As algal blooms continue to demonstrate a great risk to aquatic ecosystems, it’s important to understand the effects aggressive algal growth can have on the organisms that would normally consume them. In a predator-prey ecosystem, stability between grazers and primary producers is determined by the interactions of the species. This study observes this stability using Closed Ecological Systems (CES) containing the algal species Ankistrodesmus, Scendesmus, and Selenastrum, unknown bacteria, and the grazers Daphnia magna. CES are sealed ecosystems that prevent gas exchange with the atmosphere. CES also carry the advantage of repeatability, uncommon in ecological field research. Past research in the Taub lab suggests that if the population of algae increases too rapidly, photosynthesis will cause a pH increase, associated with the death of Daphnia. Understanding which conditions best support D. magna helps us understand how the environment affects a grazer’s ability to compete against rapid algal growth. To determine the optimal initial concentration of algae with their associated nutrients, we set up CES in 6 treatments with ~10% and ~1% algal concentrations, either with or without D. magna, each with 6 replicates. We measure population dynamics by chlorophyll fluorescence, D. magna count and size, ephippia (sexual eggs) presence, and pH indication. CES without D. magna are used to compare how algal growth proceeds without the consumers. The treatments with lower algae concentrations may allow D. magna to persist longer by controlling the algae population and associated pH increase or may experience starvation. The findings of this experiment will give us a deeper knowledge of how algal growth can pose a threat to grazers, and how this information can be applied to other grazer-algae relationships.

Research suggests that recruitment, the number of fish entering a population in a given year, is influenced by the environment. However, environmental drivers are not currently used to refine the recruitment estimates of most statistical models used in fisheries management (hereafter, population assessment models). This is increasingly relevant as fish populations experience long-term productivity shifts due to climate change. One major goal of the National Oceanic and Atmospheric Administration (NOAA) in recent years has been to incorporate environmental drivers into population assessment models. This is achieved by using time series data of environmental drivers to inform model estimates. One ongoing challenge is determining which environmental drivers have potential to improve model estimates. In this project, we aimed to determine how correlated an environmental driver time series must be to historical recruitment deviations to improve key model estimates – recruitment deviations and population depletion – in recent years for a range of species. We used R to simulate mock environmental driver time series with varying correlation levels to recruitment deviations by randomly sampling data from a normal distribution. We then compared errors in estimates between population assessment models fit with and without the simulated environmental data. Our results suggest that the more correlated an environmental driver is to historical recruitment deviations, the more accurate estimates of both recruitment deviations and population depletion become. However, our results also reveal that the correlation level necessary for environmentally-driven models to consistently produce more accurate estimates than the original model varies across species. These correlation thresholds are also generally higher than observed correlations between recruitment deviations and environmental drivers in actual fish populations. We suggest fisheries scientists run similar simulation experiments to determine which correlation levels have the potential to improve population assessment models for their target species.

Describing genetic variation in deep-sea organisms is key to understanding ecological and evolutionary processes shaping biological diversity in these fragile ecosystems that are vulnerable to anthropogenic activity. Among deep-sea species, tubeworms (Class Polychaeta) often dominate faunal biomass in hydrothermal vents where they tend to grow in towering colonies. As foundation species, tubeworms create structural habitats that support assemblages of diverse biological communities across the seafloor. However, heterogeneous environmental conditions throughout their range, such as pH and temperature, and geographic isolation, may cause population subdivision by restricting connectivity between sites. This study aims to further our understanding of tubeworm population structure by investigating genetic relationships between Ridgeia piscesae subpopulations within a deep-sea hydrothermal vent system. At the Axial Seamount, a regularly surveyed area in the study of hydrothermal vent processes on the Juan de Fuca Ridge, our knowledge of the genetic connectivity of R. piscesae subpopulations remains limited. Here, we examined genetic variation in R. piscesae individuals collected from structurally-different sites within the Axial Seamount. Specifically, we genotyped mitochondrial genes and constructed SNP-based phylogenetic trees to elucidate evolutionary relationships between worms inhabiting a chimney and diffuse-flow locations. Genetic differentiation is expected to be low when gene flow is high between populations, but these outcomes may also be influenced by other aspects, such as environmental conditions. These results allow us to evaluate the degree of genetic diversity in tubeworms within this important area and provide insight into the potential impact of human activities, such as seabed mining, on deep-sea vent dynamics.

