Overcoming hydrodynamic challenges in suspension feeding by juvenile Mya arenaria clams

• Published in: Journal of the Royal Society interface Vol. 15; no. 138; p. 20170755
• Main Authors: Du Clos, Kevin T., Jiang, Houshuo
• Format: Journal Article
• Language: English
• Published: England The Royal Society 01.01.2018; The Royal Society Publishing
• Subjects: Adaptation; Adults; Animals; Bivalve; Computer simulation; Feeding; Feeding Behavior - physiology; Filter Feeding; Hydrodynamics; Juvenile; Life Sciences–Physics interface; Models, Biological; Mollusks; Mya - anatomy & histology; Mya - physiology; Mya arenaria; Particle Image Velocimetry; Pumping rates; Siphons; Suspension Feeding; Mya arenaria; suspension feeding; juvenile; particle image velocimetry; bivalve; filter feeding
• ISSN: 1742-5689; 1742-5662; 1742-5662
• DOI: 10.1098/rsif.2017.0755

We present some of the few suspension-feeding measurements and to our knowledge the first velocity-field measurements for early post-settlement juvenile bivalve clams. We verify and extend our experimental results with numerical simulations. For 1.8–2.8 mm shell length Mya arenaria clams, pumping rates ranged 0.03–0.22 μl s−1, inhalant siphon Reynolds numbers (Re) ranged 0.16–0.79 and mean inhalant velocities ranged 0.8–3.2 mm s−1. Owing to the low Re at which they pump and the small diameters of their siphons, juvenile clams are subject to unique hydrodynamic challenges, including high siphon resistance and susceptibility to refiltration. At least three features of juvenile clam siphons differentiate them from those of adults–shorter inhalant siphon length, a more rapid increase in inhalant siphon diameter with shell length, and the presence of a prominent exhalant siphon extension. These features are probably adaptations to the challenges of suspension feeding at low Re.