Central Minnesota Research Articles

Discriminating texturally similar tills in central Minnesota by graphical and multivariate techniques

The sequence of glaciation in the midwestern United States has been defined mainly by till stratigraphy. Correlation of tills over long distances, however, is complicated by spatial variation of sediment characteristics. In east-central Minnesota three till units were previously defined. Two were considered to be lithologically identical and were correlated with the late Wisconsin advance of the Rainy lobe, whereas a third till was assigned to the contemporaneous advance of the Superior lobe. This interpretation was inconsistent with subsequent glaciological reconstructions of the Rainy and Superior lobes. In an effort to define the parent lobe of the deposits in central Minnesota, the tills were sampled, analyzed, and compared by graphical and multivariate techniques. Graphical comparisons of sedimentological parameters were inadequate to distinguish important differences among the groups. However, principal component analysis of the analytical data indicates that the original interpretation is untenable and that one of the tills formerly assigned to the Rainlylobe should now be attributed to the Superior lobe. Problems encountered with correlation of tills exposed at the surface illustrate the complexity and problems associated with subsurface stratigraphic correlation.

The role of plant genotype, environment and gender in resistance to a specialist chrysomelid herbivore.

Patchiness in herbivore attack is a well-documented phenomenon. When neighboring plants suffer vastly different levels of attack, then one suspects genotypic differences among plants to be the underlying mechanism. In this study, I use common garden experiments in two natural, but divergent, habitats at the Cedar Creek Natural History Area in central Minnesota to determine the role of plant genotype, environment and gender in plant resistance to a specialist herbivore. Resistance was measured by larval survivorship and weight. Eight clones ofRhus glabra were selected and 12 equal-aged ramets were dug up and planted in two gardens (each garden received 6 ramets per clone). First instarBlepharida rhois (Coleoptera: Chrysomelidae) larvae of known parentage were transferred to ramets and censused every other day. At the end of the experiment, larvae were collected and weighed. Analysis of variance was used to determine the importance of plant genotype, environment and gender on larval mortality and weight. The experiment was repeated in its entirety one month later. Both plant genotype and environment significantly affected larval survivorship in the first run of the experiment. No interactions were significant. Results from the second run indicated marginally significant genotype and environment main effects, and a genotype by environment interaction in larval survivorship. There was a significant genotype by environment interaction in larval weight on the same run. In neither run did clone gender have significant affects on resistance.

Classification of Forest Vegetation in North-Central Minnesota Using Landsat Multispectral Scanner and Thematic Mapper Data

Abstract Computer classifications of Landsat-5 Thematic Mapper (TM) and Multispectral Scanner (MSS) data were evaluated to determine how forest and sensor characteristics affect the classification accuracy of Minnesota forest cover types. The test area was Itasca State Park in north central Minnesota. The experiments involved comparisons of sensors differing in spectral and spatial resolution. To evaluate classification performance the Landsat classification maps were compared on a pixel by pixel basis with a digitized reference map of the Park. Classification results were compared for statistically significant differences using discrete multivariate statistics. Classification accuracies ranged from 26 to 86%, depending upon the sensor, number of classes, and performance measure used. The most significant result was that the increased spectral/radiometric resolution of the TM data resulted in 7-15% absolute increase in forest cover classification accuracy over MSS data using conventional methods. The best spectral band combination was one band each from the visible, near infrared, and middle infrared. For. Sci. 36(2):330-342.

An outbreak of psittacosis in Minnesota turkey industry workers: implications for modes of transmission and control.

