Abstract:

Submarine groundwater discharge (SGD) estimates via stationary time series measurements of radon-222 in Corpus Christi Bay (2014), Nueces Bay (2014-2016), Aransas-Copano Bays (2015), Copano Bay (2016), Baffin Bay (2016), and six stations from Aransas Bay to Baffin Bay (2017-2018). Associated porewater quality variables (temperature, pressure, dissolved oxygen, specific conductivity, salinity, pH) and nutrients (ammonium, nitrate, nitrite, nitrate+nitrite, dissolved inorganic nitrogen, phosphate, silicate, and dissolved organic carbon) were measured during sampling events. SGD-derived nutrient flux estimates are calculated as the product of Rn-222-derived SGD estimates and the porewater nutrient concentration.

Suggested Citation:

Murgulet, Dorina, Audrey Douglas, and Cody Lopez. 2023. Submarine groundwater discharge readings in semi-arid estuaries across the Texas coastal bend and associated water quality parameters obtained from 2014-09-29 to 2018-02-04. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/SJACB00R

Purpose:

Data were collected to help determine the flux of groundwater to Texas estuaries and assess the relationship between climatic conditions and submarine groundwater discharge rates. The hypothesis is that climatic conditions (e.g., drought, normal, wet) influence coastal hydraulic gradients and SGD rates and thus impact porewater nutrient concentrations and SGD-derived nutrient fluxes.

Data Parameters and Units:

Project Project Bay Bay LocationDesc Location within bay StationNo. Project station number Station Unique station code Latitude Latitude of station decimal degrees Longitude Longitude of station decimal degrees AvgSGD Average submarine groundwater discharge for station cm/d StartTime Start Time MM/DD/YYYY HH:MM EndTime End Time MM/DD/YYYY HH:MM Duration Duration hours TimeInterval (min) Integration Time min GW_endmember Groundwater Endmember Radon Activity becquerels/m3 min_SGD Minimum Submarine Groundwater Discharge Rate with old k value cm/d max_SGD Maximum Submarine Groundwater Discharge Rate with old k value cm/d avg_SGD Average Submarine Groundwater Discharge Rate with old k value cm/d stdev_SGD Standard Deviation Submarine Groundwater Discharge Rate with old k value cm/d min_SGD_new Minimum submarine groundwater discharge rate with new k value cm/d max_SGD_new Maximum Submarine Groundwater Discharge Rate with new k value cm/d avg_SGD_new Average Submarine Groundwater Discharge Rate with new k value cm/d stdev_SGD_new Standard Deviation Submarine Groundwater Discharge Rate with new k value cm/d Ra226 Radium-226 becquerels/m3 Temp temperature °C mmHg pressure mmHg DO_pct dissolved oxygen percent DO_mgl dissolved oxygen mg/L Cond conductivity µS/cm Sal salinity pH pH NH4+ ammonium µmol/L NO3- nitrate µmol/L NO2- nitrite µmol/L NO3-+NO2- nitrate+nitrite µmol/L DIN dissolved inorganic nitrogen µmol/L PO4 phosphate µmol/L SiO3 silicate µmol/L DOC dissolved organic carbon µmol/L NH4_flux ammonium flux from SGD mmol/m2d NO3+NO2_flux nitrate+nitrite flux from SGD mmol/m2d DIN_flux dissolved inorganic nitrogen flux from SGD mmol/m2d PO4_flux phosphate flux from SGD mmol/m2d SiO3_flux silicate flux from SGD mmol/m2d DOC_flux dissolved organic carbon flux from SGD mmol/m2d

Methods:

Radon-derived submarine groundwater discharge estimates and porewater water quality and nutrient concentration data from the Center for Water Supply Studies projects from 2014 through 2018 was compiled. Radon-222 derived submarine groundwater discharge calculations were verified and updated to better account for the effects of winds on atmospheric evasion losses. The average Rn-222 SGD rate and porewater chemistry for each station's time series is presented. SGD-derived nutrient fluxes are calculated as the product of Rn-222-derived SGD estimates and the porewater nutrient concentration.

