Recent changes in abundance and cell size of pelagic diatoms in the North American Great Lakes (original) (raw)

Endemism and Invasion in the Great Lakes Diatom Community

Journal of Phycology, 2002

Population dynamics and health for individual Great Lakes diatom species is explored. Information dealing with how these taxa compete with introduced species and rapid environmental changes in modern times is examined. Diatomists have identified a number of these taxa, but discussion is limited with little or no information covering the ecological range of the taxa over time. Some of these include Cyclotella americana Fricke; C. bodanica var. stellata Skvortzow; and Stephanodiscus superiorensis Theriot. A number of taxa endemic to the Great Lakes undescribed in the literature also exist. These are species wedged into taxonomic categories from the European taxonomic system. Recent advances in the understanding of diatom species boundaries, suggest these names are inappropriately used for a number of taxa identified in paleolimnological investigations of the Great Lakes. This problem developed because taxonomic information outside of the European flora is not readily available to rese...

Consideration of species-specific diatom indicators of anthropogenic stress in the Great Lakes

Robust inferences of environmental condition come from bioindicators that have strong relationships with stressors and are minimally confounded by extraneous environmental variables. These indicator properties are generally assumed for assemblage-based indicators such as diatom transfer functions that use species abundance data to infer environmental variables. However, failure of assemblage approaches necessitates the interpretation of individual dominant taxa when making environmental inferences. To determine whether diatom species from Laurentian Great Lakes sediment cores have the potential to provide unambiguous inferences of anthropogenic stress, we evaluated fossil diatom abundance against a suite of historical environmental gradients: human population, agriculture, mining, atmospheric nutrient deposition, atmospheric temperature and ice cover. Several diatom species, such as Stephanodiscus parvus, had reliable relationships with anthropogenic stress such as human population....