2023 Puget Sound

University of Washington Tacoma

TGEOS 445 - Estuarine Field Studies

Spring 2023

"Ferry on Puget Sound" by Tiffany Von Arnim

Introduction

Located in the Pacific Northwest region of the United States, Puget Sound is a complex and dynamic estuary known for its ecological significance and natural beauty. Puget Sound serves as a valuable natural laboratory for estuarine field studies, offering an array of research opportunities across disciplines such as marine biology, ecology, environmental science, and oceanography (Encyclopedia of Puget Sound 2023). The region's diverse habitats, including rocky shores, eelgrass meadows, tidal flats, river deltas, and kelp forests, support a wide range of plant and animal species. The complex interactions between physical processes, nutrient dynamics, moderate climate, and biological communities make Puget Sound an ideal setting for studying estuarine ecosystems and their responses to natural and anthropogenic influences.

Puget Sound has been home to Coast Salish Tribes that have lived here since time immemorial. Each Tribe is unique, but all share in having a deep historical connection and legacy of respect for the land, waters, and natural resources. We share that respect and hope that our work will contribute to the preservation and beauty of Puget Sound for generations to come.

Map: ESRI ArcGIS Pro - Clint Howell

Puget Sound Presentation (Greengrove 2020)

Puget Sound lies within the Puget Lowland and was formed by the geological processes related to the subduction of the Juan de Fuca Plate beneath the western edge of the North America Plate. These processes have established the broad-scale topography and geology of the region. 15-20,000 years ago, the entire Puget Lowland was covered by the Vashon glaciation. The glacier was nearly 1000 meters thick and as it advanced and then retreated over thousands of years, it shaped the lowland with tremendous amounts of force. Meltwater flowing beneath the ice is believed to have carved and shaped the channels that define Puget Sound as we know it (Shipman 2008) (Greengrove 2020).

Puget Sound is a part of the larger Salish Sea and is connected to the Pacific Ocean by the Strait of Juan de Fuca. Puget Sound is about 153 kilometers long, but only varies between 1 and 8 kilometers in width. The total surface area of Puget Sound is 2500 square kilometers with an average depth of 140 meters, and a maximum depth of 280 meters, giving it a total volume of 110 cubic kilometers of water. The estuary boasts around 3,790 kilometers of shoreline winding from the south end near Olympia to the North near Bellingham and the Canadian border. Puget Sound has a constant influx of freshwater from over ten-thousands creeks and rivers. Snowmelt flows to the Sound year-round from the Cascade Mountain range to the East and the Olympic Mountains to the West. Over 80% of surface water flowing into Puget Sound comes from twelve major river drainages: Sammamish/Lake Washington Canal, Dosewallips, Duckabush, Duwamish/Green, Hamma Hamma, Nisqually, Nooksack, Puyallup, Skagit, Skokomish, Snohomish, and Stillaguamish (Burke Museum 2023).

Major drainage basins of Puget Sound. Map: Kris Symer

Puget Sound Presentation (Greengrove 2020 - after Thompson 1981)

The streams flowing into Puget Sound feed into 4 basins, each having its own unique characteristics and ecology. The Whidbey and Hood Canal basins drain the slowest and can take up to a year to completely recirculate their waters. The South Basin is constrained by the Tacoma Narrows, and the Main Basin flushes the quickest and receives the most mixing. The constant supply of fresh water flowing down from the Cascades and Olympics is full of sediments, nutrients, and dissolved oxygen. The freshwater from the streams has a lighter density than the salt water flowing in from the Pacific Ocean which sets up estuarian circulation with colder and saltier water sinking into the depths and moving in and warmer fresher water on the surface moving out toward the Pacific Ocean. Puget Sound is an irreplaceable natural resource home to thousands of different species of birds, mammals, fish, and many other marine wildlife as well as some 4 million people (Encyclopedia of Puget Sound 2023). Careful monitoring and management are critical for the long-term health of all its residents.

The Research Team

The 2023 crew of TGEOS 445 collected data from 4 different areas of Puget Sound including Commencement Bay, Quartermaster Harbor, Main Basin, and San Juan Islands. Our purpose was to increase our understanding of Puget Sound's ecological complexities and to provide a resource for researchers, educators, students, and enthusiasts interested in understanding and appreciating the intricate workings of this unique estuarine system. The sample data that was collected included temperature, salinity, density, oxygen, fluorescence/chlorophyll, transmissivity, nutrients, phytoplankton, zooplankton, sediments, and microplastics. A description of the methods used for sampling and laboratory processes can be found on the Methods page.

The A Team

Hannah Custer, Gracelyn Snedden, Natasha Walker, Clint Howell, Tim Wahlstrom

Instructor: Cheryl Greengrove

The B Team

Mateo Schuler, Eva Marino, Tai Nguyen, Michael Paszek. Arthur Weisberg

Instructor: Cheryl Greengrove

Acknowledgments

We thank the crew members of the research vessels used throughout the quarter, Dave Thoreson (Captain R/V Weelander), Brian Bare (Captain R/V Rachel Carson), Loren Tuttle (Marine Tech R/V Rachel Carson), Charlie Seibel (First mate R/V Rachel Carson), Robert Kamphaus (other First mate R/V Rachel Carson), Thor Belle (Crew mate R/V Rachel Carson), Eric Loss (R/V Kittiwake), Kristy Kull (Marine Tech R/V Kittiwake).

We thank the supporting staff of Friday Harbor Labs

Thank you to Julie Masura, and Kieran L Claassen for assisting on our journey throughout the quarter.