Table of Contents

• Dataset Description
  • Methods & Sampling
  • Data Processing Description
• Data Files
• Parameters
• Instruments
• Deployments
• Project Information
• Funding

This dataset contains water quality measurements collected on Kiritimati island, Kiribati in 2014 and 2015.  Measured parameters include water temperature, salinity, pH, chlorophyll, turbidity, and dissolved oxygen.  Values of yes or no are also supplied to describe whether it was raining or windy at the time the samples were taken.

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.

Data are directly from field readings.

BCO-DMO Processing Notes:

* added a conventional header with dataset name, PI name, version date
* modified parameter names to conform with BCO-DMO naming conventions
* values of NA changed to nd for no data
* removed Kiritimati,Kiribati for location/country  in the data since it was same throughout. Described in the metadata.
* removed second depth value (bottom depth) which was 10m for all samples. Included this information in the acquisition description.

Extracted from the NSF award abstract:

As anthropogenic climate change intensifies, coral reefs face growing threats from associated decreases in ocean pH and increases in ocean temperature. While such stressors increase steadily through time, coral reefs also experience natural climate extremes, such as El Niño events, that rapidly reshape reef structure and function over a period of months. The El Niño event forecast for 2014/2015 presents the opportunity to study how such events affect coral reef ecosystems. This research will identify which species are most resilient to high temperature stress, and determine whether the presence of specific types of algal endosymbionts in the corals is predictive of the capacity of their coral hosts to survive temperature stress. By studying the reefs at remote sites with documented gradients in human use and pollution, the investigators will be able to tease apart the influence of El-Nino induced temperature changes from local impacts on the reef. This information will ultimately help to identify which components of the coral reef ecosystem are most vulnerable and provide a prognosis for the survival of different types of corals and endosymbionts in a warming world.

This project focuses on reefs at Christmas Island (2N, 157W) - a site that is predicted to be heavily affected by warming during El Niño. In September 2014, roughly 3 months prior to peak El Niño warming, the investigators will install an array of ocean monitoring equipment around Christmas Island. During that field trip, they will also conduct extensive ecological surveys of the reef, collect coral, water and sediment samples for the analysis of Symbiodinium communities that will be analyzed at the University of Hawaii using high throughput sequencing approaches, and characterize ocean geochemistry at both windward and leeward sites on Christmas Island. These activities will be repeated in subsequent trips during peak El Niño conditions, and post El Niño conditions, to allow the investigators to monitor the acute responses of the environment and ecosystem and their near-term recovery, respectively. During the last trip, they will drill several coral colonies to assess how the corals record such a large thermal stress in terms of skeletal morphological and skeletal geochemistry changes.