Water Quality Data (Grab Samples) from the Taylor Slough, Everglades National Park (FCE LTER), Florida, USA, September 1999 - ongoing

Water quality samples are being collected using ISCO autosamplers at all wetland sites (that is, all sites except TS/Ph-9, 10, and 11). The autosamplers contain 24 1L bottles. Water is sampled by programming the autosamplers to take composite samples once every 3 days. These samples are a composite of four 250mL subsamples drawn every 18 hours (a sampling scheme that captures a dawn, noon, dusk, and midnight sample in every three day composite). The samples are collected every 3-4 weeks and analyzed for total phosphorus (TP), total nitrogen (TN), and salinity. When sites are visited to collect these samples, we also collect a grab sample that is immediately put on ice. A portion of these grab samples is filtered through a Whatman GF/F filter immediately upon return to the lab, and the filtered samples are analyzed for inorganic nutrients such as NO2-, NO3-, NH4+, SRP, and DOC. The unfiltered fraction of these grab samples is analyzed for TP, TN, and TOC. We use these montly grab samples to generate relationships between TP and SRP, and between TN and NO2- + NO3- + NH4+. Dissolved nutrients are measured using standard rapid flow analyzer (RFA) techniques. TP is analyzed with a modified Solorzano and Sharp (1980) technique. TN is measured with an Antec TN analyzer, TOC and DOC are quantified on a Shimadzu TOC Analyzer, and salinity is measured with a YSI conductivity meter. In addition to the regular water quality monitoring, we use the rain level actuators at all freshwater sites to trigger water sampling after rain events exceed a given threshold of duration and/or intensity. As currently programmed, when the threshold of = 2.5 cm of rain per hour is passed, the autosampler at that site collects a 500mL sample 30 minutes after the threshold has been reached. Rain event samples are collected, treated, and analyzed as all other water quality samples.

本研究于所有湿地样点（即除TS/Ph-9、10、11之外的全部样点）采用ISCO自动采样器采集水质样本。该类自动采样器搭载24个1升采样瓶。通过预设程序，自动采样器每3天采集一次混合水样；每批次混合水样由每18小时采集的1份250mL子样本混合而成，该采样方案可在每3天的混合样本中覆盖黎明、正午、黄昏与午夜四个时段的水样。
样本每3至4周采集一次，检测指标包括总磷（TP）、总氮（TN）与盐度。
在前往样点采集上述批量样本的同时，研究团队还会采集瞬时水样（grab sample）并即刻置于冰上保存。返回实验室后，即刻使用Whatman GF/F滤膜对部分瞬时水样进行过滤，过滤后的水样用于检测亚硝酸盐（NO₂⁻）、硝酸盐（NO₃⁻）、氨氮（NH₄⁺）、可溶性反应性磷（SRP）与溶解性有机碳（DOC）等无机营养盐。未经过滤的瞬时水样分样则用于检测TP、TN与总有机碳（TOC）。
研究团队基于上述月度瞬时水样，建立TP与SRP之间、TN与NO₂⁻+NO₃⁻+NH₄⁺之间的定量关联模型。溶解性营养盐采用标准快速流动分析仪（RFA）技术进行检测。总磷的检测采用改良后的Solorzano与Sharp（1980）方法。总氮采用Antec TN总氮分析仪进行检测，TOC与DOC则通过Shimadzu TOC分析仪完成定量，盐度则使用YSI电导仪测定。
除常规水质监测外，研究团队还在所有淡水样点安装雨量触发装置，当降雨事件的时长和/或强度达到预设阈值时，自动启动水样采集流程。按照当前预设程序，当降雨强度达到每小时2.5厘米及以上阈值时，对应样点的自动采样器将在阈值达标后30分钟采集500毫升水样。降雨事件采集的水样与其他常规水质样本采用相同的流程进行采集、前处理与检测分析。