Previous studies have found that jellyfish benefit from warming temperatures and eutrophication, resulting in large jellyfish blooms worldwide. However, the impact of warming ocean temperatures on the cross jellyfish, Mitrocoma cellularia, which are common in the Pacific Northwest, has been relatively unexplored. This study tests the hypothesis that warmer water temperatures would increase M. cellularia growth. A total of 36 individuals were collected from the UW Friday Harbor Laboratories Dock, San Juan Island in September 2023. They were observed in individual jars without water flow, and equally distributed across four separate temperature-controlled baths at 13°C, 16°C, 18°C, and 20°C. Over the 96-hour exposure period, they were fed excess live zooplankton collected before each feeding and had daily water replacements. Surface area was measured with ImageJ, mortality, and overall condition after the acclimation period (initial), day two (mid), and day four (final). A growth rate polynomial regression characterized the final measurements of normal condition jellyfish with a maximum closest to 16°C, resulting in an R2 =0.24 and p-value <0.05. At 20°C, shriveling and mortality increased. While 20°C decreased M. cellularia growth, our results support previous studies that jellyfish are resilient to impacts of climate change within the range of near-future prediction for the Pacific Northwest. Further investigations of the adaptability of M. cellularia to changing temperatures is necessary to understand the future outcomes of their ecology. Examination of this species can inform the state of a jellyfish ecosystem’s adaptability to climate change, which will allow further studies to create solutions to combat changing environments for ocean habitats.

Zooplankton are vital to the marine food web, supplying nutrients and energy from primary producers to secondary consumers. During Diel Vertical Migration (DVM), zooplankton travel between depth and the surface during day and night to capitalize on food and avoid predation. This study investigated diel differences in zooplankton community composition at two locations, one exposed and one protected, in the San Juan Channel, WA over four days in September 2023. Zooplankton were collected using net tows from surface waters at both sites during day and night times. Samples were analyzed using a stereoscope and different taxonomic groups were counted. Copepods were the most abundant zooplankton taxa at both locations, with mean abundances up to 1000 individuals per cubic meter. At the exposed site, there was a significantly higher (p<0.05) abundance of zooplankton at night versus during the day. The exposed site had significantly higher diversity than the protected site at night (p<0.05). At both locations, species richness was significantly higher (p<0.05) at night compared to day. The exposed location also had significantly higher richness (p<0.05) compared to the protected location during the day. Our results indicate that zooplankton abundance and diversity in surface waters of the San Juan Channel are controlled by DVM, and differences in locations perhaps due to exposure to different flow regimes. This study reinforces the flexibility of zooplankton community composition and emphasizes the importance of understanding factors that influence changes in the base of the marine food web.

Climate change is increasing glacial melt worldwide, causing freshening events in marine ecosystems that rapidly decrease salinity. In the Salish Sea, summer low salinity events occur regularly from the Fraser River meltwater. This negatively impacts many organisms including sea urchins, which are resilient to other climate change impacts like marine heatwaves and reduced food availability. Previous studies found that low salinity impacts tube foot mobility and function in green sea urchins (Strongylocentrotus droebachiensis). We replicated the Salish Sea freshening events with a treatment of 20 PSU saltwater (control 30 PSU) to investigate the impacts on red sea urchin (Mesocentrotus fransiscanus) coordination and spine movement. This study implemented new techniques to quantify urchin motility to determine the negative effects that low salinity had on sea urchins over 96 hours. We quantified spine movement using image analysis to track individual spines of urchins in low and regular salinities. We also measured righting time, which is an indicator of urchin coordination. We found that urchins exposed to low salinity had significantly longer righting times and less spine movement overall. The low salinity treatment spine movement and righting time were highly correlated (p < 0.01), but not in the ambient salinity tanks (p > 0.01). We found that lower salinity waters have the potential to reduce urchin coordination and movement, which may impact urchin populations and kelp forests in the changing climate. Thus, there may be a lessened impact on the kelp forests needed to maintain ocean health.

