Eugene F. Stoermer

The diatoms: applications for the environmental and earth sciences.

Part I. Introduction: 1. Applications and uses of diatoms: prologue Eugene F. Stoermer and John P. Smol Part II. Diatoms as Indicators of Environmental Change in Flowing Waters and Lakes: 2. Assessing environmental conditions in rivers and streams with diatoms R. Jan Stevenson and Yangdong Pan 3. Diatoms as indicators of hydrologic climatic change in saline lakes S. C. Fritz, B. F. Cumming, F. Gasse and K. R. Laird 4. Diatoms as mediators of biogeochemical silica depletion in the Laurentian Great Lakes Claire L. Schelske 5. Diatoms as indicators of surface water acidity Richard W. Battarbee, Donald F. Charles, Sushil S. Dixit and Ingemar Renberg 6. Diatoms as indicators of lake eutrophication Roland I. Hall and John P. Smol 7. Continental diatoms as indicators of long-term environmental change J. Platt Bradbury 8. Diatoms as indicators of water-level change in freshwater lakes Julie A. Wolin and Hamish C. Duthie Part III. Diatoms as Indicators in Extreme Environments: 9. Diatoms as indicators of environmental change near Arctic alpine treeline Andre F. Lotter, Reinhard Pienitz and Roland Schmidt 10. Freshwater diatoms as indicators of environmental change in the high Arctic Marianne S. V. Douglas and John P. Smol 11. Diatoms as indicators of environmental change in Antarctic freshwaters S. A. Spaulding and D. M. McKnight 12. Diatoms of aerial habitats Jeffery R. Johansen Part IV. Diatoms as Indicators in Marine Estuarine Environments: 13. Diatoms as indicators of coastal paleoenvironments relative to sea-level change Luc Denys and Hein de Wolf 14. Diatoms and environmental change in brackish waters Pauli Snoeijs 15. Applied diatom studies in estuaries and shallow coastal environments Michael J. Sullivan 16. Estuarine paleoenvironmental reconstructions using diatoms Sherri Rumer Cooper 17. Diatoms and marine paleoceanography Constance Sancetta Part V. Other Applications: 18. Diatoms and archaeology Steve Juggins and Nigel Cameron 19. Diatoms in oil gas exploration William N. Krebs 20. Forensic science diatoms A. J. Peabody 21. Toxic harmful marine diatoms Greta A. Fryxell and Maria Celia Villac 22. Diatoms as markers of atmospheric transport Margaret A. Harper 23. Diatomite David M. Harwood Part VI. Conclusions: Epilogue Eugene F. Stoermer and John P. Smol Glossary Index.

Oxygen Isotope Fractionation Between Diatomaceous Silica and Water

Abstract The temperature dependence of the oxygen isotope fractionation between diatomaceous silica and water was determined by analyzing frustules of freshwater diatoms cultured in the laboratory at temperatures ranging from 3.6 to 20.0°C. Within the limits of experimental reproducibility, measured oxygen isotope fractionations were independent of species and of the isotopic composition of the water. The fractionation varied regularly with temperature according to the equation 1000lnα (silica-water) = 15.56 (10 3 T −1 ) − 20.92. This relation corresponds to a temperature coefficient of roughly 0.2‰ per °C, significantly lower than published coefficients estimated from analyses of fossil diatoms from sediments and from extrapolation of experimentally determined quartz-water fractionations to low temperatures. The magnitude of the fractionation at a given temperature was 3–8‰ lower than previously published fractionations that were determined from analyses of fossil diatoms and from experimental data for quartz. The discrepancies between the new results and those of previous studies are attributed mainly to intrinsic differences in the oxygen isotope characteristics of fresh and fossil diatoms. Fresh diatomaceous silica appears to have an isotopically anomalous surficial layer containing large amounts of readily exchangeable, relatively low- 18 O oxygen, including abundant oxygen in hydroxyl groups, with the result that partial dissolution or diagenesis may systematically shift the δ 18 O values of fossil diatom frustules to higher values by removing this relatively unstable surficial material. If the effects of partial dissolution and diagenesis are regular or predictable, then the temperature information recorded during diatom growth may prove useful for paleoclimate studies.

