Education
The forests of the sea!
Kelp forest ecosystems are highly productive, diverse and provide food and habitat for numerous species of invertebrates, fishes, birds and marine mammals [1]. However, kelp forests are threatened [2]. They face challenges, such as increasing water temperatures associated with climate change [3], shifts to alternative stable states (such as "urchin barrens" [4]) and the spread of invasive algae [5]. Many species rely on kelp forests [6], including species of conservation, management and cultural significance. All of this adds to the challenges and necessity of gathering data along the seafloor.
Bull kelp forest off the shore of Pacific Grove, California, U.S., by Pat Webster (@underwaterpat)
Scientific scuba divers have formed the backbone of kelp forest monitoring for the past 60 years, as they use underwater slates, pencils and specialized paper to survey and record species abundance and point counts along sample areas [7]. (Check out this video for more info.) However, there are logistical and safety limitations to how much seafloor divers can cover. More data from additional survey methods is necessary to gain greater insight into how best to preserve and restore these ecosystems.
Remotely Operated Vehicles (ROVs) in kelp forests
In 2022, the Seattle Aquarium's Coastal Climate Resilience (CCR) team started developing methods of using small ROVs to conduct photo/video surveys within the dark and murky waters of Washington State's kelp forests. Historically, ROVs have typically been bulky, expensive and deployed off large vessels to explore deep sea ecosystems. Our work is one of the first standardized deployments of small, relatively inexpensive ROVs to gather imagery and data within relatively shallow kelp forests (2.5–30 meters deep).
Seattle Aquarium's ROV Lutris surveying alongside a 30-meter scuba diver transect tape in Elliott Bay Marina breakwater, Seattle, Washington, U.S.
Via small and inexpensive ROVs from Blue Robotics, we have optimized camera and lighting settings to gather high-resolution imagery of the benthos (the seafloor) and the life living in, on and just above it. We gather 27.3-megapixel downward-facing photos, allowing us to capture detailed imagery of the various brown, red and green algae; encrusting and articulated coralline algae; and various mobile and sessile invertebrates (sea stars, crabs, sea urchins, anemones, sponges, tunicates, etc.); and fishes. We also capture images of the various types of seafloor itself (sand, shell debris, cobble, boulder), a key component of benthic ecosystems we capture to understand why species live and thrive in particular areas.