| AT26-10 Chemosynthetic Microbial Communities at Deep-Sea Vents (EM122). The cruise
will include 16 dives with DSV Alvin or ROV Jason, to allow time for deployment and
collection of experiments and for extensive sampling of discrete vents along the axis
of the 9°46?N to 9°53?N segment of the East Pacific Rise (EPR). We propose to deploy
experiments/sample a low temperature diffuse flow vent (e.g., Crab Spa; T: 10-30°C),
and a higher temperature vent (e.g., L-vent; T: 30-60°C). Furthermore, we will carry
out additional opportunistic sampling for a limited set of parameters (e.g., chemistry,
454- pyrotags, FISH, in situ carbon fixation) of vents that fall into these two categories,
or that might have developed since the last visit to the site (May 2012). During the
course of the cruise we will collect biomass from fluids and biofilms (deployment/recover
experimental microbial colonizers) by utilizing a Large Volume Pump (LVP) (McLane
WTS 6-1-142LV). We have successfully used this set up in previous cruises and were
able to collect up to ~2,000 liters of hydrothermal fluids resulting in enough biomass
(cell density is 2-5 x 105 cells per ml) for subsequent ?omic? analyses. During large
volume filtration, the volume filtered is recorded by the LVP onboard computer and
the vent fluid sampled is monitored with a time series temperature probe, H2S, and
pH sensors. Fluid samples for chemical analyses will be collected at each deployment
site using the isobaric gas-tight samplers, which will also be used to sample fluids
from the two focus sites for the shipboard incubations. Finally, we will deployment/recover
experimental microbial colonizers to collect microbial biofilms.We have successfully
used these devices in previous cruises to collect sufficient biomass for metatranscriptomic
analyses. |