Comment on Stadmark and Conley (2011) "Mussel farming as a nutrient reduction measure in the Baltic Sea: Consideration of nutrient biogeochemical cycles"

NOAA-National Marine Fisheries Service, NOAA Fisheries Milford Laboratory, Milford, CT, USA.
Marine Pollution Bulletin (Impact Factor: 2.79). 12/2011; 64(2):449-51; author reply 455-6. DOI: 10.1016/j.marpolbul.2011.11.024
Source: PubMed
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    ABSTRACT: Mussel farming is a highly discussed opportunity for inner coastal management measures to counteract the eutrophication of the Baltic Sea. There is currently a lack of detailed feasibility analyses for mussel aquaculture in German coastal waters. In 2010, a blue mussel (Mytilus edulis) farm began operating in the Kiel Fjord. In this study, we present an analysis combining measurements from this farm with a 3D-circulation and ecosystem model. We show that the mussel farm in the Kiel Fjord is incapable of producing harvests as large as farms in Swedish coastal waters. We assess and formulate the impact of the mussel farm on water transparency and calculate the attenuation coefficient and the Secchi depth from model data. Although water quality improvements are low due to the size of the farm, our results show that the area of increased water transparency is not limited to the farm area and even reaches the shoreline. We also examine the economic feasibility of the mussel farm and calculate the size of farm area, necessary to remove 10% of the riverine nutrient loads into the Kiel Fjord. We conclude that mussel farming can be a suitable supporting measure to improve water quality by removing nutrients and increasing water transparency in Kiel Fjord.
    Ocean & Coastal Management 06/2014; 101. DOI:10.1016/j.ocecoaman.2014.04.034 · 1.77 Impact Factor
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    ABSTRACT: Nutrient bioextraction using Gracilaria tikvahiae McLachlan was tested at two sites: one off Fairfield, CT (LIS), and the other at the mouth of the Bronx River Estuary (BRE), during the summer and fall of 2011 and 2012. The estimates of nitrogen (N) removal by Gracilaria over a 90-day growing season were up to 28 and 94 kg N ha−1 at the LIS and BRE sites, respectively. In July 2012, Gracilaria grewup to 16.5% day−1 at BRE and 4.8% day−1 at the LIS site. Tissue N contents at the same periods were 3.7% (BRE) and 1.5% (LIS), respectively. These results demonstrate rapid assimilation of nutrients fueling the growth of new Gracilaria tissue at the BRE site, while nutrients appeared to limit growth at the LIS site during the summer months. The estimated C removal by Gracilaria at the BRE and LIS sites were up to 300 kg ha−1 (LIS) and 727 kg ha−1 (BRE), respectively. The potential economic values of N and C sequestration for the period examined in this study were as high as $311 (LIS) and $940 ha−1 (BRE) for N, and $5.51 (LIS) and $13.32 ha−1 (BRE) for C if seaweed aquaculture would be included in Connecticut's Nitrogen Trading Program. This represents a potential additional economic incentive for seaweed growers, beyond the direct value of seaweed products. The findings in this study showed that seaweed (Gracilaria) aquaculture can be a useful technique for nutrient bioextraction in urbanized coastal waters, such as the estuaries of New York City (BRE) and Long Island Sound.
    Aquaculture 06/2014; 433:148-156. DOI:10.1016/j.aquaculture.2014.05.034 · 1.83 Impact Factor
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    ABSTRACT: Invertebrate animals that live at the bottom of aquatic ecosystems (i.e., benthic macrofauna) are important mediators between nutrients in the water column and microbes in the benthos. The presence of benthic macrofauna stimulates microbial nutrient dynamics through different types of animal–microbe interactions, which potentially affect the trophic status of aquatic ecosystems. This review contrasts three types of animal–microbe interactions in the benthos of aquatic ecosystems: (i) ecosystem engineering, (ii) grazing, and (iii) symbiosis. Their specific contributions to the turnover of fixed nitrogen (mainly nitrate and ammonium) and the emission of the greenhouse gas nitrous oxide are evaluated. Published data indicate that ecosystem engineering by sediment-burrowing macrofauna stimulates benthic nitrification and denitrification, which together allows fixed nitrogen removal. However, the release of ammonium from sediments is enhanced more strongly than the sedimentary uptake of nitrate. Ecosystem engineering by reef-building macrofauna increases nitrogen retention and ammonium concentrations in shallow aquatic ecosystems, but allows organic nitrogen removal through harvesting. Grazing by macrofauna on benthic microbes apparently has small or neutral effects on nitrogen cycling. Animal–microbe symbioses provide abundant and distinct benthic compartments for a multitude of nitrogen-cycle pathways. Recent studies reveal that ecosystem engineering, grazing, and symbioses of benthic macrofauna significantly enhance nitrous oxide emission from shallow aquatic ecosystems. The beneficial effect of benthic macrofauna on fixed nitrogen removal through coupled nitrification–denitrification can thus be offset by the concurrent release of (i) ammonium that stimulates aquatic primary production and (ii) nitrous oxide that contributes to global warming. Overall, benthic macrofauna intensifies the coupling between benthos, pelagial, and atmosphere through enhanced turnover and transport of nitrogen.
    Biogeosciences 12/2013; 10:7829-7846. DOI:10.5194/bg-10-7829-2013 · 3.75 Impact Factor