Fig. 3: Hydrothermal influence in the Eastern Weddell Gyre.
From: Wind-driven upwelling of iron sustains dense blooms and food webs in the eastern Weddell Gyre
a Map of the locations of isotopic helium (δ3He) data in the water column from the GLODAP database41 and the Transektokt 2020/21, at or close to the Prime Meridian (green squares), following a transect along 6° East (red squares) and a transect along 30° East (blue squares). Also indicated by colored lines and arrows are the tectonics plates boundaries (black line) and a sketched circulation of the eastern Weddell Gyre from Ryan et al.33 who described a two-core pathway of the northeastern inflow of WDW at about 20° E, the northern pathway being driven by eddy mixing in the northeastern corner of the Weddell Gyre (brown arrow), the southern one being an advective route which forms the southern branch of the inflow and extends beyond 30° E before turning westward (red arrow). The yellow arrow indicates the predominantly westward coastal flow regime south of 65° S35. The presence of the bloom is indicated by a green oval. The yellow star indicates the presence of hydrothermal vents at the Southwest Indian Ridge36. Contoured and scatter plots of δ3He (%) at or close to the Prime Meridian (b), following a transect along 6° East (c), and along 30° East (d). Density isopycnal contours are also indicated. Note the different latitude range used for the 6° East transect.
