Physical and chemical factors influencing species distributions on hydrothermal sulfide edifices of the Juan de Fuca Ridge, northeast Pacific

Abstract

This study exarnines relationships betwei.n hydrotherrnal vent s p ~c i e s and their surrouncling physical and chemical environment on 2 high-temperature sulfide edifices of thc Juan d e F U C ~ R ~d g e (northeast Pacific). Video imagery and rn situ temperature and c h e m i c ~l information were acquired during 2 remotely operated vehicle (ROV) dive prograrns in 1993 and 1995, ior a total of 78 scans. Statistical analyses of environmental and faunal data reveal a heterogeneous distribution (correspondence analyses) of hydrothermal species and demonstrate a significant influence of local physical and chemical conditions on species distnbutions (canonical correspondence analyses). Results confirm the importance of hydrogen sulfide to the distribution of vent species as well as the importance of cornplex variables such as visible flow intensity and substratum type Since less than 30% of the variance in species distnbutiori could be explained by the measured in situ factors, we conclude by stressing the need to evaluate effects of other unmeasured environmental factors such as dissolved oxygen, nitrogen compounds, food availability and biological interactions.