Salinity regimes in coastal ecosystems are highly dynamic and driven by complex geomorphic and hydrological processes. Estuarine biota are generally adapted to salinity fluctuation, but are vulnerable to salinity extremes. Characterizing coastal salinity regime for ecological studies therefore requires representing extremes of salinity ranges at various time scales relevant to ecology (e.g., daily, monthly, seasonally). This data release provides supporting data for the journal article titled, "Quantifying uncertainty in coastal salinity regime for biological application using quantile regression," by Yurek et al. (2022). A spatially-resolved model was developed that derives quantile distributions of salinity related to various landscape variables, such as tidal forcing, wind velocity and direction, and freshwater discharge into the Suwannee Sound estuary. The model also considers various time scales of freshwater streamflow, from daily to bi-weekly scales, which represent terrestrial watershed dynamics such as time-of-travel of overland flow from headwaters to the coast. This data release provides programming routines and supporting data for the model, including: (1) scripts used to run the model written in R programming language, (2) input data used to fit the model, and (3) model output predictions across the spatial extent of the Suwannee Sound estuary. The predictions of the model represent a method of quantifying uncertainty in predictions, and represent approximate ranges of salinity conditions. These predictions are intended for use in future ecological modeling studies and analyses of impacts of salinity uncertainty on estuarine biota. They are limited by the data set used here and are not intended to indicate exact levels for any given location or time.

Salinity and variability of salinity in shallow waters shape living resources and habitat within Gulf of Mexico estuaries. The salinity gradient is widely recognized as foundational in maintaining biological diversity and productivity of estuaries. A clear understanding of the factors controlling salinity and variability of salinity in estuarine surface waters is essential for proper stewardship and for sustaining ecological structure and function. Salinity data are collected by numerous Federal, State, and local agencies and universities as part of routine data collection programs. We used online databases to compile salinity data in Gulf of Mexico estuaries. The primary criteria for inclusion in the compilation were a lengthy record of continuous collection with data sondes of at least hourly intervals. Stations that represented full estuarine gradients, from fresh to saline, were prioritized. Data were compiled in separate spreadsheets for each State using comma-delimited formatting. For each State, a second spreadsheet provides information on each station. A few stations started collecting salinity as early as the mid-1980s. More stations came on line by the mid- to late 1990s. Starting in the late 2000s many more stations came on line.

Salinity and variability of salinity in shallow waters shape living resources and habitat within Gulf of Mexico estuaries. The salinity gradient is widely recognized as foundational in maintaining biological diversity and productivity of estuaries. A clear understanding of the factors controlling salinity and variability of salinity in estuarine surface waters is essential for proper stewardship and for sustaining ecological structure and function. Salinity data are collected by numerous Federal, State, and local agencies and universities as part of routine data collection programs. We used online databases to compile salinity data in Gulf of Mexico estuaries. The primary criteria for inclusion in the compilation were a lengthy record of continuous collection with data sondes of at least hourly intervals. Stations that represented full estuarine gradients, from fresh to saline, were prioritized. Data were compiled in separate spreadsheets for each State using comma-delimited formatting. For each State, a second spreadsheet provides information on each station. A few stations started collecting salinity as early as the mid-1980s. More stations came on line by the mid- to late 1990s. Starting in the late 2000s many more stations came on line.

A biogeochemistry model was developed to examine plant gross primary productivity (GPP), net primary productivity (NPP), plant respiration, soil respiration, soil organic carbon sequestration rate and storage under scenarios of drought and normal conditions at Tidal Freshwater Forested Wetlands (TFFW) sites along the Waccamaw River and Savannah River in the Southeastern United States.

The presence of salinity in shallow waters influences living resources and habitats within Gulf of Mexico estuaries. The salinity gradient is widely recognized as foundational in maintaining biological diversity and productivity of estuaries. A clear understanding of the factors controlling salinity and its variability in estuarine surface waters is essential for proper stewardship and for sustaining ecological structure and function. Salinity data are collected by numerous Federal, State, and local agencies and universities as part of routine data-collection programs. The U.S. Geological Survey compiled salinity data from existing online databases – all water samples were collected in Gulf of Mexico estuaries. The primary criterion for data from a station to be included in the compilation was a lengthy record of continuous collection using a data sonde programmed to at least hourly intervals. Stations that represented full estuarine gradients, from fresh to saline, were prioritized. Data were compiled from salinity stations in the five Gulf states and combined into one .txt file and one .feather file. Continuous data collection of salinity concentrations began at a few stations in the mid-1980s, and the number of stations with data sondes has increased over time for a total of 532,076 observations at 92 stations provided in this data release.

