Table of Contents

• Coverage
• Dataset Description
  • Methods & Sampling
  • Data Processing Description
• Data Files
• Supplemental Files
• Related Publications
• Related Datasets
• Parameters
• Instruments
• Deployments
• Project Information
• Funding

ADP field sampling:
Nortek Aquadopp 2MHz ADPs (AQD 6204 & AQD 9331) were used to  measure water velocities and tidal height in the tidal creeks at stations S0, S2, and S8.  ADP transducer heads were coated with a mixture of cayenne pepper and petroleum jelly to discourage hard fouling.    

Units were affixed to a concrete plate that was lowered from a small boat by hand and rope to the bottom of the creek channel.  Deployments were blind: effort was made to assure that the units were oriented channel-parallel and on flat bottom, but the exact location and orientation of each deployment depended greatly on the swing of the boat’s anchor in the current.  The a priori objective of each deployment was to locate a unit in the center of a straight section of creek seaward of the water quality sampling stations.  Each ADP mount was fixed to a weighted line that ran to the nearest shoreline where it was anchored and marked with a buoy.  Individual deployments lasted 8-10 weeks.  Units were recovered by retrieving the line at the shore and hand-hauling it to the surface. 

ADPs were returned to the lab for cleaning, downloading data, charging batteries and setting up the unit for the next deployment.  Units were re-deployed at the next convenient opportunity.  Gaps in the record were on the order of a week to a month.

Over the study, the ADP measured temperature (°C), velocity (u, v, w in m s-1), and pressure (decibars converted to water level (m) relative to Mean Sea Level) at a 10-minute interval. Velocity was measured across 18 to 20 vertical bins with each bin covering 30 to 40 cm. This bin setup allowed maximum water level (2 m above Mean Sea Level) to be captured by the ADP. To correct for minor differences in ADP positioning on the creek bed between deployments, velocity and water level records underwent alignment.

ADP data processing:
To process in situ data, ADP deployment records were linearly interpolated to the same 10-minute time grid across the study, and the start and end of individual ADP deployments were determined (first or last measurement above 0.35 m relative to channel bottom). Furthermore, out of water ADP measurements (pressure <2 decibar) were eliminated as were vertical ADP bins at depths above the water column and untrustworthy surface bins impacted by side-lobe interference. Average velocity (u, v) was calculated across the remaining bins. Using average binned velocity provided a continuous velocity record. A vertical average was an appropriate approximation for velocity in a well-mixed system such as Groves Creek (Blanton et al., 2010; Sullivan et al., 2015). Resulting velocity measurements (u, v) were converted to along and cross channel velocity by rotating velocity vectors per deployment by their respective principal axis angles.

BCO-DMO Processing notes:
- added conventional header with dataset name, PI name, version date
- modified parameter names to conform with BCO-DMO naming conventions
- added station, lat, lon, date, time, ISO_DateTIme columns
- ISO Date format generated from date and time values
- reduced decimal places of lat and lon to 5; reduced depth to 2

Description from NSF award abstract:
Salt marshes are critical mediators of the flux of material between the terrestrial and marine realms. The balance of material import, export, and transformation affects both the marsh itself and the surrounding estuary. Previous efforts to understand the role of marshes have concentrated either on examining temporal changes (often at low resolution) of bulk exports, or compositional changes in exported material with little regard for its temporal variability. Researchers working at the Skidaway Institute of Oceanography contend that both the quantity and quality of materials exchanged between marsh and estuary in tidally-dominated systems along the southeastern US coast vary significantly in response to semidiurnal, diurnal, tidal, meteorological and seasonal forcing, and that this variability must be included when considering the total contributions of marshes to carbon cycling along the land-ocean boundary. This study will utilize a three-pronged strategy to assess both the quantity and quality of dissolved organic matter (DOM) and particulate organic matter (POM) exported from Groves Creek, a well-characterized meso-tidal salt marsh in coastal Georgia. In particular, by evaluating how marsh function responds to a full spectrum of present environmental conditions, this project will provide tangible insight into how carbon cycling in these critical regions will respond to anticipated changes in those conditions.

This project is related to the project "Marine priming effect - molecular mechanisms for the biomineralization of terrigenous dissolved organic matter in the ocean" found at https://www.bco-dmo.org/project/554157.