Currently, we (Hans Paerl, Michael Piehler, Rachel Noble UNC-CH IMS, and Pia Moisander, Univ. of CA-Santa Cruz) are conducting a National Science Foundation (Ecology Program) supported research project aimed at understanding nutrient acquisition strategies and other ecological adaptations (including low light adaptation, buoyancy regulation) that the toxin-producing bloom former Cylindrospermopsis raciborskii uses to its advantage as it proliferates in Florida and other Southeastern US lakes, rivers and reservoirs. CLICK HERE TO FIND OUT MORE ABOUT THIS PROJECT

Liz Calandrino, graduate student of Dr. Hans Paerl, is currently working on a project entitled, Determining the invasion potential for the harmful blue-green algae (cyanobacterium) Cylindrospermopsis raciborskii at the Currituck Banks NERRS Site, North Carolina. This work is funded by a Graduate Research Fellowship from the National Estuarine Research Reserve System (NERRS) program, which is a partnership program between the National Oceanic and Atmospheric Administration (NOAA) and coastal states designed to protect the nation's estuaries. CLICK HERE TO FIND OUT MORE ABOUT THIS PROJECT

In addition to planktonic bloom-formers, some CyanoHABs are capable of attached growth and proliferation in freshwater and marine bottom (benthic) habitats, including near-shore lake and reservoir bottoms, seagrass and eelgrass beds, mudflats, intertidal salt marshes, reefs and springs. Particulalry problematic species include the non-heterocystous N 2 fixers Lyngbya wollei (in freshwater) and Lyngbya majuscula (in marine systems), and Oscillatoria spp. (in both marine and freshwater habitats). Like their planktonic counterparts, benthic CyanoHABs are indicative nutrient over-enrichment associated with human urbanization, agricultural and industrial development in watersheds and the coastal zone, and decreased grazing by herbivorous fishes due to overfishing. Their adverse impacts include smothering seagrass communities, corals and mudflats, and negatively affecting infauna. Some Lyngbya strains produce toxic secondary metabolites; including aplysiatoxins, debromoaplysiatoxin, and lyngbyatoxin A, metabolites of Lyngbya majuscula , causative agents of the acute dermal lesions following contact with this cyanoHAB. These compounds are protein kinase C activators and potent tumor promoters in vivo , issues of broad public health concern. Lyngbya strains also fix N 2 , which explains why P may stimulate growth more than N additions. These strains thrive in N-deprived waters where N 2 fixation is advantageous, and they bloom in response to land-derived nutrients (N, P, Fe), and organic matter.

With funds from the NOAA-EPA Ecology of Harmful Algal Blooms (ECOHAB) Program, the UNC-CH Institute of Marine Sciences (Hans Paerl), Univ. of Maryland's Center for Estuarine Sciences (Judy O'Neil), Smithsonian Marine Station at Ft. Pierce, FL (Valerie Paul) are investigating nutrient and other environmental factors that are promoting potentialy-toxic Lyngbya majuscula blooms in seagrass beds, coral reefs and coastal embayments on bothe the east and west coasts of Florida. CLICK HERE TO FIND OUT MORE ABOUT THIS PROJECT

Recently, the freshwater analog of Lyngbya majuscula, L. wollei, which is capable of producing skin irritants and other toxic substances (Lyngbyatoxin, saxitoxin) and has been expanding as an attached epiphyte in reservoirs and flowing waters of the the US Southeast. Particularly troubling are invasive growths of L. wollei in Florida's fabled freshwater springs that have taken place during the past decade. The massive tuftlike growths of this filamentous cyanobacterium in some springs is thought to be indicative of nutrient enrichment. In addition to producing toxins, L. wollei forms thick nuisance blooms when exposed to nutrient-enriched waters, making it a potentially useful indicator of eutrophication. Increasing groundwater nitrate levels in some areas of Florida have been implicated as a potential environmental factor responsible for the increased production of L. wollei and other epiphytic algae in springs and their receiving water bodies. We are engaged in a molecular and eco-physiological study (Jennifer Joyner; UNC-CH Marine Sciences) that is providing detailed taxonomic analyses of Lyngbya strains, characterizing the N2 fixation capabilities of L. wollei present in various springs in Central Florida, and examining the colonizing capabilities and limiting nutrients of L. wollei, in order to provide management options for water district managers seeking to control this species. This work is supported by the St. Johns Water Management District, Palatka, Florida and the Florida Dept. of Health. CLICK HERE TO FIND OUT MORE ABOUT THIS PROJECT

Table 1. Non N 2 -fixing and N 2 -fixing filamentous non-heterocystous (FNH), coccoid (C), and heterocystous filamentous (HF) cyanoHAB genera.