Are we killing the rain? Meditations on the water cycle and, more particularly, on bioprecipitation

Abstract

This essay reviews the multidisciplinary science of bioprecipitation, using it as a lens through which to envision integrative options for land use and water resource management in a new light. Bioprecipitation is the hypothesis that microbial ice nucleators, including Pseudomonas syringae, may be highly adapted causal agents of rain and snow. To the extent that land use policies, including pathogenic eradication campaigns, may inhibit the local production of biotic ice nucleators, they may be responsible for ‘killing’ a generative source of rain. Such possibilities should invite major interest in this gathering field of research. Assuming that it contributes to a richer comprehension of the hydrological cycle's dependence on circulatory biota, these findings should help to stimulate assimilative, integrated reformulations of land use and water management policies and norms.

Keywords:

• rain
• precipitation
• bioprecipitation
• integrated land and water management
• over-grazing
• public lands

Acknowledgements

I am profoundly indebted to this publication's two anonymous readers and to my Water International guide and helpmeet Marcella Nanni, as well as to Professors David Sands, Montana State University; Cindy E. Morris, INRA, Avignon, France; and Gabriel Eckstein, Texas Wesleyan University School of Law; Nico Hauwelt, senior hydrogeologist, City of Austin, Texas; Casey Duncan, Tarleton Law Library, University of Texas School of Law, and David J. Kohtz and Joyce Yinen Young, University of Texas School of Law 2012.

My deep and special appreciation goes to James Nickum, whose interventions re-shaped the essay, and to Stefano Burchi, for the kind of encouragement that only an unusually generous senior statesman could provide.

Responsibility for errors of fact or judgment is my own.

Notes

1. The term was coined by Professor David Sands in 1978 (Christner 2012).

2. The most common terminological variants are ‘ice nucleation active’ (INA) and ‘biological ice nucleators’ (BIN).

3. Telephone interview with Professor Brent C. Christner, August 2012. Notes on file with the author.

4. What would it mean to ‘kill’ ‘the’ rain? Could the eradication of a bacterial pathogen from a particular place – or from a multitude of places – have an inhibitory effect on the formation of rain? The answer is, first, not all rain: Even a highly proficient variety of ice nucleator is but one among many kinds, as was discussed in the text. Then, too, anything that fails to live, due to its prior inhibition, cannot, of course, be killed. But precipitation could be denied its potential for development, at least at some times and in some places, if one of the atmosphere's best-performing ice nucleators, let us say, should get driven from its earthly haunts in tree canopies, due to clear-cutting and deforestation; among crops, where it gets eradicated or otherwise inhibited; and in and on the ground, where soils get consolidated so forcefully that they can no longer retain moisture or support life. Could the ferocious consolidation of precipitation that has recently been experienced in several regions of the world be causally related to changes in the earthly and sky-bound concentrations and dispersal patterns of CCN- and IN-active biological agents? This idea is already under study, if more tightly conceived than in my general formulation, in relation to desertification and drought. As noted in the text, the study of dynamic cloud systems is extremely complex. Just the relation of cloud chemistry to rising temperatures has been described as ‘an enigma’ (Gillis 2012, pp. A1, A14). And current climate models are considered to be better at predicting temperature than precipitation (see, e.g., Gertner 2007, p. 74). Gaps such as these in present knowledge leave room for the bioprecipitation hypothesis to roam and for untested further hypotheses concerning distributive gains and losses in precipitation potential linked to microbial massing and other factors to enter.

5. P. syringae received sustained research attention, therefore, as an aggressive and successful pathogen responsible for basal kernel blight in respect to barley (Braun-Kiewnick et al. 2000); as a principal causal agent of halo blight in many bean cultivars (Bozkurt and Soylu 2011); as a prolific cause of bacterial shoot blight in tea plants, widely infecting them in tea-growing countries such as Japan (Tomihama et al. 2009); and as an antagonist of tomato plants, on which it causes a blight called bacterial speck across the world (see e.g. Bashan and de-Bashan 2002a, 2002b).

6. Telephone interview by the author of Professor David Sands, 24 September 2011. Notes on file with the author.

7. Telephone interview by the author of Professor David Sands, 24 September 2011. Notes on file with the author.

8. I break out for extended treatment the perennial public policy debate regarding the over-grazing of the public lands in the final section of the paper.

9. Personal interview of the author with Professor David Sands, 11 January 2012. In Professor Sands's view, genetic tagging is not a distant prospect but a current opportunity awaiting funding for research.

10. Email communication, Professor Cindy E. Morris to Jane Cohen, 19 September 2011. On file with the author.

11. Professor Morris calls on her students to imagine asking a farmer “which situation is preferable: a year with no rain and no plant disease or a year with some rain and some disease. Which of these two options would she or he choose?” (Morris 2011, email communication, see Note 10). According to Professor Sands, crop loss to P. syringae amounts to no more than 5% a year. Telephone conversation with the author, 24 September 2011. Notes on file with the author.

12. Professor Sands included this idea in a TED talk given in April, 2012 – one of the three popular introductions to bioprecipitation published or broadcast that month (Sands 2012).

13. In an earlier version of this paper, presented at IWRA World Water Congress XIV, Porto Galinhas, Brazil, September 2011, and published in its proceedings on the World Wide Web, I more fully elaborated the idea of sacrificial cropping. Manuscript on file with the author available via email transmission on request.

14. David Sands has proposed this experiment. Personal interview of the author with Professor David Sands, 12 January 2012. Notes on file with the author.