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Reposted by Patrick Rafter

USF College of Marine Science @cmarinescience.bsky.social · 23h

🌊In a new study co-led by USF professor @oceanandclimate.bsky.social Patrick Rafter, researchers used forams from the Pliocene to show that warming in the tropical Pacific may not trigger the severe decline in nutrients predicted by earlier models.
www.usf.edu/marine-scien...

How ancient plankton point to the resilience of ocean ecosystems

The researchers used a cutting-edge approach to predict future ocean conditions by examining the distant past through analyses of microscopic fossils.

www.usf.edu

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Reposted by Patrick Rafter

Ocean Carbon & Biogeochemistry (OCB) @usocb.bsky.social · 23h

New paper providing paleo perspectives on tropical ecosystems from former OCB SSC member @oceanandclimate.bsky.social

USF College of Marine Science @cmarinescience.bsky.social · 23h

🌊In a new study co-led by USF professor @oceanandclimate.bsky.social Patrick Rafter, researchers used forams from the Pliocene to show that warming in the tropical Pacific may not trigger the severe decline in nutrients predicted by earlier models.
www.usf.edu/marine-scien...

How ancient plankton point to the resilience of ocean ecosystems

The researchers used a cutting-edge approach to predict future ocean conditions by examining the distant past through analyses of microscopic fossils.

www.usf.edu

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Reposted by Patrick Rafter

Tessa Hill @tessahill.bsky.social · 2d

Working on a project that requires pulling together a lot of literature on public engagement/ community engagement in marine science disciplines. I’ve done a traditional literature search - but if you have a favorite project, paper, or scientist in this realm, please post a link or DM me! #oceans

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Patrick Rafter @oceanandclimate.bsky.social · 3d

Yep. For sure. Although about that motive… I have forgotten to cite papers that were really obvious (& written by a good friend!). I try really hard to include all relevant studies but there are so many papers nowadays. Sometimes one (or more) slip through. We can hope for peer review to catch it?!

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Patrick Rafter @oceanandclimate.bsky.social · 5d

Our communications people @cmarinescience.bsky.social worked hard on these press releases, feel free to read it and also feel free to laugh about the "rare isotopes" line (as some friends have done), but they're not wrong—15N is rare!
www.usf.edu/marine-scien...

How ancient plankton point to the resilience of ocean ecosystems

The researchers used a cutting-edge approach to predict future ocean conditions by examining the distant past through analyses of microscopic fossils.

www.usf.edu

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Patrick Rafter @oceanandclimate.bsky.social · 5d

In @jfarmersalmanac.bsky.social 's post, he rightly cites the work by @hl-ford.bsky.social as being a HUGE influence. She is not only a great scientist, she also makes sure everyone in the hotel gets to the conference on time (!) and she gave a great talk at ICP last month!

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Patrick Rafter @oceanandclimate.bsky.social · 5d

Coda:

@jfarmersalmanac.bsky.social wrote a really nice thread that goes into some more detail here: bsky.app/profile/jfar...

Jesse Farmer @jfarmersalmanac.bsky.social · 5d

Very excited to be a part of this epic journey with @oceanandclimate.bsky.social. Check out our #NSFfunded paper published in @science.org today & his thread below. After that, come back here for more... (1/n)

Patrick Rafter @oceanandclimate.bsky.social · 5d

Today, we published a study long in the making on how upper and subsurface tropical Pacific waters responded (and maybe will adjust) to warmer global climate. Here’s the story of how we got here after 15 years. many authors but shout out @jfarmersalmanac.bsky.social
🌊
www.science.org/doi/10.1126/...

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Patrick Rafter @oceanandclimate.bsky.social · 5d

So many people to thank for this (see acknowledgments below), but also my huge thanks to all the co-authors. Danny Sigman and his lab (where we made all the foram-bound N isotope measurements) and co-lead author @jfarmersalmanac.bsky.social for special shoutouts

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Patrick Rafter @oceanandclimate.bsky.social · 5d

Near the end now: Ultimately, this publication represents massive patience (and frustration) as a scientist. We could have published the early results many years ago, but they were too weird! And inconsistent with existing data! But here, we have two independent proxy tools showing the same thing

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Patrick Rafter @oceanandclimate.bsky.social · 5d

These other results suggest that warmer climates have *better* oxygenated Pacific waters. This would only play out on decadal or longer timescales, but more potentially good news with global warming (as long as future overturning circulation acts as we have reconstructed)

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Patrick Rafter @oceanandclimate.bsky.social · 5d

In other words, decreasing oxygenation of the tropical Pacific subsurface waters over the past 5 million years. This fits with observations from further back in time by @anya-hess.bsky.social, @alexauderset.bsky.social, & more

See these:
www.nature.com/articles/s41...
www.nature.com/articles/s41...