Marine ecosystems are currently experiencing changes at unprecedented rates. Implementing camera technologies to visually monitor vulnerable marine ecosystems is becoming increasingly common. Images and video can capture a variety of biological indicators of ecosystem health including species abundances, ecological interactions, and individual health and behavior which can be challenging to assess in other ways. As massive amounts of high-quality photographic data are accumulating, the tools to analyze them are often not readily available to scientists. Therefore, collected images may not be analyzed at the timescales required for scientists to assess and respond to these rapid ecological changes. To address this, we have developed a series of machine learning models that can analyze this surplus of image and video data into meaningful insights for researchers. We built the Subaquatic Ecosystem Analysis and Population Estimation Network (SEAPEN) by meticulously labeling millions of images from oceanographic datasets using a model-assisted labeling protocol. Our original models began with human annotated models, but as accuracy and precision progressed, we were able to rapidly iterate and expand SEAPEN’s capabilities. The processed images are then put through our custom training framework and are run until they output trained TensorFlow and TFLite models. These models are then sent through a series of statistical tests and further quantized until they reach our high set of QA/QC standards. SEAPEN has been tested using a variety of image data from Ocean Observatories Initiative to accurately classify organisms at deep sea ecosystems. SEAPEN is also capable of assessing coral bleaching rates, estimating fisheries stock population size, and quantifying the presence of marine debris. By utilizing large amounts of previously unused public oceanographic data, SEAPEN helps put the tools necessary to process old and new ocean data quickly into scientists’ hands.

Acorn barnacles (Balanus glandula) are among the most common species found in the Northern Pacific Ocean, inhabiting rocky surfaces across intertidal zones. These barnacles’ distribution is attributed to various factors, including surface exposure, spatial competition, and predation. The size and abundance of barnacles may serve as an indicator of the primary abiotic and biotic processes that influence barnacle populations in highly dynamic intertidal systems. This study tests our hypothesis that higher abundance and smaller-sized barnacles will be observed at higher tide elevations, while lower abundance and larger-sized barnacles will be observed at lower intertidal elevations on the shore. In September 2023, at Friday Harbor, (San Juan Island, WA) we photographed 10 quadrats (24x24cm) at low (0m), mid (1m), and high (2m) elevations. We observed barnacle distributions at two sites along the San Juan Channel. Barnacle abundance and size were measured with ImageJ. We calculated the mean and median barnacle size at each elevation and location. Small barnacles (0-1.5mm) were predominant in the high elevations, whereas large barnacles (>3mm) dominated the lower elevations. Our results are associated with a combination of abiotic and biotic factors. Abiotic factors include greater desiccation risks in the high intertidal elevation. Biotic factors involve food availability, with larger barnacles having greater access to the nutrients coming from the ocean, along with spatial competition, where higher abundance may lead to increased competition, thereby reducing available resources for each individual. Differences between sites may be attributed to diverse characteristics unique to each location.

Ocean salinity, a measure of salt concentration in seawater, is a key variable influencing water density and controls important processes like mixing and stratification. In dynamic coastal systems like Puget Sound, temporal and spatial salinity variability can present a challenge for making high resolution salinity measurements that can characterize these patterns. Salinity is typically measured using widely used conductivity cells, but they can be costly, provide spatially limited observations and can have technical limitations including drift and biofouling. This project therefore developed and validated a cost-efficient buoyancy-driven profiling float for the indirect determination of salinity for use in these dynamic coastal areas. The float is built from stock hardware and electronics, and 3D printed components. The float measures in-situ temperature and pressure through electronic sensors and determines water density at a given depth by achieving neutral buoyancy (e.g., float density equals water density). Neutral buoyancy is achieved by using a stepper motor to precisely move a piston to displace up to 6% of the float’s volume in water. Salinity is then calculated using the TEOS-10 equation of state using these three known parameters. This approach could enable the large-scale production of floats to obtain high-resolution data to better quantify patterns and change in dynamic coastal systems.

The estuarine dynamics of Puget Sound, (Washington, USA) are complex, with high spatial and temporal variability, influenced by factors that control the circulation and mixing of offshore and estuarine waters. However, determining these mixing impacts on a smaller scale can be difficult. Colvos Passage, a distinctive and understudied passageway of Puget Sound, is unlike other channels because surface currents remain consistent in direction regardless of the tides. Here, we investigate mixing in Colvos Passage as water flows into the main basin of Puget Sound during different tidal cycles using Seagliders. We conducted repeat surveys using Seaglider CTD data and fixed position CTD casts at different tidal cycles throughout the winter of 2023-2024. We measured temperature, salinity, and density from Seaglider transects to track the body of water as it exits Colvos Passage into the main basin and provide insight into the complexity of estuarine mixing and circulation. Preliminary results suggest that the body of water in Colvos Passage is well mixed throughout the progression of the tidal cycle facilitating the tracking of this water mass into the main basin. This study is the first from the University of Washington’s new Student Seaglider Center (SSC), a student-run laboratory where students gain valuable experience in testing, deployment, piloting, and scientific planning of refurbished Seagliders. The SSC continues to build on this study to understand circulation in Puget Sound which can support local forecasting and effective pollution mitigation strategies.