Diatoms Associated with Bryophyte Communities Growing at Extreme Depths in Lake Michigan

Diatom assemblages on limestone cobbles collected from 42.7 m depth in the mid-lake high region of Lake Michigan are characterized by low total abundance and low diversity. The flora present contains three associations. A large allochthonous component, comprised of planktonic species and very low numbers of benthic species usually found in shallow water is present. A limited number of dominant taxa appear to be particularly associated with deep habitats in oligotrophic lakes. Other species, usually reported from terrestrial habitats, appear to be associated with the bryophyte Fissidens fontanis which is present in the collections

QUANTITATIVE METHOD FOR DETERMINING A REPRESENTATIVE ALGAL SAMPLE COUNT 1

A method for determining a representative count of a sample dependent on number of species is presented for application to various algal communities. Constant species curves are calculated as efficiency = (number of individuals–number of species)/number of individuals and diagrammed on a plot of efficiency versus number of individuals counted. Efficiency is defined as the probability that a new species encountered is minimal. That is, as the ratio of number of species to number of individuals approaches 1, more individuals will need to be counted in order to achieve a representative count. Data and calculations of efficiency from two algal communities are presented for illustration.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66065/1/j.0022-3646.1996.00693.x.pd

Oligotrophy: the forgotten end of an ecological spectrum

Most studies that consider the relationship of diatoms and water quality have focused their attention on the questions and practicalities of water pollution or perturbations in some form or another. Many models and studies have demonstrated the environmental tolerances or changes in structure of diatom communities related to environmental challenges. This focus on the impacted end of the water quality spectrum has led, of necessity, to issues ultimately related to habitat restoration. We contend that a concentrated effort to develop more fully the theory and there is a need for practice related to oligotrophy, the other, ignored end of the water quality spectrum. We explore the historical usages of the term oligotrophy, as well as the challenges and promise of autecological and community approaches to understanding oligotrophy, and the possibility of focusing more on conservation rather than restoration in water quality issues

ECOLOGICAL, EVOLUTIONARY, AND SYSTEMATIC SIGNIFICANCE OF DIATOM LIFE HISTORIES 1

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65431/1/j.0022-3646.1997.00897.x.pd

Diatom taxonomy for paleolimnologists

The present chaotic state of diatom taxonomy presents both significant difficulties and large opportunities for paleolimnologists. Lack of complete and generally available taxonomic treatises and rapid and substantial changes in nomenclature make it necessary for persons using diatom populations to infer environmental conditions to become more deeply and directly involved in diatom systematics, in the broad sense, than is generally realized. Paleolimnologists develop collections that are extremely valuable in addressing classic questions in evolution and biogeography, and should be encouraged to use these resources to advance diatom systematics, either themselves or in collaboration.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43085/1/10933_2004_Article_319821.pd

A 200,000‐year, high‐resolution record of diatom productivity and community makeup from Lake Baikal shows high correspondence to the marine oxygen‐isotope record of climate change

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/109793/1/lno20004540948.pd

A simple, but useful, application of image analysis

Available image analysis tools are useful aids to some common tasks necessary for diatom identification. In particular, availability of this technology allows easier and more certain enumeration of closely spaced and difficult to resolve striae. Dimensional information may also be easily and accurately measured and recorded.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43075/1/10933_2004_Article_BF00176994.pd

Diatoms of Low Alkalinity Lakes in the Northeastern United States

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43083/1/10933_2004_Article_279496.pd

Evaluating diatom succession: some pecularities of the Great Lakes case

Succession of diatom communities in the Laurentian Great Lakes has several unusual aspects related to physical and chemical characteristics peculiar to these large systems and the constraints these conditions impose upon species which inhabit the Great Lakes. In such systems, paleolimnological reconstructions based on strict analogy to succession patterns in smaller lakes may be incomplete and, in some cases, positively misleading. In the Great Lakes, diatom accumulation rates appear to be regulated by interaction between concentration and supply rates of phosphorus and dissolved silicate. As phosphorus loadings increased historically, storage of diatom frustules in sediments was first increased, then limited, as concentrations of dissolved silica were reduced to levels limiting to diatom growth. Qualitative aspects of the diatom flora are also affected. Indigenous species adapted to growth in winter persist, while those with abundance maxima in summer are extirpated, presumably due to silica limitation in the summer epilimnion. Severe silica limitation also results in shifts to dominance by species whose growth strategies are particularly well adapted to sequestering dissolved silica. Because it is necessary to know the historical context in order to correctly interpret current changes in the Great Lakes diatom flora, paleolimnological studies have proven particularly valuable.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43093/1/10933_2004_Article_BF00210058.pd

Notes on Iowa Diatoms II. Species Distribution in a Subaerial Habitat

A collection made near the base of a small waterfall in Marion County, Iowa, was examined. A total of 22, - 294, specimens of diatoms were studied and found to include 40 species and varieties representing 13 genera. It was found that approximately half of the entities determined are well represented in the local aquatic flora. The remainder comprise entities described by previous authors as being characteristically found in northern, alpine, or aerial environments. In the case of five of the entities no specific determination was made