Collaborative Research: Ideas Lab: ETAUS Passive Localized Underwater Transiting Observing Systems (PLUTOS)

With the changing climate, there is an accompanying change in the abundance and distribution of organisms from the smallest single celled organisms to the largest whales. Observing these changes is critical to modeling and understanding the relationship of physical and chemical properties of the ocean to ecological factors. The Passive Localized Underwater Transiting Observing Systems (PLUTOS) project will study links between underwater sound and biology in the ocean, providing scientists with underwater "noses" and "ears" to detect animals by their sounds and the cells they leave behind. When animals make sounds in the ocean, they are indicating their presence; similarly, those same creatures shed DNA as they move through the environment, and that environmental DNA (eDNA) persists with concentration in proportion to the number of organisms and the time since they have inhabited a particular location in the ocean. For this project, the PLUTOS design will be used to look at the food web relationship of seals, fish, and copepods in coastal environments. The PLUTOS project will include multiple low-cost drifting autonomous loggers, each system is ballasted to follow a set density in the water column such that when each targeted depth is intensively sensed and sampled as the drifter moves with the currents. The fundamental idea behind PLUTOS is that clustering of multi-modal data streams including directional soundscape (e.g., 3D localized sound sources in the environment), eDNA collection and real-time sensing, and environmental properties like dissolved oxygen and temperature, will illuminate the spatial and temporal variability linking ecosystems, eDNA persistence and transport, depth-dependent directional soundscape, and coastal food web ecology together. Design will include feasibility studies of eco-friendly materials and non-disruptive passive acoustic navigation techniques. The project will include: 1) Adapting a low-cost, open-source, drifter system that addresses limitation in cost and payload of existing systems; 2) Developing and assessing the performance of species-specific in-situ eDNA sensors that are compact and low-cost and low-power; 3) Developing new approaches for directional soundscape processing, using array processing and machine learning approaches to provide localization of individuals as well as density and distribution estimates for seal populations. The resulting system will be used to evaluate the hypothesis that correlations between species-specific soundscape information (seal calls) and eDNA information (eDNA detection of seals, fish, and copepods) provide information gain on abundance and density of food web participants versus time and space versus single-variate information. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.