Dear Judy,

I was deeply saddened to hear of Frank’s passing. Although I learned at the 2025 AGU meeting in New Orleans that his condition was serious, the news nevertheless came as a great shock.

I would like to express my deepest gratitude for all that Frank gave me during my PhD years in the 1990s, when I had the privilege of working under his guidance. Frank was not only an outstanding thesis advisor, but also an extraordinary mentor who profoundly shaped my scientific career. His influence extended well beyond me, reaching the next generation through the ten PhD students whom I have had the privilege to mentor.

Frank will be remembered with great respect and gratitude. His tireless spirit in pursuing ocean science will live on in me and in many of my graduates.

Sincerely,
Kitack

Frank Millero was one of the few truly important people in my scientific career. When I heard about his passing, I knew I had to get some thoughts down on paper. These are mostly personal recollections so if there are errors or omissions they are on me. 

I first learned of Frank from one of my undergraduate mentors at the University of Otago. Not Keith Hunter, surprisingly, but David Fenby, a physical chemist who knew Frank from his work on calorimetry. Frank came from a very elite background in physical chemistry. His advisor, Loren Hepler, was a leader in classical thermodynamics in North America in the 1960s and 70s. But physical chemistry was rapidly transforming at that time, with technological advances in various forms of spectroscopy – which is where most resources (and faculty positions) were headed. Frank probably headed to RSMAS because he saw great opportunities in applying his expertise to global scale problems rather than remaining in pure chemistry (his description in his biography of the early days at RSMAS collaborating with Drost-Hansen is pretty hilarious). 

Much of his research was supported by ONR. The navy was interested in how the physical chemistry of seawater affected sound velocity in the oceans, and Frank had the ideal credentials to study this. His work on the equation of state of seawater is definitive. One student engaged in that work, Rana Fine, subsequently went off to develop her own highly successful research program. Moreover, his accomplishments did a great deal to strengthen the profile of chemical oceanography at ONR, to the benefit of many of us. 

Frank loved classical thermodynamics – all the time. He was always cornering me at the RSMAS bar to talk about Pitzer equations – then dismayed when I attempted to change the subject. He was frequently disappointed that most of us viewed thermodynamics as a tool, rather than an end in itself. Harmon Craig was an exception. Frank told me that Craig really knew thermodynamics more deeply than any of his other colleagues and this was a basis for their friendship. 

Another thing he had in common with Harmon Craig was an emphasis on accuracy in experimental measurements. I took two classes with Frank – both of which were pretty “Millero-centric” but he introduced me to Craig’s 1957 paper on isotopic standards for carbon and oxygen, which is still widely cited nearly 70 years after publication. Frank was determined to achieve accuracy in everything he did. He led efforts to get good data for carbonic acid dissociation, and hosted many consensus efforts with other workers including Mike Whitfield, Ricardo Pytkowicz, Peter Brewer and Andrew Dickson. Subsequently, Dickson led an NRC Panel on standards and intercalibration in seawater, which applied many of the lessons learned by the DIC community to the analysis of other seawater constituents. 

In the late 1970s, Frank and his student Arthur Chen developed a computational approach to distinguish anthropogenic carbon dioxide from “preformed carbon dioxide”. This was a very influential paper, leading to work by Niki Gruber, Jorge Sarmiento, and more recently Doug Wallace, to utilize this approach. 

Frank was a unifying figure in our field. His collaboration with Marko Branica led to the “Chemistry of the Mediterranean” symposia, one of the few meetings behind the iron curtain in the height of the cold war. My first GRC was in 1983. Frank was chair and he invited people from outside Chemical Oceanography that he thought we might benefit from. This included Mary Lidstrom, Werner Stumm and a manganese “duel” between Jim Morgan and Ken Nealson. Indeed, Frank was a fixture at nearly every GRC from 1969 to 2017. The exception was 2011, when he was in Prague to receive the Goldschmidt medal. 

