Marcell Experimental Forest biweekly surface water and monthly porewater chemistry at Bog Lake Peatland, 2007 - ongoing

This data set reports the chemistry of surface and porewater water from the Bog Lake peatland in the Marcell Experimental Forest (MEF) in Itasca County, Minnesota. Surface water has been collected about every other week since 1991 from a pool of water and sampling is ongoing. Once covered with ice, water was sampled in some winters about once a month. Porewaters at five depths (0 to 2 m depths) have been collected about monthly from three different nest of piezometers since 2013, though never when samplers were frozen. Samples are measured for pH, specific conductivity, anions (chloride, sulfate), cations (calcium, magnesium, potassium, sodium, aluminum, iron, manganese, strontium), silicon, nutrients (ammonium, nitrate, soluble reactive phosphorus, total nitrogen, total phosphorus), and total organic carbon. Water temperature in the pool of water at the time of sampling was usually measured. Occasionally, stable water isotopes were measured. Ultraviolet (UV) absorbance, a measure of water color or dissolved organic matter optical properties, was also measured for some samples. More solutes and values will be added as additional metadata are documented, water samples are collected and analyzed (concentrations and isotopes), or archived water samples are analyzed for stable water isotopes. The MEF is operated and maintained by the USDA Forest Service, Northern Research Station.

本数据集记录了美国明尼苏达州伊塔斯卡县马塞尔实验林（Marcell Experimental Forest, MEF）内博格湖泥炭地的地表水与孔隙水化学特征。
自1991年起，研究人员约每两周从一处水塘采集地表水样本，该采样工作目前仍在持续；冬季水塘封冻时，部分时段会以约每月一次的频率采集水样。
2013年起，研究人员通过三套独立的测压管组（piezometer nest），对深度范围0至2米内的5个深度层的孔隙水进行约每月一次的采样，但若采样器冻结则不开展采样工作。
本次检测的指标包括：pH值、比电导率、阴离子（氯化物、硫酸盐）、阳离子（钙、镁、钾、钠、铝、铁、锰、锶）、硅、营养盐（铵态氮、硝态氮、可溶性活性磷、总氮、总磷）以及总有机碳。
采样时通常会记录水塘水体的水温；部分样品还检测了稳定水同位素。
此外，部分样品还测定了紫外（UV）吸光度——该指标可表征水体色度或溶解性有机物的光学特性。
随着补充元数据的整理、水样采集与分析（浓度及同位素检测）工作的推进，或存档水样的稳定水同位素检测完成后，本数据集将新增更多溶质指标与对应检测值。
马塞尔实验林（MEF）由美国农业部林务局北方研究站负责运营与维护。