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USGS Fact Sheet FS-086-03

USGS Fact Sheet FS-086-03. Environmental Biogeochemistry of Trace Metals. What do you see What you have learned. Basic knowledge  practical application Aquatic  terrestrial Hg  As & Pb. Chat. Four chats before presentation Micphone use is encouraged

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USGS Fact Sheet FS-086-03

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  1. USGS Fact Sheet FS-086-03 Environmental Biogeochemistry of Trace Metals • What do you see • What you have learned • Basic knowledge  practical application • Aquatic terrestrial • Hg As & Pb

  2. Chat • Four chats before presentation • Micphone use is encouraged • Students submit 1 question per lecture every Monday • 3 questions/week • Pooled and assigned by Tuesday and discussed on Wednesday • We will discuss term paper during our first chat

  3. Term paper (TP) • TP due • 3/28/10 (M) • Presentation starts (4-22 last day of class) • 4/01/10 (W) • Your presentation is 35-45 minutes long • 25-30 minute presentation • 10-15 minute questions

  4. Grade policy • Homework 60% • 4 Dr. Bonzongo • 2 Dr. Ma • Term paper 30% • Presentation 10%

  5. Soil review • Complexity of soils • Intensity and capacity concepts • Weathering • Florida soils

  6. Complexity of soils • Young, I. M. and J. W. Crawford. 2004. Interactions and self-organization in the soil-microbe complex. Science. 304:1634 • Scottish Informatics Mathematics Biology & Statistics Centre(SIMBIOS) • The most complicated biomaterial • Earth’s most important resource

  7. Fig. 1. A&B: two soil thin sections (30 µm thick & 2 cm long) showing high degree of spatial variability within one undisturbed soil sample. Pore space image A/B-L: transmitted light A/B-R: cross polar light, distinguishing pores (white) from quartz grain (black) Fig. 1C: High-resolution biological thin section (30 µm thick & 600 µm long). Illumination under ultraviolet light reveals the location of fluorescently labeled microbes, (yellow)

  8. Respiration rate Fig. 3. Distribution of O2 in structured soil vs. microbial respiration rate. Each box represents a 2D soil open to atmosphere with respiration rate decreasing from top to bottom. • Red: low O2 • Yellow: atmospheric O2 • Light blue: soil matrix. • Pore-scale spatial complexity and diversity of O2 environments • Spatial proximity of high and low O2 concentration regimes. • At low microbial respiration, regions of low O2prevail

  9. Substrate used up  microbial activity↓ soil structure collapses to closed state  local O2 depletion (L) Substrate arrives in soil  microbial respiration rate ↑more open aggregated state  enhanced O2 supply (R) Red: low O2, Yellow: atmospheric O2, and Light blue: soil matrix. Fig. 4. Self-organization in the soil-microbe complex. Open structure: Optimal configurations for O2 supply in a high activity regime Closed structure: Protection from desiccation and predation in a low activity regime

  10. Complexity of soils • Young, I. M. and J. W. Crawford. 2004. Interactions and self-organization in the soil-microbe complex. Science. 304:1634 • Scottish Informatics Mathematics Biology & Statistics Centre(SIMBIOS) • The most complicated biomaterial • Earth’s most important resource • Biological Diversity (Fig. 1) • Heterogeneity • Diversity in Microenvironments (Fig. 3) • Variability to function: homogenized vs. structured soils • Scale dependency: aggregate • System Dynamics (Fig. 4) • Dynamic properties • Linking physical and biological processes

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