Figure 5. Oxygen isotope profiles from modern A. opercularis specimens SWN 35, DOGB 11, and DOGD 25 (Naturmusem Senckenberg). Solid triangles represent prominent growth rings visible on the shell (cf. Fig. 3; these growth interruptions represent the first winter). Oxygen isotope profiles are represented by solid black lines; carbon by dashed blue lines. Reprinted with permission from Elsevier Science from Hickson et al. (1999), copyright (1999).