AIMS Physico-Chemical and Nutrient Database

This dataset aggregates and summarises the water quality data collected by researchers from the Australian Institute of Marine Science from 1974 until the present. AIMS' biological oceanographers have studied the physical, chemical, and biological properties of seawater around northern Australia using a variety of methods including in situ sampling, moored sensors, and vertical profiles. This dataset contains in situ water quality information (list of analytes shown below) from northern Australia, with a large volume of data from the Great Barrier Reef, Queensland. It also contains an historical dataset transcribed from the reports of the Low Islands Expedition 1928-29 led by C.M. Yonge.

This dataset contains biogeochemical data from many research expeditions (the majority led by Dr. Miles Furnas) as well as records from water quality monitoring programmes. Some data in this record were collected as part of the Great Barrier Reef Marine Monitoring Program for Inshore Water Quality (MMP WQ), which has collected in situ water quality data, along with time-series of temperature, salinity, fluorescence, and turbidity since 2005. More information about the MMP WQ can be found on its metadata record (see link below in Related Information).

Each water sample occurs at a unique combination of geographic location, time, and date. In the AIMS database, samples are assigned a unique alphanumeric identifier (called a ‘station’), which is comprised of a 3-letter area code and a 3-digit station number (e.g. WQM324). Using this code, water chemistry information can be linked to other associated data, such as vertical profiles of the water column (i.e., CTD casts), which can be retrieved from AIMS’ CTD database (link below). Variables in this database include: depth, silicate (Si), ammonium (NH4), nitrite (NO2), nitrate (NO3), dissolved inorganic phosphorus (DIP), dissolved organic carbon (DOC), temperature (Temp), salinity (Sal), particulate nitrogen (PN), particulate phosphorus (PP), particulate organic carbon (POC), total dissolved nitrogen (TDN), total dissolved phosphorus (TDP), Chlorophyll-a (Chl), phaeophytin (Phaeo), suspended solids (SS), Secchi depth, and coloured dissolved organic matter (CDOM). All analytes may not be available at every station.

Brief description of collection, storage and analysis method for parameters:

SAL: 250 mL unfiltered sample, stored refrigerated at 4ºC in screw-top plastic bottle, analysed on Guildline Portasal Salinometer (temperature-compensated and calibrated using OSIL standard seawater as reference)

TEMP: Electronic reversing thermometer attached to Niskin

SECCHI_DEPTH: The average of the vertical disappearance and reappearance depths of a Secchi disc

SS: Filtered onto pre-weighed 47 mm 0.4 µm polycarbonate membrane filter, rinsed with deionised water, dried at 60ºC for 12 hours, gravimetric analysis

CDOM: 50 mL filtered sample (0.2 µm acrodisc), CDOM absorption coefficient at 443 nm calculated from absorbance measured by UV-visible absorption spectroscopy

NH4, NO3, NO2, and DIP: 10 mL filtered sample (0.45 µm minisart), stored frozen at -25°C, filtrate analysed on segmented flow analyser

NH4_INSITU: Unfiltered 20 mL sample, processed immediately, OPA fluorescence method (post 2005)

SI: 10 mL filtered sample (0.45 µm minisart), stored refrigerated at 4ºC, filtrate analysed on segmented flow analyser (reported as Si)

PN_SHIM and POC: 500 mL filtered onto 25 mm GF/F, stored frozen at -25ºC, analysed by high temperature combustion (Shimadzu TOC-L)

PP: 250 mL filtered onto 25 mm GF/F (0.7 µm), stored frozen at -25ºC, persulphate digestion of filter, colorific (molybdate blue) analysis on UV-Vis spectrophotometer

TDN_PER and TDP_PER: 10 mL filtered sample (0.45 µm minisart), stored frozen at -25ºC, persulphate oxidation/digestion with mixture of NaOH, boric acid and K2S2O8 in autoclave, analysed on segmented flow analyser

DOC: 10 mL filtered sample (0.45 µm minisart), acidified with 100 µL HCl, stored refrigerated at 4ºC, analysed by high temperature combustion (Shimadzu TOC-L)

CHL and PHAEO: 100 mL filtered onto 25 mm GF/F (0.7 µm), stored frozen at -25ºC, extraction into 10 mL of acetone, read on Turner Fluorometer using acidification method

Data can be downloaded from AIMS' main water quality database (see link below in Data Downloads). Data are presented as depth-weighted means calculated using surface, bottom, and any intermediate samples.

