We investigated the composition of fatty acids and oxygen consumption rate (OCR) of the settling particulate organic matter (POM) and its potential sources (suspended POM, oyster biodeposits, fouling mussel biodeposits, POM attached on oysters and farm gears) in oyster farms, and estimated their relative contribution to the settling POM using a stable isotope mixing model. The settling POM was lower in both the content of algal-originating fatty acids and OCR compared with those of the potential sources. Furthermore, the content of fatty acids and OCR of settling POM were lower inside than outside the oyster farms. The settling flux of POC was 2–18 times higher inside than outside the oyster farms, with the settling POM estimated to consume on average 5 times more oxygen in the bottom layers. The contribution of oyster biodeposits to the settling POM inside the farms was equivalent to that of other potential sources. Our study highlighted that preventing recruitment and removing sessile organisms from the cultivated organisms and farm facilities such as mussels and microorganisms could be an effective strategy for reducing the amount of POM settling inside the farms. Furthermore, we showed that the fatty acids marker would be a good indicator for predicting the potential of oxygen consumption of various POM sources.

中文翻译：

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牡蛎养殖场沉降颗粒有机物的来源和耗氧量：脂肪酸组成分析的见解

我们研究了牡蛎养殖场中沉降颗粒有机物 (POM) 的脂肪酸组成和耗氧率 (OCR) 及其潜在来源（悬浮 POM、牡蛎生物沉积物、污损贻贝生物沉积物、附着在牡蛎和农具上的 POM），并使用稳定同位素混合模型估计了它们对 POM 沉降的相对贡献。与潜在来源相比，沉降的 POM 中藻源脂肪酸和 OCR 的含量均较低。此外，牡蛎养殖场内沉降的POM的脂肪酸和OCR含量均低于养殖场外。牡蛎养殖场内部 POC 的沉降通量比外部高 2-18 倍，估计沉降的 POM 消耗的底层氧气平均多出 5 倍。牡蛎生物沉积物对养殖场内 POM 沉降的贡献与其他潜在来源相当。我们的研究强调，防止从养殖生物和农场设施中补充和去除固着生物（例如贻贝和微生物）可能是减少农场内 POM 沉降量的有效策略。此外，我们表明脂肪酸标记将是预测各种 POM 来源的耗氧潜力的良好指标。