Frank and I worked closely on metal redox chemistry, and he really impressed on me the importance of rigorous measurements that could be compared with others. He was on my thesis committee and multiple drafts were returned covered with red ink. In his kinetics work, he mentored many others – including students like Virender Sharma, but also collaborators like Magdalena Santana-Casiano, Melchor González-Davila and Whitney King, who became leaders in their own right. 

Frank wrote two books, Chemical Oceanography – a popular textbook - and his magnum opus The Physical Chemistry of Natural Waters The latter ensures that the deep advances he made in the thermodynamics of seawater will endure for generations to come. 

Frank was very proud of his Italian heritage. He used to run every day at noon – wearing bright green running shorts and a variety of red T shirts. Apparently one of these shirts said “Wops are Tops” but I never saw it. All of this provided ample material for the graduate student skits, performed annually at the Christmas party. Doug Capone played the Millero role, although this was a couple of years before I arrived. But for the record, Frank was Italian American, not Italian. I once met the proprietor of a hotel in Rome who was a friend of Frank’s. He told me “Frank’s Italian is not so good, but he speaks English with a very good Italian accent!”

I went to sea with Frank once, in Chesapeake Bay. The cruise was uneventful. But Frank had lots of tales to tell. Once in the Bahamas, he was on a trip with Bob Berner, John Morse, Rod Zika and (?) Al Mucci when pirates attempted to board the ship. Someone “dissuaded” them from boarding. I have heard conflicting versions of what happened and will say no more. Another time he was on a cruise in the Suez canal when the ship was seized…

I have read many tributes. Most are mercifully shorter than mine, but I hope we can all get together in person some time to talk about Frank and his times. 

James Moffett

Frank Millero was our scientific mentor, but he was also much more than that to both of us and to our family. Melchor first met Frank in 1988, during the organization of Chemistry of the Mediterranean Congress in what was then Yugoslavia, led by Marko Branica. At that meeting, I approached Frank to express my interest in doing a postdoctoral stay with him at RSMAS. In September of that same year, 1988, we began a series of four research stays, each lasting about six to seven months (1988–89, 1993–94, 2003–2004, and 2006). During those periods, both a deep friendship and a solid scientific training were forged, taking us from adsorption–desorption studies and CO₂ chemistry, through iron redox processes, to the application of Pitzer equations, all within the broader framework of marine chemistry.

We vividly remember arriving in Miami in 1988, when Frank said to Melchor, “There’s a polarograph here that hasn’t produced a polarogram in a long time—work on it and apply it to adsorption–desorption studies of trace metals on particulate material, such as chitin” and to Magdalena “you would start with different studies but you will focus on the Fe chemistry and organic matter interaction”. It was exciting to be able to present, every Friday at 11:30 a.m., together with Sharma, Zhang, Sara Sotolongo, and later Kitack Lee, James Moffett, and many others we overlapped with during those stays, our weekly progress—our first peaks, our first Fe(II) oxidation studies—always accompanied by a good pizza that Frank made sure to provide. Those sessions became not only scientific discussions, but also spaces to share problems, collectively search for solutions, and move forward together toward our goals.

Our visits were often preceded by stays in New Hampshire to attend the Gordon Research Conferences (GRC), after which we would travel on to Miami or, in some cases, participate only in the conference. In 1993, after attending the GRC and upon arriving in Miami, we learned that Magdalena was pregnant with our first child. From that moment on, Frank and Judy became, in many ways, third parents and grandparents to that baby, who would be born shortly after our return to the Canary Islands.

We continued attending GRC meetings over the years, where Judy naturally assumed the role of grandmother to our two children. During our stays in 2003 and 2006, Frank would spend hours sitting in his office with them, talking about many different topics—often science—and transmitting to them that unique way of being and of seeing life that only Frank had. His Italian roots also brought us together around special dinners at his home, Thanksgiving, Christmas, shared with his family, children, and friends.

