Figure 4. (a) Mixed layer depth (decibars; Martinson et al., 2008), (b) water column
chlorophyll (mg m–2), and (c) primary production rate (mgC m–2 d–1) in the region between
Anvers Island in the north and Marguerite Bay in the south. These plots are averaged for
cruises undertaken from 1993 to 2012. The immediate coastal region in the south part of the
study area (including the Rothera Time Series [RaTS] site at Rothera Base) is not contoured
because Marguerite Bay extends more than 100 km farther to the east and is not surveyed
regularly. The dashed and solid white lines denote the continental shelf break at > 1,000 m,
and coastal zone < 300 m.