Characterization of pigments in photosynthetic benthic biomass on the river bed of the Upper Clark Fork River (Montana, USA) during the algal growing season of 2020

The Upper Clark Fork River (UCFR) Long Term Research in Environmental Biology (LTREB) umbrella monitoring project generating these data is conducted separately and complementarily to the 200-million-dollar (USD) superfund project for ecological restoration of the UCFR, associated tributaries, and head water streams including Silver Bow and Warm Springs Creeks. Restoration along the UCFR in western Montana includes removal of metal-laden floodplain soils, lowering of the floodplain to its original elevation, and re-vegetation of over 70 km of the river’s floodplain closest to contaminant sources. The UCFR LTREB project includes bi-weekly water quality monitoring across the first 200 km of the river and its major tributaries along a gradient of heavy metal contamination associated with historic mining. Monitoring includes inorganic phosphorus and nitrogen concentrations, biotic standing stocks, and dissolved and whole-water heavy metal concentrations. The monitoring program began in 2017 with funding likely to be extended through 2028. The original analytical intent for data in this product was to assess the response of the river algal community to the floodplain restoration. Data are measurements of benthic biomass organic matter standing stocks and pigments associated with primary producers. Benthic biomass data were collected on the UCFR (USGS HUC 17010201) at seven monitoring sites distributed from Warm Springs (near Anaconda, MT) to Bonita (east of Missoula, MT). Data from the Deer Lodge and Garrison sites were obtained from the River Algal Succession Study, a project funded by the Montana Consortium for Research on Environmental Water Systems. Data from Bonita were obtained from the Nitrogen Fixation Algal Study, a Research Experience for Undergraduates project. Benthic samples were obtained using a cylindrical benthic sampler isolating a known area of the river bed. Five samples were obtained at each site. Estimates of organic matter in biomass were obtained from area-normalized ash-free dry mass. Algal pigment concentrations for chlorophyll and phaeophytin were obtained through the use of extraction in acetone followed by spectroscopy. Phycocyanin concentrations were measured in aqueous suspension (in-vivo) with a fluorometer. Biomass compartments were discriminated between epilithon on river bed substrate, epiphyton on filamentous algae, terrestrial coarse particulate organic carbon, deposited fine benthic organic matter, and macrophytes. Data are from the 2020 algal growing season.

生成本数据集的克拉克福克河上游（Upper Clark Fork River, UCFR）环境生物学长期研究（Long Term Research in Environmental Biology, LTREB）综合监测项目，与耗资2亿美元（美元）的UCFR及其相关支流、源头溪流（包括银鲍溪与暖泉溪）生态修复超级基金项目独立开展且互为补充。
位于蒙大拿州西部的UCFR沿岸修复工程包括移除载有重金属的漫滩土壤、将漫滩恢复至原始高程，以及对紧邻污染源的70余公里河流漫滩开展植被恢复工作。
UCFR LTREB项目沿历史采矿活动带来的重金属污染梯度，在河流前200公里河段及其主要支流开展每两周一次的水质监测。监测指标涵盖无机磷与氮浓度、生物现存量，以及溶解态与全水相重金属浓度。
本监测计划始于2017年，资助期限有望延长至2028年。本数据集的原始分析目的为评估河流藻类群落对漫滩修复工程的响应，数据内容为底栖生物量、有机物质现存量以及与初级生产者相关的色素的测量值。
底栖生物量数据采集于UCFR（美国地质调查局水文单元代码USGS HUC 17010201）的7个监测站点，站点分布范围从暖泉（蒙大拿州阿纳康达附近）至博尼塔（蒙大拿州米苏拉东部）。其中，迪尔洛奇与加里森站点的数据来源于《河流藻类演替研究》项目，该项目由蒙大拿州环境水系统研究联盟资助；博尼塔站点的数据来源于《固氮藻类研究》，该项目属于本科生科研体验计划。
底栖样本采用圆柱形底栖采样器采集，该采样器可锁定河床的已知区域，每个站点采集5份样本。生物量中有机物质的估算值通过面积归一化的无灰干重获得。叶绿素与脱镁叶绿素的藻类色素浓度通过丙酮萃取后光谱法测定；藻蓝蛋白浓度则通过荧光光度计在水悬浮液的活体状态下测定。
生物量组分可分为：河床基质上的附石藻类、丝状藻类上的附生藻类、陆地粗颗粒有机碳、沉积的细粒底栖有机物以及大型水生植物。本数据集全部来自2020年藻类生长季的采样结果。