Interagency Ecological Program: Benthic invertebrate monitoring in the Sacramento-San Joaquin Bay-Delta, collected by the Environmental Monitoring Program, 1975-2021.

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 1975-2021.
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. 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 1975-2020.

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 40+ years of monitoring effort, in response to changes in perceived need for data.

跨机构生态计划（Interagency Ecological Program, IEP）旗下的环境监测计划（Environmental Monitoring Program, EMP）依据D-1379号水权决议设立，现行强制要求为D-1641号水权决议，自1975年起持续监测旧金山河口上游（upper San Francisco Estuary, SFE）的底栖无脊椎动物大型类群。EMP的目标是在既定监测站点获取一致且精准的月度数据，并为旧金山河口上游的管理与保护工作公开相关信息。尽管EMP同时采集离散与连续水质数据，以及浮游植物、浮游动物数据，但本数据集仅收录EMP在1975年至2021年间采集的底栖无脊椎动物数据。
EMP采用Ponar采泥器（Ponar sampler）采集挖泥样本，以此监测旧金山河口底栖生境中的无脊椎动物群落。通过筛分台移除样本中粒径小于0.5mm的沉积物与颗粒，将采集到的无脊椎动物以福尔马林保存，鉴定至最低可行分类学层级并完成计数统计。
目前，监测人员每月在覆盖旧金山河口全盐度梯度范围的10个站点采集样本，每个站点采集4份重复挖泥样本。在45年以上的监测历程中，采样频率、监测站点的数量与位置，以及重复采样样本的数量均根据实际数据需求变化进行了调整。
跨机构生态计划（Interagency Ecological Program, IEP）旗下的环境监测计划（Environmental Monitoring Program, EMP）依据D-1379号水权决议设立，现行强制要求为D-1641号水权决议，自1975年起持续监测旧金山河口上游（upper San Francisco Estuary, SFE）的底栖无脊椎动物大型类群。EMP的目标是在既定监测站点获取一致且精准的月度数据，并为旧金山河口上游的管理与保护工作公开相关信息。尽管EMP同时采集离散与连续水质数据，以及浮游植物、浮游动物数据，但本数据集仅收录EMP在1975年至2020年间采集的底栖无脊椎动物数据。
EMP采用Ponar采泥器（Ponar sampler）采集挖泥样本，以此监测旧金山河口底栖生境中的无脊椎动物群落。通过筛分台移除样本中粒径小于0.5mm的沉积物与颗粒，将采集到的无脊椎动物以福尔马林保存，鉴定至最低可行分类学层级并完成计数统计。
目前，监测人员每月在覆盖旧金山河口全盐度梯度范围的10个站点采集样本，每个站点采集4份重复挖泥样本。在40年以上的监测历程中，采样频率、监测站点的数量与位置，以及重复采样样本的数量均根据实际数据需求变化进行了调整。