Effect of aquacultured oyster biodeposition on sediment N₂ production in Chesapeake Bay

Suspension feeding bivalves have the potential to mitigate estuarine and coastal marine eutrophication by permanently removing nitrogen (N) from the system. We conducted an integrated field and laboratory examination of the effect of eastern oyster biodeposition on sediment denitrification (DNF) and...

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Bibliographic Details
Published in:Marine ecology. Progress series (Halstenbek) 2013-01, Vol.473, p.7-27
Main Authors: Higgins, Colleen B., Tobias, Craig, Piehler, Michael F., Smyth, Ashley R., Dame, Richard F., Stephenson, Kurt, Brown, Bonnie L.
Format: Article
Language:English
Subjects:
Animal and plant ecology
Animal, plant and microbial ecology
Biological and medical sciences
Fundamental and applied biological sciences. Psychology
Invertebrates
Mollusca
Sea water ecosystems
Synecology
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Summary:Suspension feeding bivalves have the potential to mitigate estuarine and coastal marine eutrophication by permanently removing nitrogen (N) from the system. We conducted an integrated field and laboratory examination of the effect of eastern oyster biodeposition on sediment denitrification (DNF) and anammox (AMX) rates to quantify the N removal potential of oyster aquaculture using 2 commercial-scale sites in Chesapeake Bay, USA. Sediment N₂ production rates were measured using 2 techniques, 15N isotope tracer (n = 51) and N₂:Ar (n = 30). Oyster biodeposit N-load rates explained 21% of variation in sediment N₂ production (DNF and AMX). Oyster sediment N₂ production rates ranged from 0.00 to 1.56 mmol N m–2 d–1 and were almost always lower than reference sediments. From laboratory-based biodeposit addition and field-based forced biodeposit accumulation experiments, we found ~2.50 mmol N m–2 d–1 to be the maximum sediment N₂ production capacity of these sediments, regardless of increasing organic N or labile organic carbon delivery rates. We found no evidence to support the contention that biodeposition associated with oyster aquaculture significantly impacts annual N removal via sediment N₂ production, i.e. stimulation or inhibition, above reference rates, but there was evidence that sediment NH₄⁺ efflux rates were increased. We estimate the N removal rate via sediment N₂ production at similar oyster cultivation sites (1750 m²) with 5 × 10⁵ oysters ranges from 0.49 to 12.60 kg N yr–1, compared to 2.27 to 16.72 kg N yr–1 at reference sites. Thus, aquacultured oyster biodeposition did not have a ubiquitously enhancing effect on N removal rates via N₂ production and is therefore unlikely to be effective as a policy initiative for eutrophication mitigation.
ISSN:0171-8630
1616-1599
DOI:10.3354/meps10062