PhD Dissertation Defense: Matthew Stromberg
Thursday, January 29, 2026 · 12 - 1 PM
Off Campus
Matthew Stromberg, Ph.D. Candidate
Advisors:
Upal Ghosh and Yonathan Zohar
Title:
An Acquired Taste: Geosmin Biokinetics, Tissue Distribution, and Treatment Modeling for Atlantic Salmon in Recirculating Aquaculture Systems
Abstract:
Geosmin off-flavor compromises product quality in recirculating aquaculture systems (RAS), yet predictive tools for managing this challenge remain inadequate. Existing bioconcentration models treat water concentration with simplifying assumptions and omit removal pathways operating in commercial systems, producing parameter inconsistencies that undermine confidence in their predictions. This dissertation develops and validates a mechanistic modeling framework for geosmin biokinetics in Atlantic salmon (Salmo salar) RAS, integrating process engineering approaches with experimental aquaculture science. The research addressed three objectives through complementary experimental and modeling efforts. Controlled trials evaluated TiO₂/UV + H₂O₂ advanced oxidation for accelerating
geosmin depuration, demonstrating 4.3-fold faster tissue clearance relative to controls while revealing that dissolved organic carbon substantially reduces treatment efficacy under production
conditions. Tissue distribution studies across multiple organs established strong blood-tissue correlations (R² > 0.89) supporting blood-based monitoring as a non-lethal alternative to fillet
sampling, and identified ovarian tissue as a preferential geosmin reservoir with potential implications for depuration in maturing fish.
These experimental findings informed development of an enhanced two-compartment model incorporating bacterial biodegradation, volatilization, and dissolved organic carbon partitioning
corrections. Application to published rainbow trout data suggests that unaccounted bacterial degradation may explain the 6-fold discrepancy between fish-fitted and water-fitted rate constants reported in prior work. A three-compartment extension enabled quantitative evaluation
of removal technologies. Model application yielded the first experimentally-derived kinetic coefficients for market-size Atlantic salmon under the tested conditions: k₁ = 30–40 L kg⁻¹ d⁻¹, k₂ = 0.20–0.60 d⁻¹, kₘ = 0.03–0.06 d⁻¹, corresponding to an elimination half-life of
approximately 3.3 days.
The framework provides a foundation for predicting geosmin dynamics and evaluating treatment technologies, though transferability of parameters to other systems and conditions requires further investigation.
LOCATION: Institute of Marine and Environmental Technology (IMET) 701 E Pratt St, Baltimore, MD 21202
Agenda:
12:55 am EST - Welcome / Room Opens
1:00 pm EST - Presentation followed by questions from the audience.
After the questions from the public, the meeting will be closed for the committee discussion.
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