Distribution of anammox activity across eddies A, B and C in the ETSP region.

<p>(A) Sea surface height altimetry (SSHA) of sampled eddies A, B and C during the M90 cruise, November 22^nd, 2012. The approximate locations of sampled stations within the eddy are shown, please note that the eddies propagated westward over the sampling period. Stations sampled for nutrients only (open circles) and nutrients plus nitrogen loss rates (open triangles with station numbers) are indicated. The red and blue dotted lines indicate transects sampled across eddies A, B and C, note that three defined transects were performed across eddy A (T1a/b in blue and T2 in red). Transects shown in panels B-D represent red dotted lines, whereas additional transects T1a (blue) are shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0170059#pone.0170059.s002" target="_blank">S2</a>–<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0170059#pone.0170059.s003" target="_blank">S3</a> Figs. (B) Horizontal velocity depth profiles are adapted from Stramma et al., [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0170059#pone.0170059.ref037" target="_blank">37</a>]. Isopycnal contours are indicated by black lines, while reference isopycnals 25.4 and 26.0 kg m^-3 are highlighted by black dotted lines. (C, D) Indicate volumetric and depth-integrated anammox rates for ¹⁵N-NH₄⁺ experiments. Error bars for depth-integrated anammox rates represent the standard error. BD indicates below the limit of detection. Stations numbered in red (B0, B1, C0, and A0) were sampled in or near the eddy center while stations with black numbers (C3, C2, C1, and A1) were sampled on the eddy periphery, identified according to eddy-induced horizontal velocities, density fronts, and SSHA, shown in panels a and b. Note that the center of eddy C, based on SSHA and supported by horizontal velocities, is at -16.25°N, -80.38°E 14 km northeast of station C0. Note that data from station C2 is not included in the transect profiles shown in panel B (indicated by (C2)), but is shown in panels C, D. The coastal upwelling station is indicated by ‘A2’. The vertical black dotted lines in panels C and D indicate the edge of the respective eddies.</p

Relationship between isopycnal spacing and chlorophyll.

<p>(A) Correlation of isopycnal spacing versus longitude for eddies A (green), B (blue), and C (red), alongside coastal upwelling stations (orange) and offshore stations extending past eddy B (grey). (B) Correlation of isopycnal spacing versus depth-integrated chlorophyll. Chlorophyll at all stations was depth-integrated down to 300 m depth, except for coastal stations which were depth-integrated down to 200 m. Dotted linear regression lines indicate eddy specific trends (R_C = eddy C, R_B = eddy B and R_off = offshore). Pearson correlation values are indicated in each panel (p-values).</p