We visited him several more times in Miami, and Melchor visited him in January 2024. It was a whirlwind trip: leaving the Canary Islands on a Thursday, picking up part of an instrument at General Oceanics early Friday morning, and then spending three wonderful hours with Frank and Judy before returning the Canaries that same Friday. Although his mental decline was evident, the intensity of those moments—especially because he recognized me—made that visit an unforgettable memory that I will carry with me for the rest of my life. 

Magdalena Santana-Casiano and Melchor González-Dávila

Frank was one of the few true giants in our field. He was gracious and helpful to all. The legacy of his contributions to the chemistry of the ocean will be long enduring, and perhaps never replicated. A summary of those in Marine Chemistry will be a valuable memorial.

Jim Murray

Thank you so much for informing me of the passing of Frank Millero, one of the giants of chemical Oceanography. Like so many others I have special warm memories of Frank, though in my case they are centered on the golf courses during Gordon conferences.

Best wishes

I have one other Frank Millero story. During my post-doc with Bob Berner, he called me into his office one day. He was reviewing an NSF grant proposal of Franks. He didn’t show me the proposal (which would have been unethical) but he did show me the pages of recent publications Frank had written. I can’t remember the exact number but I can remember it was almost 1 per week for almost a year!

I will leave Dave DeMaster and others to finally reveal the working of the GRC secret committee!

Michael Krom

Thank you for the notification. A brilliant and fun-loving star has gone out. I admire him still.

Clare Reimers

Sad news. Another giant gone.

David Rickard

Very sad. It is a big loss of a legend.

Virender Sharma

I feel terrible, he was such a good friend and mentor to me over the years, always enjoyed his wonderful story-telling, which will be sorely missed!  He contributed greatly to the history of oceanography. RIP my dear friend.

Tom Bianchi

P.S. Unless I missed it, it does not mention anything about him being EIC in Marine Chemistry for all those years, I think over twenty but will check it out details.  I will contact the journal manger and request a brief IN MEMORIAM piece be published in the journal. 

Thanks so much for sharing this news. I’m so sorry to hear it, and so glad to have known Frank. 

take care,

Karen Casciotti

Sad news, thanks for letting know.

Just yesterday I was in a doctoral thesis monitoring meeting and we were discussing his equations.  

We’ve lost one of the giants of chemical oceanography.

Mustafa Yucel

Thanks for passing the sad news. Some of my fondest memories of Frank were at the Chem. O. Gordon Conferences. At a meeting in Santa Barbara, I met him as he completed a long run on the beach. He was exhausted, sweating profusely, and gulping as much water as he could swallow. I asked him why he did this to his body. “So I can eat as much pasta as I want.” was his reply.

In writing the obituary, it would be good to reference his autobiography: Reflections on My Career as a Marine Physical Chemist, and Tales of the Deep, which appeared in Annual Review of Marine Science Vol. 7 (2015), pp. 1–20.  https://doi.org/10.1146/annurev-marine-010814-015946

Best wishes,

Billy Moore

I agree with everything what was said. Frank was a giant in our field because he came from a generation where there were a bunch of chemists with a Chemistry PhD coming into Marine Chemistry and applying chemical principles into the field. This is unfortunately happening much less now. 

Peter Santschi

Thanks for letting me know.  I think of Frank often. 

Flip Froelich

Thank you for letting me know. We’ve lost a giant!

Hedy Edmonds

Well said by all. I vividly recall first encountering Frank at a Gordon Conference. His talk was a bewildering joy. He had the tools of his earlier chemistry experiences. And was searching for ways to engage with ocean scientists. We hit it off right away in the happily boisterous free time between lectures. He was always fun, wise, and gracious, and did not have a mean bone in his body.

Frank was not perfect - no one ever is - but he was a hugely positive presence throughout his career. He is sorely missed.

Peter Brewer

Yes, well said by all.  My fun memory of Frank was his delivery of "secrete message" at Chem Ocean GRC (at least for a decade?). I also remember, at GRC, he would sit on the first row and work on crossword puzzle but then ask a really good question. He is sorely missed. 

