Table of Contents

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

This dataset contains calcification rates for Porites coral 751 from Dongsha Atoll from 1954-2012. Calcification rates were collected by analyzing the CT scan of the coral. 

Coral core collection and age model. The two coral skeletal cores were collected from living Porites sp. colonies in June 2013 using an underwater pneumatic drill. The north reef flat core (“751”) was  drilled to the base of the colony and reached 1 m in length, whereas the east lagoon core  (“762”) is 0.5 m in length. Both corals lived in approximately 2 m deep water. The cores  were passed through the Siemens Volume Zoom Spiral computed tomography (CT)  scanner at Woods Hole Oceanographic Institution. Skeletal density was determined from the CT scans following the methods of DeCarlo et al. (2014). Annual calcification rates (g cm-2 yr-1 (DeCarlo et al., 2014)) were calculated as the product of annual density (g cm-3 ) and extension (cm yr-1), measured using the automated software program coralCT (DeCarlo & Cohen, 2016).  The age model determined by counting annual growth bands in CT scan images was validated by comparing skeletal δ18 O with satellite sea-surface temperature by matching midpoints of δ18 O and SST. We observe a good correlation when comparing this remote sensing SST product with higher resolution NOAA SST product and with in situ measurement of SST from the northern reef flat.

Coral CT scan code (DeCarlo & Cohen,  2016)

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
* added longitude, latitude, and collection date values to the dataset indicating location and time of sampling.

Text from the NSF award abstract:

Human carbon dioxide emissions are causing measureable changes in ocean conditions. Many of these changes negatively affect coral reef ecosystems, reducing their ability to provide food, arable land, tourist destinations and coastline protection for hundreds of millions of people worldwide. This project focuses on the effects of enhanced stratification, caused by ocean warming, on the growth of reef-building corals across the Caribbean and Bermuda. Enhanced stratification impacts primary productivity which generates food for corals. Initial data generated by the investigators suggest that Atlantic coral growth has declined in the last 5 decades in response to these changes. A laboratory-based experiment is designed to test this hypothesis. If verified, the projected decline in Atlantic primary productivity through the 21st century could potentially rival and will certainly exacerbate the effects of warming and ocean acidification on coral reef ecosystems across the North Atlantic. Support is provided for graduate research, and undergraduate participation is facilitated through the Woods Hole Oceanographic Institution Summer Fellowship and the Bermuda Institute of Ocean Sciences-Princeton Environmental Institute Summer Internship Programs. The results will be presented at national and international meetings and disseminated in a timely manner through peer-reviewed publications. All data produced through this program will be archived in the Biological and Chemical Oceanographic Data Management Office.

Anthropogenic climate change has emerged as a principle threat to coral reef survival in the 21st century. In addition to ocean warming and acidification, global climate models project enhanced stratification of the upper oceans through the 21st century and a consequent decline in productivity, by up to 50%, in the North Atlantic. This project employs controlled laboratory manipulation experiments to test the link between productivity and growth of the dominant reef-building corals across the Caribbean and Bermuda. Preliminary data generated by the investigators, including multi-decade long coral growth histories and nitrogen isotope ratios of coral tissue and skeleton, suggest that coral growth across the region has declined over the past 50 years in response to productivity changes already underway. If the link between ocean circulation, productivity decline, and coral growth is verified, the projected 21st century decline in productivity could rival and will certainly exacerbate the effects of warming and ocean acidification on North Atlantic coral reef ecosystems.