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ORIGINAL RESEARCH article

Front. Mar. Sci.
Sec. Marine Molecular Biology and Ecology
Volume 11 - 2024 | doi: 10.3389/fmars.2024.1368801

Essential amino acid carbon isotope ratios as indicators of marine macrophyte response to environmental variation

Provisionally accepted
Hee Young Yun Hee Young Yun 1Sangil Kim Sangil Kim 2Hyuntae Choi Hyuntae Choi 1Ji-Eun Kim Ji-Eun Kim 1SANG RUL PARK SANG RUL PARK 3Kyung-Hoon Shin Kyung-Hoon Shin 1*
  • 1 Hanyang Universiy, Erica, Ansan, Republic of Korea
  • 2 National Institute of Fisheries Science (NIFS), Busan, Busan, Republic of Korea
  • 3 Jeju National University, Jeju City, Jeju, Republic of Korea

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

    The carbon isotope ratios (δ 13 C) of essential amino acids (EAAs), including valine, leucine, isoleucine, threonine, and phenylalanine, in producers are crucial for explaining food-web structures in marine ecosystems. However, few studies have tested the variability of δ 13 C-EAA values in marine macrophytes, such as seagrass and macroalgae, under changing environmental conditions. In this study, we examined the responses of δ 13 C-EAA values in macrophytes to environmental changes and explored their usefulness in characterizing macrophyte groups and local environments. We tested seagrass and macroalgae collected at different spatial and temporal scales in the field, as well as lab-cultured Ulva algae at various temperature gradients (12℃, 20℃, and 27.5℃) with additional nitrogen sources. The results revealed that δ 13 C-EAA values in macroalgae were significantly altered by seasonality and the interactive effects of temperature and nitrogen addition in comparison with meancentered δ 13 C-EAA values (normalized δ 13 C-EAA values relative to the mean of the overall EAAs). The δ 13 C-EAA values detected in macroalgae within a local environment correlated with those of a co-occurring grazer, Caprella. Based on mean-centered δ 13 C-EAA values, macrophyte groups were distinguishable from other group (i.e., the bacteria group) even under diverse environmental conditions. Moreover, the seagrass group did not overlap with the green and the brown macroalgal group, but overlapped considerably with the red macroalgal group. These results suggest that the macrophyte-specific mean-centered δ 13 C-EAA values may be fairly consistent across broad spatial and temporal scales. Despite significant variation in δ 13 C-EAA values, the consistency in mean-centered δ 13 C-EAA values among specific macrophyte groups provides valuable insight into the characteristics of local trophic bases in regions under pressure from dramatic environmental changes.

    Keywords: Compound-specific isotope analysis, physiological ecology, biomarker, Trophic base, Seaweed, Producer, Climate Change

    Received: 11 Jan 2024; Accepted: 29 Jul 2024.

    Copyright: © 2024 Yun, Kim, Choi, Kim, PARK and Shin. 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: Kyung-Hoon Shin, Hanyang Universiy, Erica, Ansan, Republic of Korea

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