Meeting Abstract

P2.20  Monday, Jan. 5  Effects of ocean acidification on larval development and settlement of the common intertidal barnacle Amphibalanus amphitrite MCDONALD, Michelle R.*; MCCLINTOCK, James B.; AMSLER, Charles D.; RITTSCHOF, Daniel ; ANGUS, Robert A.; ORIHUELA, Beatriz ; Univ. of Alabama at Birmingham; Univ. of Alabama at Birmingham; Univ. of Alabama at Birmingham; Duke Univ. Marine Laboratory; Univ. of Alabama at Birmingham; Duke Univ. Marine Laboratory mrmcdona@uab.edu

Increased levels of anthropogenic CO₂ released into the atmosphere are anticipated to result in the increased acidification of the world’s oceans. Marine invertebrates that produce calcified body parts may be particularly vulnerable. Barnacles are an ecologically important group of calcified marine invertebrates that are potentially vulnerable to acidification. We examined aspects of larval development (nauplii and cyprids) and juvenile settlement in the common intertidal barnacle Amphibalanus (=Balanus) amphitrite reared in ambient seawater (pH = 8.4) and acidified seawater (pH = 7.4) conditions. pH levels were regulated by bubbling air containing different concentrations of CO₂ into experimental and control beakers containing groups of 800 naupliar larvae each and fed diatoms (Skelotosema costatum). Development of nauplii and cyprids was significantly delayed in the 7.4 pH treatment. Moreover, fewer cyprids settled and metamorphosed into juvenile barnacles at pH 7.4. Our findings indicate that early development and juvenile settlement in A. amphitrite are negatively impacted by exposure to pH 7.4, a level of ocean acidification expected to occur in the next two hundred years.