A well-oxygenated eastern tropical Pacific during the warm Miocene - Nature

Analysis of palaeoceanographic proxies sensitive to oxygen-deficient zone extent and intensity show that the eastern tropical Pacific was well oxygenated during the warm Miocene, agreeing with model simulations that suggest that the recent deoxygenation trend may eventually reverse.

www.nature.com

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Patrick Rafter @oceanandclimate.bsky.social · 5d

Now, how about those long-term trends toward higher N isotope values observed in all N isotope measurements? On these timescales (i.e., much longer than ocean overturning), these higher N isotope trends likely reflect changes in Pacific water column denitrification in oxygen-depleted waters

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Patrick Rafter @oceanandclimate.bsky.social · 5d

(Note that I always hesitate to make that statement above because of how it can be taken out of context. None of us are saying global warming is good, only that the existing data for the tropical Pacific suggest it will not lead to devastating impacts on regional fisheries.)

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Patrick Rafter @oceanandclimate.bsky.social · 5d

What do these results mean for the future? Well, using the warm Pliocene as a future analog, this would suggest an upper ocean feedback where upwelling—and the delivery of nutrients like nitrate—persists regardless of changing trade winds. This could be a rare source of good news with global warming

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Patrick Rafter @oceanandclimate.bsky.social · 5d

We built a box model to help explain how changes in wind-forcing (x axis) in the warm Pliocene might be balanced by decreased surface ocean stratification / increased buoyancy (y axis). Huge shout out to anonymous reviewer for asking for this and @oceansclimatecu.bsky.social for making it happen!

The results of a box model comparing wind stress (Tau-x; on the x axis) to buoyancy frequency (N^2; y axis). The diagonal colored lines of this figure show the changes in upwelling possible for the different x and y values. An orange arrow shows how modern conditions (estimated from Karnauskas' new 2025 paper in Journal of Climate) can retain the same upwelling rate despite weaker wind forcing.

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Patrick Rafter @oceanandclimate.bsky.social · 5d

We argue that this reduced eastern equatorial Pacific stratification during the warm Pliocene makes sense when considering that: (1) subsurface tropical waters originate at higher latitudes and (2) global warming leads to *more* warming at high latitudes. Warmer = less dense and more buoyant.

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Patrick Rafter @oceanandclimate.bsky.social · 5d

If the Pliocene trade winds were weaker—and the zonal SST gradient says they were—the only way to solve this mystery is if the upper ocean density gradient was less (i.e., it was “easier” to upwell). In other words, the Pliocene eastern equatorial Pacific subsurface must have been *less* stratified

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Patrick Rafter @oceanandclimate.bsky.social · 5d

The nutrient tongue persisted! It abides, even!

The presence of the eastern nutrient tongue during the Pliocene tells us that eastern upwelling was not very different than today.

a man with long hair and a beard is holding a glass of beer

ALT: a man with long hair and a beard is holding a glass of beer

media.tenor.com

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Patrick Rafter @oceanandclimate.bsky.social · 5d

The point of making planktic foraminifera-bound N isotopes is that they: (1) Largely record the same N isotope value as nitrate and (2) That N isotope value is safely locked inside the carbonate test of these microscopic fossils.

We found the same trends!

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Patrick Rafter @oceanandclimate.bsky.social · 5d

US Budgetary Sequester==2013 Proposal declined. I had to leave Princeton and joined @ucirvine.bsky.social. I submitted the proposal again in 2014... declined. Again in 2016—funded!

So we got to work, but now with only about 50% of the funding we needed to actually do it (!). So here we are.

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Patrick Rafter @oceanandclimate.bsky.social · 5d

... or the bulk sediment N isotopes are suggesting there was NO CHANGE in the eastern equatorial Pacific nutrient tongue over the past 5 million years.

I didn't trust this coincidence, so I asked the National Science Foundation for funding to make "gold standard" N isotope measurements on forams

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Patrick Rafter @oceanandclimate.bsky.social · 5d

The zonal difference in equatorial Pacific bulk sediment N isotopes (d15N) is a relatively steady ~4 per mil on long timescales and this is essentially identical to what I calculate using measurements of surface ocean nitrate N isotopes AT THE SAME SITES. This is either an incredible coincidence...

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Patrick Rafter @oceanandclimate.bsky.social · 5d

What's unusual about this record is: (1) both records have long-term trends to higher values over the past 5 million years and (2) The difference between these proxy N isotope measurements is essentially unchanged (on >100,000 year timescales).

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Patrick Rafter @oceanandclimate.bsky.social · 5d

The mystery of the weakened winds / upwelling deepens with our new bulk sediment N isotope (d15N) data from the east and western equatorial Pacific (top of image below). (This dataset was largely completed about 10 years ago, but their unusual nature made us cautious about publishing)

A plot showing bulk sediment N isotope measurements from the western equatorial Pacific (WEP) over the past 5 million years. Although there is higher frequency variability (see Rafter & Charles 2012 for description of the past 1 million years), these values start around 5 per mil (parts per thousand) at ~4.5 million years ago and increase about 1 per mil per million years to the present. The bulk sediment N isotopes (d15N) from the eastern equatorial Pacific show similar trends, but at lower values. They begin at about 1 per mil 5 million years ago and increase to about 5 per mil in the most recent measurements.

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Patrick Rafter @oceanandclimate.bsky.social · 5d

(Here I should note that some have suggested other temperature proxies should be used to describe the western equatorial Pacific SSTs, but here we are simply using all the available data. This seemed like the conservative approach to the data, but I’m happy to talk this over in more detail.)

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