Thomas Arnold is a professor of Biology at Dickinson College.

Myora Springs is one of many groundwater discharge sites on North Stradbroke Island (Queensland, Australia). Here spring waters emerge from wetland forests to join Moreton Bay, mixing with seawater over seagrass meadows dominated by eelgrass, Zostera muelleri. We sought to determine how low pH / high CO2 conditions near the spring affect these plants and their interactions with the black rabbitfish (Siganus fuscescens ), a co-occurring grazer. In paired-choice feeding trials S. fuscescens preferentially consumed Z. muelleri shoots collected nearest to Myora Springs. Proximity to the spring did not significantly alter the carbon and nitrogen contents of seagrass tissues but did result in the extraordinary loss of soluble phenolics, including Folin-reactive phenolics, condensed tannins, and phenolic acids by ≥87%. Conversely, seagrass lignin contents were, in this and related experiments, unaffected or increased, suggesting a shift in secondary metabolism away from the production of soluble, but not insoluble, (poly)phenolics. We suggest that groundwater discharge sites such as Myora Springs, and other sites characterized by low pH, are likely to be popular feeding grounds for seagrass grazers seeking to reduce their exposure to soluble phenolics.

Arnold, Thomas, Grace Freundlich, Taylor Weilnau, Arielle Verdi, and Ian R. Tibbetts. Impacts of Groundwater Discharge at Myora Springs (North Stradbroke Island, Australia) on the Phenolic Metabolism of Eelgrass, Zostera muelleri, and Grazing by the Juvenile Rabbitfish, Siganus fuscescens. PLOS ONE 9, no. 8 (2014): e104738. https://doi.org/10.1371/journal.pone.0104738

Copyright: © 2014 Arnold et al. This is an Open Access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Open Access publication of this article was made possible with grant support from Waidner-Spahr Library distributed through the Dickinson College Research & Development Committee.

This published version is made available on Dickinson Scholar with the permission of the publisher. For more information on the published version, visit PLOS ONE's Website. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0104738