Microbial Ecology Spatial and Temporal Distribution of the Vibrionaceae in Coastal

Relatively little is known about large-scale spatial and temporal fluctuations in bacterioplankton, especially within the bacterial families. In general, however, a number of abiotic factors (namely, nutrients and temper-ature) appear to influence distribution. Community dynamics within the Vibrionaceae are of particular interest to biologists because this family contains a number of important pathogenic, commensal, and mutualist species. Of special interest to this study is the mutualism between sepiolid squids and Vibrio fischeri and Vibrio logei, where host squids seed surrounding waters daily with their bacterial partners. This study seeks to examine the spatial and temporal distribution of the Vibrionaceae with respect to V. fischeri and V. logei in Hawaii, southeastern Australia, and southern France sampling sites. In partic-ular, we examine how the presence of sepiolid squid hosts influences community population structure within the Vibrionaceae. We found that abiotic (temperature) and biotic (host distribution) factors both influence popula-tion dynamics. In Hawaii, three sites within squid host habitat contained communities of Vibrionaceae with higher proportions of V. fischeri. In Australia, V. fischeri numbers at host collection sites were greater than other populations; however, there were no spatial or temporal patterns seen at other sample sites. In France, host presence did not appear to influence Vibrio communities, although sampled populations were significantly greater in the winter than summer sampling periods. Results of this study demonstrate the importance of understanding how both abiotic and biotic factors interact to influence bacterial community structure within the Vibrionaceae