The contribution of marine aggregate‐associated bacteria to the accumulation of pathogenic bacteria in oysters: an agent‐based model. Issue 20 (24th September 2016)

• Record Type: Journal Article
• Authors: Kramer, Andrew M.; Ward, J. Evan; Dobbs, Fred C.; Pierce, Melissa L.; Drake, John M.
• Is Part Of: Ecology and evolution. Volume 6:Issue 20(2016:Nov.)
• Page Start: 7397
• Page End: 7408
• Publication Date: 2016-09-24
• Subjects: aquatic pathogens -- attached bacteria -- marine snow -- organic aggregates -- Vibrio species -- waterborne disease; Ecology -- Periodicals; Evolution -- Periodicals; 577.05
• DOI: 10.1002/ece3.2467
• Languages: English
• ISSNs: 2045-7758

Abstract

Abstract: Bivalves process large volumes of water, leading to their accumulation of bacteria, including potential human pathogens (e.g., vibrios). These bacteria are captured at low efficiencies when freely suspended in the water column, but they also attach to marine aggregates, which are captured with near 100% efficiency. For this reason, and because they are often enriched with heterotrophic bacteria, marine aggregates have been hypothesized to function as important transporters of bacteria into bivalves. The relative contribution of aggregates and unattached bacteria to the accumulation of these cells, however, is unknown. We developed an agent‐based model to simulate accumulation of vibrio‐type bacteria in oysters. Simulations were conducted over a realistic range of concentrations of bacteria and aggregates and incorporated the dependence of pseudofeces production on particulate matter. The model shows that the contribution of aggregate‐attached bacteria depends strongly on the unattached bacteria, which form the colonization pool for aggregates and are directly captured by the simulated oysters. The concentration of aggregates is also important, but its effect depends on the concentration of unattached bacteria. At high bacterial concentrations, aggregates contribute the majority of bacteria in the oysters. At low concentrations of unattached bacteria, aggregates have a neutral or even a slightly negative effect on bacterial accumulation. These results provide the first evidence suggesting that the concentration of aggregates could influence uptake of pathogenic bacteria in bivalves and show that the tendency of a bacterial species to remain attached to aggregates is a key factor for understanding species‐specific accumulation. Abstract : Marine aggregates may act as vectors for the transport of pathogenic bacteria into shellfish because they are retained more efficiently than individual bacterial cells. The relative contribution of aggregates and unattached bacteria is an open question, and we developed a model to simulate accumulation of vibrio‐type bacteria in oysters. We show that the contribution of aggregates depends primarily on the concentration of unattached bacteria in the water because they form both the colonization pool for aggregates and a direct source of uptake.