Joshua Weitz
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joshuasweitz.bsky.social
Joshua Weitz
@joshuasweitz.bsky.social
10K followers 3.1K following 2.2K posts

Professor of Biology & Institute for Health Computing, U of Maryland; explores how viruses impact human & environmental health;

'Asymptomatic' (JHU Press - https://bit.ly/asymptomatic_book)
&
'Science Matters' (https://substack.com/@joshuasweitz) .. more

Videos

Joshua S. Weitz is an American biologist. He is both a professor of biology and the Clark Leadership Chair in Data Analytics at the University of Maryland. Previously, he was a professor at Georgia Tech, where he was the founding director of the Interdisciplinary Graduate Program in Quantitative Biosciences. In 2017, he was elected a Fellow of the American Association for the Advancement of Science. .. more

Biology 28%
Environmental science 26%
Posts Replies Media Videos
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joshuasweitz.bsky.social
Joshua Weitz @joshuasweitz.bsky.social · Sep 24
New from #SCIMaP - analysis of the White House’s Proposed FY 2026 National Science Foundation Budget.

Take-home: Slashing NSF by >50% will lead to ~$11 billion in economic loss and extensive job loss and reduced training opportunities in communities nationwide.

Report: osf.io/e8rnc

a 🧵
Economic loss from the White House's NSF FY 2026 Proposed Budget

joshuasweitz.bsky.social
Joshua Weitz @joshuasweitz.bsky.social · 7h
As noted in the thread, there are signs of wins to come (at least in top-line numbers), which will then require vigilance & monitoring to see how agencies spend appropriated funds.

www.aip.org/fyi/congress...
Congress Set to Finalize Science Budgets Rejecting Trump Cuts
The bipartisan deal still reduces funding for many science agencies, including NSF and NASA.
www.aip.org

joshuasweitz.bsky.social
Joshua Weitz @joshuasweitz.bsky.social · 7h
and for more on what Congress has proposed:

www.science.org/content/arti...
Congress set to reject Trump’s major budget cuts to NSF, NASA, and energy science
Appropriators agree instead to keep this year’s spending nearly level
www.science.org

joshuasweitz.bsky.social
Joshua Weitz @joshuasweitz.bsky.social · 7h
For more on the White House vision:

joshuasweitz.substack.com/p/white-hous...
White House Funding Cuts to the National Science Foundation Threaten America’s Global Leadership in Science
Examining the White House's proposed 56% budget cut for NSF as FY 2026 looms.
joshuasweitz.substack.com

joshuasweitz.bsky.social
Joshua Weitz @joshuasweitz.bsky.social · 7h
NSF seeks feedback on 2026-30 strategic plan, including

"Goal 2. Advance American leadership in science and technology by empowering STEM talent."

as Congress pushes back against the White House's FY26 budget that would *slash* STEM talent support.

Respond by Jan 27:
www.nsf.gov/od/updates/n...
Number of people involved in NSF activities according to the White House’s NSF budget projections, from 330K in FY2024 to 90K in FY2026 - 140K fewer. Source: https://joshuasweitz.substack.com/p/white-house-funding-cuts-to-the-national

joshuasweitz.bsky.social
Joshua Weitz @joshuasweitz.bsky.social · 9h
Looking forward to this panel today..

Entitled to Your Own Facts? Science and Public Policy in a “Post-Truth” America

via The American Academy of Political & Social Science

www.aapss.org/events/entit...
Entitled to Your Own Facts? Science and Public Policy in a “Post-Truth” America - Jan 13, 4pm

joshuasweitz.bsky.social
Joshua Weitz @joshuasweitz.bsky.social · 13h
New with @tn-marine-micro.bsky.social, exploring how viral-mediated infection and lysis can fuel the marine food web:

theconversation.com/viruses-aren...
Viruses aren’t all bad: In the ocean, some help fuel the food web – a new study shows how
Marine viruses attack cells, but the material that spills out helps fuels marine life around the world.
theconversation.com

joshuasweitz.bsky.social
Joshua Weitz @joshuasweitz.bsky.social · 1d
Science and Litigation Matters

(post on IDC rates... message applies more broadly)

substack.com/home/post/p-...

Reposted by Joshua S. Weitz

tn-marine-micro.bsky.social
Wilhelm Lab at the University of Tennessee @tn-marine-micro.bsky.social · 1d
Such a great team that included @sullivan-lab.bsky.social , @ab-knox.bsky.social, @jdebruyn.bsky.social, Debbie Lindell and so many amazing staff and students. And yes - still more to come from this project.

artsci.utk.edu/ut-research-...
UT Research Shows Viral Impact on Ocean Oxygen - College of Arts and Sciences
An international research team unveils how viral lysis of blue-green algae in the Sargasso Sea enhances ecosystem-scale productivity. Newly published interdisciplinary research led by the University o...
artsci.utk.edu

joshuasweitz.bsky.social
Joshua Weitz @joshuasweitz.bsky.social · 1d
💯

Space limited in a single post... but clearly there are *many* things wrong with the claim that somehow those vaccines no longer subject to the standard recommendation prevent diseases that are less serious/common.

joshuasweitz.bsky.social
Joshua Weitz @joshuasweitz.bsky.social · 1d
Paper jointly first-authored by two outstanding early career scientists:

Naomi Gilbert
scholar.google.com/citations?us...
&
Daniel Muratore
scholar.google.com/citations?us...

and a collaborative group spanning UT-Knoxville, UMD, Georgia Tech, Ohio State & Technion.

