Project: Zooglider assessment of zooplankton frontal gradients across the BIOSWOT-Med region

NSF Award Abstract:
Ocean fronts are regions of sharp horizontal discontinuities that can alter phytoplankton growth rates and community composition, zooplankton distributions and grazing activity, and predator foraging success. This study is using Zooglider, an autonomous ocean sampler equipped with a range of sensors and capitalizing on a unique opportunity to investigate frontal gradients and plankton communities in the western Mediterranean Sea. It is timed to coincide with a rapid crossover phase of a new NASA satellite mission. The combination of satellite and field-collected data will provide high resolution of the bio-physical consequences of oceanic frontal processes. The project incorporates training for graduate and undergraduate students as well as public outreach. Results are broadly communicated by partnering with a major public aquarium that serves 450,000 visitors per year, including by exhibiting novel porcelain ‘Zooware’ meant to convey the sensory experience of exploring the ocean’s planktonic fauna.

This project focuses on advancing understanding of frontal processes in the western Mediterranean Sea, at a ‘crossover’ site where NASA’s new Surface Water Ocean Topography (SWOT) satellite is making high-frequency sea surface height measurements using a high-resolution sensor. Measurements from the SWOT satellite are resolving small changes in sea-surface height, making it possible to follow the development and temporal progression of ocean frontal systems. The investigator is assessing the consequences of these frontal systems by testing the hypotheses that 1) zooplankton, marine snow particles, and predators are altered in these ocean frontal regions with a size-dependent or trait-dependent response; 2) particle-grazing zooplankton are more closely associated with layers of marine snow than with layers of living phytoplankton; 3) vertical thin layers of zooplankton are more likely to form in frontal than non-frontal regions; and 4) higher predators such as zooplanktivorous fish and marine mammals are more detectable in frontal regions The project makes use of an autonomous ocean instrument, the Zooglider. It includes a shadowgraph imaging Zoocam for resolving zooplankton and marine snow; a dual frequency Zonar to resolve mesozooplankton and larger sources of acoustic backscatter; and a sensitive hydrophone for recording ambient sounds, especially from marine mammals and fishes. These autonomous measurements are coordinated with complementary measurements from a ship-based sampling program, other autonomous vehicles, and satellite remote sensing.