BLOOM Ecological Reconnaisance (BLOOMER / KM0715) Cruise
CMORE - BLOOM E cological R econnaisance (BLOOMER / KM0715)
MIT Cruise Summary
Amendment experiments
1) Our major undertaking was to track changes in whole community expression patterns in response to a variety of amendments over the course of approximately one diel cycle.
Briefly, 20L carboys with water from 75m, including controls and 3 amendment conditions (all with a biological replicate), were maintained in on-deck incubators and shaded to mimic ~3% incident light levels of 75m.
Conditions
1) Un-amended control
2) + PO
4
(5 uM final conc.; ~100x in situ levels)
3) Mix 90% 75m seawater +10% 700m seawater (c.a. ~ 300x NO3, 4x PO4, 5x
SiO2, etc.. in situ level)
4) + HMWDOM (~10x in situ levels)
Samples were collected for RNA isolation at six timepoints throughout the diel cycle, and community DNA samples were collected at the initial and final timepoints. Flow cytometry samples were also collected at each time point for total cell counts and for
RNA isolation from flow-sorted Prochlorococcus . RNA and DNA samples will be subjected to pyrosequencing, to obtain gene expression ratios with the aim of revealing dynamics in the treatments and natural samples.
Sampling scheme
This experiment was conducted twice at the “bloom” station (#5) and once at station
ALOHA (#19)
2) An additional amendment experiment was carried out to contrast the differences in community expression patterns with HMWDOM amendments to mesopelagic water at station ALOHA. The experimental setup was similar but slightly simplified to that above.
Community Profiles
At both the “bloom” station (#5) and at station ALOHA (#19) samples were collected from depth profiles for both DNA and RNA isolation for whole community expression profile analysis.
Depth Volume for RNA Volume for DNA
25m
75m
125m
500m
3L
3L
3L
3L
7L
7L
7L
7L
Cruise Summary
Experiment
Diel/Amendment #1
Station
5 (“bloom”)
Cast Date
6 8/11
19 8/13 Diel/Amendment #2
Diel/Amendment #3
Profile #1
5 ("bloom")
19 (ALOHA)
5 (“bloom”)
Profile #2 19 (ALOHA)
Mesopelagic
HMWDOM amendment
19 (ALOHA)
18 8/16
15 8/12
17 8/17
18 8/17
