Skeletal cores were collected from Porites coral colonies in April 2010 (n = 4), May 2012 (n = 3), September 2012 (n = 6), November 2015 (n = 16), and May 2016 (n = 1). All cores were collected from colonies at 3-17 m depth using pneumatic or hydraulic drills with diamond drill bits. Cores collected in 2010 and 2012 were sampled from healthy colonies and were between 50 and 200 cm in length. In 2015, cores were collected from bleached Porites colonies, and were limited to 5-10 cm length in accordance with United States Fish and Wildlife Service permitting restrictions. The core collected in May 2016 was collected from a recently dead portion of a massive colony that experienced significant tissue mortality during the 2015-16 bleaching event. Core holes left in the coral colonies were filled with cement plugs, sealed with underwater epoxy, and secured flush with the existing colony surface. Visual inspections of coral colonies several years after coring demonstrated full recovery and complete tissue overgrowth of the cement plug.
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Coral skeletal cores, ecological survey data, seawater samples, and in situ instrument time series were collected during expeditions aboard:
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\n- NOAA ship Hi\u2019ialakai (2\u20134 April 2010, 3\u20135 May 2012)
\n- Pangaea Exploration S/V Sea Dragon (13\u201316 September 2012)
\n- R/V Machias (12\u201315 November 2015)
\n- NOAA ship Oscar Elton Sette (17\u201323 May 2016)
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Research activities and sample collection were conducted under U.S. Fish and Wildlife Service Pacific Reefs National Wildlife Refuge Complex Research and Monitoring Special Use Permits:
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\n- 12521-10001 (effective date: 15 Jan 2010; expiration date: 30 May 2010)
\n- 12521-12001 (effective date: 7 Feb 2012; expiration date: 31 Dec 2012)
\n- 12521-12005 (effective date: 29 Aug 2012; expiration date: 30 June 2014)
\n- 12521-14001 (effective date: 1 Jan 2015; expiration date: 31 Dec 2015)
\n- 12513-15001 (effective date: 11 Nov 2015; expiration date: 31 Dec 2015)
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and in compliance with Presidential Proclamation 8336.
These data were published in Barkley et al., 2018 (Figure 5).
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The dataset contains historical coral reef bleaching events on Jarvis Island reconstructed from stress bands in Porites coral cores. Samples are collected between 2010 and 2016.
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Coral cores were oven-dried and scanned with a Siemens Volume Zoom Helical Computerized Tomography (CT) Scanner at WHOI and at the University of North Carolina Biomedical Research Imaging Facility. Density banding and stress band presence was evaluated in 3-D CT scans of coral cores using the automated coralCT software (DeCarlo and Cohen 2016). Density time series were extracted and averaged from individual polyp growth tracks, which accounts for the different ages of skeleton in horizontal cross sections due to uneven growth geometry, in 0.1 mm increments from the top of the skeletal core up to 70 cm down core. Density values were converted to Z-scores by subtracting the long-term core mean density from each raw density value and dividing by the long-term standard deviation. High-density stress bands were defined as bands greater than 1 mm thick that spread across the entire width of the core where density values exceeded two standard deviations of the whole core density mean (i.e. a Z-score greater than 2). Stress bands that formed prior to 2010 were identified based on density banding patterns counted downward from the core top. Stress bands that were forming in 2015-16 were dated based on their location at the very top of the core (indicating that they were forming during the time of collection).