Joonas Virtasalo
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Joonas Virtasalo
@mudjones.bsky.social
100 followers 110 following 35 posts
Senior Scientist at the Geological Survey of Finland (GTK). Interested in science and the sea, the beauty of sediments and sedimentary processes
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mudjones.bsky.social
Two days on an interesting topic❗
🌊28 Oct 2025, seminar Particle Dynamics in Coastal Marine Environments
🧪29 Oct 2025, workshop of #RCF #Phytotrans project on the same topic.
Thank you to the invited speakers and participants!
@gtk-fi.bsky.social
Particle Dynamics on Coastal Marine Environments seminar logo. A vortex where particles of different color aggregate and disaggregate. Group photo of participants in the Phytotrans project's Particle Dynamics in Coastal Marine Environments workshop outside the Geological Survey of Finland office.
October 29, 2025 at 1:07 PM
mudjones.bsky.social
Another successful deployment of the #Finmari benthic lander.

It will measure near-bottom flow, particle and nutrient dynamics for the next 10 weeks in the RCF #PHYTOTRANS project.

@gtk-fi.bsky.social @finmari-ri.bsky.social @syke.fi @tvarminne.bsky.social @spilling.bsky.social
FINMARI benthic lander ready for deployment
August 7, 2025 at 1:53 PM
mudjones.bsky.social
🧪New article on the mineralogy of Baltic Sea #ferromanganese concretions
🌊Mn layers are birnessite with microbially-mediated dendritic texture. Fe layers are ferrihydrite with admixed detrital grains; the layers remain after the dissolution of birnessite.
RCF #Fermaid project
doi.org/10.1016/j.gc...
Synchrotron-µ-XRF maps showing Fe (red) and Mn (green) distributions in (a) discoidal, (b) crust, and (c) spheroidal concretions from the Baltic Sea. The white scale bars equal 500 µm. Original reference: Wasiljeff et al. 2025: Mineral phases and growth conditions of morphologically diverse shelfal ferromanganese concretions. Geochimica et Cosmochimica Acta 400, 227–247, https://doi.org/10.1016/j.gca.2025.05.012
June 29, 2025 at 5:53 AM
mudjones.bsky.social
📣Seen any groundwater springs in the sea? #SecuCoast citizen science campaign is collecting observations!

🧪Submarine springs may be visible as freshwater spots in the sea, as pits on the seafloor, or as openings in the sea ice.

🌊More info and a reporting form:
secucoast.weebly.com/citizen-scie...
A freshwater spot on the sea, emerging from a seafloor spring. An opening on the sea ice, caused by submarine groundwater discharge.
June 28, 2025 at 4:40 AM
mudjones.bsky.social
Oletko nähnyt pohjavesilähteitä meressä? #SecuCoast -hankkeen kansalaistiedekampanja kerää havaintoja!

Merenpohjalähteet erottuvat tavallisesti makean veden kohtina meressä, merenpohjan kuoppina tai aukkoina merijäässä.

Lisätietoja ja havaintojen ilmoituslomake:
secucoast.weebly.com/fi.html
A freshwater spot on the sea, emerging from a seafloor spring. An opening on the sea ice, caused by submarine groundwater discharge.
June 28, 2025 at 4:32 AM
mudjones.bsky.social
📣Seminar: Particle Dynamics in Coastal Marine Environments
28 Oct 2025, Geological Survey of Finland (GTK)

🌊Join us for a full-day seminar exploring the role of particle dynamics in coastal environments

🧪Registration and abstract deadline 30 July 2025
Register here: forms.office.com/e/D0t9pex0PX
Seminar announcement: Particle Dynamics in Coastal Marine Environments Join us for a full-day seminar exploring the role of particle dynamics and the biological pump in coastal environments. We welcome researchers, students and professionals from science, government and industry. The seminar is arranged in collaboration with the PHYTOTRANS project, funded by the Research Council of Finland. Where: Geological Survey of Finland (GTK), Vuorimiehentie 5, Espoo, Finland When: Tuesday, 28 October 2025 at 9:00-16:00. Participation is free of charge. Registration and abstract submission deadline: 30 July 2025 Abstracts (max 200 words) for contributed talks can be submitted through the registration form. Contact: Joonas Virtasalo
May 22, 2025 at 12:59 PM
mudjones.bsky.social
The #Finmari benthic lander was successfully deployed today. It will measure near-bottom flow, particle and nutrient dynamics for the next 6 weeks in the RCF #PHYTOTRANS project.

