Coastal environments are important in many ways: they provide food and energy
for coastal communities, have a variety of unique biologic habitats, and influence global
climate. These environments can change due to either anthropogenic or natural
phenomena over a wide range of time scales. However, the often overlooked long-term
(centennial to millennial) processes may be hidden behind short-term fluctuations
observed today. The need for a reference baseline of coastal habitats provides a new
opportunity for paleontology, which is ideally equipped to document the long-term trends
and reconstruct historical and ancient environments and communities.
However due to taphonomic processes such as decay and diagenesis, there will
always be some bias inherent to the fossil record. This bias has been often viewed as a
negative aspect, undermining the utility of paleontological data for retrieving ecological
and environmental records. Yet, fossils are still one of the best sources of direct data
about the past faunas and their ecosystems. To overcome the biases introduced by the
fossilization process, researchers have used observations and experiments in modern
systems as models to compare fossil deposits, a method called actualistic paleontology.
Over recent years, such actuopaleontological approaches have been used increasingly to
exploit distinct signatures of fossil deposits in environmental reconstructions, quantify
effects of anthropogenic processes on invertebrate faunas and regional ecosystems, and
even augment archaeological studies
Three studied included in this dissertation exploit different aspects of
paleontological techniques to study coastal systems, including both Recent and fossil
settings. Two of the studies use modern environments to serve as models for investigating
preservation potential and potential biases that affect subfossil and fossil assemblages
forming in intertidal environments, from whether certain fauna will be preserved to the
biases inherent in a shell deposit. The final study, conducted at a fine geologic resolution,
focuses on the morphology of a fossil ancestor of an extant mactrid bivalve that is
ecologically important in many present-day coastal habitats and well-studied by
ecologists and malacologists. The study attempts to quantify morphological effects of
environmental changes that occur over geological time scales.