Estuarine monitoring for decision support of agri-food effluent management

卡文迪什农场在PEI的新安南经营着一家大型土豆加工厂。来自这个设施的废水**排放到芭芭拉-韦特河口。由于城市污水的排放、农业的普遍营养强化和卡文迪什污水的排放，河口已经经历了富营养化。富营养化**表现为片状藻类或海生菜的过度生长，导致当地海草**物种的取代)。在严重的情况下，海生会在夏末腐烂，导致氧气减少，从而可能导致生活在河口的生物死亡。卡文迪什农场正在考虑移除污水排放，**并将污水用于土地。考虑到土地应用将相当昂贵，而且卡文迪什农场的污水本身可能会也可能不会对河口的影响做出重大贡献，成本效益分析对于做出这样的决定是**必不可少的。要检查的第一个问题是，进入河口的营养物质有多少是由卡文迪什农场贡献的？这将通过测量流量、营养物浓度和确定进入Barbara-Weit河口的营养物来源来实现。其次，**这项研究将回答该河口目前的健康状况或富营养化水平的问题。这部分将通过对河口进行密集的溶解氧监测来实现。利用研究人员已经开发的区域(圣劳伦斯湾南部)模型，这项研究将使用氧气数据来**回答需要多少氮减少才能改善河口的氧气状况的问题。作为富营养化的第二个衡量标准，我们将利用声纳调查来研究海草和生菜的相对分布情况。可以预测恢复自然植物栖息地需要多少养分去除的区域模型也在开发中。这项研究将为卡文迪什农场提供信息，以**评估污水在土地上应用的成本效益，为河口提供基线监测，以记录**从河口清除污水的效益，还将为**区域模型提供数据，以便能够对圣劳伦斯南湾进行累积影响评估。

Cavendish Farms operates a large potato processing plant in New Annan, PEI. Wastewater from this facility**discharges into the Barbara-Weit estuary. The estuary has undergone eutrophication as a result of municipal**sewage effluent, general nutrient enrichment from agriculture, and the Cavendish effluent. Eutrophication**manifests as an overgrowth of sheets of algae, or sea lettuce, causing displacement of the native seagrass**species). In severe cases, the sea lettuce decomposes in late summer leading to reduced oxygen with potential**mortality of organisms living in the estuary. Cavendish farms is considering removing the effluent discharge,**and land applying the wastewater. Given that land application would be quite costly, and that Cavendish Farm**effluent may or may not itself be contributing significantly to estuarine impacts, a cost benefit analysis is**essential to making such a decision. The first question to be examined is how much of the nutrients entering the**estuary are being contributed by Cavendish Farms? This will be accomplished through measuring the flow,**nutrient concentrations, and determining the origin of nutrients entering the Barbara-Weit estuary. Secondly,**the study will answer the questions of the current health status, or level of eutrophication in this estuary. This**will be partly accomplished by intensive dissolved oxygen monitoring of the estuary. Using regional (Southern**Gulf of St. Lawrence) models already developed by the investigator, this research will use the oxygen data to**answer the question of how much nitrogen reduction is required to improve the oxygen status of the estuary. As**a second measure of eutrophication, the relative distribution of seagrass and sea lettuce will be examined using**boat sonar survey. Regional models that can predict how much nutrient removal is required to restore the**natural plant habitat are also under development. This research will give Cavendish Farms the information to**assess the cost benefits of land application of effluent, provide baseline monitoring for the estuary to document**the benefits of removal of the effluent from the estuary should that occur, and will also contribute data to**regional models to enable cumulative impacts assessment in the Southern Gulf of St. Lawrence.