PS 66-27 - Biogeographical analysis of deep-sea abyssal bottom habitats: Using an abiotic province scheme and metazoan occurrence databases

Friday, August 11, 2017
Exhibit Hall, Oregon Convention Center
Brandon Genco, Geography, University of Hawai'i at Manoa, Honolulu, HI
Background/Question/Methods

Our aim was to test congruence of deep-sea province boundaries to biological occurrence data. Province boundaries are from a proposed environmental biogeography scheme (Watling et al., 2013). No attempt has been made to test congruence of provinces to the spatial patterns of the majority of animal taxa within. The environment variables include: bathymetry/topography, salinity, oxygen, temperature, and POC flux. These variables are expected to be impacted by climate change.

Two biological databases of deep-sea metazoan records were used to test the abiotic province scheme’s boundaries. These are the unpublished Census of Diversity of Abyssal Marine Life (CeDAMar), which includes secondary factors, and the online version of the same dataset (GBIF), where primary data are limited to species occurrence information (Stuart et al., 2008) . To test congruence, rarefied alpha diversity to distance relationships within provinces were calculated, using an expected mid-domain effect (MDE) null hypothesis with class replicates per province. An Ideal error equation was developed to calculate resolution loss in bathymetry derived from satellite alimentary. This gives dimensional values of a hypothetical feature not detected for a regional depth. Semivariance distance relationships were explored for diversity metrics of gastropods in the Northwest Atlantic.

Results/Conclusions

A MDE was not observed for species diversity (CeDAMar), and was rejected for genera diversity (GBIF). Many taxa showed no spatial diversity patterns to province centroids. Most significant trends were opposite than expected for a MDE. Spatial relationships coincided with important Deep-Sea taxa (e.g. polychaetes). The ideal error equation, suggests deep-sea rugosity is underestimated, and provides a tool to apply error estimates to bathymetry data.

Geostatistical analysis of gastropods showed significant spatial trends associated with the 1st order topography of the continental margin. Congruence of biological diversity patterns to abyssal provinces was not observed. Provinces may need to be re-delineated to include factors related to 1st and 2ndorder topographic features within, or abutting, provinces. Results indicate evolutionary theories of diversification in the deep-sea may need to be reevaluated.