Effects of changes in nutrient loading and composition on hypoxia dynamics and internal nutrient cycling of a stratified coastal lagoon
Effects of changes in nutrient loading and composition on hypoxia dynamics and internal nutrient cycling of a stratified coastal lagoon
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DOI：
10.5194/bg-14-4423-2017
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发表时间：
2017-10
期刊：
影响因子：
4.9
通讯作者：
Yafei Zhu;Andrew McCowan;P. Cook
中科院分区：
文献类型：
--
作者：
Yafei Zhu;Andrew McCowan;P. Cook
抽象的。采用三维水动力-地球化学耦合水质模型，研究了流域营养盐负荷和组成的变化对层状海岸泻湖系统（Gippsland湖）浮游植物动态、缺氧发展和内部营养盐动态的影响。该研究表明，初级生产对溶解无机氮和颗粒有机氮负荷的变化同样敏感，这突出表明需要更好地了解颗粒有机物的生物利用度。分层和沉积物碳富集的缺氧和随后的沉积物磷释放在国王湖的主要驱动力。高初级生产刺激了冬季洪水带来的大氮负荷贡献了几乎所有的沉积物碳沉积（相对于集水负荷），这是最终负责夏季底层水缺氧。有趣的是，内部循环的磷更敏感的变化比总磷负荷的氮负荷，突出了潜在的重要性，氮负荷施加控制系统，成为磷限制（如在夏季固氮蓝藻水华）。因此，目前的研究强调，需要减少总氮和总磷的河口系统的水质改善。
Abstract. The effects of changes in catchment nutrient loading and composition on the phytoplankton dynamics, development of hypoxia and internal nutrient dynamics in a stratified coastal lagoon system (the Gippsland Lakes) were investigated using a 3-D coupled hydrodynamic biogeochemical water quality model. The study showed that primary production was equally sensitive to changed dissolved inorganic and particulate organic nitrogen loads, highlighting the need for a better understanding of particulate organic matter bioavailability. Stratification and sediment carbon enrichment were the main drivers for the hypoxia and subsequent sediment phosphorus release in Lake King. High primary production stimulated by large nitrogen loading brought on by a winter flood contributed almost all the sediment carbon deposition (as opposed to catchment loads), which was ultimately responsible for summer bottom-water hypoxia. Interestingly, internal recycling of phosphorus was more sensitive to changed nitrogen loads than total phosphorus loads, highlighting the potential importance of nitrogen loads exerting a control over systems that become phosphorus limited (such as during summer nitrogen-fixing blooms of cyanobacteria). Therefore, the current study highlighted the need to reduce both total nitrogen and total phosphorus for water quality improvement in estuarine systems.