Operational Plans

Phase I, Bloom experiment

Image of chlorophyll concentration

Bloom mapping

Evolution of biological signals within the bloom will be followed for nine days. Local blooms, if present, are likely to be driven by the confluence of eddies advecting westwards at average speed of 3-6 miles per day. The objective is to understand what sustain local blooms, which species are blooming, how the phototrophy/heterotrophy is affected, and what do these blooms leave in their wake.

Upon arrival at BLOOM location at 22.75N, 157.00W on July 31 03:00, FRRf survey will be performed to acquire information about the spatial characteristics of the bloom. Following the survey, double core/science CTD cast will be performed at the center of the local bloom, followed by deployment of sediment traps, SID incubator, and nitrogen fixation array. Bloom mapping will resume at 22:30 using pumping CTD operating in YOYO mode. The ship will then transit to OUT-BLOOM location where two CTD casts will be performed to collect water for incubations led by Jennifer Brum. Following that, a regular daily sampling schedule will be established with a pair of core/science casts at OUT-BLOOM location at 6:00, and at IN-BLOOM location at 20:00 (see the attached schedule spreadsheet). Pumping CTD will be deployed twice a day, during transects between OUT-BLOOM and IN-BLOOM locations. The IN-BLOOM and OUT-BLOOM positions will vary from day to day to acquire the most complete description of the bloom biological properties. There will be open wire time at these two locations to be used for extra CTD casts.

Two-three casts will be performed at each of IN-BLOOM and OUT-BLOOM stations: the first cast will serve the needs of core measurements; the second 1-2 casts will serve the specific CMORE science needs. There will be 8 standard CTD depths (Table 1).

 

Table 1. Hydrocast depths/core

Depth

Bottles

Comments

200 m

4

fixed

150 m

3

fixed

DCM

3

variable

100 m

3

fixed

75 m

3

fixed

45 m

2

fixed

25 m

3

fixed

5 m

3

fixed

 

There will be 13 core cast with full sampling schedule (approximately one full core sampling/day). The full core sampling schedule will include

The remaining casts will be performed with limited core sampling schedule. The minimal core sampling will include

Download the cruise schedule (Excel) for the detailed description of full/minimal sampling.

Sediment traps will be deployed on the first day of the bloom mapping experiment. The traps will be deployed from the stern using the A-frame and the Sea-Mac winch. Power requirement for the winch is 440 VAC, three phase at 10 amps. After deployment we request that the Bridge verify that the radio transmitters are functioning and directionally correct. The TS-SID incubator will be deployed alongside of the sediment traps.

The array will drift for 8 days before recovery. The trap array is equipped with 2 ARGOS satellite transmitters (platform #s 01833, 03028, 60482, 60484), 2 strobe lights, and 2 radio transmitters (channel 72, 156.625 MHz). Daily positions of the array shall be transmitted by email directly to the ship, therefore the ship will not need to keep within site of the array until the time of the recovery. Assistance from the bridge is requested in plotting the drift track of the array. We request the use of the ship's radio direction finder for locating the array before recovery.

The TS-SID incubator is equipped with radio transponder and the flasher. Keeping track of this device may require more effort.

Notes:
1. We will transect between the IN-BLOOM and OUT-BLOOM locations (about 10 nm) twice per day.
2. The dumping area will have to be established at least 10 nm downward of the BLOOM location, outside of the IN-BLOOM location.

Ship-deck incubations

Water for the first ship-deck incubation will be collected at Station 1 (22.5N, 157.50W, July 30, 18:00) prior to arrival to the bloom location. The incubation experiment will start shortly afterwards, and will be terminated on August 3, 20:00. Second incubation will be initiated on August 4 early morning, and will last till August 7, 20:00. Third incubation will be initiated on August 8 early morning, and will b terminated on August 13, 9:30. Water for all incubations will be collected in OUT-BLOOM stations.

There will be four large incubators on the upper deck, each with eight 20L carboys capacity, and two small incubators, with 4x20L carboy capacity. Two of the large incubators will be used to investigate responses of MLD water (45 meter depth) to 10% enrichment with 500m, 300m, and 200m water, at 40% and 16% light level. Remaining incubators will be used for other CMORE experiments. The deep water enrichment pattern is described in Table 2.

 

Table 2. Deck enrichment incubations.

 

40% light (Incubator 1)

16% light (Incubator 2)

10% 500m

2 carboys

2 carboys

10% 300m

2 carboys

2 carboys

10% 200m

2 carboys

2 carboys

control

2 carboys

2 carboys

 

pH shift incubation will be performed in parallel to deep water enrichment incubations. Water from 45 m depth will be incubated at the ambient pH level (pH = 8.1), and at low pH level (pH = 7.8) induced by bubbling the water with 760 ppm CO2 mixture. Water from 45 m depth enriched with 10% of 300m water will also be incubated at theses two pH levels (Table 3).

 

Table 3. Deck pH shift incubations.

 

pH = 8.1

pH = 7.8

10% 300m

2 carboys

2 carboys

control

2 carboys

2 carboys

Small-scale lab incubations

Two small scale (2L) incubators with computer-controlled temperature, light, and pH will be used in the lab to study physiological responses of phytoplankton to temperature, light, and pH shift. These incubations will be run through the length of the cruise.

Phase II: Eddy hopping

The objective of this phase is to determine whether local biogeography is affected by the presence of upwelling/downwelling eddies. To investigate that, CTD stations will be performed at the centers of five eddies along the cruise track as described in section 1.1. The actual transect during this phase will be defined by the end of the Phase I, based on the most actual SSH/Ocean Color data.

Phase III. Intensive eddy mapping

The objective is to determine the variability of biological signals across an upwelling eddy. After completion of Phase II on August 11, 21:00 the ship will transect through a single eddy (presently centered at 25.50N, 157.50W) with 8 stations separated by 30 nm. Intensive sampling schedule (double casts CTD every 5 hours) will be initiated. This will be the most demanding sampling schedule with double CTD casts very 5 hour. By this time most of the cruise participants should become familiar with the details of core measurements, and should be able to assist the BEACH team in this their effort. The eddy mapping transect will end at 25.50N, 159.00W on August13, 04:00. Upon completion of this transect, the ship will transit to 23.75N 159.00W to perform last CTD cast in the upwelling region. On August 13, 18:00 the ship will start transit to Snug Harbor (ETA August 14, 08:00).

Note: The location, and the orientation of this transect will be defined by the end of the Phase I, based on the most actual SSH/Ocean Color data.

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