Long-term monitoring of water and sediment quality to identify freshwater inflow effects from 1984-01-01 to 2019-10-01

Long-term sampling to identify freshwater inflow effects on benthos began in 1984 and continued through 2019. Five estuaries were sampled. Benthic organisms are ideal bioindicators of freshwater inflow effects in bays and estuaries because they are fixed in space and integrate ephemeral processes in the over-lying water column over long periods of time. Freshwater inflow regulates water quality, which drives benthic abundance, productivity, diversity, and community structure. Texas estuaries have different long-term characteristic fauna that reflect the long-term average salinity and sediment conditions in each bay system. Within estuary systems, the secondary bays have distinct communities compared to the primary bays because secondary bays are closer to freshwater inflow sources and are more oligohaline and/or brackish in nature than primary bays that are more marine influenced. Similar responses occur over time when conditions change with droughts and floods. Because of the relationship between salinity and community structure, benthos community conditions can indicate a “sound ecological environment” as required by 2007 Texas Senate Bill 3.