Eutrophication is a challenge to coastal waters around the globe. In many places, nutrient reductions from land-based sources have not been sufficient to achieve desired water quality improvements. Bivalve shellfish have shown promise as an in-water strategy to complement land-based nutrient management. A local-scale production model was used to estimate oyster (Crassostrea virginica) harvest and bioextraction of nitrogen (N) in Great Bay Piscataqua River Estuary (GBP), New Hampshire, USA, because a system-scale ecological model was not available. Farm-scale N removal results (0.072 metric tons acre⁻¹ year⁻¹) were up-scaled to provide a system-wide removal estimate for current (0.61 metric tons year⁻¹), and potential removal (2.35 metric tons year⁻¹) at maximum possible expansion of licensed aquaculture areas. Restored reef N removal was included to provide a more complete picture. Nitrogen removal through reef sequestration was ~ 3 times that of aquaculture. Estimated reef-associated denitrification, based on previously reported rates, removed 0.19 metric tons N year⁻¹. When all oyster processes (aquaculture and reefs) were included, N removal was 0.33% and 0.54% of incoming N for current and expanded acres, respectively. An avoided cost approach, with wastewater treatment as the alternative management measure, was used to estimate the value of the N removed. The maximum economic value for aquaculture-based removal was $105,000 and $405,000 for current and expanded oyster areas, respectively. Combined aquaculture and reef restoration is suggested to maximize N reduction capacity while limiting use conflicts. Comparison of removal based on per oyster N content suggests much lower removal rates than model results, but model harvest estimates are similar to reported harvest. Though results are specific to GBP, the approach is transferable to estuaries that support bivalve aquaculture but do not have complex system-scale hydrodynamic or ecological models.

中文翻译：

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美国新罕布什尔州大湾皮斯卡塔夸河口的牡蛎通过生物萃取去除氮。


富营养化是全球沿海水域面临的挑战。在许多地方，陆地来源的养分减少不足以实现预期的水质改善。双壳类贝类已显示出作为补充陆地营养管理的水中策略的前景。由于没有系统规模的生态模型，因此使用当地规模的生产模型来估计美国新罕布什尔州大湾皮斯卡塔夸河口 (GBP) 的牡蛎 ( Crassostrea virginica ) 收获和氮 (N) 的生物提取。农场规模的氮去除结果（0.072 公吨英亩^-1年^-1 ）被放大，以提供当前（0.61 公吨年^-1 ）和潜在去除（2.35 公吨年^-1 ）的全系统去除估计值）最大限度地扩大许可水产养殖区。恢复后的珊瑚礁 N 去除也包括在内，以提供更完整的图片。通过珊瑚礁封存去除的氮大约是水产养殖的 3 倍。根据之前报告的速率，估计与珊瑚礁相关的反硝化作用在 N 年^-1中去除了 0.19 吨。当包括所有牡蛎过程（水产养殖和珊瑚礁）时，当前和扩大面积的氮去除量分别为输入氮量的 0.33% 和 0.54%。采用避免成本的方法（以废水处理作为替代管理措施）来估算去除的氮的价值。当前和扩大的牡蛎养殖区基于水产养殖的清除的最大经济价值分别为 105,000 美元和 405,000 美元。建议将水产养殖和珊瑚礁恢复相结合，以最大限度地提高氮减排能力，同时限制使用冲突。 基于每个牡蛎氮含量的去除率比较表明去除率比模型结果低得多，但模型收获估计与报告的收获相似。尽管结果是针对 GBP 的，但该方法可以转移到支持双壳类水产养殖但没有复杂的系统规模水动力或生态模型的河口。