Amphibalanus amphitrite begins exoskeleton mineralization within 48-hours of metamorphosis

Barnacles are ancient arthropods that, as adults, are surrounded by a
hard, mineralized, outer shell that the organism produces for protection.
While extensive research has been conducted on the glue-like cement that
barnacles use to adhere to a surfaces, less is known about the barnacle
exoskeleton, especially the process by which the barnacle exoskeleton is
formed. Here we present data exploring the changes that occur as the
barnacle cyprid undergoes metamorphosis to become a sessile juvenile with
a mineralized exoskeleton. Scanning electron microscope (SEM) data show
dramatic morphological changes in the barnacle exoskeleton following
metamorphosis. Energy dispersive x-ray spectroscopy (EDS) indicates a
small amount of calcium (8%) 1-hour post-metamorphosis that steadily
increases to 28% by 2-days following metamorphosis. Raman spectroscopy
indicates calcite in the exoskeleton of a barnacle 2-days following
metamorphosis and no detectable calcium carbonate in exoskeletons up to
3-hours post-metamorphosis.  Confocal microscopy indicates during
this 2-day period, barnacle base plate area and height increases rapidly
(0.001 mm2/hr and 0.30 µm/hr, respectively). These results provide
critical information into the early life stages of the barnacle, which
will be important for developing an understanding of how ocean
acidification might impact the calcification process of the barnacle
exoskeleton.