Padre Island National Seashore
Gulf Coast I&M Network Long-Term Water Quality Monitoring: Padre Island National Seashore
As Padre Island National Seashore's (PAIS) seaward boundary extends only 500 m into the Gulf of Mexico � where the park has very limited control of water quality dynamics, it can be argued that the most important water resource to the park is the Laguna Madre. The Laguna Madre is currently a very large (1500 km 2 ), shallow (1 m) hyper-saline lagoon (approximately 80 km 2 are within PAIS). Over the past thousand years there have been tremendous alterations to the Laguna, as storms cut channels through the barrier island, no doubt greatly affecting water chemistry. These cuts eventually fill and the Laguna is again isolated from the Gulf. As the inflow of freshwaters is typically out-gained by evaporation, the result is hyper-saline water � commonly ranging 35-55 PPT, although near record rains of 2010 produced salinities below 20 PPT. The shallow waters of the Laguna support an abundant submerged aquatic vegetative community and are considered the most productive fishery on the Texas Gulf Coast . Cutting through the length of the Upper Laguna Madre is the Gulf Intracoastal Waterway (GIWW). This maintained (US Army Corps of Engineers) dredged channel (which runs along the western park boundary) represents the largest anthropogenic disturbance in the Laguna.
The Gulf Coast I&M Network (GULN) entered a Task Agreement with Texas A&M University Corpus Christi to install and maintain two real-time continuous recording water quality stations in the Upper Laguna Madre. Fifteen minute data are collected for temperature, specific conductance, salinity, pH, stage, dissolved oxygen and turbidity. These stations, one at South Bird Island ( http://lighthouse.tamucc.edu/qc/171 ) and the other at Baffin Bay (http://lighthouse.tamucc.edu/qc/170), became operational in June 2008. Due to the high biofouling nature of the hyper-saline waters the sites are visited every two weeks.
The Gulf of Mexico Alliance (GoMA) � the five US Gulf States working primarily with the USEPA and NOAA to monitor the quality of estuarine and near-shore Gulf waters � provides additional water quality stations throughout the region. Coordination with GoMA is important to assure the GULN program is monitoring the exact same parameters using approved methods. Monthly grab samples for GoMA parameters began in October 2010. These are the same parameters and same methods used by GULN at Gulf Islands National Seashore.
Grab samples at both stations include: