The relationships between infauna, suboxic sediments, and organic enrichment are well documented (Weston 1990; Rees et al. 1992; Hargrave et al. 1997). This system is much like that described by Pearson and Rosenberg (1978) as presented in Figure 4. Rhoads and Germano (1982) took this concept one step further by assigning categories to the various successional stages in an attempt to integrate the biotic and geochemical responses to organic enrichment. To be used reliably, successional stage determinations must be made within the biological and physical context of each study, are necessarily subjective, and are unlikely to be more than broadly informative between analysts. Similarly, the majority of parameters presented in Table 1 are site- and study-specific. Acting in a similar manner to a cone penetrometer, the SPI wedge penetration depth into soft sediments may be generally useful as a proxy for sediment fabric if calibrated, but results will be sensitive to differences in equipment and deployment.
