The 2008 North Atlantic Spring Bloom Experiment: Observations of a Stationary Eddy on the Eastern Flank of the Reykjanes Ridge

Four Seagliders and two Lagrangian floats were deployed before the onset of the North Atlantic Bloom (NAB) at 59.0°N 20.5°W in early April 2008. The Seagliders surveyed around the Langrangian floats, which were designed to drift in the mixed layer and meandered northwest across the Icelandic Basin during the development of the bloom, finally becoming entrained in an anticyclonic eddy on the flank of the Reykjanes ridge, near 61.5°N 25.5°W, during the month of May. A persistent 10-km scale chlorophyll patch in the northeastern quadrant of the eddy is clearly visible in measurements by the in-situ optics sensors on the autonomous platforms and in imagery from the Aqua MODIS satellite on 12 May 2008. From 2 - 22 May, a process cruise by the R/V Knorr provided CTD casts and water samples necessary to calibrate the in-situ sensors, as well as continuous flow-through and ship-mounted RDI 75 and 150 kHz ADCP measurements in bow-tie survey patterns in the study region to complement the floats and Seagliders. The physical and biological structure of the eddy is described using the integrated dataset. A quantitative understanding will be developed from this description in future work, with the ultimate goal of identifying biophysical couplings that affect the spatial and temporal development of the phytoplankton community.