Prymnesium parvum Blooms in Florida (2005-present)

Effects of the toxin producer known as golden algae have been localized within the state to small ponds and the Intracoastal Waterway.

Prymnesium parvum, also known as golden algae, is a naturally occurring microscopic member of the phytoplankton community. This algal species is found in brackish waters worldwide and has been noted in Florida waters since 2005 (See Figure 1).

Prymesium parvum bloom, Lake Hanna, March 21, 2011Figure 1 Prymnesium parvum bloom, Lake Hanna, March 21, 2011

It is a known toxin producer and has caused large-scale fish kills in other parts of the United States and the world. It can cause ecological and economic harm particularly to aquaculture industries. In Florida, fish kills caused by P. parvum have been localized to small ponds in residential areas and golf courses and the Intracoastal Waterway (See Figure 2).

Locations of Prymesium parvum blooms in Florida waters, 2005 - September 2013Figure 2 Locations of Prymnesium parvum
blooms in Florida waters (2005-September 2013)

Prymnesium parvum is found throughout the water column, and the formation of a resting stage in the sediment, called a cyst, has been hypothesized. In Florida, P. parvum can be found year round. However, fish kills have been recorded only in winter months when water temperatures are below 30°C (86°F), and salinity is between 1 and 5 parts per thousand. Research has shown that P. parvum can produce allelopathic compounds--chemicals that inhibit growth in another species of plant--that give the cells a competitive advantage over other phytoplankton and grazers. P. parvum also produces an ichthyotoxin, or fish toxin, called prymnesin, which affects gill-breathing organisms by rupturing gill membranes. To date, no adverse health impacts have been noted for humans or non-gill-breathing wildlife that have come in contact with waters experiencing a P. parvum bloom.

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FWC Facts:
The organism that causes red tide in Florida, Karenia brevis, owes its name to a state researcher of harmful algal blooms, Dr. Karen Steidinger.

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