Studies on Gull Lake, Michigan

The seasonal and depth distribution of phytoplankton in Gull Lake, a moderately large, temperate, dimictic, recreational lake in southern Michigan, U.S.A., is described and discussed. Diatoms (Fragilaria crotonensis, Cyclotella michiganiana, Asterionella formosa, and Synechococcus) grow mainly in summer. Diatoms grew under the winter ice, and objections are lodged to the classic explanation of seasonal growth in temperate lakes, and to a recent hypothesis concerning the `paradox of the plankton'. Two raphe-bearing large diatom species were considered to be truly planktonic. A Synechococcus species was similar to that described previously only from Loch Leven.     

The phytoplankton of spring Lake,Michigan

Summary Spring Lake in Michigan U.S.A. is a highly productive body of water, containing many rare and unknown phytoplanktonic algae. A list of 283 species identified and their general distribution during the eight months of collection is brought.     

Sulfhydrolase Activity in Sediments of Wintergreen Lake, Kalamazoo County, Michigan

The hydrolysis of p-nitrophenyl sulfate, p-nitrocatechol sulfate, and [³⁵S]sodium dodecyl sulfate was examined in anoxic sediments of Wintergreen Lake, Michigan. Significant levels of sulfhydrolase activity were observed in littoral, transition, and profundal sediment samples. Rates of sulfate formation suggest that the sulfhydrolase system would represent a major source of sulfate within these sediments. Sulfate formed by ester sulfate hydrolysis can support dissimilatory sulfate reduction as shown by the incorporation of ³⁵S from labeled sodium dodecyl sulfate into H₂³⁵S. Sulfhydrolase activity varied with sediment depth, was greatest in the littoral zone, and was sensitive to the presence of oxygen. Estimations of ester sulfate concentrations in sediments revealed large quantities of ester sulfate (~30% of total sulfur). Both total sulfur and ester sulfate concentrations varied with the sediment type and were two to three orders of magnitude greater than the inorganic sulfur concentration.     

Long-Term Patterns of Protozoan Colonization in Douglas Lake, Michigan

Long-term patterns of noninteractive and interactive protozoan colonization of polyurethane foam (PF) artificial substrates in Douglas Lake, Michigan, were examined for a 14-yr period. Species-time data were fitted to the Mac Arthur-Wilson equilibrium model, S =?eq(1 - e^Gt), and examined through time from 1969-1982. Comparisons were made to historical water chemistry measurements. No long-term changes in water chemistry were evident. Similarly, equilibrium species number (?eq) and colonization rate (G) oscillated about a mean through time. Protozoan colonization of PF substrates appeared stable for extended periods and showed modest variation from year to year. Examination of 7-yr-old substrates in 1982 revealed little difference from young (< 50 days) substrates. Previous reports of senescence of artificial substrate communities may have been due to habitat loss within the substrates. No evidence existed for chemical or biological degradation of the lake.     

Assisting suicide in Michigan

Perhaps no American state has seen more legal activity on assisting suicide than Michigan, but despite legislation, a study Commission, several legal cases and a state Supreme Court ruling, the state seems much further from a humane resolution of the question than when the activities of Dr. Jack Kevorkian began in June of 1990. This note summarizes major legal events over a twelve-month period (ending May, 95), which included jury acquittal of Dr. Kevorkian, the inconclusive report of the Michigan Commission on Death and Dying, the failure of the state legislature to enact legislation to replace the expired absolute but temporary prohibition, and the decision of the Michigan Supreme Court in Mich v. Kevorkian declaring assisting suicide a common law felony and ruling that in certain circumstances a person assisting suicide can be prosecuted for murder. The Commission's model decriminalization proposal and the bills subsequently introduced in the legislature (all of which to varying degrees surrounded assisting suicide with restrictions and safeguards), as well as the decision of the Supreme Court, are discussed. Certain puzzling features of the latter, especially with regard to the kind of causation that can turn helping another commit suicide into murder, are noted.     

The Re-establishment of Meromixis in Hemlock Lake,Michigan, After Artificial Destratification

The limnological characteristics of meromictic Hemlock Lake, Michigan, are outlined. The changes brought about by artificial destratification, and those accompanying re-establishment of meromixis, are then described. A mechanism for the return of meromixis is suggested, and its events compared with an analogous case in a Tasmanian reservoir.     

Forest distribution and site quality in southern Lower Michigan, USA

Aim The primary objectives of this research were to determine whether current forest patches in southern Lower Michigan are a proportionate sample of forest types present in the pre‐settlement cover and, if not, to establish the degree to which certain types are over‐ or under‐represented in the contemporary landscape. This determination is useful not only because any conservation policy designed to restore the present forest to pre‐settlement biodiversity through preservation of existing stands requires an accurate understanding of the degree to which these stands in sum mirror past forest diversity, but also because it fills a gap in the existing ecological literature. Location The research was conducted within four counties in southern Lower Michigan, USA (Ionia, Livingston, Tuscola and Van Buren). Methods Soil survey data were used to characterize the range of site quality across the study area and the areal extent of each quality category. The geographic locations of all current forest patches in each county were then determined from land use maps and were overlaid on the site quality classification. This procedure yielded the observed distribution of forest relative to site quality. The expected areal extent of forest within each category of site quality on the landscape was determined by assuming a random distribution and multiplying the total area of forestland by the proportion of landscape within each category of site quality. This procedure calculated the expected distribution of forest in terms of site quality by dividing the total forestland among the landscape types, relative to how well represented the landscape types were. The observed and expected distributions were then compared both in terms of absolute difference and normalized difference. Results Overall results indicate that categories of site quality that support a large proportion of the present‐day forest patches are generally composed of agriculturally inferior soil and are over‐represented with forest. Surviving or reforested tracts are concentrated on inferior types of habitat. Main conclusions Results suggest that the present‐day forest patches may not be a proportionate sample of the primeval forest. Rather, they are concentrated on agriculturally‐inferior (coarse‐textured, steeply‐sloped, or poorly‐drained) types of habitat. Unless these stands are for some unknown reason compositionally richer than their pre‐settlement counterparts, these results suggest that the existing forest resource in southern Lower Michigan is an inferior (biased) sample of the primeval cover. Furthermore, because forest types associated with the most heavily‐developed agricultural sites have apparently suffered the most loss of habitat, species more characteristic of these types may have experienced a greater decline in overall importance across the landscape. This study suggests that policy aimed at increasing the potential biodiversity of the area should include provisions that encourage the redevelopment of forest habitat on those sites no longer supporting their equal share of forest.     

Hematozoa of waterfowl from Michigan

Two hundred eighteen and 127 wild waterfowl (Anatidae) of five species were sampled from the Kellogg Biological Station area (Michigan, USA) during the summer (1 June to 24 August 1995) and fall (9 September to 8 October 1995), respectively. Twelve (6%) of those sampled in summer and 13 (11%) sampled in the fall were infected with hemosporids. Haemoproteus nettionis, Haemoproteus greineri, and Leucocytozoon simondi infected both summer and fall birds, with H. nettionis the most common (4% summer; 7% fall). Mean intensities were low; the highest mean intensity was 4.6+/-1.1 gametocytes per 5,000 uninfected erythrocytes for H. nettionis in summer. Of 123 local waterfowl, none were infected with any blood parasite. Thirty-five captive year-round resident waterfowl also were sampled and no blood parasites were found.