UTILITY OF MARINE BENTHIC ASSOCIATIONS AS A MULTIVARIATE PROXY OF PALEO-BATHYMETRY: A DIRECT TEST FROM RECENT COASTAL ECOSYSTEMS OF NORTH CAROLINA
Multivariate ordinations were used to determine whether modern benthic marine invertebrate communities can be effectively used to extrapolate bathymetry. Samples were analyzed using detrended correspondence analysis (DCA). The DC1 scores of samples correlate tightly with the actual depth values of the samples, confirming that samples ordinate along an axis that primarily reflects bathymetry and its environmental correlatives. Moreover, when the DC1 scores are calibrated with modern ecological data, the resulting estimates of sample depths are a robust proxy of their actual bathymetry.
In coastal ecosystems of North Carolina, bathymetry appears to be a primary controlling factor, with faunal assemblages changing predictably in terms of their taxonomic composition with depth. This relation is remarkable also because coastal habitat variation and anthropogenic effects may act as confounding factors here, particularly in inlets, harbors, and estuarine settings.
Although it is arguable that individual case studies such as this one can support broader generalizations, these results are promising and consistent with multiple paleontological studies. Fossil communities may provide robust quantitative estimates of bathymetry with potential applications to paleoecology and stratigraphy.