Table of Contents

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

Hydrographic data and water samples were collected at standard CTD stations: CTD profiles measurements (down casts) with water sampling (up casts). The CTD rosette was equipped with a SBE 911 plus CTD system, conductivity, temperature and pressure sensors (SeaBird Electronics), WetLabs ECO-AFL/FL fluorometer, WET Labs ECO-NTU turbidity sensor, Sea-Bird SBE 43 dissolved oxygen sensor, photosynthetically active radiation (PAR) sensor and also surface radiation (SPAR) sensor.

Location: New England Shelfbreak 40 S 71 W, depth 0-2000m

This dataset was not cleaned to remove outliers. See processing notes below about missing data identifiers.

Sea-Bird Software used for AR29 data:
Data acquisition: SBE Seasave, version 7.23.2
Data processing: SBE Data Processing, version 7.26.7.114

Sea-Bird Software used for RB1904 and TN368 data:

Data acquisition: SBE Seasave, version 7.26.7.107
Data processing: SBE Data Processing, version 7.26.7.114

Bad data is indicated with a flag:
Bad data flag=-9.990e-29

BCO-DMO Processing Notes (Data Version 1, 2020-03-27, AR29):
- submission contained ctd casts of cruise AR29 with numbers [133-143]
- added conventional header with dataset name, PI name, version date
- modified parameter names to conform with BCO-DMO naming conventions
- converted latitude and longitude coordinates to decimal degrees in the lat and lon columns
- concatenated all downcast seabird data files into one dataset.
- added ISO_DateTime_UTC field
- converted values indicated in seabird files as bad (-9.990e-29) to nd.

Dataset Version 2 (2021-04-20) replaces Dataset Version 1 (2020-03-27).
- This dataset update was made to add data from TN368 data in 2019.
- Imported seabrid .cnv files from TN368 and reimported the .cnv files from AR29 into the BCO-DMO data system. Imported the AR29 files again in this version instead of using the data from the previous version 1 of this dataset because temperature data t090C and t190C for cast 134 between depths 110 to 120 was not imported correctly in the version 1 data. It appears to have been an error when uploading the fixed with seabird file.
- Combined all the data into one table with additional columns for Cruise and Cast from information in the file names.
- As was done in version 1 of this dataset, the NMEA Lat, Lon and Time (UTC) in the seabird header was used as the data source for columns lat, lon, and ISO_DateTime_UTC.
- lat,lon rounded to 5 decimal places.
- column names renamed to match version 1 of this dataset which conform to the BCO-DMO naming conventions.
- Only -9.990e-29 was interpreted as a missing data identifier. These values will be displayed differently based on the file type downloaded by the user. It will be blank values in .csv files, NaN in matlab files, etc.
- The data submitter indicated this dataset was not cleaned for outliers. The following values are in this dataset: 90e-29, 9.0E-28,9.90E-27, 9.90E-27,-9.990e-29, 990e-29, 1.0000E-12. CPar data in AR29 cast 143 had some values: 9.2221E-13, 9.1837E-13, 9.2295E-13, 9.2564E-13, 9.2370E-13
- Data sorted by datetime then pressure (prDM).

Dataset Version 3 (2021-09-28) replaces Dataset Version 2 (2021-04-20).
- This dataset update was made to add CTD casts from AR29 cruise (added cast 001-011, 022-040, 047-068, and 079-095).
- Imported newly submitted seabird .cnv files from AR29 and imported the existing .csv from v2.
- Combined all the data into one table with additional columns for Cruise and Cast from information in the file names.
- As was done in version 1 & 2 of this dataset, the NMEA Lat, Lon and Time (UTC) in the seabird header was used as the data source for columns lat, lon, and ISO_DateTime_UTC.
- lat,lon rounded to 5 decimal places (same as v2)
- column names renamed to match version 2 of this dataset which conform to the BCO-DMO naming conventions
- Only -9.990e-29 was interpreted as a missing data identifier. These values will be displayed differently based on the file type downloaded by the user. It will be blank values in .csv files, NaN in matlab files, etc.
- Data sorted by datetime then pressure (prDM)

BCO-DMO data manager notes version 4 (replaces version 3)
- merged all available ctd cast .cnv files for all 3 cruises
- converted latitude and longitude to decimal degrees
- As was done in version 1, 2 & 3 of this dataset, the NMEA Lat, Lon and Time (UTC) in the seabird header was used as the data source for columns lat, lon, and ISO_DateTime_UTC.

