The Annual Distribution and Stratification of Phytoplankton at Aurora Lake, Portage County, Ohio

Author Institution: Old Dominion College, Norfolk, VirginiaA 13-month study of a hard-water lake in northeast Ohio has provided a quantitative and qualitative record of the seasonal changes of the phytoplankton. Maximum production occurred during the summer and winter periods. The summer pulse was dominated by the cyanophyte species: Microcystis aeruginosa, Anabaena spiroides, A. circinalis, and A phanizomenon flos-aquae. The dominants of the winter pulse were the diatoms Fragilaria crotonensis and Asterionella formosa, which formed separate peaks under an ice cover in December and January, respectively. The January development extended into March with the highest concentrations for the year being reached at approximately 1,400,000 cells per liter. The Chlorophyta were represented by 34 species, but quantitatively were of minor importance. The Pyrrophyta were uncommon and were represented by only 3 species. Periods of maximum and minimum phytoplankton development correspond closely in duration and magnitude at the surface and at one meter, with a slight tendency for pulses at two meters to lag behind. Vertical distribution indicated that the cyanophyte species, Phacus sp., and Fragilaria crotonensis were more numerous in the upper layers, whereas Asterionella formosa, Synedra sp., Closterium sp., and Melosira granulata occurred in greater numbers in the lower strata. Microcystis aeruginosa was noted to change its level of greatest concentration with the seasons

Diurnal Distribution of Phytoplankton from a Single Station at the Mouth of the James River

Author Institution: Old Dominion College, Norfolk, VirginiaEight sets of water samples were taken to a depth of 36 ft during a 24 hr period. A homogeneity was found in the vertical distribution of the total phytoplankton in samples from 7 of the 8 hydrocasts. Skeletonema costatum and Asterionclln japonica were the most numerous phytoplankters in every sample, with the majority of their counts each exceeding 500,000 cells per liter

Phytoplankton in Virginia Lakes and Reservoirs: Part II

Phytoplankton composition from 16 Virginia lakes and reservoirs are discussed with emphasis on the dominant taxa, algal bloom producers, and potentially harmful species at these locations. This is a companion study to the more comprehensive publication regarding Virginia freshwater phytoplankton by Marshall (2013)

Cyanobacteria Dominance in the Oligohaline Waters of Back Bay, Virginia

Back Bay and its flora have historically been influenced by the interaction of freshwater flow in combination with frequent intrusion of saline water into its basin. These events have resulted in a dynamic environmental setting influencing the abundance and composition of its phytoplankton community. Dominating these oligohaline waters is a diverse representation and high abundance of freshwater filamentous and colonial cyanobacteria. These include the nonheterocystous Planktolyngbya contorta, Planktolyngbya limnetica, and Pseudanabaena limnetica, taxa implicated as bloom producers in Bay waters with N:P molar ratios ranging from 23:1 to 74:1

Trachelomonas Spp. and Other Euglenophyceae Taxa in a Southeastern Virginia Lake

Trachelomonas species from Lake Kilby, a reservoir lake in southeastern Virginia are described with supportive electron micrographs. The most abundant Trachelomonas species wereT. hispida and T. volvocina. Other members of the Euglenophyceae occurring in this lake are identified

Phytoplankton Studies Within the Virginia Barrier Islands. III. Phytoplankton Composition in a Saline Pond on Smith Island

The phytoplankton that characterized the Smith Island pond was diverse, with several species of diatoms, dinoflagellates and blue-green algae dominant throughout the year. A total of 146 spp. were noted, predominantly composed of ultra and nanoplankters, that includes representatives from coastal waters. The island ponds are considered eutrophic habitats whose composition is influenced by overwash conditions and in turn introduce populations to surrounding pools and water channels

Pfiesteria Piscicida and Dinoflagellates Similar to Pfiesteria

Pfiesteria pisiccida is a microscopic, unicellular organism that is classified as both a mixotrophic and heterotrophic dinoflagellate, which has been associated with both fish deaths and a cause of human illness (Burkholder et al., 1992; Glasgow et al., 1995; Burkholder and Glasgow, 1997). This species possesses a complex life cycle that includes motile forms (e.g. zoospores, gametes, amoebae) and a cyst stage that may remain dormant in the sediment (Burkholder et al., 1995b). Pfiesteria piscicida is known to have toxin and non-toxin producing populations, where cyst transformation into the toxic motile zoospores may be initiated by the presence of certain unknown fish excretions, or secretions (Burkholder et al., 1995a; 1999). These zoospores can attack fish and cause their death, then pass through several vegetative and reproductive stages, including the formation of amoebae and cysts that may leave the water column and pass to the sediment (Burkholder et al., 1995b; Glasgow et al., 1998). These transitions occur over a relatively short time period, so their concentrations in the water after a fish kill are often greatly diminished. This rather rapid departure into the sediment resulted in this species to be initially labeled the Phantom dinoflagellate (Burkholder et al., 1992)

Phytoplankton in Virginia Lakes and Reservoirs

This study involves a phytoplankton summer/autumn survey in 46 Virginia lakes and reservoirs during 2010-2012. A total of 307 taxa were identified which included several filamentous and colonial cyanabacteria in bloom concentrations. With the exception of one natural lake, the other sites sampled represent impoundments created decades ago, with the majority presently classified as meso- or eutrophic. Among the cyanobacteria were 6 known toxin producers (Anabaena circinalis, Anabaena spiroides, Aphanizomenon flos-aquae, Cylindrospermopsis raciborskii, Limnothrix redekei, and Microcystis aeruginosa). The study characterizes phytoplankton populations in these aging freshwater habitats taken from a large number of sites over a broad geographical extent in Virginia. The results portend future concerns for increased presence of less favorable algal populations in Virginia lakes and reservoirs, including an increased occurrence of algal blooms, and presence of potential harmful species

Phytoplankton Populations in Back Bay, Virginia

Cyanobacteria, diatoms and chlorophyceans dominated the seasonal assemblages of phytoplankton in a two year study of Back Bay, Virginia. Seasonal differences in composition and development were found between the two years, with highest concentrations occurring in summer and early fall when a piconanoplankton assemblage of cells was dominant

Succession in a Dune Community at Mentor Headlands, Ohio

Continual sand deposition on the Lake Erie shore, adjacent to the mouth of the Grand River, has led to the formation of a developing sand dune community and through the years a successional pattern of plant growth. An analysis was made of the general plant composition of the area by means of four transects directed from the bare beach inland. Definite zonation of specific plant species was present throughout the community in parallel formation. Named for the dominant plant types they contained, the major stages were: dune grass, poplar, aspen, and oak