QUANTITATIVE DIFFERENCES BETWEEN BENTHIC ALGAL COMMUNITIES ALONG A DEPTH GRADIENT IN LAKE MICHIGAN1,2

This study analyzes the impact of conditions associated with depth upon benthic algal communities in Lake Michigan. Diatom abundance was greater at 9.1 and 14.6 m depths than 6.5, 22.6 and 27.4 m. Shallow (6.5 m), mid‐depth (9.1 and 14.6 m) and deep (22.6 and 27.4 m) zones were distinguishable on the basis of community composition, structure and abundance. Dominance of benthic species, high diversity and low abundance in shallow communities probably resulted from substantial substrate disturbance by wave action in this productive zone. Dominance of benthic species, high diversity and high abundance characterized mid‐depth communities where less wave disturbance enabled algal accumulation. Preponderance of living planktonic taxa, low diversity and low abundance delineated deep communities where planktonic algae accumulated and low light levels reduced growth of benthic species.

ECOLOGICAL, EVOLUTIONARY, AND SYSTEMATIC SIGNIFICANCE OF DIATOM LIFE HISTORIES1

In spite of high species diversity and many years of study, most diatom life history strategies remain unknown. Floristics, taxonomy, and applied studies continue to dominate scientific efforts on diatoms; however, as Stebbins implied, it is difficult to pursue these ventures without an understanding of diatom reproductive biology. Recent research has added significantly to classic literature and has further expanded understanding of both the diversity of sexual behavior and the importance of life history strategies to ecology, evolution, taxonomy, and systematics of diatoms. Since the turn of the century, when reduction division was first convincingly demonstrated during gametogenesis in Rhopalodia (Klebahn 1896) and Surirella (Karsten 1912), it has been accepted that most diatoms have a diplontic life history (van den Hoek et al. 1995). Before and since that time, a great deal of work has been directed toward description and classification of diatom life histories (reviewed by Klebahn 1896, Geitler 1932, 1973, 1984, Fritsch 1935, Drebes 1977, Round et al. 1990, Hori 1993, Mann 1993, Roschin 1994), whereas far less effort has been directed at the ecologic and systematic implications of diatom life histories. The purpose of this review is not to reiterate or classify all the reported types of sexual reproduction in diatoms, but to provide current perspectives relating diatom life history strategies to systematic, ecologic, and evolutionary issues.

Early Eutrophication in the Lower Great Lakes

New Evidence from Biogenic Silica in Sediments New evidence from studies of biogenic silica and diatoms in sediment cores indicates that eutrophication in the lower Great Lakes resulted from nutrient enrichment associated with early settlement and forest clearance. Diatom production peaked from 1820 to 1850 in Lake Ontario, at about 1880 in Lake Erie, but not until 1970 in Lake Michigan. This is the first reported sediment record of the silica-depletion sequence for the Great Lakes.

A morphometric method for correcting phytoplankton cell volume estimates

SummaryCell volume calculations are often used to estimate biomass of natural phytoplankton assemblages. Such estimates may be questioned due to morphological differences in the organisms present. Morphometric analysis of 8 species representative of phytoplankton types found in the Great Lakes shows significant differences in cell constituent volumes. Volume of physiologically inert wall material ranges from nil, in some flagellates, to over 20% of the total cell volume in certain diatoms. Likewise, “empty” vacuole may comprise more than 40% of the total cell volume of some diatoms, but less than 3% of the volume of some flagellates. In the organisms investigated, the total carbon containing cytoplasm ranged from 52% to 98% of the total cell volume and the metabolizing biovolume ranged from 30% to 82%. Although these differences complicate direct biomass estimation, morphometric analysis at the ultrastructural level may provide ecologically valuable insights.