Welcome any/all feedback!

/🧵

joshuasweitz.bsky.social
Joshua Weitz @joshuasweitz.bsky.social · 1d
This was a multi-year, *international* effort made possible by multiple funding organizations, critically the NSF and the Simons Foundation, and supported by the captain and crew of the RV Atlantic Explorer, Rod Johnson & the BATS team, & colleagues across labs.

joshuasweitz.bsky.social
Joshua Weitz @joshuasweitz.bsky.social · 1d
"Seasonal enhancement of the viral shunt catalyzes a subsurface oxygen maximum in the Sargasso Sea"

Gilbert, Muratore et al.
www.nature.com/articles/s41...
Title page from Seasonal enhancement of the viral shunt catalyzes a subsurface oxygen maximum in the Sargasso Sea https://www.nature.com/articles/s41467-025-67002-1

joshuasweitz.bsky.social
Joshua Weitz @joshuasweitz.bsky.social · 1d
In sum: combining oceanographic & transcriptomic & population level measurements, we find that cellular-scale viral infection processes have an ecosystem-scale impact, with infections linked to enhanced productivity.

joshuasweitz.bsky.social
Joshua Weitz @joshuasweitz.bsky.social · 1d
For those interested in the technical side of things, the measurement of infection was done via the iPolony method, led by Debbie Lindell's team at the Technion, which is helping to drive discoveries of lineage-specific virus-host interactions in aquatic systems:

pubmed.ncbi.nlm.nih.gov/32918065/

joshuasweitz.bsky.social
Joshua Weitz @joshuasweitz.bsky.social · 1d
As the paper shows, virus infection in this oxygen-rich band of the ocean is higher than in surrounding waters. Corroborating evidence suggests viral infection and lysis fueled bacterial growth, which, in turn, stimulated the growth of Prochlorococcus & enhanced O2 production.
O2 saturation & infected Prochlorococcus at different depths

joshuasweitz.bsky.social
Joshua Weitz @joshuasweitz.bsky.social · 1d
to observations of viral activity/abundances and ecosystem features (including enhanced microbial abundances and O2 levels) via an intensive, sampling strategy over day-night cycles and across depths.

joshuasweitz.bsky.social
Joshua Weitz @joshuasweitz.bsky.social · 1d
Now out (and yes, years later, because science is hard - it simply is - and because of long delays stemming from the pandemic), our study connects historical data from the Bermuda Atlantic Time Series showing a seasonal sub-mixed layer oxygen saturation

www.st.nmfs.noaa.gov/copepod/time...
a Oxygen saturation data are binned by 5 m depth windows and 12-day means throughout the year. The black line indicates interannual average mixed layer depth for a 10-day window as determined by 0.125 kg/m3 change in potential density from a reference pressure of 10 db. The color bar is scaled such that white refers to an oxygen saturation state of 100% (in balance with the atmosphere), blue colors are undersaturated (suggesting respiration), and red colors are supersaturated (suggesting positive net primary production). Gray lines indicate the annual depth trajectory of potential density surfaces binned at 0.1 kg/m3 resolution, such that color changes between gray lines are along-isopycnal changes in oxygen saturation (with changes from white to red indicating oxygen production and changes from white to blue indicating respiration). Data were retrieved from http://bats.bios.edu/bats-data/

joshuasweitz.bsky.social
Joshua Weitz @joshuasweitz.bsky.social · 1d
... and viral lysis may accelerate remineralization and in turn lead to enhanced productivity by the very microbes they are infecting. In a NSF-supported cruise on late 2019, our team set off to understand the ways in which virus-host linkages transformed ecosystems.

joshuasweitz.bsky.social
Joshua Weitz @joshuasweitz.bsky.social · 1d
But there are nuances; perhaps viral infections generate sticky aggregates that could lead to export of carbon out of the surface to the deeper ocean...

