Date of Award

Fall 12-16-2016

Level of Access

Open-Access Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Oceanography

Advisor

Pete Jumars

Second Committee Member

Damian Brady

Third Committee Member

John Crimalid

Additional Committee Members

Richard Wahle

Xudong Zheng

Abstract

Benthic marine suspension feeders provide an important link between benthic and pelagic ecosystems. The strength of this link is determined by suspension-feeding rates. Many studies have measured suspension-feeding rates using indirect clearance-rate methods, which are based on the depletion of suspended particles. Direct methods that measure the flow of water itself are less common, but they can be more broadly applied because clearance-rate measurements are affected by properties of the cleared particles. We present pumping rates for three species of suspension feeders, the clams Mya arenaria and Mercenaria mercenaria and the tunicate Ciona intestinalis, calculated using a direct method based on particle image velocimetry (PIV). Past uses of PIV in suspension-feeding studies have been limited by strong laser reflections that interfere with velocity measurements proximate to the siphon. We used a new approach based on fitting PIV-based velocity profile measurements to theoretical profiles from computational fluid dynamic (CFD) models, which allowed us to calculate inhalant siphon Reynolds numbers (Re). We used these inhalant Re and measurements of siphon diameters to calculate exhalant Re, pumping rates, and mean inlet and outlet velocities. Measured flows covered a wide range of Reynolds numbers, with inhalant Re ranging from 8-520 and exhalant Re from 15-1073. Pumping rates ranged from 1.7-7.4 l h-1 for Mya, 0.3-3.6 l h-1 for Mercenaria, and 0.07-0.97 l h-1 for Ciona. Combining PIV data with CFD models may be a useful approach for future suspension feeding studies.

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