Why did we do it?! Our look into the writing of a Geochemical Perspectives article

How did it all start? When I (Fred) was first contacted to write an article for Geochemical Perspectives by the Editorial Board, and strongly encouraged by Eric Oelkers to do so, I was somewhat uncertain as to the expectations of such an article. I had just retired and wondered how much time I was willing to devote to science as opposed to traveling with my wife Judy, hiking, running, and mountaineering. Interestingly, my retirement years so far have not been much different than when I worked full time but there is certainly considerably more freedom to do what I want. Early in my ruminations, I asked my last Ph.D. student, Andreas Andersson at Scripps Institution of Oceanography, to co-author the article with me, which he happily consented to do. However, he too had some reservations, mainly involving the fact that he had just accepted an Assistant Professorship at SIO with all the pressures thereof.

of some length in which we could deal rigorously with a scientific topic of interest but also gave us the freedom to inject into it some of the excitement, fun, and personal interactions we have had in our careers. Thus, our narrative starts with a synopsis of our careers and progresses through some of the major scientific topics that we have dealt with and the trials, tribulations, and rewards of engaging in the enterprises of research and education. The scientific “meat” of our article then follows.


What is the topic of our article? Because of its contemporary relevance, we chose to address the co-evolution of the Phanerozoic (past 545 Ma of Earth’s history) ocean- atmosphere-carbonate sediment system, with emphasis on the history of the CO2-carbonic acid system of seawater through this time period. This necessitated consideration of the compositional and isotopic features of the carbonate sedimentary record that constrain any interpretation. It also necessitated a look at experimental data that might provide boundaries on the carbon chemistry of seawater during Phanerozoic time. Not only was the carbon chemistry of seawater important to resolve but also the history of the carbon dioxide (CO2) composition of the atmosphere, as the two are intimately linked. The contemporary environmental problem of the acidification of ocean surface waters easily became an important part of our story. This is an environmental problem that both of us had been involved with for some time. It took us a longer time to write the article than we anticipated because of the long story journey we chose, our physical separation by 2,500 miles, and the amount of information we had to distill, including our own material and that of many other authors. It was certainly an effort of love.

What did we conclude? Much, but perhaps for many readers, the contemporary problem of ocean acidification is of most concern. The writing of our article confirmed for us once again that the present rates of increasing atmospheric CO2, temperature, and surface ocean acidity are well outside the rates we have seen for at least 800 Ka. The burning of fossil fuels and land-use activities, such as deforestation, that release carbon dioxide to the atmosphere are certainly responsible for much of the rate changes on the time scale of human generations. Fossil fuel CO2 emissions today amount to 9.7 billion tons of carbon annually and that of land-use activities to about one billion tons. Surface ocean waters absorb about 26% of these emissions and the waters are becoming acidic.


We emphasized in our article that most experimental work on many calcifying organisms has shown that under increased atmospheric CO2 levels attempting to mimic those of the future of this century, and hence decreased seawater carbonate ion concentration and carbonate saturation state, most calcifying organisms will not calcify as rapidly as they do under present-day CO2 levels. Because of decreased calcification rates and also increased carbonate dissolution rates in a future higher CO2, warmer world, with lower pH and carbonate saturation state seas, the rate of accretion of reefs is likely to slow and their dissolution may even exceed calcification. The potential of increasing nutrient and organic carbon inputs from land, occurrences of mass bleaching events, and increasing intensity and perhaps frequency of hurricanes and cyclones as a result of sea surface warming will only complicate matters more.


This composite of stresses will have severe consequences for the ecosystem services that reefs perform, including acting as a fishery, a barrier to storm surges, a source of calcareous sediment to maintain beaches, and an environment of aesthetic appeal to tourist and local populations. Thus, if this is all that people take away from our article, it was certainly worth our time in writing it!

About the authors

Fred Mackenzie is Emeritus Professor of Oceanography and Geology & Geophysics in the School of Ocean and Earth Science and Technology, University of Hawaii. Current research includes modeling of the Earth surface system through geologic time; biogeochemical cycling of carbon, nutrients and CO2 exchange in coastal oceans; effects of ocean acidification on carbonate ecosystems; kinetics and thermodynamics of mineral-solution reactions; and implications of global change for sustainability in Pacific island nations. Fred is an ardent athlete, lifetime traveler, and mountaineer, climbing peaks in the Colorado and Canadian Rockies, the Cascades, the European Alps, Scotland, Corsica, Ecuador, Peru, Bolivia, and Chile. His last expedition was to the 6,348 m Volcan Parinacota on the Bolivia/Chile border. Fred is a Fellow of six professional societies, including The Explorer’s Club. Some awards are: Universite Libre de Bruxelles Francqui International Medal of Science, Society for Sedimentary Geology Pettijohn Medal, Geochemical Society Patterson Medal, International Association of Geochemistry Vernadsky Medal, and American Chemical Society Geochemistry Medal.

Andreas Andersson is an Assistant Professor of oceanography at Scripps Institution of Oceanography (SIO). His research interest deals with global environmental change owing to both natural and anthropogenic processes, and the subsequent effects on the function, role, and cycling of carbon in marine environments. His current research is mainly concerned with the effects of ocean acidification on coral reefs and in near-shore coastal environments. Andreas was born and raised in Sweden but relocated to Hawaii to attend college and later graduate school. After completion of his Ph.D he spent several years in Bermuda at the Bermuda Institute of Ocean Sciences before moving to SIO in the summer of 2011.