SALTEx soil oxidation-reduction (redox) potential measurements from the GCE LTER Seawater Addition Long-Term Experiment (SALTEx) between July 2016 and March 2017

SALTEx (Seawater Addition Long-Term Experiment) is a field experiment designed to simulate saltwater intrusion in a tidal freshwater wetland to predict how chronic (Press) and acute (Pulse) salinization will affect this and other tidal freshwater ecosystems. The SALTEx experiment was initiated in 2012 and consists of 31 field plots , each 2.5 m on a side. There are three treatments (Press, Pulse, and Fresh) and two types of controls (with and without sides), each consisting of six replicates. The Press treatment plots receive regular (4 times each week) additions of a mixture of seawater and fresh river water. Pulse plots receive the same mixture of seawater and river water during September and October, which is historically a time of low flow in the river when natural saltwater intrusion occurs. The Fresh treatment plots receive regular additions of fresh river water. Treatment water is added during low tide to facilitate its infiltration into the soil, and all plots are inundated by astronomical tides at high tide. Response measurements include porewater chemistry, specifically concentrations of chloride, sulfate, sulfide, dissolved organic carbon (DOC), ammonium-N, nitrate/nitrite-N, dissolved reactive phosphorus, total phosphorus, total nitrogen, organic nitrogen, carbon:nitrogen ratio, organic-carbon:organic-nitrogen ratio, and pH.

海水添加长期试验（Seawater Addition Long-Term Experiment，SALTEx）是一项旨在模拟潮汐淡水湿地海水入侵过程的野外原位试验，用于预测慢性（Press）与急性（Pulse）盐渍化对该湿地及其他潮汐淡水生态系统的影响。该试验于2012年启动，共设置31个野外样地，单个样地边长为2.5米。试验包含3种处理组（Press、Pulse与Fresh）及2类对照组（带围边与无围边），每组均设6个重复样地。其中，Press处理组样地每周定期施加4次海水与淡水河流的混合水体；Pulse处理组样地仅在每年9月至10月施加上述混合水体——历史水文数据显示，该时段河流径流量偏低，自然海水入侵现象频发；Fresh处理组样地则定期添加淡水河流水体。所有处理组水体均于低潮时施加，以促进其渗入土壤；所有样地均会在高潮时被天文潮汐淹没。试验的响应监测指标包括孔隙水化学特征，具体涵盖氯化物、硫酸盐、硫化物、溶解性有机碳（DOC）、铵态氮、硝态氮/亚硝态氮、溶解性活性磷、总磷、总氮、有机氮、碳氮比、有机碳-有机氮比及pH值。