enviromicro-journals.onlinelibrary.wiley.com/doi/full/10....
Viral ecology comes of age
Click on the article title to read more.
enviromicro-journals.onlinelibrary.wiley.com

joshuasweitz.bsky.social
Joshua Weitz @joshuasweitz.bsky.social · 1d
The hypothesis, now known as the viral shunt, is that viral infection and lysis of cells releases organic matter back into the environment, which can be taken up by heterotrophic bacteria and remineralized, fueling the microbial loop and keeping organic matter 'small'.
The lysis of microbes by viruses releases cellular material into the environment. Some of this cellular material can be utilized by microbes for subsequent metabolic processes. Here, we note that available dissolved organic material (DOM) and particulate organic material (POM) is utilized primarily by heterotrophs (the thicker arrow leading downward from the DOM/POM pool). Note that many other processes are not included in this schematic, e.g. sinking out of the system, exudation during growth, light input, or the influx of inorganic carbon and nutrients. Abbreviations: DOM, dissolved organic material; POM, particulate organic material. From: https://pubmed.ncbi.nlm.nih.gov/22991582/

joshuasweitz.bsky.social
Joshua Weitz @joshuasweitz.bsky.social · 1d
Phage are abundant, diverse, and may also transform ecosystem functioning. In the late 1990s, multiple scientists, including @jedfuhrman.bsky.social, @tn-marine-micro.bsky.social, @virosphere.bsky.social, hypothesized ways that viruses make an outsized impact.

joshuasweitz.bsky.social
Joshua Weitz @joshuasweitz.bsky.social · 1d
We now know that phage are ubiquitous in marine environments, with virus densities exceeding 10 million per ml at the surface, 1x-100x greater than microbes.

www.nature.com/articles/nmi...
a, Microbial abundance versus virus abundance coloured by depth. Each point represents a biological sample. Contours denote regions of equal probability distribution in the data set. b, Histogram of the logarithm of VMR. Top and bottom panels correspond to near- and sub-surface water column samples, respectively. The red arrow denotes the median value and the blue arrows denote the central 95% range of values. The numbers associated with each arrow denote the non-transformed value of VMR. from: https://www.nature.com/articles/nmicrobiol201524

joshuasweitz.bsky.social
Joshua Weitz @joshuasweitz.bsky.social · 1d
... but exploring the ecological role of viruses became relevant with landmark papers in the late 1980s that revealed previously untold numbers of marine viruses (or formally, virus-like particles):

www.sciencedirect.com/science/arti...

joshuasweitz.bsky.social
Joshua Weitz @joshuasweitz.bsky.social · 1d
There's more to say on the therapy side of things...

joshuasweitz.substack.com/p/phage-vs-b...
Phage vs. Bacteria: Confronting The Growing Problem of Drug-Resistant Pathogens
Part 2 of a short series introducing the ways in which phage (i.e,. viruses that infect bacteria) can transform human and environmental health.
joshuasweitz.substack.com

joshuasweitz.bsky.social
Joshua Weitz @joshuasweitz.bsky.social · 1d
Phage have been studied for 100+ years, were critical to the development of modern molecular and cell biology... but were just as often neglected (for many reasons) in the realms of ecology and therapy.

www.nobelprize.org/prizes/medic...
Nobel Prize in Physiology or Medicine 1969
The Nobel Prize in Physiology or Medicine 1969 was awarded jointly to Max Delbrück, Alfred D. Hershey and Salvador E. Luria "for their discoveries concerning the replication mechanism and the genetic ...
www.nobelprize.org

joshuasweitz.bsky.social
Joshua Weitz @joshuasweitz.bsky.social · 1d
This study of paradoxical boosts to productivity from viral infection focuses on bacteriophage: viruses that exclusively infect, take-over, and (often) kill their microbial hosts, releasing new viruses into the environment.

www.ncbi.nlm.nih.gov/books/NBK493...
Bacteriophages
Bacteriophages, also known as phages, are viruses that infect and replicate only in bacterial cells. They are ubiquitous in the environment and recognized as the earth's most abundant biological agent...
www.ncbi.nlm.nih.gov

Reposted by Jesse M. Shapiro, Simon Roux, Curtis A. Suttle

joshuasweitz.bsky.social
Joshua Weitz @joshuasweitz.bsky.social · 1d
Viruses transform microbes, populations, & ecosystems.

In new work jointly led w/@tn-marine-micro.bsky.social + more, we find a link between enhanced viral infection and productivity 50 meters below the surface in the otherwise nutrient limited Sargasso Sea.

a 🧵

www.nature.com/articles/s41...
"Seasonal enhancement of the viral shunt catalyzes a subsurface oxygen maximum in the Sargasso Sea" https://www.nature.com/articles/s41467-025-67002-1

joshuasweitz.bsky.social
Joshua Weitz @joshuasweitz.bsky.social · 2d
"This is about whether the Fed will be able to continue to set
interest rates based on evidence and economic conditions, or
whether instead, monetary policy will be directed by political pressure or intimidation."

A summary if/then/else that applies broadly across science, policy, and rule of law.

Reposted by Stephen M. Walt, Anna O. Law, Elizabeth Saunders , and 29 more

cthomasjamh.bsky.social
Charlie Thomas @cthomasjamh.bsky.social · 2d
This is the sort of statement that was expected from every university president and law firm partner over the last year. That those statements weren’t made played a huge part in where we are now and people will remember.
joshuajfriedman.com Joshua J. Friedman @joshuajfriedman.com · 2d
Jerome Powell: "This is about whether the Fed will be able to continue to set interest rates based on evidence and economic conditions—or whether instead monetary policy will be directed by political pressure or intimidation."