Climate change has resulted in environmental changes that pose direct and indirect challenges to marine organisms. One such organism that has been widely studied is the common murre (Uria aalge), which has experienced decreased reproductive success and adult survival in response to climate change-induced ocean warming. Because common murres molt flight feathers relatively synchronously, they may be especially vulnerable to environmental stresses, such as the challenge this may pose on obtaining food. In this study, we explore the degree to which shifting environmental conditions impact adult survival of common murres at a physiologically sensitive point: flight feather molt. The data we used for this study include: monthly expert-verified observations of bird carcasses from the Coastal Observation and Seabird Survey Team (COASST) citizen science program collected from the outer coast of Northern Washington south down to Humboldt, California; significant wave height data from the National Data Buoy Center (as a proxy for storminess); spring transition date (from the Columbia Basin Research website) as an indication of annual production potential; and Bakun upwelling index (from the Pacific Fisheries Environmental Laboratory website) as a measure of upwelling strength and production potential. We annualized both the bird and environmental data over the years 2003-2021. For this project, my role was to conduct statistical analyses using the statistical program R. I employed generalized additive mixed models to determine the relationship between the proportion of adult carcasses in molt and the environmental variables. To select models, I used Akaike Information Criterion corrected for small sample size (AICc). Our research will give insights into how the combined effects of physiological and environmental stressors may impact upper trophic seabirds as climate change continues to intensify.

The population structure of species occupying deep-sea hydrothermal vents is strongly influenced by geological processes. The formation and maintenance of vents can create a patchwork of habitats across the sea floor, which are subject to catastrophic events that can extirpate whole communities. Therefore, the population structure of vent species is not only influenced by adaptation, life history, and dispersal but also by geological processes and oceanographic processes. Characterizing the genetic diversity and connectivity of species between vents can provide information about these processes. The Axial Seamount, located on the Juan De Fuca Ridge located off the Pacific Northwest coast of the USA, is a well-studied hydrothermal vent system. Here, sulfide worms (Paralvinella sulfincola) can be found on and around chimney vents, building tubes that contribute to chimney formation and habitats for other organisms. We predict low gene flow and low connectivity between different vent populations of this species because their reproductive life history strategies depend on pheromone signaling. Such signaling likely results in individuals mating more frequently with their closest conspecifics. However, little is known about the larval dispersion dynamics of this species. Sulfide worms were collected to investigate the connectivity and genetic diversity of their populations. Mitochondrial and nuclear genes were amplified from DNA extracted from worms that were collected from two locations within the Axial Seamount (Inferno and El Guapo chimneys, located within the ASHES and International District vent fields, respectively), to determine genetic diversity at each site and to test whether these sites constitute one or two separate populations. This research will ¬¬¬¬assist in understanding the connectivity and genetic diversity of sulfide worms within the Axial Seamount system across multiple vent fields and contribute to a broader understanding of how populations are established and maintained in this unique and dynamic ecosystem.