From June through November 1986, an outbreak of psittacosis occurred in turkey industry workers in central Minnesota. A total of 186 suspect cases were identified, and 122 cases (66%) were serologically confirmed. Cases occurred in three turkey processing plants, two rendering plants, one farm, and one "further processing" plant (where meat is removed from previously eviscerated carcasses and consumer products, such as roasts, are made). As in previous outbreaks, workers exposed to the viscera of infected birds were at greatest risk of becoming infected. However, our data showed that 31 (25%) of the confirmed cases occurred in workers at the further processing plant who had contact only with previously eviscerated carcasses. Although the specific source of infection and the mode of transmission in these workers are unclear, the use of gloves and masks by all processing workers during an outbreak might help to limit exposure. Control measures, which focused on identifying and treating ill turkey flocks, were initiated in early September; however, cases continued to occur in turkey industry workers through November. One of the flocks suspected of causing illness appeared healthy and, therefore, was not treated. Chlamydia psittaci infection in this flock was confirmed by culture after the flock had been processed. A rapid test for diagnosing C. psittaci infection in turkey flocks at the time of processing might be useful in preventing exposure of large numbers of workers.

Lyme disease and migrating birds in the Saint Croix River Valley

During a study of migrating land birds in 1987, we examined over 9,200 individual birds representing 99 species from the Saint Croix River Valley, a Lyme disease-endemic area of east central Minnesota and northwestern Wisconsin. We found that 250 deer tick (Ixodes dammini) larvae and nymphs infested 58 birds from 15 migrant species; 56 ticks (22.4%) were positive for the Lyme disease spirochete Borrelia burgdorferi. Five ground-foraging migrant bird species favoring mesic habitats, veery (Catharus fuscescens), ovenbird (Seiurus aurocapillus), northern waterthrush (S. novaboracensis), common yellowthroat (Geothlypis trichas), and swamp sparrow (Melospiza georgiana), accounted for nearly three-quarters of parasitized individuals. Nearly half of the spirochete-positive ticks were removed from migrating birds taken in a riparian floodplain forest. Recaptured migrants with infected ticks indicate that they transmit B. burgdorferi to hexapod larvae. We suggest that birds may be both an important local reservoir in the upper Mississippi Valley and long-distance dispersal agents for B. burgdorferi-infected ticks to other regions of the continent.

On the formation of the tunnel valleys of the Superior lobe, central Minnesota

When considering the formation of tunnel valleys, most researchers have appealed to basal melting as the primary source of water. Erosion of the tunnel valleys can then be accomplished by steady-state drainage over a long period or by storage and subsequent catastrophic release. However, field relationships in a large system of tunnel valleys formed by the Superior lobe in central Minnesota indicate that another source of water must be considered. The Minnesota tunnel valleys are composed of individual segments 10–20 km long, and the segments commonly terminate in subaerial outwash fans at recessional ice margin positions. Eskers, associated with the tunnel valleys, are also composed of short segments, frequently beginning at moulin kames and terminating at the head of outwash fans. The dominant source of the water responsible for tunnel-valley formation was seasonal meltwater from the glacier surface that reached the bed through moulins and crevasses. The apparent continuity of the valleys resulted from the headward development of the englacial drainage system during ice retreat.

Lithology, sedimentology, and genesis of the Wadena drumlin field, Minnesota, U.S.A.

Studies on both the regional and small scales of the lithology, sedimentology and stratigraphy of the Wadena drumlin field in central Minnesota, U.S.A., provide insights to the processes that operated within the Wadena lobe during the drumlin-forming phase. Horizontal changes in the down-glacier direction in the nature of the drumlin till include an increase in the carbonate content, decrease in grain size and magnetite content, and variations in fine-fraction mineralogy. These changes also occur with depth at individual sites. It is inferred that these patterns reflect progressive incorporation and mixing of the substrate, which for much of the drumlin field is a till of northwestern origin, with the till already in transit within the base of the Wadena lobe derived from the northeast. Factors contributing to enhanced erosion within the Wadena drumlin field include increased vertical strain rates over a major subglacial highland, the presence of deformable bed material, and a lowered ice profile which permitted elevated rates of bed deformation. The patterns of mixing are generally consistent with substrate incorporation either by regelation or in the context of a deforming bed, although neither of these processes adequately explain all of the observed features of the drumlin till. Where localized departures from the generalized pattern exist, it can be shown that these are the result of either syn- or post-depositional processes, primarily winnowing, or the influence of a different substrate. Additional data are presented, including macrofabric measurements and detailed site descriptions, that are consistent with an accretionary, progressive build-up of the drumlin forms.

