Australian Rivers Institute, Griffith University, Logan campus, 86 University Dr, Meadowbrook, Queensland, QLD 4131, Australia.
School of Environment and Science, Griffith University, Logan campus, 86 University Dr, Meadowbrook, QLD, 4131, Australia.
Mar Pollut Bull. 2024 Sep;206:116704. doi: 10.1016/j.marpolbul.2024.116704. Epub 2024 Jul 14.
Extreme rainfall from an ex-tropical cyclone caused a major flood event in the Logan River system in southeast Queensland, Australia. This resulted in a significant flood plume, containing nutrients and sediment, being discharged into the adjacent estuary/Bay system. The spatial extent of higher phytoplankton biomass (Chl a) matched the distribution of higher nutrient and sediment concentrations post-flood, suggesting nutrients fuelled phytoplankton production. Particulate nitrogen (PN) constituted over 50 % of total nitrogen in floodwaters, with lower proportions of dissolved inorganic nitrogen (DIN) and phosphate (PO-P). Phytoplankton utilised DIN rapidly but may have maintained growth due to the release of ammonia from suspended sediments and microbial mineralisation of particulate organic nitrogen. Ammonia release from intertidal sediments contributed minimally (0.85 %) to daily phytoplankton nitrogen demands. Our study highlights the need to understand the fate of particulate nitrogen in coastal systems and its role in stimulating phytoplankton growth.
热带气旋带来的极端降雨导致澳大利亚昆士兰州东南部的洛根河系统发生重大洪水事件。这导致大量含有营养物和泥沙的洪水羽流被排放到相邻的河口/海湾系统中。更高的浮游植物生物量 (Chl a) 的空间范围与洪水后更高的营养物和泥沙浓度的分布相匹配，表明营养物质促进了浮游植物的生产。颗粒态氮 (PN) 在洪水中占总氮的比例超过 50%，而溶解无机氮 (DIN) 和磷酸盐 (PO-P) 的比例较低。浮游植物迅速利用 DIN，但由于悬浮沉积物中氨的释放和颗粒有机氮的微生物矿化，可能维持了生长。潮间带沉积物的氨释放对每日浮游植物氮需求的贡献极小 (0.85%)。我们的研究强调了需要了解沿海系统中颗粒态氮的归宿及其在刺激浮游植物生长方面的作用。
