Photosynthesis and circadian rhythms regulate the buoyancy of marimo lake balls

Dora Cano Ramirez, Saskia de Fraine, Olivia Griffiths, Antony Dodd*

*Corresponding author for this work

Research output: Contribution to journalLetter (Academic Journal)peer-review

11 Citations (Scopus)
344 Downloads (Pure)


Marimo are unusual, attractive and endangered spherical aggregations of the filamentous green macroalga Aegagropila linnaei (Figure 1A–E) [1]. Globally rare, marimo populations persist in cold freshwater lakes in Japan, Iceland and Ukraine. Marimo occupy both the lake bed and rise to the lake surface [2,3]. Here, we show that marimo buoyancy is conferred by bubbles arising from photosynthesis. We find that light-induced acquisition of buoyancy by marimo is circadian-regulated. We identify that there are circadian rhythms of photosynthesis in marimo, which might explain the circadian rhythm of buoyancy in response to light. This identifies a circadian-regulated buoyancy response in an intriguing and little-studied plant. Cano-Ramirez et al. show that marimo lake balls are buoyant in the light because photosynthesis causes bubbles to form on the balls. They identified a circadian rhythm in the time marimo take to become buoyant, and identified circadian rhythms of photosynthesis in marimo. These processes might underlie movements of marimo within the water column.

Original languageEnglish
Pages (from-to)R869-R870
Number of pages2
JournalCurrent Biology
Issue number16
Publication statusPublished - 20 Aug 2018


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