Table of Contents

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

Codes in the data:
* ND: not determined
* BDL: below detection limit
* DNP: Data not presented

Water column sample collection and in-situ measurements:

Water-column samples for analysis of Chl a, nitrate, nitrite, phosphate, urea, ammonium and net primary productivity, and continuous profiles of temperature and salinity were collected using a conductivity-temperature-depth sensor (SBE 911 plus) with a 12 Bottle Frame & Carousel (SBE 32) consisting of 12 niskin bottles. Nutrient samples were collected from the niskin bottles using acid cleaned tubing and were filtered through a 0.2 µm filter. Whole water samples to measure net primary production were collected directly from CTD bottles using acid cleaned tubing and drained into acid cleaned 10L carboys. Measurement of net primary production was done using stable isotopes. Whole water samples were taken with a niskin bottle from the surface, mix layer, and chlorophyll maximum and transferred into acid-cleaned 250 mL, 500mL, 1000ml or 2000ml PETG incubation bottles in triplicate. Primary productivity was measured by adding tracer additions (<10% of the ambient dissolved inorganic carbon) of NaH13CO2 and incubating for 12-24 hours in flow-through seawater incubators under neutral density screening. Dark bottles were also incubated. After 12-24 hours, incubations were terminated by filtration through pre-combusted (450 degree C for 2 h) GF/F filters. Filters were stored at -20 degree C until analysis in the laboratory. Filters were analyzed on a Europa 20/20 isotope ratio mass spectrometer equipped with an automated nitrogen and carbon analysis for gas, solids, and liquids (ANCA-GSL) preparation module. Analysis also resulted in particulate nitrogen (PN) and particulate carbon (PC) values.

NO3 & NO2: Dissolved nitrate and nitrite was determined at sea using an Astoria Pacific nutrient autoanalyzer using standard colorimetric methods with a detection limit of 0.14 µM (Parsons et al., 1984; Price and Harrison, 1987). In surface waters, nitrate and nitrite were determined using the same autoanalyzer equipped with a liquid waveguide capillary cell (World Precision Instruments) (Zhang, 2000) to achieve a detection limit of 0.02 µM.

PO4: Dissolved phosphate was determined at sea using an Astoria Pacific nutrient autoanalyzer using standard colorimetric methods with a detection limit of 0.03 µM (Parsons et al., 1984; Price and Harrison, 1987).

NH4: Dissolved ammonium was determined at sea using the manual orthophthaldialdehyde method (Holmes et al., 1999).

Urea: Dissolved urea was determined at sea using an Astoria Pacific nutrient autoanalyzer using standard colorimetric methods with a detection limit of 0.08 µM (Parsons et al., 1984; Price and Harrison, 1987).

Temperature: In-situ temperature was measured using a conductivity-temperature-depth sensor (SBE 911 plus).

Salinity: Salinity was calculated from in-situ conductivity, as measured using a conductivity-temperature-depth (CTD) sensor (SBE 911 plus).

Chl: Chlorophyll a was determined at sea using the non-acidification method with a Turner 10-AU fluorometer (Welschmeyer et al., 1994).

NPP: Net primary production was measured using stable isotopes (Mulholland et al., 2006).

PNPC: Particulate nitrogen and carbon samples were collected by filtering whole water samples through pre-combusted (450 degree C for 2 h) GF/F filters. Filters were stored at -20 degree C until analysis in the laboratory. Filters were analyzed on a Europa 20/20 isotope ratio mass spectrometer equipped with an automated nitrogen and carbon analysis for gas, solids, and liquids (ANCA-GSL) preparation module.

BCO-DMO Data Manager Processing Notes:
* added a conventional header with dataset name, PI name, version date
* modified parameter names to conform with BCO-DMO naming conventions
* After discussing with data contributors:
* Formatted date as yyyy-mm-dd
* rounded lat/lon to four decimal places, depth to 0 decimal places, and temp/sal to one decimal place.

NSF abstract:

Deposition of atmospheric nitrogen provides reactive nitrogen species that influence primary production in nitrogen-limited regions. Although it is generally assumed that these species in precipitation contributes substantially to anthropogenic nitrogen loadings in many coastal marine systems, its biological impact remains poorly understood. Scientists from Pennsylvania State University, William & Mary College, and Old Dominion University will carry out a process-oriented field and modeling effort to test the hypothesis that deposits of wet atmospheric nitrogen (i.e., precipitation) stimulate primary productivity and accumulation of algal biomass in coastal waters following summer storms and this effect exceeds the associated biogeochemical responses to wind-induced mixing and increased stratification caused by surface freshening in oligotrophic coastal waters of the eastern United States. To attain their goal, the researchers would perform a Lagrangian field experiment during the summer months in coastal waters located between Delaware Bay and the coastal Carolinas to determine the response of surface-layer biogeochemistry and biology to precipitation events, which will be identified and intercepted using radar and satellite data. As regards the modeling effort, a 1-D upper ocean mixing model and a 1-D biogeochemical upper-ocean will be calibrated by assimilating the field data obtained a part of the study using the adjoint method. The hypothesis will be tested using sensitivity studies with the calibrated model combined with in-situ data and results from the incubation experiments. Lastly, to provide regional and historical context for the field measurements and the associated 1-D modeling, linked regional atmospheric-oceanic biogeochemical modeling will be conducted.

Broader Impacts. Results from the study would be incorporated into class lectures for graduate courses on marine policy and marine biogeochemistry. One graduate student from Pennsylvania State University, one graduate student from the College of William and Mary, and one graduate and one undergraduate student from Old Dominion University would be supported and trained as part of this project.