AIMS Long-term Monitoring Program sediment analysis data 1992-1996, northern Great Barrier Reef

As a sub-project of the now discontinued water quality component of the AIMS Long-term Monitoring Project, sediments were examined along cross-shelf transects commencing at the mouths of the Johnstone and Barron Rivers, which drain heavily cultivated areas. Results were compared with sediments from a transect commencing near the Pascoe River, which drains an uncultivated area of Cape York. Observations were made between November 1992 and April 1996. Sampling was conducted in alternate dry and wet seasons 1992-1993 but only in wet (summer) season 1994 and 1995. Inshore stations were located within 1 km of the shore and seaward stations approximately 20km offshore.Stations were located along and across the Great Barrier Reef shelf from 3 river mouths (Barron, Johnstone and Pascoe) out to individual reefs: Pascoe River mouth, off Portland Roads, Dolphin Reef, Bourke Reef; Barron River mouth, Port Douglas, Low Isles, Green Island, Thetford Reef, Fitzroy Island; Flying Fish Point (at the mouth of the North Johnstone River), Russell Heads, North Barnard Island, Flora Reef, Feather Reef, Ellison Reef.Nutrient flux samples were examined for dissolved inorganic nutrients (ammonium, nitrite, nitrate, phosphate) using standard automated techniques. Solid-phase nutrients were measured in bulk sediment samples for total organic carbon, total carbon, total nitrogen and total phosphorus. Total carbonate was estimated by the difference between total carbon and total organic carbon concentrations multiplied by 8.33. This research was undertaken to determine the extent of temporal and spatial variability of nutrient regeneration rates and nutrient concentrations in surface sediments of the far northern GBR shelf by:1. assess the role of river run-off in delivering nutrient and sediment loads in the GBR by monitoring changes in the quantities of nutrients (and related variables) in the interstitial porewaters and bulk sediments.2. measure the rates of nutrient flux across the sediment-water interface in order to determine the flux nutrients between the sediments and the overlying water column. Parameters measured: Carbon/Nitrogen Total Bulk Sediment, Particulate Organic Carbon (POC), Sedimentary Organic Carbon, Total Dissolved Carbon, Dissolved Inorganic Nitrogen, Total Dissolved Nitrogen, Total Dissolved Phosphorus, Salinity.The water quality component of the AIMS Long-term Monitoring Project has a separate metadata record.

本数据集为现已终止的AIMS长期监测项目水质子项目的分支研究。研究针对以约翰斯通河与巴伦河河口为起始点的跨陆架断面沉积物展开分析，这两条河流均流经高强度耕作区域。研究将上述采样沉积物与以帕斯科河河口附近为起始点的断面沉积物进行对比，帕斯科河流经约克角的未耕作区域。

观测周期为1992年11月至1996年4月。1992-1993年的采样在干湿季交替开展，而1994年与1995年仅在湿季（夏季）进行采样。近岸站位设置在距岸1公里范围内，离岸站位则位于约20公里的外海区域。站位沿大堡礁（Great Barrier Reef, GBR）陆架分布，覆盖3个河口（巴伦河、约翰斯通河与帕斯科河）直至各珊瑚礁体，具体站位包括：帕斯科河河口、波特兰兹外海、海豚礁、伯克礁；巴伦河河口、道格拉斯港、低岛、绿岛、塞福德礁、菲茨罗伊岛；飞鱼角（北约翰斯通河河口处）、拉塞尔角、北巴纳德岛、弗洛拉礁、费瑟礁、埃利森礁。

营养盐通量样品采用标准自动化技术分析溶解态无机营养盐（铵盐、亚硝酸盐、硝酸盐、磷酸盐）。研究对全量沉积物样品中的固相营养盐进行检测，分析指标包括总有机碳、总碳、总氮与总磷。总碳酸盐通过总碳与总有机碳浓度的差值乘以8.33进行估算。

本研究旨在明确大堡礁北部远岸陆架表层沉积物中营养盐再生速率与营养盐浓度的时空变化程度，具体通过以下两项工作实现：
1. 通过监测间隙水与全量沉积物中营养盐（及相关变量）的含量变化，评估河流径流向大堡礁输送营养盐与沉积物负荷的作用。
2. 测定沉积物-水界面的营养盐通量速率，以明确沉积物与上覆水柱之间的营养盐交换通量。

本次检测的参数包括：全量沉积物碳氮比、颗粒有机碳（Particulate Organic Carbon, POC）、沉积有机碳、总溶解碳、溶解态无机氮、总溶解氮、总溶解磷、盐度。

AIMS长期监测项目的水质组件拥有独立的元数据记录。