USGS Fact Sheet FS Environmental Biogeochemistry of Trace Metals  Basic knowledge  practical application  Aquatic  terrestrial  Hg  As & Pb  What do you see  What you have learned

 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 Chat

 TP due  3/28/10 (M)  Presentation starts (4-22 last day of class)  4/01/10 (W)  Your presentation is minutes long minute presentation minute questions Term paper (TP)

 Homework60%  4Dr. Bonzongo  2Dr. Ma  Term paper30%  Presentation10% Grade policy

 Complexity of soils  Intensity and capacity concepts  Weathering  Florida soils Soil review

Complexity of soils  Young, I. M. and J. W. Crawford 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

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)

Fig. 3. Distribution of O 2 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 O 2 Yellow: atmospheric O 2 Light blue: soil matrix. Pore-scale spatial complexity and diversity of O 2 environments Spatial proximity of high and low O 2 concentration regimes. At low microbial respiration, regions of low O 2 prevail Respiration rate

Fig. 4. Self-organization in the soil-microbe complex. Open structure: Optimal configurations for O 2 supply in a high activity regime Closed structure: Protection from desiccation and predation in a low activity regime Substrate arrives in soil  microbial respiration rate ↑  more open aggregated state  enhanced O 2 supply (R) Substrate used up  microbial activity ↓  soil structure collapses to closed state  local O 2 depletion (L) Red: low O 2, Yellow: atmospheric O 2, and Light blue: soil matrix.

Complexity of soils  Young, I. M. and J. W. Crawford 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