New paper in Biogeosciences

The long-awaited global compilation of the N isotopic composition of nitrate (nitrate δ15N) (begun in 2002) is out! A ridiculous amount of work 17 years in the making, but here it is… for all 10 (maybe 12) of you that care!

But wait, there’s more. We used this dataset to train a neural network to estimate nitrate δ15N on the World Ocean Atlas grid. (Yes, it is better than a multiple linear regression; detailed in the online reviews.)

It’s called,

Global trends in marine nitrate N isotopes from observations and a neural network-based climatology

Read the paper here:

All the observations are available via BCO-DMO here: Compiled dataset consisting of published and unpublished global nitrate d15N measurements from from 1975-2018

The Neural Net estimates can be downloaded here:
Estimated nitrate d15N modeled using an ensemble of artificial neural networks (EANNs)

But you can also download a ODV collection of the obs and model results here: prafter_2019_d15N_WOA09.Data.


stories from the end of 2018


Check out the color palettes I made for Ocean Data View—all inspired by Wes Anderson’s movies. I thought this was an original idea, but I found out it had been done (for R) more than a year earlier (as soon as I posted this on Twitter). Either way, it looks good:

You can use these color palettes yourself, by visiting

Visited and gave a talk at University of South Florida, College of Marine Science. Great place. Great people.


On a sad note, I also had to deal with the passing of my dog Jake. He had a good, long life, but my wife and I were very sad to see him go.


Published the first of two papers on Gulf of California seawater 14C since the last ice age. This paper creates 4 glacial-interglacial records of single-species benthic foraminifera 14C content. One of these is an epifaunal species, which is the first record of the like. The main point of the paper is to investigate alternate explanations (e.g., bioturbation, authigenic carbonate precipitation, and more) for depleted 14C observed during the deglaciation in a nearby site (the canonical record of Marchitto et al. 2007). Check it out!

Screen Shot 2019-02-02 at 3.02.02 PM.png

I also attended a meeting that was seemingly custom-made for me: a joint GEOTRACES-PAGES meeting to discuss modern and paleoceanographic tracers! What’s more, it was in Aix-en-Provence, France. And they asked me to give a plenary lecture. I was very honored.




I also visited the *AMAZING* Museum of Oceanography in Monaco, which is just down the way from where good friend Roberta Hansman works (for the IAEA) (see last photo).

April-October Update

Difficult to update the webpage when you’re having the craziest / busiest / funnest (sp?) year of your life. Here are some of the many cool things I got into since my last update.

MARCH 2018:
Attended another Ocean Memory workshop / meeting / get-together. I drove up with a new Ocean Memory friend, we surfed, we then picked up another friend (after her special birthday) and drove into the Santa Cruz mountains (where Djerassi is). I’m very lucky to be involved with these weird, wonderful, and crazy smart people. Next stop: Catalina Island (I’m organizing!)

All of us are artists and scientists and this is the moment when we conceived of the “Sawtooth Collective”. More to come…
banana slugs are real. 
these are famous people. sitting on a piece of art in the woods. that’s what kind of place we were working in. 
fantastic dinners for the Ocean Memory investigators
my lodging was in an old horse stable. this was my source of heat. i loved it.

APRIL 2018:
I officiated a wedding in Pioneertown, CA.

Me, my wife, and a cactus (center).

May 2018:
Attended the Tropical Pacific Observing System 2020 planning workshop in Boulder, CO.


JUNE 2018:
Attended the National Academies Keck Futures Initiative mid-grant meeting.


Also visited some friends at JCVI to talk about a new project. This will be some straight-up incredible stuff—if it works!


JULY 2018:
I received a mini-fellowship to learn about “paleo pCO2” methods. In my proposal, I asked to make some preliminary measurements of boron isotopes with my buddies James Rae and Will Gray in St. Andrew’s Scotland. We got some very interesting results and I also went surfing in the Atlantic.

AUGUST 2018:
Goldschmidt conference in Boston, MA. Very fun times.

the charles river

Travel starts to slow down, but everything is now coming due (lots of job applications going out the door). Also gave a talk at USC.


Gave a talk at UW—the University of Washington. I had been waiting for this day for a long time. Gave the best talk of my life, had many great conversations, ate some good food, enjoyed some fall foliage… so many great friends.



Podcast Preview

Did I mention I am starting a podcast? It is called, “Oceanography Is Fun”… because it is! We (myself and co-host Kate Mackey) have been talking with ocean and climate scientists about how they got where they are, their challenges, their successes, and their advice for others. We will begin releasing episodes after we have a few for you to peruse—sometime in March. We have some interviews finished and will be conducting several more at next month’s Ocean Sciences meeting. Frequency is expected to be a new episode every 2 weeks. Here’s a tentative image for the pod:


Blogging Backlog (Sept. 2017-Dec. 2018)

December 2018 events

AGU. Chaired an interesting session on the climate-volcanism connection. Crazy line-up of speakers:


Wally couldn’t make it, so we had an informal series of lightning talks by Kim Cobb and more.

November 2018 events

My paper describing a new model for nitrate consumption in iron-limited ocean regions was published in Nature Communications in October, but it had a major error (their fault—they didn’t perform all the proof corrections I asked). It was finally fixed and here it is ( prafter-2017-NatureCommFront


I also paid a visit to my pals at Cal Tech to talk oceanography, science, and proxies:


October 2018 events

I was on the Comer family farm in Wisconsin for the Comer Family Foundation Climate Conference (a.k.a. “The Changelings Meeting”). Great people, great food, beautiful place, great time. Here I am presenting my research on producing a glacial-interglacial carbon budget of the Gulf of California—work that suggests increased deglacial seafloor volcanism (in review at PNAS) to Wally Broecker:


September 2018 events

Visited Friday Harbor Laboratory in Puget Sound, WA for the Ocean Memory Workshop. It was jus as weird as it sounds. For example, we made this thing (this is me standing with John Baross, an important figure in origin-of-life science):



Blogging backlog


August 2017: While back east, I visited the Smithsonian’s deep sea coral archives in Washington D.C. Not sure we will get interesting, usable data, but my trip was fruitful (I learned a lot).

July 2017: Gordon Chemical Oceanography (in New London, NH)
I was very happy to give a talk at the Gordon Seminar, then present my poster at the Gordon Conference. Great talks by old and new friends.

June 2017: I was one of 4 scientists to be honored by AGU as an “Outstanding Reviewer” for 2 journals. This kind of thing makes me very excited because my reviews for one journal (GBC) were all modern biogeochemical studies. My reviews for the other journal (GRL) were all paleoceanographic studies.


April 25th: Visited Rutgers University. Gave the “Ice and Fire and CO2” talk. Stayed with Yair Rosenthal (thanks!)

A (literal) song of ice and fire and CO2

I’ve been giving a talk on my latest research titled “A song of ice and fire and CO2,” which is (of course) an homage to the sometimes-great/sometimes-ridiculous series of books by George R. R. Martin. (You may have heard of the most popular television series in the world called Game of Thrones, which is based on these books.)

I gave this talk at Pomona College the other day and was pleasantly surprised that most of the students “got it”. I say this because it’s a complicated story and they were all undergraduates.

Not only did they get it, but one student actually WROTE A SONG ABOUT MY RESEARCH!

Here it is:

My sincerest thanks for Anika Arvanitis for her work!