Primary utricle structure of six Halimeda species and potential relevance for ocean acidification tolerance

Katherine E. Peach, Marguerite S. Koch, Patricia L. Blackwelder, Debbie Guerrero-Given, Naomi Kamasawa

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


Variations in utricle morphology may be responsible for different tolerances to ocean acidification (OA) within the macroalgal genus Halimeda, an important sediment producer on reefs. However, differences in species' utricle morphology and their relationship to calcification and crystal formation have not been well articulated. In the present study, we characterized the utricle morphologies of six Halimeda species. Primary utricle ultrastructure was quantitatively and qualitatively compared to tissue inorganic content and crystal microstructure. Morphologies differed across species and several morphometric relationships were revealed. Primary utricle size (r2=0.70) and diffusion pathway length (r2=0.87) had inverse relationships with inorganic content based on regression analyses, and corresponded to crystal microstructure form. Species with large utricles and long diffusion pathways contained more narrow (~0.15 μm) aragonite needles and minimal micro-anhedral crystal formations. In contrast, species with small utricles and short diffusion pathways elucidated aggregates of micro-anhedral crystals and wider aragonite needles (~0.30 μm). Species' utricle characteristics generally corresponded to specific evolutionary lineages. Thus, characteristics of Halimeda utricle morphology may control long-term adaptive responses to OA, an idea articulated in the broader literature.

Original languageEnglish (US)
Pages (from-to)1-11
Number of pages11
JournalBotanica Marina
Issue number1
StatePublished - Feb 2017


  • Halimeda
  • aragonite
  • diffusion pathway
  • microstructure
  • ultrastructure

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Aquatic Science
  • Plant Science


Dive into the research topics of 'Primary utricle structure of six Halimeda species and potential relevance for ocean acidification tolerance'. Together they form a unique fingerprint.

Cite this