Award: OCE-1536650

The overall goal of this multi­institutional interdisciplinary project was to increase our understanding of the ecology of hydrothermal vent ecosystems and the ecological physiology of the animals that inhabit them. The overall project used the combination of high­-resolution seafloor mapping and photographic imaging of the seafloor coupled with physical sampling and in-site sensing to document the geologic, chemical and biological characteristics and patterns at each of the sites we visited. The documentation of these patterns is fundamental to understanding the processes behind the patterns of change in community structure in this vent biogeographic province. By comparing these observations we sought to describe in detail, any changes in geology, chemistry, temperature, and ecosystem composition at several hydrothermal vent fields that may have occurred since the sites were first visited in 2005. The aspect of the collaborative project supported through this award was focused on seafloor mapping. To optimize our efforts at sea, we collected seafloor mapping data throughout the duration of our research cruise aboard the Research Vessel Falkor and were able to collect useful data not only to our planned research, but also to help other researchers studying other processes and phenomena in the region. Our primary goals were to quantify the detailed characteristics of the seafloor by using sonar systems to create high-resolution maps of seafloor depth (bathymetry) at specific sites that were first visited in 2005. Our hypothesis was that any dramatic geologic changes between 2005 and 2016 would have resulted in quantifiable differences in the shape of the seafloor - potentially induced by volcanic or tectonic activity. Colleagues on the research cruise used other techniques to look at chemical and biological changes at the site. Results from our mapping work show that the seafloor at the sites visited, and in the region surround the sites, has remained relatively unchanged in the 11 years between surveys. This suggests that the geologic processes that directly affect the shape of seafloor at these sites are stable over the time period of a decade, and that no major volcanic or tectonic events have occurred. We observed no significant differences in the characteristics of the seafloor through sonar mapping. This is confirmed by visual observations at specific locations throughout the study sites. These observations of seafloor characteristics are consistent with observations of the distribution and composition of biological communities and hydrothermal vents at these sites during our research cruise. Overall this indicates that the rates and patterns of change in this environment are slow, and that the geologic processes are relatively stable throughout the study sites visited. Last Modified: 04/30/2019 Submitted by: Vicki Ferrini