Comparative taphonomy of molluscan death assemblages from the gulf of mexico

Biodiversity in our world is unequivocally linked to climate. Due to anthropogenic climate change, ecosystems are changing at rates that are affecting the continuity of ecosystem services we depend upon, creating a greater need for biomonitoring and restoration efforts. Since the Industrial Revolution, there have been increasing changes in marine ecosystems, leading to growing concern about potential losses in marine biodiversity. This is largely due to factors such as habitat loss, pollution, overfishing, introduction of invasive species, eutrophication, and acidification (Harnik et al., 2012). Live-dead studies provide one approach for assessing recent changes in ecosystems in response to human activities. Live-dead comparisons typically focus on the taxonomic composition and relative abundance of species in samples of the living community versus the occurrence and abundance of species in associated death assemblages (Kidwell, 2009). Death assemblages refer to the accumulation of skeletal remains such as bones, teeth, and shells. Live-dead studies have been used to assess discordance in disturbed ecosystems preand post-human impacts, which can help inform conservation and restoration decisions (Terry, 2009; Kidwell, 2009). However, before death assemblages can be used to reconstruct past communities, or be used as reference points for pre-impact communities, we have to understand the ways in which post-mortem taphonomic processes potentially bias the biological and ecological information contained in these assemblages. Postmortem taphonomic biases can include both abiotic and biotic factors such as transport, corrosion, predation, and digestion, that work to destroy skeletal materials before they have a chance to be incorporated into stratigraphic records (Denys, 2002). Post-mortem processes could result in live-dead mismatch that is not representative of recent or historical biological changes.