The modern distribution of marine species has been strongly affected by glacial and interglacial events during the Pleistocene that likely promoted alternating periods of vicariance and dispersal (respectively). In cold temperate regions, glacial and interglacial events also forced southward contraction then allowed northward expansion of species ranges. Thus periods of increased isolation and range contraction alternating with periods favoring dispersal and range expansion have created a complex temporal and spatial mosaic of species histories. These histories are recorded, in part, in patterns of genetic variation among populations and, in part, in fossil and subfossil records of species distributions and paleoenvironments.
Our goal is to integrate molecular and paleontological information, including paleoceanography, to understand post-Pliocene factors influencing "connectivity" (a term used to describe the continuum from isolation to panmixis) in marine taxa. A team of international researchers will provide syntheses describing the history of coastal and oceanic marine species including fossil-forming taxa such as foraminifera, molluscs, and fishes, and soft-bodied invertebrates and algae.
Issues we seek to clarify include: (1) How integrating molecular and paleontological data improve reconstruction of the biogeographic histories of marine species and mutually enrich these oftentimes separate disciplines; (2) whether fossil-forming taxa can act as good models for interpreting the evolutionary histories of soft-bodied organisms; (3) what are the shared (or distinguishing) evolutionary histories of various taxa and geographic regions? (4) what we can learn of the historical ecologies of species? The lessons from these syntheses that will improve our ability to understand and predict outcomes of future climate change.
The symposium will present an up-to-date overview of marine biogeography and lead to an objective (preliminary) schema for classifying the historical, physical and biological factors that contribute to biogeographic transitions in the seas. We expect this approach will shed new light on old problems such as how, in a medium in continuous motion like the sea, biogeographic patterns are formed in organisms with apparently long-lived dispersal phases and, conversely, why some organisms with apparently limited dispersal potential have very broad geographic ranges. The symposium will improve understanding of the forces that generate and maintain marine biodiversity on geological timescales.