Application of laboratory‐derived criteria to an outdoor stream ecosystem

Field assessments of laboratory‐derived water quality criteria were conducted in 520 meter long outdoor experimental streams located in Central Minnesota, USA. This report presents an overview of the published studies, the objective was to evaluate the level of protection offered to aquatic stream populations by laboratory‐derived criteria. Eight pollutants were tested from 1976 to 1984; duration of pollutant additions lasted from 12 to 75 weeks. Primary emphasis was in measuring community structural changes. Examples of population effects observed were in survival, growth, reproduction, diversity, emergence and behavioral differences. Stream impacts appeared to differ with each pollutant tested. Effects observed on the stream populations were at or above the recommended criteria concentrations. For two pollutants (pentachlorophenol and ammonia nitrogen), no margin of safety was evident. Laboratory‐derived criteria and results from single species tests were good predictors of population impacts in the exp...

Responses of zooplankton andChaoborus to temephos in a natural pond and in the laboratory

Application of the organophosphorus insecticide temephos to a natural pond in central Minnesota was followed by reduction within 24 hr in all cladocerans, inDiaptomus leptopus and inChaoborus americanus, and increases in cyclopoid copepods, copepod nauplii and the rotiferKeratella cochlearis. Daphnia pulex that reappeared 35 days post-application were ex-ephippial. After application, reproduction of cladocerans andDiaptomus was markedly reduced compared to the previous year, an effect attributed to temephos.Daphnia population density was strongly reduced into the fall season, long after the spring applications, compared with both a reference pond's and the previous season's populations. On-site bioassays demonstrated 24-hr mortalities ofDaphnia andChaoborus that were comparable to the population decreases in the pond. Laboratory toxicity tests showedDaphnia was the most sensitive followed byChaoborus andDiaptomus. Comparable results were seen in the pond population changes,in situ bioassays and laboratory toxicity data forDaphnia and forChaoborus, but sensitivities in the pond were somewhat greater than in the laboratory. Risk assessment research calls for long-term field reproduction analysis to avoid a false “recovery” report, combined with laboratory life cycle analysis and short acute exposure tests.

Holocene environmental changes in Lily Lake, minnesota inferred from fossil diatom and pollen assemblages

A postglacial core was taken from Lily Lake, a soft-water lake, located on carbonate-poor till in eastern Minnesota. Pollen analysis allowed the reconstruction of watershed vegetation change. Diatom assemblages from the core were compared with 255 surface sediment assemblages from Minnesota, Maine, Labrador, and the Canadian arctic. Late-glacial assemblages were similar to Canadian arctic lakes. During the mid-postglacial period of warmer and drier climate, fossil diatom assemblages at Lily Lake were similar to those in the surface sediment of modern eutrophic hardwater lakes in Central Minnesota. The shift to hardwater diatom assemblages coincided with a shift to prairie species in fossil pollen assemblages at about 8000 yr B.P. At about 3400 year B.P. the fossil diatom assemblage that characterized presettlement times was established.

Estimating the Sum of Alternating Series

Click to increase image sizeClick to decrease image size Additional informationNotes on contributorsJames D. HarperJames D. Harper received his B.A. in mathematics from Humboldt State University in 1978 and his M.A. (1980) and his Ph.D. (1984) from the University of Oregon. From 1984 to 1987, Dr. Harper was an Assistant Professor at St. Cloud State University in Central Minnesota. He is now an Assistant Professor at Eastern Washington University in Cheney, Washington, where he teaches graduate as well as undergraduate mathematics. Besides mathematics, his activities include long distance running, biking, hiking, and reading science fiction.This article is dedicated to the faculty of St. Cloud State University, especially to Bob and Gail Earles, Jim Kepner, Ralph Carr, and Sandy Keith.

