Ryan Sponseller

PhD position in Physical Geography, focusing on greenhouse gas dynamics in streams and groundwater

We are hiring a PhD student at Umeå University to work on GHG dynamics in boreal streams and groundwater. See the following advertisement and reach out with any questions!
www.umu.se/en/work-with...
@grocherros.bsky.social

Rising atmospheric CO2 reduces nitrogen availability in boreal forests - Nature Nitrogen isotope tree-ring chronologies show that rising atmospheric CO2 has reduced nitrogen availability in boreal forests in Sweden, suggesting that elevated atmospheric CO2 is causing oligotrophic...

I am really excited to share our new paper, published today in Nature. We show that rising atmospheric CO2 is linked to decling nutrient availability in boreal forest, with implications for the future carbon sink. Kudos to lead author @kelleyrbassett.bsky.social.
www.nature.com/articles/s41...

Does discharge Q drive chemistry C in intermittent streams?

No. They depend more on dry-wet transitions

Highly variable CQ at low Q change to consistent CQ at high Q, signalling a switch from a biogeochemistry-driven dry to flow-driven wet state

agupubs.onlinelibrary.wiley.com/doi/10.1029/...

I'm so excited to share our new paper in Global Change Biology: A network of 18 wildfire chronosequences reveals key environmental drivers and knowledge gaps in the boreal nitrogen balance, with @michael-gundale.bsky.social and others. doi.org/10.1111/gcb....

Asymmetric competition among stream fishes: Do food web pathways affect competitive outcomes? Limiting resources are often unevenly distributed among competing consumers, as larger, more aggressive, fast growing, early emerging, or rapidly reproducing species disproportionately exploit food o...

Asymmetric competition among stream fishes: Do food web pathways affect competitive outcomes? - George - 2024 - Ecosphere - Wiley Online Library esajournals.onlinelibrary.wiley.com/doi/full/10....

Please check out our paper! Share too! #invasivespecies #ecology #foodweb #conservation

New job! Please repost - Post doc @oxuniearthsci.bsky.social on The Security of #CarbonDioxide Drawdown During #EnhancedRockWeathering

Does downstream #carbonate formation happen? How? How much? How quick?

Apply by 12 June

my.corehr.com/pls/uoxrecru...

Global Soil Methane Uptake Estimated by Scaling Up Local Measurements We develop a data-driven approach to refine this global estimate by incorporating local data of 79,800 flux measurements from 198 sites, this novel approach links the global SMU budget to local SMU f....

Global Soil Methane Uptake Estimated by Scaling Up Local Measurements: Jiang et al. in @globalchangebio.bsky.social onlinelibrary.wiley.com/doi/10.1111/...

Last week to apply!

Conceptual figure illustrating predicted biogeochemical responses to changes in network connectivity and streamflow. (a) At the watershed outlet, we predicted NO3− export would increase in response to increasing watershed‐scale connectivity and streamflow, resulting in an enrichment of NO3− downstream. As watershed‐scale connectivity (active surface drainage network length) and streamflow decrease in the dry‐down, NO3− export will decrease due to N source limitations. (b) Throughout the watershed, we predicted the seasonal dry‐down period to be the greatest potential for denitrification to occur given the availability of both NO3− and dissolved organic carbon, anoxic conditions, and decreased streamflow.

Big CONGRATS to @kacizarek.bsky.social!!! Her new paper is out in @agu.org's JGR-B!

The paper has a little bit of everything -- N biogeochemistry, intermittent stream hydrology, concentration-connectivity relationships!

Check it out here: agupubs.onlinelibrary.wiley.com/doi/full/10....

Map of global lake distribution, colored by the number of SWOT overpasses per 21 day cycle. There are many lakes with a high number of SWOT overpasses at high northern latitudes, but there are also tens of thousands to more than a million lakes on every continent. Lakes are graphed by latitude and longitude on the edges of the figure.

Do you work on lakes globally? Check out what is, to my mind, the most complete global database of lakes (~6M) and associated attributes, newly published in WRR. Also the basis for SWOT lake data. agupubs.onlinelibrary.wiley.com/doi/full/10....

🚨We are hiring🚨ECR with a PhD within 7 years? Tenure track position (akin to Assistant Prof) in Earth and Env Data Science at U of Gothenburg, Sweden. Expertise in remote sensing and machine learning. Work on climate change, Earth systems, biodiversity, #EO, #UAV Deadline May 10 tinyurl.com/58ft38du

Work with me on getting depth-discrete profiles of water quality using high-frequency loggers and microCTD measurements! And then let’s be creative to infer mechanisms that could improve mechanistic modeling.

