Dataset: Kiritimati 2014-2015: Surface water

Surface sampling:

For the YSI, this was done off the side of the boat, at 1m depth. For the Aqufluor, this was done by swimming out from the boat, ~10m away from the vessel to avoid contamination from paint chips, gasoline, etc.

Other Sampling:

Bottom depth at all sampling locations was 10m.

YSI Measurements: Place YSI sensor into the water, and lower to 1m depth. Wait for readings to stabilize, and then record all parameters.

AquaFluor measurement procedure:

1. Test solid secondary standard and turbidity standard to ensure the instrument has not drifted throughout the day. Use this same procedure. Compare to the measurement from the beginning of the calibration.
2. Turbidity and In vivo Chl a will either be collected independently and taken as a subsample of the for chl a samples
3. In either case a 500 mL Nalgene bottle will be used, and should be collected in the same matter as the chl a sample (see 1.1)
4. Take as many independent chlorophyll and turbidity samples as you can but you will only take one sub-set sample from the extracted chlorophyll nalgenes.
5. When conducting the independent sampling, you will reuse one 500 ml brown nalgene. Wash with sterile seawater in-between samples.
6. Fill the cuvette 3/4 of the way using a transfer pipette. If you get the outside of the cuvette wet, dry completely with a kimwipe.
7. For the sub-samples of extracted chlorophyll, use the same 30cc syringe as used for nutrients.
8. Insure cleanliness of the cuvette, which are dry on the outside
9. Insert the sample (be aware of orientation), the black sample compartment does not need to be closed when reading the sample
10. Press the <Read> button. The instrument will measure and average the fluorescence signal for 10 seconds
11. The reading result will display on the top line of the Home screen, log this result
12. The top left corner will then display “WAIT” for 3 seconds. Once “WAIT” disappears, another sample can be read
13. We are going to reuse cuvettes. After you complete one sample clean the cuvette with sterile seawater and dry completely with a kimwipe. Additionally, clean the transfer syringe used for the sample with sterile seawater and dry with a kimwipe.