Estimating the Sum of Alternating Series

Click to increase image sizeClick to decrease image size Additional informationNotes on contributorsJames D. HarperJames D. Harper received his B.A. in mathematics from Humboldt State University in 1978 and his M.A. (1980) and his Ph.D. (1984) from the University of Oregon. From 1984 to 1987, Dr. Harper was an Assistant Professor at St. Cloud State University in Central Minnesota. He is now an Assistant Professor at Eastern Washington University in Cheney, Washington, where he teaches graduate as well as undergraduate mathematics. Besides mathematics, his activities include long distance running, biking, hiking, and reading science fiction.This article is dedicated to the faculty of St. Cloud State University, especially to Bob and Gail Earles, Jim Kepner, Ralph Carr, and Sandy Keith.

Aging women in Minnesota: Rural—non-rural differences in life-history text

Much of the literature on rurality attempts to identify a point on a ‘size-of-place’ continuum at which the social organization of a given place begins to take on attributes defined as ‘rural’. The size of place which exhibits characteristically rural features has declined in our increasingly urbanized society. In looking at rural-urban differences of the elderly and the aging experience then, we ought to focus on even smaller places to detect the differences that a rural-non-rural gradient makes. The present study focuses on the more rural end of the rural-urban continuum and makes comparisons within a single region. The present discussion is based on life histories collected from a sample of thirty older rural women in a four-county area in central Minnesota during the summer and fall of 1986. Several themes are attributed to rural residents more than those living in non-rural settings. If these themes are important, life-orienting themes, they can be expected to structure individual accounts of life histories. The thirty subjects were grouped according to two classifications of rurality. A self-identification classification system is used throughout the discussion which groups the women into ‘rural’, ‘mixed’ and ‘non-rural’ groups. The life history texts were analyzed using the Minnesota Contextual Content Analysis program (MCCA), which scored meanings in the life history texts in two ways. Differences between scores of the three groups are discussed, along with the orienting themes contained in these life histories. Our conclusion is that the rural-non-rural segment of the rural-urban continuum is somewhat more complex than a single gradient.

A climatic-limnologic model of diatom succession for paleolimnological interpretation of varved sediments at Elk Lake, Minnesota

Sediment traps placed in the profundal region of Elk Lake, north central Minnesota during the 1979 spring and 1983–84 fall and spring seasons monitored seasonal diatom production for two climatically distinctive periods. The spring of 1979 was one of the coldest and wettest on record. Ice out at Elk Lake was 10 days later than average, and spring circulation was short. Fragilaria crotonensis dominated the late spring and early summer diatom production in association with Synedra and Cyclotella species, perhaps because rates of phosphorus supply were low compared to silica. The winter of 1983–84 was drier than usual, and the early but cold spring of 1984 caused ice out at Elk Lake to be about 1 week earlier than normal. Spring storms promoted a long and full circulation that allowed Stephanodiscus minulutus to bloom, presumably in response to increased phosphorus loading related to deep and vigorous circulation. The two dominant diatoms in Elk Lake, F. crotonensis and S. minutulus may reflect climatic patterns that control lake circulation. The climatically regulated occurrence of these diatoms is generally, but not specifically, comparable to their distribution in lake surface sediments throughout Minnesota. A combination of regional and lake-specific studies on the controls of diatom succession and distribution provides climatic insights for interpreting paleolimnogical records of diatoms.

