ROMA (ITALPRESS) – How do peat mowers capture carbon in saturated water environments, where the availability of CO2 can be limited? The answer could be found in a place so far undamaged: the surface of their cells. This is what emerges from an international study published in the New Phytologist magazine, conducted for Italy by researchers of the Institute of Research on Earth Ecosystems of the National Research Council (Cnr-Iret), along with colleagues from Spain, France, Germany, the United States and Japan. The research shows for the first time a relationship between the chemical properties of the cellular surfaces of the Sphagnum and their photosynthetic performance under submerged conditions, connecting two aspects so far mainly studied separately: superficial chemistry and physiology of photosynthesis.
The peat bogs occupy about 3% of the Earth’s surface, but contain almost one third of the carbon present in the soils of the planet. A fundamental part of this capacity depends on the whiskers of the genus Sphagnum, protagonists of the formation of peat and the operation of these ecosystems. To better understand the mechanisms underlying carbon acquisition, researchers analyzed 20 species of Sphagnum and four clones cultivated in the laboratory, combining the analysis of the chemical properties of cell surfaces with photosynthesis and fluorescence measurements of chlorophyll along a broad pH gradient. The results show that the species differ in the quantity of reactive chemical groups present on the cell surface and that a greater presence of these groups is associated with a greater assimilation of CO2. The photosynthesis has been kept in all species even in conditions of water saturation, but with different responses depending on the species and the pH. In particular, Sphagnum palustre L. showed a particularly stable response in the entire pH range analyzed, suggesting a greater ability to adapt to environmental changes.
“The chemistry of the surface has been studied for a long time to understand processes such as ion exchange, acidification and binding of pollutants – explains Anna Di Palma, researcher of the cnr-Iret and first author of the study – Our work shows that the chemistry of biosurfaces should also be considered in the study of how Sphagnum acquire carbon in aquatic environments.” “The peat pots represent important allies against climate change, because they accumulate peat under conditions of stagnation and absence of oxygen, storing large amounts of carbon subtracted to the atmosphere”, continues the scientist. “With climate heating and degradation of these ecosystems, however, the peat decays faster and can free CO2 and CH4, transforming these resources from tanks to greenhouse gas sources, thus contributing to boost heating.”.
Surface chemistry could therefore have a wider role than previously recognized: not only in carbon acquisition, but also in the strategies with which the different species of Sphagnum respond to environmental conditions. The species characterized by more reactive surfaces have also shown a greater potential for bonding dissolved metals, a result that opens possible prospects for biomonitoring, water treatment and the restoration of the peatlands. Another result is the clones of Sphagnum cultivated in axenic conditions, that is in the absence of associated microorganisms. These have maintained the main chemical characteristics observed in natural mosses, confirming their interest as experimental models for the study of Sphagnum and as possible basis for sustainable cultivation programs and Sphagnum farming.
Overall, the study suggests that in order to understand the role of the Sphagnum in the peat pots it is necessary to look at different scales, from the chemistry of the cell surface to the operation of the entire ecosystem. The differences observed among the species could in fact help explain their distribution along the gradients of pH and water availability and, consequently, influence the functioning of the peatlands and their role in the global carbon cycle.
– Cnr press office photos –
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