Defense Date


Document Type


Degree Type

Master of Science

Degree Name

Marine Science

First Advisor

D. Abigail Renegar, Ph.D.

Second Advisor

Robert Smith, Ph.D.


Harmful algal blooms, Karenia brevis, Florida red tide, Southeastern Atlantic estuaries


Phytoplankton communities are vital to oceanic ecosystems. While most are harmless or beneficial, a select group possesses the capability to produce toxins and cause mass die-offs of marine organisms. Florida red tide, caused by blooms of the dinoflagellate Karenia brevis, is common in the Gulf of Mexico, although blooms have been transported to the Atlantic coast and impacted estuaries where K. brevis is not normally found. An in-depth overview of compiled estuary research evaluated the possibility of the continued spread of Florida red tide blooms to Southeastern Atlantic estuaries and the likelihood of establishment in non-native regions. A rank-scoring system was used to better depict the potential for red tide expansion. With inland river systems providing estuaries with freshwater, excessive nutrient build-up supports eutrophication. Waterflow dynamics prove to be a contributing factor in bloom establishment. Florida and North Carolina estuaries, which tend to have poor flowrates and excessive anthropogenic nutrient loading, have had documented cases of red tide blooms. Georgia and South Carolina estuaries, in contrast, have high flowrates and little nutrient loading, and few algal blooms have occurred. Although bloom populations of K. brevis have been successfully transported beyond native ranges, complete establishment has not yet occurred. Based on key environmental factors, the possibility of red tide expansion to Southeast Atlantic estuaries is low to moderate, but climate change and rising sea levels may result in an increased risk of further expansion.