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An assessment framework for Tampa Bay Water's Hydrobiological Monitoring Program (HBMP) has been established based on the relationship between freshwater flow and primary environmental indicators monitored under the HBMP. The underlying paradigm is based on the understanding that reduced flows can result in water quality conditions adverse to biological populations if these conditions exceed a specific magnitude and/or are beyond a certain duration. HBMP water quality parameters identified as primary indicators include salinity (due to osmotic pressure controlling distribution of fish, benthos, and vegetation among other ecological effects), dissolved oxygen (due to the aerobic stress to fish and benthos that can occur due to depressed dissolved oxygen concentrations), and chlorophyll-a (due to excessive phytoplankton blooms that may increase biological oxygen demand and can result in depressed dissolved oxygen concentrations). These primary indicators were identified because they specifically relate to linkages in the HBMP conceptual model as well as State of Florida water quality standards and a great deal of effort has been allocated to understanding these relationships. To this end, special studies have been implemented to further scientific information related to the effects of flows and withdrawals on the magnitude, duration, and distribution of phytoplankton as one aspect of the larger HBMP assessment framework. In this paper, we provide a summary of recent special studies completed in the lower Alafia River, focused on in situ fluorometer chlorophyll-a measurement, interpretation, and predictive capability. We share lessons learned and our steps for moving forward in efforts to relate flow (and withdrawal-related effects) on phytoplankton in the lower Alafia River. [ABSTRACT FROM AUTHOR]

Benthic infaunal communities are important indicators of environmental change because they are comprised of organisms with limited mobility that respond rapidly to stress. As part of the Comprehensive Everglades Restoration Plan to restore natural water flows across the Florida peninsula, infaunal communities have been monitored since 2005 in relation to changing water quality and sediment characteristics at 9 sites in the southern Indian River Lagoon (IRL) and St. Lucie Estuary (SLE). Abiotic and biological differences separated the sites into 3 zones, with salinity and the abundance of fine-grained sediments emerging as major drivers of infaunal abundance, species richness and distribution. Degraded communities in the middle SLE were populated by opportunistic and pollution-tolerant taxa, while communities in the southern IRL were abundant and biodiverse. A total of 76 taxa and one-third of all infauna were lost across the three zones in 2016 and 2017, which was likely caused by harmful algal blooms and discharges of sediment and nutrientladen inland freshwater following an El Niño event and Hurricane Irma. This study highlights the importance of long-term monitoring to inform adaptive management practices and lays the groundwork for further analyses to understand how natural and anthropogenic stressors affect this dynamic system. [ABSTRACT FROM AUTHOR]

Seven species of seagrass have been found in the Indian River Lagoon (IRL), making it an unusually diverse location at the global scale. From 1994 to 2019, the lagoon-wide distribution of these species reflected variations in temperature, salinity, and the availability of light at depth, which were related to latitudinal differences in hydrology and hydrodynamics along the IRL. In general, species richness was higher near the four southern inlets, and fewer species were found in areas with longer residence times for water. At a finer scale, the distribution of species varied among depths, with the greatest number of species found at mid-depths (~0.4-0.9 m). Prior to 2011, these patterns remained relatively consistent for ~ 40 years, but several, intense and prolonged phytoplankton blooms disrupted them. The areal extent of all seagrasses decreased by over 50%, the offshore ends of canopies moved shoreward and shallower, distributions of species along gradients of latitude and depth were disrupted, and mean percent cover decreased. Major changes in distribution and abundance of seagrasses arose when salinity, temperature, and availability of light at depth exceeded limits derived for each species. These substantial and widespread changes engendered concerns for recovery or rehabilitation of seagrasses in the lagoon. [ABSTRACT FROM AUTHOR]