SPATIAL AND TEMPORAL DISTRIBUTION OF BENTHIC DIATOMS IN NORTHERN LAKE MICHIGAN

Benthic diatom communities were sampled from natural substrates along a depth tran- sect in northern Lake Michigan to examine spatial and seasonal distribution patterns and define assemblages of associated taxa. Information-theory diversity, evenness, and richness were signifi- cantly higher in deep assemblages than in shallow assemblages, with the boundary falling between 5 and 10 m in winter and fall, 10 and 20 m in spring, and 20 and 31 m in summer. Planktonic taxa are abundant on benthic substrates in the deep zone, primarily as dead fallout. In shallow water, large numbers of living planktonic taxa overwinter beneath the ice on benthic substrates. Cluster analysis of samples was used to identify and define diatom assemblages from deep, mid- depth, and shallow water. The deep-water assemblage contains motile and nonmotile benthic species that have been reported from alpine and boreal oligotrophic lakes. The mid-depth assemblage is rich in epipsammic taxa. The shallow-water assemblages contain cosmopolitan taxa that are collected often in nearshore plankton samples. These shallow assemblages do not persist throughout the year as do the deep and mid-depth assemblages. Cluster analysis of taxa provides further definition of species associations and the degree of cor- relation among species. Correlations among benthic taxa are strengthened when planktonic taxa are removed from the analysis, indicating that plankton fallout represents an addition of information which is poorly related to distribution of the benthic species. The most stable and diverse community is found at the deepest sampling depths where environ- mental conditions are most stable, the mid-depth community exists in fluctuating but predictable conditions, and the shallow assemblages occur in the zone of maximum physical fluctuation or natural stress. Substrate types are correlated with the species assemblages, but the high diversity of substrate types in shallow water does not support the most diverse assemblage. The discrete species assem- blages seen in an oligotrophic area of this large dimictic lake apparently respond sensitively to tem- porally and spatially dynamic environmental parameters.

QUANTITATIVE METHOD FOR DETERMINING A REPRESENTATIVE ALGAL SAMPLE COUNT1

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.

Biogenic silica and phosphorus accumulation in sediments as indices of eutrophication in the Laurentian Great Lakes

Biogenic silica (BSi), total phosphorus (TP), and biologically available phosphorus (AVP) were measured in short cores from Lake Michigan, Lake Erie, and Lake Ontario. Peaks in BSi concentration and peaks in BSi:TP or BSi:AVP ratios provided stratigraphic signals of water column silica (Si) depletion as a response of increased diatom production to P enrichment and decreased diatom production resulting from silica depletion. By contrast the stratigraphic record of P accumulation provided very weak signals of the historical nutrient enrichment in the water column. These results indicate that system P recycling has a higher rate constant than Si recycling and, as a consequence, that relatively small levels of P enrichment can increase diatom production and sedimentation eventually causing Si depletion and Si-limited diatom production in the water mass.

A MORPHOMETRIC STUDY OF LEAD AND COPPER EFFECTS ON DIATOMA TENUE VAR. ELONGATUM (BACILLARIOPHYTA) 1

Polyphosphate bodies containing lead were induced in laboratory cultures of Diatoma tenue var. elongatum Lyngb. by the addition of phosphorus and 0.05 μg‐atoms/l Pb to P deficient medium. Morphometric analysis of cells exposed to Pb showed a significant decrease in number of mitochondria with a concomitant increase in their volume and an increase in membranous organelles in the vacuole compared to phosphorus starved and phosphorus sufficient controls. Exposure of cultures to 0.08 μg‐atoms/l copper resulted in reduction of the number of polyphosphate bodies formed during luxury uptake but no other significant morphological changes in cellular organelles. Ecological implications of the interactions between nutrients and low level trace metal contamination are discussed.