The Bremner Contribution to N-15 Isotope Ratio Analysis

1. The Bremner Contribution to N-15 Isotope Ratio Analysis C.E. Clapp, A.P. Edwards, H.H. Cheng, D.R. Keeney & W.E. Larson

2. Jack Bremner started work at Iowa State in 1959 on an ‘inherited mass spectrometer’ to carry out research to improve the methodology of 15N analysis. In the early 1960s he showed that both the amount of NH4 and the time required for isotope-ratio analysis of NH4 could be greatly decreased by modification of the techniques normally required for this analysis. It was possible to obtain accurate and precise isotope-ratio values with as little as 40µg of NH4 -N and to perform more than 50 15N analyses in a normal working day.

3. The most important advance in 15N-tracer methodology since that time has been the development of automated mass spectrometers and optical emission spectrometers for 15N analysis. Jack carried out this research on ‘’Determination and isotope-ratio analysis of different forms of nitrogen in soils: 1-7”, with Art Edwards (1965), H.H. Cheng (1966), Dennis Keeney (1966, 1967), and J. Silva (1966). The 15N-tracer work was continued with papers by Darrell Nelson (1968, 1970), Ali Tabatabi (1969, 1978), and Roland Hauck (1976, 1982).

4. Determination and Isotope-Ratio Analysis of Different Forms of Nitrogen in Soils: 1. Apparatus and Procedure for Distillation and Determination of Ammonium J.M. Bremner and A.P. Edwards 2. A Simplified Procedure for Isotope-Ratio Analysis of Soil Nitrogen H.H. Cheng and J.M. Bremner 3. Exchangeable Ammonium, Nitrate, and Nitrite by Extraction-Distillation Methods J.M. Bremner and D.R. Keeney 4. Exchangeable Ammonium, Nitrate, and Nitrite by Direct-Distillation Methods D.R. Keeney and J.M. Bremner 5. Fixed Ammonium J.A. Silva and J.M. Bremner 6. Mineralizable Nitrogen D.R. Keeney and J.M. Bremner 7. Urea D.R. Keeney and J.M. Bremner

5. Additional N-15 References • Cheng, H. H., Bremner, J. M., and Edwards, A. P. Variations of nitrogen-15 abundance in soils. Science 146:1574-1575 (1964). • Bremner, J. M., Cheng, H. H., and Edwards, A. P. Assumptions and errors in N-15 tracer research. In: The Use of Isotopes In Soil Organic Matter Studies (Report of FAO-IAEA Technical Meeting, Brunswick-Volkenrode, 1963). pp. 429-445. Pergamon Press, New York (1966). • Hauck, R. D., Bartholomew, W. V., Bremner, J. M., Broadbent, F. B., Cheng, H. H., Edwards, A. P., Keeney, D. R., Legg, J. 0., Olsen, S. R., and Porter, L. K. Use of variations in natural nitrogen isotope abundance for environmental studies: a questionable approach. Science 177:453-454 (1972). • Bremner, J. M. and Tabatabai, M. A. Nitrogen-15 enrichment of soils and soil-derived nitrate. J. Environ. Qual. 2:363-365 (1973). • Bremner, J. M. and Hauck, R. D. Advances in methodology for research on nitrogen transformations in soils. In: Nitrogen in Agricultural Soils (F. J. Stevenson, ed.). pp. 467-502. American Society of Agronomy, Madison (1982).

6. A concluding statement in one of Jack’s papers states: “It should be pointed out that even if it were possible to determine the δ15N of the nitrate derived from every nitrate-producing surface soil and subsoil in a region under study, it would still be impossible to calculate a reliable δ15N value for soil-derived nitrate entering surface water in this region. Calculation of this value would require information that is impossible to obtain, including the percentage contribution of each surface soil and subsoil in the study region to the nitrate entering the surface water.”

7. October 3, 2008 In Honor of Dr. Jack M. Bremner I first met with Jack Bremner in the early ‘70s at an International meeting in Germany and continued to meet him over many years either at Conferences or Workshops or when he was a visiting scientist at one institution or another. I first became acquainted with his scientific work some years earlier when I was studying for my PhD on the chemistry and structure of humic substances. This work quickly brought me into contact with his groundbreaking studies on the extraction and composition of soil organic matter that he carried out at Rothamsted Experimental Station. Subsequently, our scientific paths crossed again and again as I not only continued to work on soil organic matter but also on the forms and amounts of nitrogen and sulphur in soil and the cycling of these elements through soil organic matter. The fundamental studies that Jack carried out in these areas, particularly the development of well-founded and reliable analytical techniques, have made an enormous contribution to soil science and were pivotal to the rapid progress that was made in the succeeding decades. His work was always underpinned by a strong adherence to scientific principles and the rigorous application of good basic science. It is this characteristic which made his work so influential and of lasting value. He leaves a towering legacy of achievement as a scientist that will serve as testament and memorial to him and ensure that his many contributions will be recognised and remembered for many years to come. Even so, the lasting memory for those of us who knew him will be for his personality and humanity. His kindness, his wit, his intelligence, his encouragement and sound advice are the things that we will remember. In this context it is important to recognise the role and influence of his wife Mary. Jack and Mary worked as a team and travelled the world together. My fondest recollections are of convivial meals in restaurants around the world, after a long day in the lecture halls, with Jack and Mary holding court and Jack recounting some of his vast collection humorous stories. I may be wrong but it seemed to me that the words flowed more freely from him on these occasions. At one conference I attended, Jack strode to the podium and announced in his usual faltering way that if he gave the paper it would take all day and he promptly switched on a portable tape recorder and put it in front of the microphone. The recording was of Mary reading the paper and Jack’s role was to change the slides. It turned out to be a first class presentation and exactly on time! A perfect example of team work. However, Jack did have to answer the questions. Although we never worked together, I counted him as a friend and mentor and he supported me on several occasions throughout my career. For that I am very grateful but I am even more grateful for the lasting contributions that he made to soil science. Roger Swift President, International Union of Soil Science, and Executive Dean, Faculty of Natural Resources, Agriculture and Veterinary Science, The University of Queensland, Australia