Wei-Jun Cai

P.s., I have every edition of his "Chemical Oceanography" textbook on my bookshelf. 

Frank was a great colleague, mentor and friend to all of us, and he will be truly missed. I'm not a fan of AI generated text but these seem to do a reasonable job describing his career, but they don't communicate Frank's humanity and caring and nurturing, or relate funny stories each of us could tell (e.g., carrying mangos in his t-shirt and then his belly breaking out in a bad rash afterwards). That's what I'd add to the obituary for our community. He always cracked us up with the secret committee reports at so many GRC's.

Greg Cutter

As many of you have said Frank was a giant amongst us! Although I interacted a lot less with him than most of you, he had a marked influence on me scientifically and professionally along with Fred Mackenzie, George Luther, Bob Byrne, and Ken Bruland (and several others).

What I appreciated most about Frank was that behind this brilliant and rigorous scientist was a fantastic charming and warm human being with a great sense of humor! 

My interactions with him were primarily at ACS Geochemistry Division symposia and at Chem Ocean GRC. I will never forget an ACS meeting in Denver in the early 90’s to which he invited me to give a presentation at a special session on lanthanide and actinide elements honoring Greg Choppin. Upon arriving at the session, I went to greet him and thank him for the opportunity to present our work along so many accomplished scientists. He cheerfully greeted me then asked me about the packet of overheads I was carrying… at the same time asking to see them. I naively handed them to him! He immediately proceeded to take half the pile and give me the other half back stating with a wry smile that I would assuredly not need that many… I was speechless and floored as I had spent a lot of time preparing for this special session. 

He did return the overheads a minute or so later but did not fail to warn me that he would be carefully watching the clock during my talk.

Many of us from the session later went out to dinner, where I became much better acquainted with Frank and learned to appreciate his wonderful personality! Over the next few decades I continued to appreciate and admire him and the assistance he so freely provided me!

Sorry for the long message but I wanted to share this experience. He and I laughed together about it for many years… 

Frank will be sorely missed!

Aloha, Eric DeCarlo

Thank you for informing me about this very sad news. 

I first met Frank when attending my very first meeting in Goteborg, Sweden. I was a 22-years old first-year MSc student from Utrecht making my first steps in (Sulfur)science and during the opening dinner I ended up on a table with Frank Millero, John Morse and you. The peculiar mix of discussing outstanding scientific issues, funding problems/successes, social talks and cultural differences (was the first time I had dinner with non-EU persons) is still on my mind. Since, I have had interactions with Frank about Pitzer’s equations, shallow carbonate dissolution and editorial interactions. A great loss for our field and of course his friends and family.

Jack Middelburg

Who enjoys science more than Frank did? His excitement about research was obvious in every conversation. He demonstrated his passion for science by having several lifetime-equivalents of peer reviewed publications. 

Frank was very nurturing toward early career scientists and, in general, had strong concerns about the wellbeing of others. He was a wellspring of interesting stories, some observational and some mischief of his own making. Although he will be very deeply missed, it is impossible to think of him without it bringing a smile to my face and an improvement in my day.

Bob Byrne

I agree with all the comments made regarding Frank’s humanity and intellectual prowess. I first met Frank at an Ocean Sciences Meeting via Tom Church, who painted a picture of a towering figure for me in advance of the meeting. I found Frank engaging, fun to chat with and willing to teach and learn.

A fond memory of Frank is when he received the Goldschmidt Medal (2011) in Prague with much grace and dignity. In giving the citation, I noted in closing “Frank is the gold standard for Marine Chemistry and for that we affectionately call him “Godfather”.” He was touched by the audience’s overwhelming applause, which helped to make up for the fact that he was missing his first CO Gordon Conference since its inception in 1969. Judy was thrilled and very proud of him.

Frank will be missed by his family and his scientific family. Thanks for the memories.

George Luther