As dam removals become more frequent across the United States and globally, understanding kelp forest response to coastal dam removals, in particular, is critical for managing nearshore habitat. Dam removals impact flow and sediment regimes of rivers, both of which can influence coastal kelp forests. The removal of the Elwha River, WA dams released ~19 Mt of sediment into marine ecosystems. This sediment flux dramatically influenced the turbidity of the nearshore water column and permanently increased the amount of sediment released from the river. The objectives of this study were two-fold. First, I developed methods to remotely sense and quantify the abundance of canopy forming kelps from aerial images. Next, I determined how changes in suspended sediment concentration and light attenuation during and following a major dam removal event in the Elwha River impacted the growth of nearshore bull kelp, Nereocystis luetkeana. By incorporating remote sensing to quantify the relative abundance of bull kelp in the area, my study observed that following dam removal, bull kelp abundance declined in the study area. This was an unexpected finding because I calculated that suspended sediment concentration decreased following dam removal, thus improving conditions for kelp growth. Although suspended sediment concentration decreased after the dam removals, other factors, such as an increase in herbivorous predation, could have played a large role in suppressing bull kelp abundance. The supervised classification scheme that I developed for remotely monitoring kelp abundance will make analyzing larger areas feasible in future studies, which may help to better identify regional trends in kelp abundance. Marine aerial monitoring remains an important avenue to better predict and manage future kelp forest response to dramatic changes in the ecosystem.

Humans hear through the conversion of pressure waves vibrating in the inner ear into chemical signals released by activated hair cells. Loss of function of hair cells due to damage can result in permanent hearing loss. Zebrafish are one of the model organisms used to study hair cells, since zebrafish have hair cells similar to humans. Unlike humans, zebrafish can regenerate their hair cells after damage. Regeneration occurs when support cells differentiate into hair cells. Determining how zebrafish support cells differentiate into hair cells is important to understand if human support cells can be induced to differentiate in a similar way. This requires comparing the structural differences between support cells and hair cells. One important aspect of neuronal signaling is the release of calcium ions from the cell’s endoplasmic reticulum (ER). This experiment looked to answer whether the ER in zebrafish hair and support cells was quantifiably different. Since structure mediates function and support cells do not signal to neurons, their ER structure should not be equivalent to the hair cells’. To test this, I manually segmented and reconstructed serial block-face scanning electron microscope (SBF-SEM) images of both cell types’ ER into 3D. Using SBF-SEM as a reconstruction method allowed for more detailed visualization of both the cell volume and the ER, in contrast to other methods such as confocal microscopy. Support cells had an ER volume of 50.51 µm3, while hair cells had an ER volume of 29.09 µm3. Support cells had a higher ER to cell volume and ER surface area to volume ratio than hair cells. It can be concluded that ER structures of support and hair cells are quantifiably different. Quantifying ER differences between support and hair cells is an important step toward discovering solutions to deafness caused by damage to human hair cells.

Humans are incapable of regenerating a majority of their major tissues following traumatic injury. Xenopus tadpoles have the ability to regenerate a variety of complex tissues quickly following tail amputation, but lose this regenerative competency during metamorphosis. Though tadpoles have been extensively used to study regeneration, we do not yet understand the roles that stress signals from injury play in directing regenerative gene expression. We have found that inhibition of the stress responsive transcription factor Hypoxia Inducible Factor 1α (Hif1α) with the Hif1α inhibitors 2-methoxyestradiol (2ME) and Echinomycin (Ech) prevents regeneration. In particular, inhibition of Hif1α decreases Wnt mediated gene expression. Wnt is known to be one of the primary signaling processes necessary for proper Xenopus regeneration, specifically tail regeneration. While we have shown that Hif1α and Wnt regulate expression of similar gene programs in regeneration, we predicted that there are unique processes that Hif1α regulates to facilitate growth. To investigate how Hif1α and Wnt regulate regeneration, we utilized the two Hif1α antagonists, as well as the Wnt antagonist, IWR-1 (IWR) which I have previously shown inhibits regeneration. To determine Hif1α and Wnt regulated genes, we performed RNA-sequencing 24 hours post amputation. I then identified genes downregulated in Hif1α inhibited tadpoles, which are likely Hif1α dependent. I then removed genes downregulated by Wnt in order to isolate genes uniquely regulated by Hif1α. With the 250 genes uniquely regulated by Hif1α, I used PANTHER to perform gene set enrichment based on Gene Ontology terms. The main biological process of interest found to be regulated by Hif1α during regeneration was DNA replication. By determining how Hif1α uniquely regulates DNA replication during regeneration, we will continue to enhance our understanding of the roles that stress signals play in directing how regenerating cells meet increased proliferative demands post traumatic injury.

Bias in healthcare is often hidden and expressed through unintentionally prejudiced communication between providers and patients. These “implicit biases'' often relate to a patient’s race, gender, or sexual orientation. Implicit biases are automatic attitudes and stereotypes that can operate outside personal awareness and lead to unequal treatment, health disparities, and a lack of patient support. Although much research focuses on implicit bias, the perspectives of those who experience it and the impact it has on these individuals is less explored. Of particular importance are voices of Black, Indigenous, and People of color (BIPOC) and those with marginalized gender identities or sexual orientations (LGBTQ+). These groups have historically suffered from health inequities. For example, research indicates that BIPOC people may be undertreated for pain and LGBTQ+ people may be refused care. The UnBIASED project at the University of Washington and the University of California, San Diego addresses implicit bias in patient-provider communication through computational sensing tools to provide communication feedback. Through 25 interviews with people who identified as BIPOC, LGBTQ+, or both, we explored patients' perspectives on experiencing implicit bias when communicating with healthcare providers. We analyzed interviews through an inductive qualitative approach to understand negative and positive experiences, and identify participants' ideal solutions for improving patient-provider communication. For example, participants suggested having a patient advocate, providing feedback to the provider, and improving providers’ cultural competence. We report on these findings with the goal of describing common pain points and specific sources of dissatisfaction among patients who experience implicit bias. These findings help raise awareness of clinical implicit bias from the perspectives of patients, encourage further research, and suggest patient-driven, patient-centered solutions for how implicit bias can be overcome at personal and institutional levels.

Dam removals are becoming more common as many dams reach the end of their lifespans. As a consequence, it is important to understand the characteristics of the sediment accumulated behind them for sometimes over 100 years when it is released. These sediments can contain organic matter that is deposited in river deltas and reservoirs and can have an impact on the ecosystem. The Elwha River dams were removed starting in 2011, releasing 19Mt of sediment, and also a fraction of organic material that is unknown, some of which made its way to nearshore subtidal deposits. To characterize the relationship specifically between organic content and sediment size in sub-tidal deposits, box cores were collected and examined using x-radiography, wet sieving, and loss on ignition procedures. In subsamples with a lower percent of mud, the percent of organic matter is less than in subsamples that contained more mud. There is also a relationship between both percent mud and organic matter with the distance that the samples were collected from the river, with more mud and organic matter being found farther from the river mouth. These relationships can be explained by the settling velocity of flocculated sediment because organic matter better combines with mud particles and flocs sink slower than sediment of a larger size. This study is useful for future dam removals to determine what range of impacts it might have downstream.