Postdoc (2 years) in aquatic ecosystem ecology

We are hiring a postdoc at Umeå University in aquatic ecosystem ecology. See the link for details!
www.umu.se/en/work-with...
@grocherros.bsky.social

Reviews and syntheses: Variable inundation across Earth's terrestrial ecosystems Abstract. The structure, function, and dynamics of Earth's terrestrial ecosystems are profoundly influenced by how often (frequency) and how long (duration) they are inundated with water. A diverse ar...

My @pnnl.bsky.social colleague James Stegen leads "Reviews and syntheses: Variable inundation across Earth's terrestrial ecosystems" bg.copernicus.org/articles/22/...

Bimodality and alternative equilibria do not help explain long-term patterns in shallow lake chlorophyll-a - Nature Communications Shallow lakes have long been considered an example of alternative equilibria in ecological systems. Here, the authors combine empirical data and simulations to show that the relationship of shallow la...

If plankton to plants
is catastrophic or not
time the great tester
In our group a highlight has been using long-term monitoring data to test ideas in ecology. Here we asked “does the theory of the alternative stable states in shallow lakes stand the test of time?” doi.org/10.1038/s414...

"Abrupt transformation of west Greenland lakes following compound climate extremes associated with atmospheric rivers". This new article in PNAS by Jasmine Saros and colleague Vendy Hazuková is pretty striking www.pnas.org/doi/full/10....

Images of calcium carbonate deposits as travertine, covering leaves, as microbialites, on a macroinvertebrate, as a whiting event in a lake, and as a benthic microbial mat.

My first post on bsky to announce my first solo author paper is out in @aslo.org L&O Letters. doi.org/10.1002/lol2...
Thanks to lots of amazing conversations with collaborators and a call out on that other social media to gather info on lakes, rivers, streams, wetlands, etc with calcium carbonate.

Does tree presence promote or hamper soil organic matter turnover? Well... both! Read about our exciting results from the treeline ecotone in Abisko, Sweden. #gadgil #priming #litterdecomposition onlinelibrary.wiley.com/doi/epdf/10....

From land to sea with a focus on the climate Gerard Rocher-Ros wants to understand the flow of carbon and nutrients to find solutions to climate change.

As of January 1st, Stress Response Modeling at IceLab has officially welcomed @grocherros.bsky.social as a new Assistant professor! Read more about Gerard:
www.umu.se/en/feature/r...
#complexsystems #ecology #environmentalscience #climatechange #carbonflows

We often think of rivers as linear features, but lateral dynamics are just as important and often overlooked!

In our paper we present a framework for the study and management of rivers which emphasises lateral connectivity.

#floodplainconnectivity #riverrestoration

Link to paper shorturl.at/ri3lA

Current and Historical Resource Nitrogen Supply Affects the Eco‐Physiological Traits and the Ionome of a Diazotrophic Cyanobacterium Diazotrophic cyanobacteria can overcome nitrogen (N)-limitation by fixing atmospheric N2; however, this comes with increased energetic, iron, molybdenum, and boron costs. Here, we examined the change...

Check out our new paper in Ecology Letters! We examined how the N-fixing cyanobacteria Dolichospermum's ionome and physiology changed in response to short—and long-term adaptation to different N supplies. Take home: There is a lot more than Fe changing in diazotrophs.
doi.org/10.1111/ele....

Nice opportunity here!

The sky above Umeå has been colorful lately (when it's not pitch black that is).
Everyone in IceLab has seen these.
Except the fish. 🐠
They're just doing their regular fishy things.

I am soon recruiting two PhDs and a postdoc, to work on carbon, methane, metabolism in arctic stream networks. Glad to chat potential opportunities during #AGU24 @agu.org ! There is also soon another postdoc position on oxygen responses to peatland restoration with @ryansponseller.bsky.social ⬇️

Diel dissolved organic matter patterns reflect spatiotemporally varying sources and transformations along an intermittent stream Stream dissolved organic matter (DOM) is a globally important carbon flux and a locally important control on stream ecosystems, and therefore understanding controls on stream DOM fluxes and dynamics ...

New article by Rebecca Hale and others in Limnology and Oceanography: "Diel dissolved organic matter patterns reflect spatiotemporally varying sources and transformations along an intermittent stream" aslopubs.onlinelibrary.wiley.com/doi/full/10....