8. October 2, 2008 In Honor of Dr. Jack M. Bremner: It is indeed an honor for me to prepare a letter in honor of one of the giants of /Soil Science/, our friend and colleague, Dr. J.M. Bremner.  He had an outgoing personality and was always willing to help others. Jack was well-known for his monumental achievements in /Soil Chemistry/Soil Biochemistry/.  His basic research in these areas had practical significance for soil management and for the use of agricultural chemicals for maximizing crop yields while at the same time protecting the environment.  A particularly strong point of his career was the development of analytical methods for determining the different forms of soil nitrogen: methods which have been used in research laboratories world-wide. I admired Jack not only for his scientific achievements but also for his tenacity in solving a long-time problem he had with oral expression.  When I first met Jack, I had difficulty communicating with him because of his speech impediment.  Over the years he overcame this problem, or at least partially so, but only after persistence and hard work.  Jack never let this handicap detract him from interacting with others, and, in fact, he was often the center of attention during scientific discussions. Whereas Jack was a perfectionist in the development of scientific methods, he was somewhat less than perfect behind the wheel of an automobile.  As time went on, I soon found out why his good wife Mary always did the driving.  On one occasion, while at the University of Illinois, Jack insisted on getting behind the wheel (undoubtedly under Mary's objection) for a social function at our home.  I had given him detailed road instructions and he was successful in finding his way over. When it came to return, I could see that Jack was puzzled as to which direction to go.  I took him to his car and pointed out the way -- straight ahead for three blocks to a dead-end, left turn to a second dead-end (another three blocks), right turn and he would be in familiar territory. I stood at the side-walk to see if Jack made the proper first turn, and guess what, he turned the wrong way (right instead of left).  It took some time for him to get his bearings and even longer to find his way home. For obvious reasons, Jack was late getting to the lab the next day. Respectfully submitted, Frank Stevenson Professor Emeritus, University of Illinois

9. October 1, 2008 In Honor of Dr. Jack M. Bremner: I was very sad when I heard that Jack Bremner had passed away. Jack was one of the great soil scientists of our time. I first met Jack at the International Soil Science Congress at Madison, Wisconsin, in 1960. At that time we had lengthy discussions on the role of nitrogen in humic substances, that is, whether it was an integral molecular component or adsorbed on loosely held on internal and/or external humic surfaces. Prior to meeting Jack in person, I had read his papers on soil organic matter and soil nitrogen which he had published while still working at Rothamsted. Over the years, I met him frequently at meeting of the SSSA and the ISSS. Each time we met, we had discussions on humic substances. When I became an   honorary member of the NCR-59 Committee of the USDA, I had the opportunity to meet Jack more frequently over a 20-year period. There were about 15-20 of us who belonged to this committee. At these meetings, each of us reported on what we had done during the past year and then presented plans for future research. Jack was our "guru' at these gatherings. He was not only an eminent authority on soil-N, but also very familiar with the chemistry of soil organic mater. We all told him of our difficulties, and he would suggest ways of how we could overcome them. He was always upbeat, positive and very generous. During the International Soil Science Congress in Moscow in 1974, Prof. M.M. Kononova invited Jack and me to a special reception at the Dokuchairev Institute. When we arrived at the Institute, we were surprised by the unusual abundance of delicious foods, cakes, and drinks on the tables. Professor Kononova, a number high-ranking Russian officials and a small number European scientists, including Wolfgang Flaig, were present. We had high-spirited discussions on soil organic matter, while consuming a lot of food and drinks and all had a good time. In addition to being an outstanding scientist, Jack was also a good teacher. Several of his former students have become prominent soil scientists. Soil science has lost a great scientist, and many of us have lost a fine colleague and friend. Last but not least, I want to convey my condolences to Mrs. Bremner and other members of the family. Morris Schnitzer ECORC, Agriculture and Agri-Food Canada, Ottawa, ON, K1A 0C6, Canada

10. September 29, 2008 In Honor of Dr. Jack M. Bremner: Jack was a brilliant applied scientist.  He took great pride in the precision and accuracy of his experimental results.  Two of his innovations helped me.  One was to extract soil organic matter using sodium salts and the other to break bonds between soil particles and organic matter by sonifying soil in water only.  Jack was a modest man with a great sense of humour.  At Rothamsted, he always started his talk with a joke.  It was usually about a canny Scot and a mug Englishman!  Jack had a slight tendency to stammer.  He overcame this brilliantly by having an overhead projector to hand so that he could write the offending word out.  He was also an excellent sportsman by far and away the best tennis player at the lab, until Jim Quirk arrived.  Jack was also blessed with a charming and understanding wife. Best wishes, Bill Emerson Retired CSIRO Adelaide, Australia