We pulled together as a community to meet the challenges of the past year head on. Flexibility has long been the cornerstone of our success. From mitigating the initial and then rippling impacts of the pandemic, to delivering on research efforts, to proposing new basic and applied research, APL-UW scientists, engineers, and staff have overcome the obstacles to our collective success.

In 2021 APL-UW oceanographers reported important results from observation programs spanning the world's oceans, from the Arctic to the tropics. Engineering advances pushed the persistence and navigation precision of undersea gliders, and delivered a prototype mechanical system to the Nuclear-Test-Ban Treaty Organization. Acousticians discovered new and unanticipated properties of the seabed, and reported progress in ultrasonic therapeutic clinical trials. Glaciologists and sea ice experts continue to document and explain the dramatic changes to the cryosphere as the Earth warms. Also during 2021, an X-ray instrument on the Perseverance rover began to reveal the composition and structure of rocks on the Martian surface with greater detail than ever before.

APL-UW oceanographers have led a program to deploy moored instruments in the Bering Strait to measure the flow of Pacific waters to the Arctic since 1990. Total Bering Strait transport has increased by more than 50% since the 1990s, the summer waters are 2–4°C warmer, and winter waters are now even fresher than during summer.

The OOI Cabled Array hosts more than 150 scientific instruments, providing a daily, year-round portal for scientists to study deep and coastal ocean processes. APL-UW acousticians are using the data streams to quantify the volume and heat of hydrothermal discharges from the seafloor, discover the distribution, abundance, and movements of mid-trophic level sea creatures, and listen for trends in shipping noise.

Melt probes can descend through hundreds of meters of glacial ice using modest electrical power. At Greenland Summit Station the APL-UW Ice Diver dove over 100 m deep into the ice, retrieved meltwater samples, and was then recovered to the surface. A new probe is in development to aid the search for the oldest ice on Earth that resides near the bottom of the Antarctic Ice Sheet.

APL-UW researchers are integral partners in the design and production of observing technologies, data services, and communication networks to study the initiation, maintenance, and transport of harmful algae blooms on the Washington coast. In summer 2021 the Laboratory collaborated with the Quileute Tribe Natural Resources program to build and deploy coastal moorings to detect occasional low-oxygen zones that threaten tribal fisheries.

Undergraduate student researchers made notable achievements in 2021. APL-UW staff mentored winning student research teams developing underwater vehicles, and undergraduate science majors joined air-sea remote sensing experiments aboard the R/V Rachel Carson. The inauguration of the APL-UW Undergraduate Internship Program entrained seven students in two cohorts. They collected ocean observations, improved lab instrumentation, analyzed mountain snow data, and studied sonar detection and classification processes with an applied naval platform developed and built at APL-UW.

APL-UW was able to respond quickly to the pandemic and create safe work environments, thereby lessening the impact to our research efforts and, by extension, our financial well-being. The U.S. Navy remains the largest sponsor of APL-UW research and development. Robust revenues support a range of strategic investments in Laboratory staff and facilities.