Outwelling from tidal salt flats adjacent to the Norman River, Gulf of Carpentaria, Queensland

An array of oceanographic instruments was deployed to coincide with the first summer spring high tide inundation of the salt flats adjacent to the Norman River in November 1985. The instruments were deployed at two sites. Site A was located in the Norman River, where two Interocean Model S4 current meters were suspended in a bottom mounted frame 0.5m and 1.3m above the bottom. A second mooring was deployed, to which an Aanderaa current meter and an Aanderaa water level recorder were attached 1m below the surface. All meters logged data at five minute intervals and each mooring also included an Analite optical fibre nephelometer linked to an Aanderaa data logger, which logged data every 5 minutes.Site P was located in a narrow tidal creek, which drains into the Norman River and has a watershed comprised of only salt flats. An Aanderaa current meter was mounted on the bottom at this site.At site A, water samples were collected from 1m above the bottom and 1m below the surface using 5 litre Niskin bottles every 4 hours over two complete tidal cycles (14-17 November). During this time samples were also collected along the creek in which site P was located using 2 litre glass bottles. Near bottom and near surface water samples were also collected from sites ranging from 10km seaward of the mouth of the Norman River to 50km upstream of the river mouth before (13th November) and after (17th November) the tidal inundation. Water samples were filtered through preweighed 0.4µm Nucleopore polycarbonate membrane filters and stored frozen until analysis for dissolved orthphosphate, nitrate, nitrite and silicate. Separate samples were passed through 25mm diameter GF/F glass fibre filters, which were frozen until analysis for chlorophyll a.The Aanderaa current meters also recorded temperature and conductivity. In addition temperature, salinity and suspended solids were measured with a CTD probe, which included an optical fibre nephelometer. Vertical profiles were measured along the Norman River on the 13th and 17th of November; at hourly intervals for 48 hours at site A; and every 4 hours along the creek from site P. This research was undertaken to measure, for the first time, the outwelling of salt and nutrients from salt flats to a river estuary.

1985年11月，为匹配诺曼河（Norman River）毗邻盐滩首次遭遇夏季大潮漫滩的时段，本研究团队布设了一套海洋观测仪器阵列。仪器共布设至两个站位：站位A位于诺曼河内，两套Interocean S4型海流计（Interocean Model S4 current meter）被安装在底置框架上，分别距水底0.5m与1.3m处；另一套锚系同步布设，其上搭载了一台Aanderaa海流计与一台Aanderaa水位记录仪，安装位置距水面1m以下。所有观测仪器均以5分钟为间隔记录数据，每套锚系还配备了一台与Aanderaa数据记录仪相连的Analite光纤浊度计（Analite optical fibre nephelometer），同样以5分钟间隔采集数据。站位P位于一条狭窄的潮汐汊道（tidal creek），该汊道汇入诺曼河，流域仅由盐滩构成，此处安装了一台固定于水底的Aanderaa海流计。在站位A，研究人员于两个完整潮汐周期（11月14日至17日）内，每4小时使用5升Niskin采水器（Niskin bottle）分别在距底1m与距水面1m处采集水样；同期还在站位P所在的潮汐汊道沿线使用2升玻璃瓶采集水样。在大潮漫滩前（11月13日）与后（11月17日），研究人员还在诺曼河河口向海10km至河口上游50km的沿线站位，采集了近底与近表层水样。所有水样均通过预先称重的0.4μm Nucleopore聚碳酸酯膜过滤器（Nucleopore polycarbonate membrane filter）过滤，冷冻保存以待分析溶解态正磷酸盐、硝酸盐、亚硝酸盐与硅酸盐；另有部分水样通过直径25mm的GF/F玻璃纤维过滤器（GF/F glass fibre filter）过滤，滤膜冷冻保存以待叶绿素a含量分析。Aanderaa海流计还同步记录了温度与电导率，此外研究团队使用搭载光纤浊度计的CTD剖面仪（CTD probe）测量了温度、盐度与悬浮颗粒物浓度。垂直剖面测量于11月13日与17日沿诺曼河开展，在站位A以每小时1次的频率连续48小时采集数据，在站位P所在的潮汐汊道则每4小时采集一次数据。本研究旨在首次量化盐滩向河口水体输出的盐分与营养盐通量。