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ORIGINAL RESEARCH article

Front. Freshw. Sci.
Sec. Freshwater Species Evolution and Ecology
Volume 2 - 2024 | doi: 10.3389/ffwsc.2024.1421114

Comparison of carbon uptake strategies between Chara aspera and Chara tomentosa growing in the brackish Baltic Sea and in the freshwater lakes of Estonia

Provisionally accepted
Gerli Albert Gerli Albert 1*Liina Pajusalu Liina Pajusalu 1Daniel W. Pritchard Daniel W. Pritchard 2Christopher D. Hepburn Christopher D. Hepburn 3Kaire Torn Kaire Torn 1Tiina Paalme Tiina Paalme 1Arno Põllumäe Arno Põllumäe 1Georg Martin Georg Martin 1
  • 1 Estonian Marine Institute, Faculty of Science and Technology, University of Tartu, Tallinn, Estonia
  • 2 Other, Dunedin, New Zealand
  • 3 Department of Marine Science, Division of Sciences, University of Otago, Dunedin, Otago, New Zealand

The final, formatted version of the article will be published soon.

    The carbon acquisition strategies of aquatic photosynthetic organisms play a key role in the growth and survival of a species. There is much research indicating that the predicted changes (e.g., the balance between carbonate species: CO2, HCO3 -, CO3 2-) in the seawater carbonate chemistry, due to ocean acidification, could affect benthic primary producers and their communities.However, considerably less is known about brackish water (e.g., the Baltic Sea), and even less about the possible effects of acidification on freshwater biota. This study aimed to compare the carbon uptake strategies of two dominant charophyte species: Chara aspera and Chara tomentosa growing in freshwater lakes of Estonia and in the brackish NE Baltic Sea. This could indicate how they might respond to the predicted increasing CO2 concentration linked to climate change scenrios. Carbon use strategies in charophytes were determined by analysing natural carbon isotope signatures (δ 13 C), pH drift experiments and photosynthesis vs. dissolved inorganic carbon curves. The study showed that freshwater and brackish water C. aspera and C. tomentosa likely use different carbon uptake mechanisms. Our results indicated that freshwater charophytes preferentially use CO2 and brackish water charophytes HCO3 -, likely due to their local acclimatization to different growth environments. Also, C. tomentosa and C. aspera from the studied lakes are likely carbon saturated (photosynthetic processes are operating at their maximum efficiency due to the availability of dissolved inorganic carbon in their environment) and probably will not gain photosynthetic advantages from acidification. However, the predicted increase in CO2 concentration may positively affect the growth of the charophytes in the brackish Baltic Sea.

    Keywords: Charophytes, Carbon physiology, ocean acidification, macrophytes, Increasing

    Received: 21 Apr 2024; Accepted: 10 Sep 2024.

    Copyright: © 2024 Albert, Pajusalu, Pritchard, Hepburn, Torn, Paalme, Põllumäe and Martin. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Gerli Albert, Estonian Marine Institute, Faculty of Science and Technology, University of Tartu, Tallinn, Estonia

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