Instruments:

Durridge RAD-7 Radon in air detector

Provenance and Historical References:

Technical Reports and Peer-reviewed Publications: Nueces Estuary 1) Douglas, A. R., D. Murgulet & H.A. Abdulla. 2021. Impacts of hydroclimatic variability on surface water and porewater dissolved organic matter in a semi-arid estuary. Marine Chemistry 235: 104006. DOI: 10.1016/j.marchem.2021.104006 2) Douglas, A. R., D. Murgulet & P. A. Montagna. 2021. Hydroclimatic variability drives submarine groundwater discharge and nutrient fluxes in an anthropogenically disturbed, semi-arid estuary. Science of The Total Environment 755:142574. DOI: 10.1016/j.scitotenv.2020.142574 3) Douglas, A. R., D. Murgulet & R. N. Peterson. 2020. Submarine groundwater discharge in an anthropogenically disturbed, semi-arid estuary. Journal of Hydrology 580:124369. DOI: 10.1016/j.jhydrol.2019.124369 4) Murgulet, D., M.S. Wetz, A. Douglas, W. McBee, N. Spalt, & K. Linares. 2015. Evaluating Groundwater Inflow and Nutrient Transport to Texas Coastal Embayments. TGLO Contract No. 14-081-000-7949. Texas General Land Office, Austin, TX. pp 277. https://www.glo.texas.gov/coastal-grants/projects/14-081-groundwater-inflow-coastal-embayments.html 5) Murgulet, D., M. Trevino, A. Douglas, N. Spalt, X. Hu & V. Murgulet. 2018. Temporal and spatial fluctuations of groundwater-derived alkalinity fluxes to a semiarid coastal embayment. Science of The Total Environment 630:1343-1359. DOI: 10.1016/j.scitotenv.2018.02.333 Mission-Aransas Estuary 1) Douglas, A., D. Murgulet, M.S. Wetz, N. Spalt, C. Lopez, & H. Wang, 2017. Evaluating groundwater inflow and nutrient transport to Texas coastal embayments. TGLO Contract No. 15-047-000-8392.Texas General Land Office, Austin, TX. pp 109. https://www.glo.texas.gov/coastal-grants/_documents/grant-project/15-047-evaluating-groundwater.pdf 2) Spalt, N., D. Murgulet & H. Abdulla, 2020. Spatial variation and availability of nutrients at an oyster reef in relation to submarine groundwater discharge. Science of The Total Environment 710:136283. DOI: 10.1016/j.scitotenv.2019.136283 3) Spalt, N., D. Murgulet & X. Hu. 2018. Relating estuarine geology to groundwater discharge at an oyster reef in Copano Bay, TX. Journal of Hydrology 564:785-801. DOI: 10.1016/j.jhydrol.2018.07.048 Upper Laguna Madre Estuary 1) Lopez, C., D. Murgulet, A. Douglas, & V. Murgulet, 2018. Impacts of Temporal and Spatial Variation of Submarine Groundwater Discharge on Nutrient Fluxes to Texas Coastal Embayments, Phase III (Baffin Bay). TGLO Contract No. 16-060-000-9104. Texas General Land Office, Austin, TX. pp 106. https://www.glo.texas.gov/coastal-grants/projects/16-060-evaluating-groundwater-inflow.html 2) Lopez, C.V., D. Murgulet, & I. Santos, 2020. Radioactive and stable isotope measurements reveal saline submarine groundwater discharge in a semiarid estuary. Journal of Hydrology 590: 125395. DOI: 10.1016/j.scitotenv.2022.153814 Coastal Bend 1) Murgulet, D., A. Douglas, C. Lopez, B. Gyawali, & V. Murgulet, 2019. Impacts of Temporal and Spatial Variation of Submarine Groundwater Discharge on Nutrient Fluxes to Texas Coastal Embayments. TGLO Contract No. 17-182-000-9819. Texas General Land Office, Austin, TX. pp 76. https://www.glo.texas.gov/coastal-grants/projects/17-182-impacts-of-termporal-and%20spatial-variation-of-submarine-groundwater-discharge.html 2) Murgulet, D., C.V. Lopez, & A.R. Douglas, 2022. Radioactive and stable isotopes reveal variations in nearshore submarine groundwater discharge composition and magnitude across low inflow northwestern Gulf of Mexico estuaries. Science of the Total Environment 823: 153814. DOI: 10.1016/j.scitotenv.2022.153814

Individual Files: