Browsing by Subject "Fossil pigments in lake sediments as indicators of productivity, evolution, eutrophication and sources of organic matter"
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Item Chlorophyll derivatives in surface muds from the English lakes(American Society of Limnology and Oceanography, 1960) Gorham, E.Chlorophyll derivatives, total carbon, and total sulfur have been estimated in surface muds from the depths of five widely differing bodies of water. All three components increase in passing from muds of large infertile lake, with waters low in phytoplankton and poor in lime and potash, to muds of smaller and more fertile lakes, with big phytoplankton crops and more plentiful supplies of lime and potash in their waters. Certain differences in the absorption spectra of acetone extracts may be related to the balance between organic materials originating inside and outside the lakes, and to the length of time they spend in an oxidizing environment.Item A comparison of the abundance and diversity of fossil pigments in wetland and woodland humus layers.(1973) Sanger, J.E.; Gorham, E.Item 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.Item 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.Item Fossilized pigments as stratigraphic indicators of cultural eutrophication in Shagawa Lake, northeastern Minnesota(1976) Gorham, E.; Sanger, J.E.Item 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.