Abstract:

For the purpose of monitoring water quality, discrete hydrographic measurements and grab samples were collected monthly via small boat-based trips at six stations established throughout Baffin Bay from 2018-01-15 to 2018-12-11. Grab samples were analyzed for organic and inorganic nutrients, and chlorophyll a. From March through December of the sampling period, chlorophyll a concentration was analyzed for whole samples as well as <20 µm and <2.75 µm size-fractionated samples.

Suggested Citation:

Wetz, Michael. 2021. Monthly discrete hydrographic measurements of Baffin Bay, TX, USA from 2018-01-15 to 2018-12-11. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/HCK0G337

Purpose:

The purpose of this study was to continue monitoring the water quality of the Baffin Bay system.

Data Parameters and Units:

Date (mm/dd/yyyy) - sampling date Time (hh:mm) - collection time (Central Standard Time) Latitude (DD) - Latitude, south is negative (decimal degrees) Longitude (DD) - Longitude, west is negative (decimal degrees) Site (unitless) - sampling site (BB 1, BB 2, BB 3, BB 4, BB 5, BB 6) Rep (unitless) - replicate A or B Level (m) - depth at which measurements/samples were collected (meters) Chl_Size_Frac (unitless) - Chlorophyll size fraction (whole, <20µm, <2.75µm) Chlorophyll_a (µg/L) - chlorophyll a content (micrograms per liter) Conductivity (µS/cm) - conductivity (microsiemens per centimeter) Salinity (unitless) - salinity DO (mg/L) - Dissolved oxygen concentration (milligrams per liter) DO_Pct (%) - Dissolved oxygen saturation pH (pH units) - pH Temperature (°C) - temperature (degrees Celsius) Depth (m) - total water depth at site (meters) Secchi (m) - secchi depth (meters) Turbidity (NTU) - turbidity (nephelometric turbidity unit) DOC (µM) - dissolved organic carbon (micromoles per liter) TDN (µM) - total dissolved nitrogen (micromoles per liter) TOC (µM) - total organic carbon (micromoles per liter) TN (µM) - total nitrogen (micromoles per Liter) Ammonium (µM) - ammonium (micromoles per liter) N_N (µM) - nitrate + nitrite (micromoles per liter) Nitrite (µM) - nitrite (micromoles per liter) ortho_P (µM) - orthophosphate (micromoles per liter) Silicate (µM) - silicate (micromoles per liter) Comments (unitless) - comments concerning sampling or data Abbreviations within dataset: “NR” (Not Recorded) – measurements/data were not recorded or are not included in dataset “BDL” (Below Detection Limit) – For organic and inorganic nutrients, the value derived from analysis fell below the detection limit of the instrument

Methods:

At each site, hydrographic measurements were collected with a YSI ProPlus multi-parameter instrument from the surface to the bottom at intervals of 0.5 m. A vertical profile was obtained in this manner for temperature, salinity, conductivity, dissolved oxygen concentration and saturation, and pH. A secchi measurement was obtained by submerging a secchi disc in a spot out of direct sunlight to a depth at which it could no longer be seen, and total depth was obtained by lowering the secchi disc to the bottom. Discrete grab samples were collected at 10 cm below the surface and 10 cm above the bottom (using a Van Dorn bottle) in acid-washed, polycarbonate amber bottles, and were stored on ice until processing. Refer to Wetz et al. 2017 for further methodological details.

Instruments:

YSI Professional Plus Multi-Parameter Probe Seal QuAAtro autoanalyzer Shimadzu TOC-Vs analyzer with nitrogen module Turner Trilogy fluorometer

Provenance and Historical References:

Wetz, Michael S., Emily K. Cira, Blair Sterba‐Boatwright, Paul A. Montagna, Terence A. Palmer, and Kenneth C. Hayes. 2017. Exceptionally high organic nitrogen concentrations in a semi‐arid South Texas estuary susceptible to brown tide blooms. Estuarine Coastal and Shelf Science. 188:27–37. DOI:10.1016/j.ecss.2017.02.001

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