School of the Environment, Trent University, 1600 West Bank Drive, Peterborough, K9L 0G2, ON, Canada; Université de Toulon, PROTEE, EA 3819, CS60584, 83041, Toulon Cedex 9, France.
School of the Environment, Trent University, 1600 West Bank Drive, Peterborough, K9L 0G2, ON, Canada; Water Quality Centre, Trent University, 1600 West Bank Drive, Peterborough, K9L 0G2, ON, Canada.
Chemosphere. 2018 Mar;195:683-692. doi: 10.1016/j.chemosphere.2017.12.109. Epub 2017 Dec 21.
Nutrient loadings from either point or non-point sources to the environment are related to the growing global population. Subsequent negative impacts of nutrient loading to aquatic environments requires a better understanding of the biogeochemical cycling and better tools to track their sources. This study examines the carbon (C), nitrogen (N) and phosphorus (P) discharge and cycling in a Mediterranean coastal area from rivers to marine sediments and assesses the anthropogenic contributions. Carbon and N concentrations and isotope compositions in rivers particles, surface sediments, and sediment cores were investigated to build up a quantitative multiple-end-member mixing model for C and N isotopes. This model predicts the contribution of four natural and one anthropogenic sources to the sediments and highlighted the anthropogenic fraction of P based on the relationship with anthropogenic δN. Although P is a monoisotopic element and total P concentration has been the sole index to study P loading, this study suggests an alternative approach to differentiate anthropogenic and non-anthropogenic (diagenetic) P, revealed point and non-point sources of P, and the corresponding P loading. Also, the diagenetic P background has been calculated for the 50-cm sediment layer of the whole Bay.
从点源或非点源向环境输入的养分负荷与全球人口的增长有关。随后，养分负荷对水生环境的负面影响需要更好地了解生物地球化学循环，并需要更好的工具来追踪其来源。本研究考察了从河流到海洋沉积物的地中海沿海地区的碳（C）、氮（N）和磷（P）排放和循环，并评估了人为贡献。研究了河流颗粒、表层沉积物和沉积物芯中的 C 和 N 同位素的浓度和同位素组成，以建立 C 和 N 同位素的定量多端元混合模型。该模型预测了四种自然源和一种人为源对沉积物的贡献，并根据与人为 δN 的关系突出了 P 的人为部分。尽管 P 是一种单同位素元素，总 P 浓度一直是研究 P 负荷的唯一指标，但本研究提出了一种区分人为和非人为（成岩作用）P 的替代方法，揭示了 P 的点源和非点源以及相应的 P 负荷。此外，还为整个海湾的 50 厘米厚的沉积物层计算了成岩作用 P 的背景值。
