Notes on Iowa Diatoms X: New and Rare Diatoms from Iowa

Four diatoms new to science are described and illustrated: Fragillaria vaucheriae f. contorta nov. fo., Navicula cryptogaster spec. nov., Surirella iowensis spec. nov., Surirella stoermerii spec. nov

Diatoms New to Ohio and the Laurentian Great Lakes

Author Institution: Department of Biological Sciences, Bowling Green State UniversityEpiphytic diatoms (Bacillariophyta) were collected from three marshes along the southern shoreline of Lake Erie during the summer and fall of 1977. Geographical distributions of 24 taxa new to the state of Ohio are described, and 149 and 34 taxa are reported as new for Lake Erie and the Laurentian Great Lakes, respectively. We attribute the large number of taxa new to the lake to a lack of previous littoral diatom studies, sampling technique, and habitat diversity within the littoral zone

The Effect of Sewage-Treatment-Plant Effluent on Diatom Communities in the North Branch of the Portage River, Wood County, Ohio

Author Institution: Department of Biology, Bowling Green State UniversityThe North Branch of the Portage River was sampled by means of artificial substrates in order to determine the effect of sewage-treatment-plant effluent on the diatom communities. The effluent appears to be a source of nitrogen and phosphorus for the river. Diatom-community composition appears to be affected by the effluent; Gomphonema parvulum, in particular, was especially abundant at stations with a high content of Poe Ditch effluent. A total of 111 diatom taxa was observed in this study; 24 of these taxa were previously unreported from Ohio

Benthic Algae of Lake Erie (1865-2006): A Review of Assemblage Composition, Ecology, and Causes and Consequences of Changing Abundance

Author Institution: Department of Natural Resource Ecology and Management, Iowa State UniversityAuthor Institution: Department of Biological Sciences, Bowling Green State UniversityPeer-reviewed literature and published reports were used to summarize knowledge of benthic algal assemblage composition and ecology in Lake Erie, and causes and consequences of temporal variation in algal abundance. Macroalgal assemblages in rocky littoral and soft substrate habitats have been reasonably well described and studied, as has the epiphyte/metaphyte assemblage associated with rocky littoral macroalgae. In contrast, little information exists for non-epiphytic microalgae in littoral habitat. During the period when algal records were reported (1865-2006), the rocky littoral macroalgal assemblage was often dominated by the chlorophyte genera Cladophora and Ulothrix and the rhodophyte Bangia, whereas the charophytes Chara and Nitella were most abundant in littoral soft substrate. In addition to substrate effects, assemblage composition varied as a function of depth, temperature, light levels, and nutrient concentrations. Under certain conditions, macroalgal taxa appeared to outcompete and exclude other taxa from littoral habitat. However, these organisms have also facilitated increased algal diversity by supporting epiphytes/metaphytes. In Lake Erie, significant temporal change in benthic algal abundance has been associated with: 1) eutrophication (prior to 1972), 2) oligotrophication following the Great Lakes Water Quality Agreement (1972-1985), and 3) invasion by Dreissena mussels (1986-2006). Increasingly eutrophic conditions were reflected by high abundance and frequent shoreline fouling by Cladophora, declining charophyte (such as Chara, Nitella) abundance, and invasion of rocky littoral habitat by euryhaline Bangia. Subsequent indicators of oligotrophication included declining Cladophora abundance, and increased diatom abundance in deepwater habitat. Effects of filter-feeding Dreissena (such as increased water clarity, phosphorus excretion) were likely causes for Cladophora resurgence in the 1990s, and likely contributed to return of Chara and Nitella to formerly occupied habitat. Algal assemblages clearly reflect environmental conditions in aquatic ecosystems. To accurately assess present and future conditions in Lake Erie, continued study of all benthic assemblages is recommended, with greater attention directed toward microalgae in littoral habitat than has occurred in the past

Algology and Algologists at Bowling Green, a Short History

This paper summarizes the past 34 years of studies of algae by Rex Lowe and his students and collaborators at Bowling Green State University, Ohio, USA. Sixty-two students have received graduate degrees in this academic program focusing on systematics, ecology and environmental assessment. The taxonomic/floristic research initially focused on northern Ohio streams but is now continental to international in scope focusing on the algal flora of the Great Smoky Mountains National Park and on the South Island of New Zealand. Ecological research has focused on factors that regulate the structure and function of benthic algae. Variables that have been examined include abiotic resources (nutrients and light), grazers and physical disturbance. Studies on environmental assessment have focused primarily on the impact of point-source loads of chemicals into water bodies.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42903/1/10750_2005_Article_1601.pd

The Frustular Morphology and Distribution of Cyclotella gamma Sov. (Bacillariophyceae)

Diatom collections from several lentic aquatic habitats in northern lower Michigan were found to contain a large benthic centric diatom. Comparison with type material revealed this diatom to be Cyclotella gamma Sov. Specimens ranged in size from 20 to 35 μm and had striae densities of 5 to 8 in 10 μm. Valves are granular externally and possess central and marginal strutted processes internally; as well as a single, well-developed labiate process. The striae are alveolate in nature. Cyclotella gamma is probably more common than records indicate which may in part be attributable to its confusion with C. meneghiniana Kiltz

Eighty years of food-web response to interannual variation in discharge recorded in river diatom frustules from an ocean sediment core.

Little is known about the importance of food-web processes as controls of river primary production due to the paucity of both long-term studies and of depositional environments which would allow retrospective fossil analysis. To investigate how freshwater algal production in the Eel River, northern California, varied over eight decades, we quantified siliceous shells (frustules) of freshwater diatoms from a well-dated undisturbed sediment core in a nearshore marine environment. Abundances of freshwater diatom frustules exported to Eel Canyon sediment from 1988 to 2001 were positively correlated with annual biomass of Cladophora surveyed over these years in upper portions of the Eel basin. Over 28 years of contemporary field research, peak algal biomass was generally higher in summers following bankfull, bed-scouring winter floods. Field surveys and experiments suggested that bed-mobilizing floods scour away overwintering grazers, releasing algae from spring and early summer grazing. During wet years, growth conditions for algae could also be enhanced by increased nutrient loading from the watershed, or by sustained summer base flows. Total annual rainfall and frustule densities in laminae over a longer 83-year record were weakly and negatively correlated, however, suggesting that positive effects of floods on annual algal production were primarily mediated by "top-down" (consumer release) rather than "bottom-up" (growth promoting) controls

The Effects of pH on a Periphyton Community in an Acidic Wetland, USA

Despite the importance of peatlands, the algal ecology of peatlands and the periphyton communities which are abundant in these habitats are relatively understudied. We performed an in situ manipulation of pH in an intermediate fen in northern lower Michigan in order to examine how hydrogen ion concentrations structure an epiphytic algal community. Levels of pH were manipulated in enclosures from the control level (pH = 5) to an acid treatment (pH = 4) by adding H 2 SO 4 and a neutral treatment (pH = 7) by adding NaOH. Algal communities growing on sections of Chamaedaphne calyculata (L.) Moench stems were examined after 22 days of colonization. Chlorophyll  a concentration was significantly greater only in the acid treatment (~5.5 mg m −2 ) relative to the control (~3.5 mg m −2 ). Taxa richness was lower in the acid treatment. The algal assemblages were dominated by filamentous green algae and a filamentous taxon, Mougeotia spp., was significantly greater in the acid treatment relative to the control. Increases in Zygnemataceae and Oedogonium spp. most likely account for the higher chlorophyll a in the acid treatment. Most treatment differences were detected in the neutral treatment, including increased abundances of Closterium polystichum Nygaard, Cosmarium sp., Peridinium inconspicuum Lemmermann, and Synedra acus Kütz. Unexpectedly, there was no strong response of the desmid community. These data can be informative in the development of algal monitoring programs in peatlands when assessment of acidification is desired.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42904/1/10750_2005_Article_1605.pd