The South Atlantic Bight: a living laboratory

The swath of US coastline that extends from Cape Hatteras, NC to Cape Canaveral, FLA, known as the South Atlantic Bight, is a broad but relatively shallow section of the Atlantic that reaches to the gulf stream. Situated near its coastal midpoint, the University of Georgia Skidaway Institute of Oceanography houses a research hub into the bight that allows marine scientists and oceanographers near-constant access to this dynamic biological environment.

A new study led by Franklin College marine scientists at the Skidaway Institute of Oceanography (SkIO) scientists demonstrates the power of that proximity. The research shows how patterns in the ocean structure of South Atlantic Bight affect where different types of zooplankton swim and live, how the ocean water is layered and mixed, and its significant influence on life beneath the surface:

The study, led by former SkIO master’s student Kyle Aaron, found that in areas where ocean waters were well mixed, zooplankton communities were less diverse. These areas were dominated by mostly small, slow-moving, gelatinous organisms. But in areas where upwelling of cold deeper water caused layering, there was more diversity and an increase in larger zooplankton that were faster and contained more carbon, such as shrimp and other crustaceans. 

“When populations are diverse and you have more fast-swimming, high-carbon-content animals in the water column, that might present an opportunity for larger animals to be around to feed,” explained Aaron, who conducted the study while working in SkIO faculty member Adam Greer’s lab. 

Zooplankton play a vital role in the ocean food web. Their abundance can indicate the health and productivity of marine ecosystems, as they serve as a crucial food source for larger predators, such as adult fishes and even large animals like whale sharks and right whales. 

“Not all zooplankton have equal value to predators. Some are crustacean and high in carbon content, and others are gelatinous and relatively low in carbon,” Greer explained. “Since zooplankton are an intermediate link in the ocean food web, the dominance of particular groups, and associated oceanographic properties, has important implications for broader characteristics of the ocean food web.”

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Image: author photo of sunset on the South Atlantic Bight, Nov, 2019.