This page contains a Flash digital edition of a book.
BE A Walk in Yosemite INSPIRATION │ KNOWLEDGE


A walk in Yosemite Valley or any other woodland scene is replete with casual microbe sightings. They are good places to practice and extend your microbe-watching skills.


An aerial view of Grand Prismatic Spring. The Grand Prismatic Spring in Yellowstone National Park is the largest hot spring in the United States, and the third largest in the world. The vivid colors in the spring are the result of pigmented bacteria in the microbial mats that grow around the edges of the mineral-rich water. © UNAVCO


One of the most dramatic sights for microbe watchers in Yosemite Valley is the many black streaks running down its majestic granite walls. These are cyanobacteria. Being photosynthetic, they are able to derive their metabolic energy from sunlight and they obtain carbon to make their PMs from carbon dioxide. And they are able to fix atmospheric nitrogen as well. They need only a source of minerals, which the granite supplies, and water, which runs down these pathways in the spring. Then they prosper. Their resting cell forms survive summer’s heat and dryness along with winter’s frigid temperatures in order to resume growing the following spring when water and warmth return.


Near a stream in the right season you will see lupine growing in the sandy soil. If you examine the roots of one of them you will discover nodules. If you cut open one of these nodules with a pocket knife, you will note its blood-red interior, sure evidence that nitrogen-fixing bacteria belonging to the rhizobial group are active there, just as they were in the root nodules of legumes. Close by, you are likely to notice alder trees, catkin-bearing relatives of birch trees. They, too, add to the environment’s fertility by housing on their roots nitrogen-fixing bacteria belong to the genus Frankia. Even the black streaks of cyanobacteria on the canyon wall make a small contribution of fixed nitrogen.


Small lodge pole pines on the edge meadows march in to make a forest where there is now grassland. Some of these trees will bear the scars of last winter’s snow and fungal attack. Blackened clusters of needles cover some of their lower branches, evidence of fungi having grown in a warm, humid chamber formed as snow melted first in this region. Last year’s crop of deciduous leaves, now apparently completely gone, in fact have been reduced to their plant-nourishing nitrogenous and mineral constituents by a consortium of cellulose-degrading microbes̶a mixture of fungi and bacteria working cooperatively.


In the late spring you will see mushrooms, the macroscopic fruiting bodies of ascomycete and basidiomycete fungi. Some might be boletes that an experienced mushroomer would rejoice to collect and eat, others poisonous and sometimes deadly amanitas. A pocket field guide and the company of an experienced collector will help you identify which are which. With a little research, any walk through a woodland or riparian environment can be rich with microbial sightings.


Excerpt from March of the Microbes by John L. Ingraham Harvard University Press, www.hup.harvard.edu


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84  |  Page 85  |  Page 86  |  Page 87  |  Page 88  |  Page 89  |  Page 90  |  Page 91  |  Page 92  |  Page 93  |  Page 94  |  Page 95  |  Page 96  |  Page 97  |  Page 98  |  Page 99  |  Page 100  |  Page 101  |  Page 102  |  Page 103  |  Page 104  |  Page 105  |  Page 106  |  Page 107  |  Page 108  |  Page 109  |  Page 110  |  Page 111  |  Page 112  |  Page 113  |  Page 114  |  Page 115  |  Page 116  |  Page 117  |  Page 118  |  Page 119  |  Page 120  |  Page 121