The Effects of Salinity on the Bay
Estuaries function as transition zones between the salt environment of the sea and the freshwater of the river. Salinity fluctuation in these dynamic environments has been shown to be a dominant feature of estuaries, and to a great extent, has helped determine the type and distribution of organisms found in these systems. A complex suite of factors - including local rainfall, river flow, tides, winds and basin configuration - determine salinity in an estuary. The alteration of a single variable such as river flow can significantly affect salinity and therefore the biota of any estuary. Alterations of any of these patterns, especially increases in salinity, could eliminate the barriers between species and cause significant changes in resident species assemblages in estuaries.
ANERR's monitoring program has compared trends in annual and seasonal salinity patterns. Looking at long-term daily average salinity graphs, it is clear that all sites show a general increase in salinity throughout the bay, especially during the drought years. This is particularly troubling for the East Bay region, since it is not only the fresher part of the bay but also the most important nursery area in the bay. This increase in salinity could have pronounced effects on habitats and species within the Apalachicola Bay and could cause shifts in species and distribution. The data being collected in this project is important and is used to assess long-term changes in the bay caused by upstream water diversions, land-use changes, global climate change and human-made alterations. The short-term effects of hurricanes, local storm events and natural events can also be determined. This information can be used to separate natural from human-induced changes.
The System-Wide Monitoring Program at Apalachicola Research Reserve
The System-Wide Monitoring Program at ANERR consists of continuous water quality monitoring, continuous meteorological monitoring and monthly nutrient and chlorophyll-a monitoring.
ANERR has been continuously monitoring water quality parameters - including, temperature, water level, salinity, dissolved oxygen, pH and turbidity - at four locations within the bay since 1992. Water quality parameters are monitored in the field by instruments called dataloggers. The dataloggers are calibrated and programmed prior to deployment. Every two to three weeks the dataloggers are switched out to ensure data collection is uninterrupted and to avoid errors due to biological fouling, such as encrusting by barnacles or heavy algal growth. The dataloggers are taken back to the lab where they are tested against standards to determine drift due to any fouling or equipment failure and cleaned. The data is downloaded, reviewed and checked for quality by research staff and then sent to the Central Data Management Office. This information is then compiled into monthly files, and daily averages are computed and graphed.
ANERR has been conducting monthly nutrient and chlorophyll-a monitoring since 2002. Samples are collected every month at 11 sites in the bay and analyzed for concentrations of nitrate-nitrite, ammonium, total dissolved nitrogen, orthophosphate, total dissolved phosphate and chlorophyll-a. Apalachicola Bay does not routinely experience nutrient over-enrichment. There is concern that reduced river flows may actually deliver inadequate amounts of proper dissolved nutrients to the bay, with negative impacts on phytoplankton productivity that is necessary to support food chain in the bay.
ANERR has maintained a weather station in the marshes of upper East Bay since 2001. Parameters recorded are temperature, relative humidity, barometric pressure, wind speed, wind direction, precipitation and photosynthetically active radiation.
All of this data is is available for download from the Centralized Data Management Office. Real-time meteorological data is also available from the same website.
