Interagency Ecological Program: Benthic invertebrate monitoring in the Sacramento-San Joaquin Bay-Delta, collected by the Environmental Monitoring Program, 1975-2022.

The Interagency Ecological Program’s (IEP) Environmental Monitoring Program (EMP) was initiated in compliance with the Water Right Decision D-1379 (now mandated by Water Right Decision D-1641) and has monitored benthic invertebrate macrofauna in the upper San Francisco Estuary (SFE) since 1975. The objectives of the EMP are to obtain consistent and accurate monthly data at established monitoring stations and to report this information for the purpose of management and conservation of the upper San Francisco Estuary. While the EMP also collects discrete and continuous water quality data, along with phytoplankton and zooplankton data, this dataset only includes the benthic invertebrate data collected by the EMP from 1975-2022. EMP monitors invertebrate communities in the benthos of the SFE by collecting dredge samples with a Ponar sampler. Sediment and particles smaller than 0.5mm are removed from the sample using a sieve table. The invertebrates present are preserved in formalin, identified to the lowest possible taxonomic level, and enumerated. Currently, samples are collected monthly at 10 sites across the range of salinities found in the SFE. Four replicate dredge samples are collected at each site. The frequency of sampling, number and identity of sampling sites, and number of replicate samples has changed through the 45+ years of monitoring effort, in response to changes in perceived need for data. Links to other EMP datasets can be found on the EMP website: https://emp-des.github.io/emp-reports/data-links.html.跨机构生态项目（Interagency Ecological Program，IEP）下属的环境监测计划（Environmental Monitoring Program，EMP）依据水权决议D-1379发起，现由水权决议D-1641强制推行，自1975年起持续对旧金山湾上段（San Francisco Estuary，SFE）的底栖大型无脊椎动物开展监测。EMP的核心目标为在固定监测站点获取一致且精准的月度监测数据，并将相关信息公开汇报，用于旧金山湾上段的生态管理与保护工作。尽管EMP同时采集离散与连续水质数据，以及浮游植物、浮游动物相关数据，但本数据集仅收录EMP在1975年至2022年间采集的底栖无脊椎动物数据。EMP采用Ponar采泥器（Ponar sampler）采集采泥样本，以此监测SFE底栖生境中的无脊椎动物群落：通过筛分台去除样本中粒径小于0.5毫米的沉积物与颗粒物，样本中的无脊椎动物将以福尔马林固定，鉴定至尽可能低的分类学层级并进行计数统计。目前，监测工作在SFE盐度梯度范围内的10个站点每月开展样本采集，每个站点采集4份平行采泥样本。四十余年来，根据实际数据需求的变化，采样频率、监测站点的数量与编号以及平行样本数量均经历过多次调整。其他EMP数据集的相关链接可访问EMP官方网站获取：https://emp-des.github.io/emp-reports/data-links.html。