New in @PNASNews: Sam Birch estimates river flow and sediment transport rates on ancient Mars and present-day Titan using only channel width and slope. doi.org/10.1073/pnas.2206837…

6/7 The order in which fish populations would have been isolated by this geological mechanism matches the order implied by genetic data.

5/7 As rivers eroded through different types of rock, the extent of metamorphic rock in the upper Tennessee shrank – trapping Greenfin Darter populations in separate tributaries, where they have started to evolve into different species.

4/7 We realized that Greenfin Darters only live in metamorphic rock – not in sedimentary rock. Data from the Tennessee Valley Authority @TVANews.

3/7 We studied the Greenfin Darter as an example. DNA shows that Greenfin Darters living in different tributaries of the upper Tennessee River are genetically distinct, which means they have been isolated from one another for a long time. What’s the mechanism?

New in @sciencemagazine: Maya Stokes shows how rivers eroding through different types of rocks help explain high freshwater biodiversity in old mountain ranges like the Appalachians. With @TJNear @DaeminKim3 @TVAnews doi.org/10.1126/science.add9…

Sediment transport rate depends on how many grains are in motion and how fast they are moving. Santiago Benavides @s_j_benavides shows that when bedload flux is on-off intermittent (punctuated by rare, large bursts), it's because of the "how fast" part. doi.org/10.1029/2022GL101919

Mrs. @MITgeomorph, a.k.a. @LisaVPerron, has been busy writing books for children. Her debut, out today, has some beautiful landscapes and other charismatic patterns from the natural sciences. More info and ordering options here: lisaperronbooks.com/books/#p…

Our paper about grain shape is featured on the cover of @Nature. Led by @EricDealFluvial, with @VendittiLab, @s_j_benavides, @RiverProfile, Ken Kamrin & Qiong Zhang. nature.com/nature/volumes/61…

This week in @Nature, @EricDealFluvial shows how grain shape matters in sediment transport. Work with Ken Kamrin, @VendittiLab, @s_j_benavides. nature.com/articles/s41586-0…