Date of Completion

9-9-2013

Embargo Period

9-9-2013

Advisors

Dr. J. Evan Ward, Dr. Joseph Bushey

Field of Study

Oceanography

Degree

Master of Science

Open Access

Open Access

Abstract

Bioaccumulation of mercury (Hg), especially as methylmercury (CH3Hg), in the aquatic food web is a continuing public health concern. Extensive research has been conducted regarding the uptake of Hg by various aquatic animals via three main vectors: sediment, bioseston, and water, but virtually no research exists with respect to uptake of CH3Hgor inorganic mercury (Hg(II)) associated with marine snow. Marine snow composed of various organic and inorganic materials has been studied as an effective vertical transporter of nutrients and metals scavenged from the euphotic zone to the benthos. As various aquatic species utilize marine aggregates as a food source, particularly bivalve molluscs, these organisms could potentially accumulate CH3Hgand Hg(II) from marine snow into their tissues to a greater degree than from smaller particles. For this study, marine snow was produced from sieved seawater in glass jars spiked with stable-isotope enriched in 199CH3Hg and 200Hg(II) using a roller-table. Blue mussels, Mytilus edulis, were then placed into the jars with the marine snow for two hours. Following the feeding assay, mussels were allowed to depurate for 12, 36, and 72 hours after the feeding period. All tissues from the animals were collected with attention focused on the digestive gland and visceral mass. Overall, the results indicate that the mussels rejected the marine snow. Rather, the mussels were ingesting and assimilating 199CH3Hg and 200Hg(II) from particulates smaller than marine snow. My results conclude that small particles may be a more important source up uptake than marine snow.

Major Advisor

Dr. Robert Mason

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