NSF award abstract:

The continental shelf break of the Middle Atlantic Bight supports a productive and diverse ecosystem. Current paradigms suggest that this productivity is driven by several upwelling mechanisms at the shelf break front. This upwelling supplies nutrients that stimulate primary production by phytoplankton, which in turn leads to enhanced production at higher trophic levels. Although local enhancement of phytoplankton biomass has been observed in some circumstances, such a feature is curiously absent from time-averaged measurements, both from satellites and shipboard sampling. Why would there not be a mean enhancement in phytoplankton biomass as a result of the upwelling? One hypothesis is that grazing by zooplankton prevents accumulation of biomass on seasonal and longer time scales, transferring the excess production to higher trophic levels and thereby contributing to the overall productivity of the ecosystem. However, another possibility is that the net impact of these highly intermittent processes is not adequately represented in long-term means of the observations, because of the relatively low resolution of the in-water measurements and the fact that the frontal enhancement can take place below the depth observable by satellite. The deployment of the Ocean Observatories Initiative (OOI) Pioneer Array south of New England has provided a unique opportunity to test these hypotheses. The combination of moored instrumentation and autonomous underwater vehicles will facilitate observations of the frontal system with unprecedented spatial and temporal resolution. This will provide an ideal four-dimensional (space-time) context in which to conduct a detailed study of frontal dynamics and plankton communities needed to examine mechanisms controlling phytoplankton populations in this frontal system. This project will also: (1) promote teaching, training and learning via participation of graduate and undergraduate students in the research , (2) provide a broad dissemination of information by means of outreach in public forums, printed media, and a video documentary of the field work, and (3) contribute to improving societal well-being and increased economic competitiveness by providing the knowledge needed for science-based stewardship of coastal ecosystems, with particular emphasis on connecting with the fishing industry through the Commercial Fisheries Research Foundation.

The investigators will conduct a set of three cruises to obtain cross-shelf sections of physical, chemical, and biological properties within the Pioneer Array. Nutrient distributions will be assayed together with hydrography to detect the signature of frontal upwelling and associated nutrient supply. The investigators expect that enhanced nutrient supply will lead to changes in the phytoplankton assemblage, which will be quantified with conventional flow cytometry, imaging flow cytometry (Imaging FlowCytobot, IFCB), optical imaging (Video Plankton Recorder, VPR), traditional microscopic methods, and pigment analysis. Zooplankton will be measured in size classes ranging from micro- to mesozooplankton with the IFCB and VPR, respectively, and also with microscopic analysis. Biological responses to upwelling will be assessed by measuring rates of primary productivity, zooplankton grazing, and net community production. These observations will be synthesized in the context of a coupled physical-biological model to test the two hypotheses that can potentially explain prior observations: (1) grazer-mediated control and (2) undersampling. Hindcast simulations will also be used to diagnose the relative importance of the various mechanisms of upwelling. The intellectual merit of this effort stems from our interdisciplinary approach, advanced observational techniques, and integrated analysis in the context of a state-of-the-art coupled model. The project will address longstanding questions regarding hydrodynamics and productivity of an important ecosystem, leading to improved understanding of physical-biological interactions in a complex continental shelf regime. Given the importance of frontal systems in the global coastal ocean, it is expected that knowledge gained will have broad applicability beyond the specific region being studied.