Salinity and variability of salinity in shallow waters shape living resources and habitat within Gulf of Mexico estuaries. The salinity gradient is widely recognized as foundational in maintaining biological diversity and productivity of estuaries. A clear understanding of the factors controlling salinity and variability of salinity in estuarine surface waters is essential for proper stewardship and for sustaining ecological structure and function. Salinity data are collected by numerous Federal, State, and local agencies and universities as part of routine data collection programs. We used online databases to compile salinity data in Gulf of Mexico estuaries. The primary criteria for inclusion in the compilation were a lengthy record of continuous collection with data sondes of at least hourly intervals. Stations that represented full estuarine gradients, from fresh to saline, were prioritized. Data were compiled in separate spreadsheets for each State using comma-delimited formatting. For each State, a second spreadsheet provides information on each station. A few stations started collecting salinity as early as the mid-1980s. More stations came on line by the mid- to late 1990s. Starting in the late 2000s many more stations came on line.

The presence of salinity in shallow waters influences living resources and habitats within Gulf of Mexico estuaries. The salinity gradient is widely recognized as foundational in maintaining biological diversity and productivity of estuaries. A clear understanding of the factors controlling salinity and its variability in estuarine surface waters is essential for proper stewardship and for sustaining ecological structure and function. Salinity data are collected by numerous Federal, State, and local agencies and universities as part of routine data-collection programs. The U.S. Geological Survey compiled salinity data from existing online databases – all water samples were collected in Gulf of Mexico estuaries. The primary criterion for data from a station to be included in the compilation was a lengthy record of continuous collection using a data sonde programmed to at least hourly intervals. Stations that represented full estuarine gradients, from fresh to saline, were prioritized. Data were compiled from salinity stations in the five Gulf states and combined into one .txt file and one .feather file. Continuous data collection of salinity concentrations began at a few stations in the mid-1980s, and the number of stations with data sondes has increased over time for a total of 532,076 observations at 92 stations provided in this data release.

Model generated soil pore water salinity (psu) values under scenarios of drought and normal conditions at Tidal Freshwater Forested Wetlands (TFFW) sites along the Waccamaw River and Savannah River in the Southeastern United States.

Model generated soil pore water salinity (psu) values under scenarios of drought and normal conditions at Tidal Freshwater Forested Wetlands (TFFW) sites along the Waccamaw River and Savannah River in the Southeastern United States.

A critical aspects of the uniqueness of coastal drought is the effects on salinity dynamics of creeks and rivers. The location of the freshwater-saltwater interface along the coast is an important factor in the ecological and socio-economic dynamics of coastal communities. Salinity is a critical response variable that integrates hydrologic and coastal dynamics including streamflow, precipitation, sea level, tidal cycles, winds, and tropical storms. The position of the interface determines the composition of freshwater and saltwater aquatic communities as well as the freshwater availability for water intakes. Many definitions of drought have been proposed, with most describing a decline in precipitation which has a negative impacts on water supply. Indices have been developed incorporating data such as rainfall, streamflow, soil moisture, groundwater levels, and snow pack. These water availability drought indices were developed for upland areas and may not be ideal for characterizing coastal drought. The availability of real-time and historical salinity datasets provides an opportunity for the development of a salinity-based coastal drought index. The challenge for the salinity data analysis is to characterize the salinity dynamics in response to drought while excluding responses attributable to the occasional and (or) periodic saltwater intrusion events. An approach similar to the Standardized Precipitation Index was modified and applied to salinity data obtained from sites in South Carolina and Georgia. Evaluation of the coastal drought index indicates that the index can be used for different estuary types, for regional comparison, and as an index for wet (high freshwater inflow) and drought conditions. This data release will provide all the supporting data for the journal article including salinity datasets (with estimated missing values) and the computed indices.