With increasing temperatures and changing ocean conditions, it is important to measure the effects felt on both a species specific and ecosystem level, to better understand the consequences of this change. To investigate this issue specifically off of the Northeast US Atlantic Coast, I worked collaboratively with the National Oceanic and Atmospheric Administration, using both bottom temperature and sea surface temperature as oceanographic variables to examine whether the changes observed have influenced fish consumption over time across seventeen prominent fish species. We calculated average annual fish consumption per species from 1993-2018, where I then compared this to both sea surface temperature and bottom temperature using generalized additive models. Additionally, we plotted the above variables independently using generalized linear models and linear models to analyze their respective trends. I also created a sea surface temperature model to compare the extreme temperature changes the ecosystem was experiencing. Overall, increasing trends in both sea surface temperature and bottom temperature were detected, and within species’ consumption trends, four species showed significant increases in consumption (buckler dory (Zenopsis conchifer), fourspot flounder (Hippoglossina oblonga), longhorn sculpin (Myoxocephalus octodecemspinosus), striped searobin (Prionotus evolans)) whereas two indicated significant decreases in consumption (Atlantic cod (Gadus morhua), thorny skate (Amblyraja radiata)). When compared to sea surface and bottom temperature, three species' consumption rates were found to be significantly influenced by these variables (longhorn sculpin, thorny skate, spiny dogfish (Squalus acanthias)). Given these results, it is likely that the adaptability of species and their respective mobility will influence the degree of impact by changing ocean conditions, constituting both winners and losers in this changing time period. Therefore, we recommend further analysis to better understand how various related biological factors influenced by climate change will be impacted in the future to develop a more thorough understanding of the consequences of this change.

Ocean acidification leads to the decrease in availability of dissolved oxygen. Carbon enters the atmosphere from a wide variety of sources, most notably the burning of fossil fuels, and this atmospheric carbon is absorbed by the ocean. Algae need carbon, and as more carbon enters the water, algae can reproduce rapidly. Dissolved oxygen is taken in as this algae blooms as well as decomposers breaking down the algae once it dies, leading to a severe decrease in the oxygen content of the water. A severe lack of dissolved oxygen in water is called hypoxia. Because of ocean acidification, hypoxic events are increasing in and around the Puget Sound, an area notable for its aquaculture, specifically of the pacific oyster. Triploid oysters are a rarely occurring genotype of oyster that are larger and sterile than most other oysters. These traits can be cultivated, either by selective breeding or chemical alteration, and are essential for oyster aquaculture. However, the effect of hypoxia on oysters, especially on triploid oysters. is relatively unknown. How does varying oxygen levels affect diploid, chemically induced and “natural” triploid pacific oyster mass? We placed thirty of each type of oyster in tanks of 100, 80, 60, 40 and 20 ppm tanks, a total of three tanks of each treatment. The oysters were fed regularly. We recorded the average oyster mass of each oyster before and after one month of each treatment. This shows the change in oyster mass depending on each treatment over time. We expect to see the mass of chemically induced and selectively bred triploid oyster will decrease with reduced dissolved oxygen concentration because there will be less oxygen because they will reduce their metabolic rate to cope, hindering growth. As oceans acidity increases, it is important for oyster fisheries to know how  oysters react to decreased oxygen content to be better prepared for the future, especially when choosing which kinds of oysters will tolerate these changes best. 

The health of Sockeye salmon (Oncorhyncus Nerka) stocks are of high importance to the cultural well-being and sovereignty of Coast Salish tribes. There are multiple ecotypes of Sockeye that include anadromous, potamodromous Kokanee, and resident Sockeye that all carry distinct and significant cultural value for Indigenous communities, as well as distinct ecological roles within the ecosystems they inhabit. Sockeye are impacted by anthropogenic stressors such as habitat degradation and pollution, which can cause shifts in food web dynamics, population declines, and impact commercial and traditional fisheries. To more effectively manage these diverse life histories for conservation, it is crucial to understand the distinct ecological functions that may cause ecotypes to differ in their vulnerability to anthropogenic stressors, thus requiring different management strategies. We will analyze carbon and nitrogen isotopic signatures of Sockeye from Lake Washington to differentiate their ecological niches. Muscle samples were collected from 46 frozen sockeye samples, freeze dried, and then analyzed using mass spectrometry. Preliminary results suggest that there are significant differences between the isotopic signatures of anadromous and potamodromous ecotypes. We hypothesize further interpretation of the results coupled with genetic analysis will identify differing ecological roles in accordance with the diverse life history strategies Lake Washington Sockeye display. This study has been conducted as part of ongoing collaborative efforts with partners at the Snoqualmie Tribe, and the Kokanee Work Group, which aims to restore the Kokanee and Sockeye populations of Lake Sammamish. The results of this work will directly inform management actions taken by our partners to conserve the native Sockeye populations of King County, Washington.