@gtk-fi.bsky.social @finmari-ri.bsky.social @syke.fi @spilling.bsky.social
FINMARI benthic lander being deployed.
April 17, 2025 at 9:22 AM
mudjones.bsky.social
Maanjäristysten laukaisemat sameusvirtaukset vaikuttavat syvänmeren hautavajoamien pohjan elämään

Toistuvien virtausten ansiosta hautavajoamien pohjaeläinyhteisöjen lajisto ja toiminta ovat ympäröivää syvänmerenpohjaa monimuotoisempia.

@gtk-fi.bsky.social

www.gtk.fi/ajankohtaist...
Tomografiakuva korkkiruuvimaisista Gyrolithes-suvun jälkifossiileista (halkaisijaltaan noin 1 mm), jotka kiertyvät alaspäin sameusvirran kerrostaman sedimenttikerroksen pohjasta. Nämä rakenteet ovat matomaisen eläimen tekemiä onkaloita, jotka ovat jälkeenpäin täyttyneet rikkikiisumineraalilla.
April 7, 2025 at 9:47 AM
mudjones.bsky.social
🌊Earthquake-triggered mass flows regulate benthic communities and bioturbation in the hadal trenches.

@gtk-fi.bsky.social #marinegeology

www.gtk.fi/en/current/e...
Tomographic image of corkscrew-like Gyrolithes trace fossils (ca. 1 mm in diameter) extending downward from the bottom of a sediment layer deposited by a turbidity current. These structures are burrows made by a worm-like animal, later filled with pyrite mineral.
April 4, 2025 at 10:14 AM
mudjones.bsky.social
🧪It is possible to grow #ferromanganese concretions in the laboratory.

🔬The bright patches at the edge of a concretion in the tomography image precipitated during a 12-week laboratory experiment.

⚗️The ferromanganese growth captured Co, V, Ni, Zn, and Mo from solution.

RCF #FERMAID project
Overlay computed tomography image of the edge of a ferromanganese concretion. The bright patches are ferromanganese material that precipitated during a 12 weeks laboratory experiment. Reference: Majamäki, R., Wasiljeff, J., Purkamo, L., Hultman, J., Asmala, E., Yli-Hemminki, P., Jørgensen, K., Koho, K., Kuva, J. & Virtasalo, J.J. 2025: Microbially-enhanced growth and metal capture by ferromanganese concretions in a laboratory experiment. Geobiology 23, e70010.
February 28, 2025 at 8:23 AM
mudjones.bsky.social
Magnetotactic bacteria in the Baltic Sea #ferromanganese concretions produce bullet-shaped magnetosomes.🧪

The magnetosomes are spherical or cubic in the oceanic ferromanganese nodules.

RCF #FERMAID project

Full article:
agupubs.onlinelibrary.wiley.com/doi/10.1029/...
Scanning transmission electron microscope image of a magnetite magnetosome from a Baltic Sea ferromanganese concretion (Wasiljeff et al. 2024, Geochemistry, Geophysics, Geosystems).
February 11, 2025 at 1:41 PM
mudjones.bsky.social
📢WE ARE HIRING!
We invite applications for a 3-year #postdoc position in marine multichannel seismic surveys. The research targets glacial geomorphic features in the northern Baltic Sea, aiming to reconstruct previous glacial dynamics.

More info and how to apply:
valtiolle.fi/en/jobs/post...
November 13, 2024 at 7:36 AM