Dataset: viable cell counts
Deployment: FK141215

This data set is associated with PI Douglas Bartlett (NSF OCE-1536776) and Schmidt Ocean Institute R/V Falkor cruise FK141215. The cruise occurred December 15-21, 2014 in the Challenger Deep within the territorial waters of the Federated States of Micronesia. During this cruise the Leggo lander was deployed multiple times and drops 1 and 3 recovered seawater samples that were analyzed. Additional details can be found at: https://schmidtocean.org/cruise/expanding-mariana-trench-perspectives/ and https://scripps.ucsd.edu/labs/dbartlett/contact/challenger-deep-cruise-2014/

Leggo Lander Drop 1:
Time (in Guam) deployed/recovered: December 16, 9:00/19:26.
Position at deployment: 11° 21.9836 N 142° 25.9533 E, middle section of the Challenger Deep.
Greatest depth of dive: approximately ~10,900 m.
In situ temperature on seafloor: 2.6°C.
Notes: This drop recovered seawater samples from about a meter off the seafloor. This included a 3 L Niskin bottle of seawater and ~ 150 mls of seawater collected in a pressure-retaining seawater sampler. The PRS sampler held more than 81% of the in situ pressure. 

Leggo Lander Drop 3:
Time (in Guam) deployed/recovered December 18/19, 13:14/10:14.
Position at deployment 11° 22.1122 N 142° 35.2510 E, eastern section of the Challenger Deep.
Greatest depth of dive: 11,168 m (uncorrected) correct depth = 10,929 m.
Notes: This drop utilized the lander equipped with a camera system and a 30 liter Niskin bottle. The Niskin bottle and a trap in front of the camera were baited with jack mackerel. The camera obtained high definition video clips and still images of amphipods feeding on the bait. 23 amphipods were collected within the Niskin bottle. The temperature within the Niskin water measured back on ship was 10.8°C.

Viable cell counts:
This dataset includes viable cell counts on the bacteria in the seawater collected in the Niskin bottles during Leggo drop 1 and 3. Seawater dilutions were plated onto Marine 2216 plates and incubated at 4 degrees C. Note: Leggo1 is the first drop of the Leggo Lander and the values reflect the viable cell counts from its 2 liter Niskin bottle. Leggo3 is the third drop of the Leggo Lander, with its camera payload and associated jack mackerel baited 30 liter Niskin bottle. Amphipods were collected in the Niskin bottle.

Colony Identification:
Data from the identification of bacteria cultured from the Leggo drop 1 and 3 Niskin bottles are available as a supplemental file (.txt). These identifications were performed using standard methods associated with PCR amplification of the 16S rRNA gene followed by dideoxy sequencing at Retrogen Inc.