Table of Contents

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

"SUMMARY OF PROJECT RESULTS" excerpt from technical report 86-3 (Fox et al., 1986):

Shipboard measurements of nutrients, dissolved oxygen, and water column CTD-Oxygen characteristics were analyzed and processed in the Warm Core Rings program. Data were obtained from Ring 81-D in September-October 1981, from Ring 82-B in April, May, June and August, for Ring 82-E in August and for Ring 82-H in October. In addition to the planned extensive field experiments, two ship of opportunity samplings provided nutrient samples for analysis onshore to provide an excellent time-series of nutrients variations in warm core rings.

The nutrient studies consisted of three types of water column sampling. One was the full water column characterization at each major sampling location; the second was a set of diel productivity series of samples in the upper 100 m; the third was a set of mid-depth samples to examine nutrient regeneration. Each cruise provided more than 60 sets of samples with 12 to 24 samples per set. These have been analyzed for nitrate, nitrite, phosphate and silicate.

The nutrient data were processed to determine nutrient distributions in warm core rings, the source water (Sargasso Sea and Gulf Stream) and the surrounding Slope Water. Final data reports have been distributed to other Warm Core Rings investigators for the nutrient results for Ring 81-D, the time series observation for Ring 82-B in April, June and August, the results for Ring 82-E in August, and for ring 82-H in October. The in-situ CTD and oxygen data from cruises AT-110, KN093 and KN095 have been used on the URI Prime computer for plotting data for analysis with the nutrient data. CTD-Oxygen data reports for the time-series observation in Ring 82-B in April and June have been distributed. Two interpretive manuscripts of nutrient distributions in rings have been submitted for publication. The initial results of this study have been presented at several national meetings.

Excerpts from Fox et al. 1986 extracted from PDF of the original report through optical character recognition and added to section "Methods & Sampling" and reviewed by a BCO-DMO data manager.

* Matlab .m files (see supplemental file: nutrients_matlab_format.zip) containing data structures were concatenated, matlab datenum converted to additional human-readable date and times (ISO 8601 format), and exported as csv.

NSF abstract:

Warm core rings acting between western boundary currents and the continental shelf exert significant impact on the physical and biological environments of the slope seas and coastal oceans, which are major contributors to the global primary production. However, compared to that of eddies in the open ocean, the role of Gulf Stream warm core rings in the biophysical processes of the shelf-slope system has received less attention, and contrasting results exist. This study will elucidate the key biophysical mechanisms by investigating the biomass characteristics and the dominant physical mechanisms controlling the vertical nutrient delivery associated with Gulf Stream warm core rings. The improved understanding on nutrient dynamics from this research will contribute to the stewardship of living marine resources, and better ecosystem management. Research findings will be presented to the general public through public lectures. This project will also support the training of undergraduate students outside of oceanography through the Summer Undergraduate Research Program at the Woods Hole Oceanographic Institution.

This project investigates the physical-biological processes associated with the evolution of Gulf Stream warm core rings in the shelf-slope system of the Northwest Atlantic, with a focus on the dominant physical processes controlling vertical nutrient delivery. The research will include analyses of satellite data, historical in situ data, and numerical simulations. For better understanding of the relative importance of several mesoscale biophysical processes, the photoautotrophic biomass within the warm core rings will be characterized first using satellite observed sea surface height and chlorophyll concentration. The investigators will then conduct idealized numerical modeling experiments to identify the dominant physical processes responsible for vertical nutrient delivery including vertical mixing and vertical advection induced by frictional decay, eddy-induced Ekman pumping, and wind-sea surface temperature interaction. The findings from the idealized modeling will be further synthesized in a realistic coupled biophysical model for the Northwest Atlantic region.