Meeting Abstract

49.8  Jan. 6  Tolerance of the Early Life History Stages of to Environmental Conditions: Possible Limits to Dispersal SMART, T.I.; University of Oregon tsmart@uoregon.edu

Exposure to extreme environmental conditions has been shown to cause lethal and sub-lethal effects on survival and development in marine invertebrates, affecting both dispersal and abundance. is a tube-building polychaete found in mudflats and beaches both in temperate and tropical regions. Across its range, this species is exposed to a wide variety of environmental conditions that can be detrimental to the planktonic early life history stages. A description of the reproduction and early development of the Coos Bay, Oregon population will be presented. The effects of a range of temperatures and salinities on survival of embryos and larvae were investigated in the laboratory. Newly fertilized embryos and larvae were exposed to five temperatures from 5 to 30�C and survival and development success determined. Larvae were also exposed to four salinity treatments for 24 hours, after which survival was assessed. Temperate Oregon embryos and larvae did not survive high temperatures as well as expected, considering the geographic distribution of this species. However, these stages did survive temperatures comparable to those common during the reproductive season in this region. By comparison, both juveniles and adults showed much stronger tolerance to the extreme conditions possible in estuaries. Local adaptation of the planktonic stages of a marine species to environmental conditions may limit the dispersal capabilities of that species and its distribution and can serve to isolate populations, thus leading to speciation over time.