本数据集整合并汇总了澳大利亚海洋科学研究所（Australian Institute of Marine Science，AIMS）研究人员自1974年至今收集的水质数据。AIMS的生物海洋学家采用原位采样（in situ sampling）、锚定传感器、垂直剖面探测等多种手段，对澳大利亚北部周边海域海水的物理、化学及生物特性开展了研究。本数据集包含澳大利亚北部海域的原位水质信息（检测物清单详见下文），其中包含大量来自昆士兰州大堡礁（Great Barrier Reef）的相关数据。此外，数据集还收录了由C.M. Yonge主持的1928-1929年低群岛科考队报告中转录的历史数据集。

本数据集包含多项科考任务（多数由迈尔斯·弗纳斯博士主持）获取的生物地球化学数据，以及水质监测项目的相关记录。其中部分数据源自大堡礁近岸水质海洋监测计划（Marine Monitoring Program for Inshore Water Quality，MMP WQ），该计划自2005年起持续收集原位水质数据，以及温度、盐度、荧光度、浊度的时间序列数据。如需了解MMP WQ的更多详情，可查阅其元数据记录（详见下文“相关信息”中的链接）。

每份水样均对应唯一的地理位置、时间与日期组合。在AIMS数据库中，每份水样被分配一个唯一的字母数字标识符（称为“站位”），该标识符由3位字母区域代码与3位数字站位编号组成（例如WQM324）。通过该标识符，可将水化学信息与其他关联数据进行关联，例如水体垂直剖面数据（即CTD剖面），此类数据可从AIMS的CTD数据库中获取（链接见下文）。本数据库包含的变量包括：水深、硅酸盐（Si）、铵态氮（NH4）、亚硝酸盐（NO2）、硝酸盐（NO3）、溶解态无机磷（DIP）、溶解态有机碳（DOC）、温度（Temp）、盐度（Sal）、颗粒态氮（PN）、颗粒态磷（PP）、颗粒态有机碳（POC）、总溶解态氮（TDN）、总溶解态磷（TDP）、叶绿素a（Chl）、脱镁叶绿素（Phaeo）、悬浮颗粒物（SS）、赛氏盘透明度（Secchi depth）以及有色溶解态有机物（CDOM）。并非所有检测物在每个站位均可获取到有效数据。

各参数的采集、存储与分析方法简述：
- 盐度（SAL）：取250 mL未过滤水样，置于螺旋盖塑料瓶中，于4℃冷藏保存，使用Guildline Portasal Salinometer进行分析（该仪器具备温度补偿功能，以OSIL标准海水作为校准参考）
- 温度（TEMP）：使用安装于尼斯金采水器（Niskin）上的电子颠倒温度计进行测量
- 赛氏盘透明度（SECCHI_DEPTH）：取赛氏盘垂直下沉消失深度与上浮重现深度的平均值
- 悬浮颗粒物（SS）：将水样过滤至预先称重的47 mm、0.4 µm聚碳酸酯滤膜上，用去离子水冲洗滤膜后，于60℃烘干12小时，采用重量法进行分析
- 有色溶解态有机物（CDOM）：取50 mL经0.2 µm Acrodisc滤器过滤后的水样，通过紫外-可见吸收光谱法测量吸光度，计算得到443 nm处的CDOM吸收系数
- 铵态氮（NH4）、硝酸盐（NO3）、亚硝酸盐（NO2）与溶解态无机磷（DIP）：取10 mL经0.45 µm Minisart滤器过滤后的水样，于-25℃冷冻保存，采用流动注射分析仪对滤液进行分析
- 原位铵态氮（NH4_INSITU）：取20 mL未过滤水样，即刻进行处理，采用邻苯二甲醛（OPA）荧光法（2005年之后采用该方法）
- 硅酸盐（SI）：取10 mL经0.45 µm Minisart滤器过滤后的水样，于4℃冷藏保存，采用流动注射分析仪对滤液进行分析（报告值以Si计）
- 颗粒态氮（PN_SHIM）与颗粒态有机碳（POC）：取500 mL水样过滤至25 mm GF/F滤膜上，于-25℃冷冻保存，采用高温燃烧法（岛津TOC-L总有机碳分析仪）进行分析
- 颗粒态磷（PP）：取250 mL水样过滤至25 mm、0.7 µm GF/F滤膜上，于-25℃冷冻保存，将滤膜进行过硫酸盐消解后，采用紫外-可见分光光度计进行钼蓝比色分析
- 总溶解态氮（TDN_PER）与总溶解态磷（TDP_PER）：取10 mL经0.45 µm Minisart滤器过滤后的水样，于-25℃冷冻保存，采用NaOH、硼酸与过硫酸钾混合液在高压灭菌锅中进行过硫酸盐氧化/消解，随后采用流动注射分析仪进行分析
- 溶解态有机碳（DOC）：取10 mL经0.45 µm Minisart滤器过滤后的水样，加入100 µL盐酸进行酸化，于4℃冷藏保存，采用高温燃烧法（岛津TOC-L总有机碳分析仪）进行分析
- 叶绿素a（CHL）与脱镁叶绿素（PHAEO）：取100 mL水样过滤至25 mm、0.7 µm GF/F滤膜上，于-25℃冷冻保存，用10 mL丙酮进行萃取，采用酸化法在Turner Fluorometer上进行读数

数据可从AIMS的主水质数据库下载（详见下文“数据下载”中的链接）。本次发布的数据为采用表层、底层及所有中间层水样计算得到的深度加权平均值。