Andrew D Chapman

Some Known and Suspected Toxigenic Cyanobacteria from Around the World This list includes taxa that have had toxins identified, have been implicated in toxic events in the field, or have elicited a positive response in laboratory assays. New toxigenic cyanobacteria species are continually being discovered and data concerning known and suspected tox...

Background: Blooms of marine phytoplankton may adversely affect human health. The potential public health impact of low-level exposures is not well-established, and few prospective cohort studies of recreational exposures to marine phytoplankton have been conducted. Objective: We evaluated the association between phytoplankton cell counts and su...

Application of 31P-NMR analysis to lake sediment has improved our understanding of the chemical nature of phosphorus (P) in lake deposits (Reitzel et al. 2007; Torres et al. 2014). A recent 31P-NMR study verified the presence of polyphosphate (poly-P) in a single, short sediment core from Lake Apopka, but failed to find poly-P in sediment cores fro...

Accurate identification of cyanobacteria using traditional morphological taxonomy is challenging due to the magnitude of phenotypic plasticity among natural algal assemblages. In this study, molecular approach was utilized to facilitate the accurate identification of cyanobacteria in the Sacramento-San Joaquin Delta and in Clear Lake in Northern Ca...

Historic changes in lake phosphorus (P) loading are often determined in paleolimnological investigations by assessing stratigraphic changes in sediment total P. Polyphosphate (poly-P) in sediments may provide additional information on historic lake trophic status, because phytoplankton store surplus P intracellularly as poly-P when supplies exceed...

The eutrophication of water resources, mainly attributed to antrophogenic activities such as sewage and agricultural runoffs, has led to a worldwide increase in the formation of cyanobacterial harmful algal blooms (Cyano-HABs). Cyano-HABs have the ability to produce and release toxic compounds, commonly known as cyanotoxins, which comprise a potent...

We conducted a study of recreational exposure to microcystins among 81 children and adults planning recreational activities on either of three California reservoirs, two with significant, ongoing blooms of toxin-producing cyanobacteria, including Microcystis aeruginosa (Bloom Lakes), and one without a toxin-producing algal bloom (Control Lake). We...

Fisher, M.M., S.J. Miller, A.D. Chapman and L.W. Keenan. 2009. Phytoplankton dynamics in a chain of subtropical blackwater lakes: the Upper St. Johns River, Florida, USA. Lake Reserv. Manage. 25:73–86.Spatial and seasonal patterns in phytoplankton biovolume and community composition were examined for a chain of lakes in the Upper St. Johns River (U...

Nutrient addition bioassays were conducted to examine the relationship between inorganic nutrient enrichment and phytoplankton community structure and function in Lake George in the St. Johns River System, Florida, USA. Additionally, a nitrogen budget for the lake was developed and included data from the period of this study. We identified the fact...

Observations of historical and recent phytoplankton samples from five hypereutrophic Florida lakes indicate that nitrogen-fixing cyanobacteria in the genus Cylindrospermopsis Seenayya et Subba Raju have entered these water-bodies sometime in the last 30 years. Cylindrospermopsis forms a year-round bloom in one of the five lakes, dominates seasonall...

Effects of temperature, irradiance, and nitrogen availability on the encystment and growth of the freshwater dinoflagellates Peridinium cinctum Ehrenberg and Peridinium willei Huitfeld-Kaas were studied in culture. Lack of nitrogen was the main trigger of encystment in both species. Irradiance had a secondary effect on the percentage of the populat...

Toxigenic cyanobacteria are common components of Florida's surface waters and may pose a threat to their ecology and a risk to human health. The Lake County Water Authority, the Florida Department of Health, the St. Johns River Water Management District, the South Florida Water Management District, and the Lee County Health Department have all rece...

Algal samples were analyzed from 3 lakes, Crane Prairie Reservoir and Odell Lake in Oregon and an Anonymous North East System, using both standard taxonomic criteria for identification and DNA sequencing techniques. Two toxin-producing Anabaena populations, one with consistent akinete structure and another with variable akinete structure, were inve...

Weekly water samples were taken to measure stable isotope composition (δ13C and δ15N) of particulate organic matter (POM) in Lake Wauberg, Florida, from June 1994 to May 1995. The average δ13C of POM was -19.3‰, consistent with an autochthonous origin from phytoplankton production, and exhibited a seasonal pattern that coincided with changes in wat...

The primary producer community of Lake Apopka, a large (125km2), shallow (mean depth, 1.7m), polymictic Florida lake, shifted from macrophyte dominance to phytoplankton dominance in the 1940s. Today, frequent wind resuspension of highly organic, unconsolidated sediments supports a meroplanktonic community that is predominantly diatoms, but during c...

Historic changes in lake phosphorus (P) loading are often determined in paleolimnological investigations by assessing stratigraphic changes in sediment total P. Polyphosphate (poly-P) in sediments may provide additional information on historic lake trophic status, because phytoplankton store surplus P intracellularly as poly-P when supplies exceed...