Georgia Harmful Algal Blooms

SECOORA funds a project that incorporates high-resolution, quantitative Harmful Algal Bloom (HAB) monitoring in the Skidaway River Estuary to determine environmental conditions conducive to HAB formation in Georgia estuaries. This project builds upon NOAA’s existing citizen science-based initiative, the Phytoplankton Monitoring Network.

SECOORA is supporting the Skidaway Institute of Oceanography, University of Georgia Marine Extension, Georgia Sea Grant in documenting the relationship between cell densities of HAB species and water quality in the Skidaway River Estuary (shown above). Image credit: Clark Alexander, Skidaway Institute of Oceanography.

Harmful Algal Blooms in Georgia

Harmful Algal Blooms (HABs) are a pressing concern for Georgia’s waterways. Compared to neighboring states, HABs are understudied and this likely results in an underestimation of their prevalence.

Historical reports show that HABs were first observed in the coastal estuaries of Sapelo Island in 1956 and 1972. More recently in 2017, a HAB event occurred in the Skidaway River at the same time as an oyster mortality event. While the two events have not been officially linked, researchers recognize the need to learn more about HAB impacts on native oysters.

Monitoring Efforts

It is hypothesized that blooms on the Georgia coast will increase due to nutrient runoff caused by increased shoreline development and global rises in temperature. To fill the gap and begin a monitoring program for HABs in Georgia, SECOORA is supporting Natalie Cohen and her team at the University of Georgia Skidaway Institute of Oceanography and Marine Extension & Georgia Sea Grant to document the relationship between cell densities of HAB species and water quality parameters in the Skidaway River Estuary. The project goal is to identify environmental conditions that are conducive to HAB formation in Georgia estuaries. By understanding these conditions, the team and stakeholders can better predict and mitigate the impact of these blooms on our coastal ecosystems.  

Mallory Mintz, a graduate student at the University of Georgia Skidaway Institute of Oceanography, is sampling the Skidaway River Estuary for water quality parameters using a ProDSS YSI Sonde.

Natalie Cohen and her team are taking daily samples during low tide at the Skidaway River Estuary. They are sampling for the seasonal biological and chemical shifts in the phytoplankton community and mainly monitoring for the presence and abundance of Akashiwo sanguinea, a harmful algal blooming organism. While not inherently toxic, Akashiwo generates a surfactant substance that adversely affects wildlife by obstructing fish gills and enveloping bird feathers.

Above is the recorded Akashiwo sanguinea cell densities shown in near real-time. The information provided includes the date of the data point, the total number of Akashiwo cells counted, and the concentration of cells per milliliter of water sampled. It is hypothesized that a count of 100 cells/mL could be an indication of poor water conditions, but more research is needed to define the exact levels that cause harm.

Empowering the Community

Volunteers with the Phytoplankton Monitoring Network, a NOAA-funded citizen science initiative, review data in a lab at the University of Georgia Marine Education Center and Aquarium. Image credit: UGA Marine Extension and Georgia Sea Grant

Frequently Asked Questions

What is Akashiwo sanguinea?

Akashiwo sanguinea (A. sanguinea) is a harmful algal blooming organism. Akashiwo is a single-celled eukaryote that is capable of both photosynthesizing and consuming prey. It is not clear whether it produces a toxin, but it is known to produce a soap-like substance that negatively impacts wildlife by clogging fish gills and coating bird feathers. When bird feathers are coated in this substance, they lose their water-repellant properties and insulation abilities.

Why is Akashiwo sanguinea a concern?

High cell densities (~250 cells/mL) of A. sanguinea were the suspected cause of an oyster larvae die-off event in the Skidaway River Estuary (Pfeiler 2020). The exact cause of the event is unclear, and could be related to nutrient availability, temperature, salinity, and/or picoplankton prey presence selecting for the growth of A. sanguinea (Pfeiler 2020).

How is Akashiwo sanguinea being measured?

The University of Georgia Skidaway Institute of Oceanography employs a comprehensive monitoring approach for HABs in the Skidaway River Estuary. The team conducts weekly measurements of water quality, nutrients, and cell densities in non-summer months. During summer months and through fall, the sampling frequency increases daily to capture seasonal biological and chemical transitions in the phytoplankton community, and allow them to begin documenting their relationship with water quality parameters. Cell counts are obtained via aFlowCAM fluid imaging system.

How can I learn more?

Interested in learning more about Harmful Algal Bloom research in Georgia? Here are some helpful links:



SECOORA Harmful Algal Bloom Plan (updated May 2023)

This document is an addendum to the SECOORA Regional Coastal Ocean Observing System Strategic Operational (RCOOS) plan, which establishes priorities for contributing to our improved understanding, management, and stewardship of valued coastal ocean resources. This document will serve as a guide for future investments in regional harmful algal bloom (HAB) observing and monitoring in the SECOORA region.
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