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Browsing by Author "Sanger, J.E."

Now showing 1 - 11 of 11
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    The chemical composition of lakes in the north central United States
    (American Society of Limnology and Oceanography, 1983) Gorham, E.; Dean, W.E.; Sanger, J.E.
    Lake waters of the north-central U.S.A. arc classified into five groups, based on increasing specific conductivity and changes in ionic composition from east to west, from Wisconsin through Minnesota to North and South Dakota, The most dilute group of waters has specific conductivities <29 µmhos -cm-’ at 25°C; the most concentrated group has specific conductances that range from 7,000 to 73,000 µmhos. As conductivity increases all major ions increase, but there is a shift in cation dominance from Ca2+ to Mg2’ to Na’, and in anion dominance from HC03- to SOd2-. This shift partly reflects a westward increase in climatic aridity, and partly a westward sequence of glacial drifts from noncalcareous to calcareous and hence to calcareous with abundant sulfur-bearing minerals. Levels of pH, K, Cl, F, B, and SiO, also show a distinct westward increase. Concentrations of NO,- and Mn increase from east to west, but the trend is less distinct. Concentrations of Fe vary widely without any trend over the range of conductivity. Color, mostly from dissolved organic matter, is controlled chiefly by lake depth, except for lakes with extensive peatlands in their drainage basins.
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    The chemical composition of lakes in the north-central United States
    (1982) Gorham, E.; Dean, W.E.; Sanger, J.E.
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    The diversity of pigments in lake sediments and its ecological significance
    (American Society of Limnology and Oceanography, 1970) Sanger, J.E.; Gorham, E.
    Thin-layer chromatography shows a large number of pigments (chlorophyll derivatives and carotenoids) in profundal lake sediments, diversity being somewhat greater in eutrophic than in oligotrophic lakes. Sedimentary pigments are much more numerous (24-47) than those of upland vegetation (7-8), aquatic macrophytes (12-E), and planktonic algae (10-21). Algal decomposition, which is accompanied by a marked increase in number of pigments, seems the most likely cause for the extreme diversity of sedimentary pigments.
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    Fossil pigments in the surface sediments of a meromictic lake
    (American Society of Limnology and Oceanography, 1972) Gorham, E.; Sanger, J.E.
    Pigment concentration and diversity were measured in surface sediments on a transect across a small, meromictic lake in northwest Wisconsin. Pigment concentrations increase several fold and diversity by a third from the shallowest to the deepest sediments. Monimolimnetic chlorophyll derivatives are about 3X and carotenoids nearly 2X the hypolimnetic maxima in holomictic, eutrophic Minnesota lakes. Lower pigment concentrations at the deepest point along the transect suggest slumping of littoral detritus.
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    Plant pigments in woodland soils
    (1967) Gorham, E.; Sanger, J.E.
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    Some relationships between algal standing crop, water chemistry, and sediment chemistry in the English lakes
    (American Society of Limnology and Oceanography, 1974) Gorham, E.; Lund, J.W.G.; Sanger, J.E.; Dean, W.E.
    Estimates of standing crop, derived approximately from algal counts in surface waters, have been used to separate the English Lakes into three groups of low, intermediate, and high fertility. The fertile lakes are proportionally poorer than the infertile lakes in p-algae, but richer in “large algae” and Cyanophyta. The fertile lakes are richer in dissolved ions, especially calcium and bicarbonate, in filter-passing and particulate vitamin Bx, in sedimentary sulfur, and in sedimentary chlorophyll derivatives and carotenoids. The relationship noted by Pearsall between lake fertility and agricultural activity is shown by a strong correlation between algal standing crop and the percentage of the drainage basin under cultivation. Sediment ratios of carbon to sulfur and of chlorophyll derivatives to carotenoids decline with increasing lake fertility, whereas the ratio of carbon to nitrogen shows little change. This study lends support to the use of sedimentary pigments as indicts to lake productivity. The pigment data also indicate that much of the organic matter in sediments of productive lakes comes from autochthonous sources within the lakes.
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    Stratigraphy of fossil pigments as a guide to the postglacial history of Kirchner Marsh, Minnesota
    (American Society of Limnology and Oceanography, 1972) Sanger, J.E.; Gorham, E.
    Successional developments in the postglacial ecology and limnology of Kirchner Marsh revealed by concentration and diversity of sedimentary plant pigments include a peak of aquatic production (indicated by maximum pigment concentrations in sedimentary organic matter) reached during the early postglacial warm, humid interval at about 10,000 B.P. Production levels then declined. Very low levels of aquatic production (indicated by low pigment concentrations) seem indicated by about 6,000 B.P., in the middle part of a warm, dry interval following which pigment concentrations remained low (except for a brief interval about 5,000 B-P.), but with a marked rise in the ratio of chlorophyll derivatives to carotenoids, indicating an increase in allochthonous organic input accompanying the return of cooler moister conditions. These resulted in an encroachment of oak forest on the prairie, followed by the succession to reed-swamp on the lake. A return to more truly aquatic conditions was reflected by an increase in sedimentary pigments from about 3,000 B.P. to a peak at 1,700 B.P., accompanied by a decline in the ratio of chlorophyll derivatives to carotenoids. Subsequently pigment concentrations fell, and their ratio increased sharply, as emergent aquatics became well established and caused a rapid evolution of pond to grass-sedge meadow. The pigment data are generally in harmony with the ecological conclusions from pollen and macrofossils, but they provide much more information on changes in aquatic productivity at the site. Ratios of chlorophyll derivatives to carotenoids, along with measurements of pigment diversity, reveal changes in the balance between autochthonous and allochthonous organic contributions to the sediment and provide substantial evidence for the presence or absence of open-water conditions.