Soil surface temperature measurements from the GCE-LTER Seawater Addition Long-Term Experiment (SALTEx) Project

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. We are measuring soil surface temperature in the plots as one of the response variables for the SALTEx project.

SALTEx（Seawater Addition Long-Term Experiment，海水添加长期试验）是一项野外模拟试验，旨在模拟潮汐淡水湿地中的海水入侵过程，以预测慢性（Press）与急性（Pulse）盐化作用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，每个样地边长为2.5米。试验包含3种处理组（Press、Pulse与Fresh）以及2种对照组（带围边与不带围边），各组均设置6个重复样地。其中，Press处理组样地每周定期（每周4次）添加海水与淡水河水的混合水体；Pulse处理组样地仅在每年9月至10月添加与Press组相同的海水与河水混合水体——该时段为该河流历史上的枯水期，天然海水入侵事件频发；Fresh处理组样地则定期添加淡水河流水体。处理用水均在低潮时段施加，以促进其渗入土壤；所有样地在高潮时段均会因天文潮汐而被淹没。本项目将样地内土壤表层温度作为响应变量之一开展监测。