADMs could be a deterrent to reconstruction. To minimize the cost, the authors have resorted to the use of a bioabsorbable mesh, GalaFLEX, as a replacement to ADMs. The comparative safety of using GalaFLEX in combination with AlloDerm versus AlloDerm alone in prepectoral reconstruction is reported. 

Methods: Consecutive patients who underwent immediate, expander-implant, prepectoral breast reconstruction were included in this retrospective study. Patients were stratified into two groups: those who received AlloDerm-GalaFLEX combination versus AlloDerm alone. In AlloDerm-GalaFLEX reconstructions, the lower third of the expander was covered by the AlloDerm while the rest of the expander was covered by GalaFLEX. Complications following reconstruction were compared between the groups. 

Results: AlloDerm alone was utilized in 128 patients (249 breasts) and AlloDerm-GalaFLEX in 135 patients (250 breasts). Rate of any complication was 7.6% in the AlloDerm alone group and 6.4% in the AlloDerm-GalaFLEX group. Rate of infection, skin necrosis, seroma, capsular contracture, prosthesis exposure/extrusion, and prosthesis loss were ≤3.0% in the AlloDerm-GalaFLEX group and did not differ significantly from those in the AlloDerm only group. 

Conclusions: GalaFLEX bioabsorbable matrix is a less costly alternative to ADMs in two-staged, prepectoral reconstruction with comparable safety outcomes. Further long-term data and clinical experience are needed to better understand the safety of this matrix for use in breast reconstruction.

First place – undergraduate student podium

Kay Hall – History

State v. Towessnute and State v. Meninock: State Conservation and Indigenous Rights

The catastrophic effect of the 2020 fire season on the Pacific Northwest was only one example of the risks the area will confront as the climate continues to warm. Washington State has a long history of conflicting viewpoints over how the environment and its natural resources should best be handled, a situation that is especially troubling given the key role that management strategies play in determining the resilience or vulnerability of the environment. Systematic subversion of treaty rights is at the heart of this conflict. In 1915, Alec Towessnute was charged for fishing at Prosser Falls despite the guarantees of the 1855 Treaty with the Yakama that all usual and accustomed fishing places would be protected in perpetuity. He was accused of violating the newly passed Fisheries Code, an attempt by the new State Fish Commissioner to implement state-sponsored conservation. In State v. Towessnute and the subsequent State v. Meninock, the Washington State Supreme Court determined that state power took precedence over treaty rights. The decision began a century of tension between state-sponsored conservation and Native rights and stewardship. This legal microhistory uses case records, media coverage, speeches, and personal statements to tell the stories of Towessnute and Meninock, highlighting their early use of civil disobedience as a political tool. Towessnute and Meninock bring timely insights, drawn from the axis of law and resistance, to the topics of Native American identity and rights, as well as their role in the broader discussion of conservation and environmental management moving forward.

First place – undergraduate student poster

Forrest Fearington – Neuroscience

Investigating a Potential Mechanism of Noise-Induced Synaptopathy

Noise is the most common cause of preventable hearing loss, affecting 31 million Americans. A less-studied subcategory of noise-induced hearing loss is known as hidden hearing loss, in which the synapses connecting inner ear hair cells to afferent ganglion neurons are damaged (termed synaptopathy). This damage is suspected to be caused by excess glutamate release in the synaptic cleft. However, the exact mechanism of synaptopathy remains unknown, and there is currently no FDA approved treatment. Here we investigate a potential mechanism of noise-induced synaptopathy. We hypothesize that excess glutamate release following noise damage will cause AMPA receptors lacking the GluA2 subunit to leak excess calcium into the ganglion cell, and that heterogenous distribution of this GluA2 subunit will be negatively correlated with calcium entry and damage to the ganglion cell. This hypothesis was tested by using noise to damage hair cells in the zebrafish lateral line, an established vertebrate model for studying noise-induced hearing loss. Following noise damage, GluA2 and GluA4 subunit distribution and intracellular calcium levels were determined. Synaptic integrity and ganglion cell death were also assessed at different time points after noise exposure. This research can shed light on the suspected mechanism of AMPA-receptor mediated synaptopathy following acoustic trauma, thus uncovering a potential pharmacological target. Given the absence of an FDA approved treatment and the inefficacy of hearing aids in mitigating hidden hearing loss, our research has the potential to fill a health care gap for a currently untreatable condition.