AB 1:1-16 (2007)  -  DOI: https://doi.org/10.3354/ab00001

ABSTRACT: This study quantifies patterns in settlement and colonization of hydrothermal vent invertebrates and explores relationships with the biotic and abiotic factors that may influence these patterns. Colonization was measured between 2001 and 2003 in 2 segments of the Juan de Fuca Ridge, by deploying sets of basalt blocks at vents with different flow characteristics, over different spatial (cm to 100 km) and temporal (1 to 2 yr) scales. Spatial variation in colonization was greater between vents within a segment (m to km scale) than between segments, which we suggest reflects a species-specific response to varying environmental conditions at a particular vent. For gastropods, gregarious settlement enhanced colonization, while post-settlement mortality influenced colonization patterns of polychaetes. In 2003, we characterized the spatial variability in environmental conditions among 3 vent sites, through discrete in situ measures of the temperature and chemical properties of venting fluid near basalt blocks. Most colonist and settler abundances were positively correlated with vent fluid properties, notably dissolved H₂S and temperature. Our results suggest that the variation in settlement and colonization of hydrothermal vent species is mainly influenced by the properties of the vent fluid, but biological interactions can also have a significant influence on colonization processes. Our study is the first to experimentally quantify colonization by invertebrates at Juan de Fuca Ridge vent sites, and extends the understanding of the role of physical and biological factors in the regulation of early life-history stages.

KEY WORDS: Colonization · Settlement · Hydrothermal vent · Post-settlement mortality · Gregarious settlement · Temperature · Dissolved sulphide · Juan de Fuca Ridge