1. ©2010 Elsevier, Inc. Chapter 19 Behavior and Interactions among Microorganisms Dodds & Whiles

2. ©2010 Elsevier, Inc. FIGURE 19.1 A composite scanning electron micrograph of a cross section of a periphyton community. The area is approximately 1mm 2. Diatom species present include Melosira varians (long cylinders), Gyrosigma attenuatum (sygmoid shaped), and various smaller species of Navicula and Nitzschia. A layer of debris and extracellular exudates is at the bottom of the mat. (Photo courtesy of Jennifer Greenwood; reproduced with permission from Greenwood et al., 1999).

3. ©2010 Elsevier, Inc. FIGURE 19.2 A bacterium containing magnetosomes, indicated by the arrow. (Image courtesy of Richard Blakemore).

4. ©2010 Elsevier, Inc. FIGURE 19.3 Random walk strategy for positive chemotaxis in still (A) and flowing (B) water. The organism tumbles and moves a short distance if the concentration of the attractant is not increasing. If the concentration is increasing, the same direction is maintained. Darker regions represent higher concentrations of a diffusing attractant.

5. ©2010 Elsevier, Inc. FIGURE 19.4 Representation of traditional views of a pelagic food web and the microbial loop.

6. ©2010 Elsevier, Inc. FIGURE 19.5 Judy Meyer.

7. ©2010 Elsevier, Inc. FIGURE 19.6 Virus-like particles attached to a bacterium from a freshwater lake. The arrow points to one of the virus-like particles. (Reproduced with permission from Pina et al., 1998).

8. ©2010 Elsevier, Inc. FIGURE 19.7 Consumption of particles by several species of ciliated protozoa as a function of size. Note that different species have different maximum clearance rates and that clearance rates vary with particle concentration within a species. (Reproduced with permission from Fenchel, 1980).

9. ©2010 Elsevier, Inc. FIGURE 19.8 Consumption of particles by the ciliated protozoan Glaucoma scintillans as a function of particle concentration. (Reproduced with permission from Fenchel, 1980).

10. ©2010 Elsevier, Inc. FIGURE 19.9 Ranges of observed consumption rates of bacteria by several groups of benthic organisms from marine and freshwaters. (Data from 12 laboratory and field studies compiled by Bott, 1995; reproduced with permission).

11. ©2010 Elsevier, Inc. FIGURE 19.10 Filtering and ingestion rates of algal cells (Chlamydomonas reinhardtii) by Daphnia magna as a function of algal concentration. Although the filtering rate falls off sharply with increased concentration, the ingestion rate increases up to a point and then becomes constant. (Reproduced with permission from Porter et al., 1982).

12. ©2010 Elsevier, Inc. FIGURE 19.11 The filtering apparatus of a rotifer, Epiphanes senta. (Reproduced from G. Melone, 1998, Hydrobiologia 387/388, 131–134, Fig. 9, with kind permission from Kluwer Academic Publishers).

13. ©2010 Elsevier, Inc. FIGURE 19.12 A deformed adult mink frog, Lithobates septentrionalis, from central Minnesota. This animal shows multiple hind limbs bilaterally, as well as duplicated and fused pelvic elements. (Used with permission of the Regents of the University of California and the University of California Press).

14. ©2010 Elsevier, Inc. FIGURE 19.13 Rita Colwell.

15. ©2010 Elsevier, Inc. FIGURE 19.14 Competition of two diatom species for silicon (A) and phosphorus (B). Species 1 has a relatively higher affinity for low concentrations of silicate but is outcompeted at higher concentrations. The situation is reversed at higher concentrations.

16. ©2010 Elsevier, Inc. FIGURE 19.15 Scheme showing how the data in Figure 19.14 translate into relative success of two diatom species based on nutrient ratios.

17. ©2010 Elsevier, Inc. FIGURE 19.16 Conceptual diagram of successional sequence of an algal biofilm and the associated increases in nutrient and light competition. The type of grazer is indicated at each stage. (After Steinman, 1996).

18. ©2010 Elsevier, Inc. FIGURE 19.17 Some aquatic organisms involved in mutualistic interactions: the pouch of the water fern Azolla (A) that contains endosymbiotic Nostoc (B), (C) Nostoc parmelioides containing the midge Cricotopus nostocicola, (D) Hydra with endosymbiotic Chlorella, (E) the diatom Epithemia with cyanobacterial endosymbionts (courtesy of Rex Lowe), and (F) bacteria attached to a heterocyst of Anabaena flos-aquae (courtesy of Hans Paerl).