Rickard Stenow's Thesis Chapter Published by ISME After Successful Defense on September 6th
Congratulations to AMRI Researcher Rickard Stenow, his supervisor, AMRI Co-PI Helle Plough and co-authors on their recently published ISME article, September 18th.
Single cell dynamics and nitrogen transformations in the chain forming diatom Chaetoceros affinis
Rickard Stenow, Elizabeth K. Robertson, Martin J. Whitehouse & Helle Ploug
The ISME Journal (2023)
Link to article: https://www.nature.com/articles/s41396-023-01511-z
The article unveils new insights into the survival strategies of phytoplankton. These plants often form colonies, which was thought to be a disadvantage when nutrients are scarce. Using cutting-edge techniques involving stable isotopes and high-precision mass spectrometry, Stenow and co-authors examined the behavior of a specific chain-forming diatom, Chaetoceros affinis, and its interactions with attached bacteria.
The investigation showed surprising strategies these phytoplankton use to thrive. In the early stationary phase, these diatoms displayed remarkable consistency in how they used carbon and nitrogen, even within chains of cells. Astonishingly, they found that up to 5% of the nutrients assimilated by the diatoms were shared with nearby bacteria, supporting the rapid growth of these microscopic neighbors.
As the diatoms progressed through different growth phases, their behavior evolved. They shifted from forming long chains to behaving as individuals during the middle phase, where they exhibited a heightened ability to absorb nitrogen from their surroundings. In the late stationary phase, their nutrient usage transformed once more, balancing nitrogen fixation with the uptake of ammonium.
Most notably, Rickard and researchers observed a unique survival strategy in these phytoplankton chains during nitrogen-limited conditions. In this scenario, the diatoms facilitated "microbial gardening" by supporting nearby bacteria, and nutrients were efficiently transferred within the chain. This discovery challenges established ideas about how nutrients circulate in plankton communities, shedding new light on the fascinating world of ocean microorganisms and their resilience in the face of environmental challenges.
Authors and Affiliations
Department of Marine Sciences, University of Gothenburg, Box 461, SE, 405 30, Gothenburg, Sweden
Rickard Stenow, Elizabeth K. Robertson & Helle Ploug
Swedish Museum of Natural History, Box 50 007, SE, 104 05, Stockholm, Sweden
Martin J. Whitehouse