Correlation of North American Ordovician bentonites by using apatite chemistry

Middle Ordovician bentonites in the central and southeastern United States have been correlated on the basis of rare-earth element (REE) concentrations of primary apatite phenocrysts. Ratios of light to heavy REE, such as La/Tb or Ce/Yb, produce the best separation of the four studied bentonites. The Deicke bentonite has been correlated over a distance of more than 1000 km, from southern Minnesota to central Tennessee, and the Millbrig bentonite has been correlated over 750 km, from central Minnesota to central Missouri. The successful discrimination of closely spaced bentonites over a long distance demonstrates that apatite chemistry is a powerful correlation tool on a continental scale.

Freezing Induced Field Soil Water Changes During Five Winters in West Central Minnesota

ABSTRACT SOIL freezing induced movement of soil water in the top 1.5 m of a Barnes loam soil (fme-loamy, mixed, Udic Haploboroll) was studied over the winters of 1982 to 83 through 1986 to 87 under fall plow, fall chisel, and no till systems each with and without residue. Measurements consisted of frost depth, snow depth, soil water content, air temperature, snowfall, and precipitation. Changes in soil water were determined relative to soil water content just before freezing. Changes in water content were related to depth of soil freezing and initial fall soil water content. Frost penetration was inversely related to snow depth. However, early season snowfall has a greater effect than later snowfall. Fall plowing traps the least snow and has the deepest frost. No till-residue plots trap the most snow and have the least frost. Uniform frost penetration was measured over all treatments in a year with virtually no snowfall. Initially dry soil grained water. Initially wet soil lost water. Greatest accumulation of water was measured 14 days before complete thawing, which is after maximum frost penetration when surface melting had started. In both wet and dry years water accumulated in frozen soil zones. Accumulation roughly coincided with arrival of the freezin front. Accumulation below the frozen zone occurred at the beginning of spring thaw or during mid-or late winter periods of snowmelt. Apparently water from snowmelt or surface soil thaw passed through frozen soil to unfrozen soil beneath.

Tolerance of Soybean (Glycine max) and Sunflower (Helianthus annuus) to Fall-Applied Dicamba

The influence of fall (late September or late October)-applied dicamba (3,6-dichloro-2-methoxybenzoic acid) on spring-planted soybean [Glycine max(L.) Merr.] and sunflower (Helianthus annuusL.) was studied at five sites in Minnesota during 1983 and 1984. At the two southern Minnesota locations, only late-October applications of dicamba at the highest rate (4.5 kg ae/ha) reduced yields of spring-planted soybean and sunflower. At the central and the two northern Minnesota locations, both late-September and late-October applications of dicamba at 1.1 kg/ha and higher caused injury and yield reductions to soybean and sunflower planted the following year. The two southern Minnesota locations had generally higher levels of precipitation, higher temperatures, higher organic matter soils, and lower pH levels compared to the central and northern Minnesota locations. These climatic and soil characteristics reduced dicamba persistence at the two southern Minnesota locations.

Xenillus itascensis, sp. n. (Acari: Oribatei), an intermediate host ofMonoecocestusspp. (Eucestoda: Anoplocephalidae)

Abstract Xenillus itascensis, sp. n. is an intermediate host of Monoecocestus spp. (Eucestoda: Anoplocephalidae). This robust species was collected in Itasca State Park in north central Minnesota from leaf litter.

Pocket gophers (Geomys bursarius), vegetation, and soil nitrogen along a successional sere in east central Minnesota.

Pocket gophers (Geomys bursarius: Geomyidae Rodentia) are shown to affect soil resources and thus, indirectly, vegetation. Gophers reduce average soil nitrogen near the surface and increase point-to-point heterogeneity of soil nitrogen by moving nitrogen-poor subsurface soil to the soil surface. Data from 22 old fields at Cedar Creek Natural History Area, Minnesota, USA show correlations of soil nitrogen, vegetation, and gopher mounds that are consistent with this indirect mechanism by which gophers affect local species composition and old field succession.

Mica-bearing olivine pyroxenite of possible lamproite-kimberlite affinity in central Minnesota

Mica-bearing olivine pyroxenite of possible lamproite-kimberlite affinity in central Minnesota