Research Article: Acorn Barnacles Secrete Phase‐Separating Fluid to Clear Surfaces Ahead of Cement Deposition

Date Published: March 14, 2018

Publisher: John Wiley and Sons Inc.

Author(s): Kenan P. Fears, Beatriz Orihuela, Daniel Rittschof, Kathryn J. Wahl.


Marine macrofoulers (e.g., barnacles, tubeworms, mussels) create underwater adhesives capable of attaching themselves to almost any material. The difficulty in removing these organisms frustrates maritime and oceanographic communities, and fascinates biomedical and industrial communities seeking synthetic adhesives that cure and hold steadfast in aqueous environments. Protein analysis can reveal the chemical composition of natural adhesives; however, developing synthetic analogs that mimic their performance remains a challenge due to an incomplete understanding of adhesion processes. Here, it is shown that acorn barnacles (Amphibalanus (=Balanus) amphitrite) secrete a phase‐separating fluid ahead of growth and cement deposition. This mixture consists of a phenolic laden gelatinous phase that presents a phase rich in lipids and reactive oxygen species at the seawater interface. Nearby biofilms rapidly oxidize and lift off the surface as the secretion advances. While phenolic chemistries are ubiquitous to arthropod adhesives and cuticles, the findings demonstrate that A. amphitrite uses these chemistries in a complex surface‐cleaning fluid, at a substantially higher relative abundance than in its adhesive. The discovery of this critical step in underwater adhesion represents a missing link between natural and synthetic adhesives, and provides new directions for the development of environmentally friendly biofouling solutions.

Partial Text

Barnacle Husbandry: Cyprids were settled on glass‐bottomed Petri dishes (Ted Pella) and reared at the Duke University Marine Laboratory for two weeks, at which point they were juvenile barnacle. Barnacles were shipped to the Naval Research Laboratory where they were placed in ASW (Instant Ocean at 32 ppt) and housed in an incubator operating at 23 °C on a 12 h day/night cycle. ASW was changed three times a week immediately before each feeding.

The authors declare no conflict of interest.




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