Chapter 13 Carbon Dodds & Whiles ©2010 Elsevier, Inc.

FIGURE 13.1 Lake Nyos, Cameroon, Africa. This is the site of a catastrophic CO2 release that killed 1,700 people in 1986. (Image courtesy of George Kling). ©2010 Elsevier, Inc.

FIGURE 13.2 The relative concentrations of inorganic compounds involved in the bicarbonate equilibrium as a function of pH. ©2010 Elsevier, Inc.

FIGURE 13.3 Water jet in Lake Nyos upon installation of a CO2-releasing pipe into the hypolimnion. (Photograph courtesy of Michel Halbwachs). ©2010 Elsevier, Inc.

FIGURE 13.4 A general diagram of aerobic breakdown of organic carbon by organisms. (Modified from Rheinheimer, 1991). ©2010 Elsevier, Inc.

FIGURE 13.5 Breakdown of leaves in streams. (A) Breakdown of alder follows a typical exponential decay pattern, (B) decomposition of beech leaves increases following a flood (at around 80 days), (C) decomposition rates (k) of various species as a function of lignin content, and (D) rates as a function of nitrate concentration in the stream. (Data for B, and D from Gessner and Chauvet, 1994; data from C from Suberkropp and Chauvet, 1995). ©2010 Elsevier, Inc.

FIGURE 13.6 A general diagram of breakdown of organic material across a redox gradient. Organisms are shown in solid boxes, and chemical pools are shown in dashed boxes. Curved arrows with solid lines indicate alternative electron acceptors for oxidation of organic carbon, and the preferred redox of each of these transformations approximately corresponds with the redox curve drawn on the right. (Redrawn from Westermann, 1993). ©2010 Elsevier, Inc.

FIGURE 13.7 Diagram of a hypothetical nutrient cycle. This will be the general format used to represent nutrient cycles. Oxic processes are above the center line and anoxic processes are below. Those that move on the center line are required, independent of O2 concentration. Inorganic forms are listed from left to right, from reduced to oxidized. Thus, transformations are generally occurring with potential energy if they move from left to right in the top half of the diagram or from right to left in the bottom half of the diagram. ©2010 Elsevier, Inc.

FIGURE 13.8 A diagram of the generalized carbon cycle. ©2010 Elsevier, Inc.