CORAL RESILIENCY IN BONAIRE NATIONAL MARINE PARK

A multi-year investigation in Bonaire National Marine Park (BNMP) focuses on corals growing on mooring buoy anchors created from cement blocks and discarded petroleum barrels. Objectives of the research are to document and assess the health of these coral recruits, and evaluate the bioenvironmental conditions required to maintain coral growth in the shallow-water zone of the decimated Acropora palmata and A. cervicornis. This project tested for and assessed the hypothesis of ocean acidification affecting one of the healthiest reefs in the Caribbean. A dry island such as Bonaire, with no major river input into the leeward side of the island, provides an ideal location for such an analyses as it yields a relatively pure ocean chemistry signal. The persistence of corals on anchors placed in BNMP in the 1960’s and 1970’s takes advantage of the maximum timeline for coral recruits. The study can thus be taken as a natural inoculation experiment under ambient field conditions.

200ml water samples were collected at 25 BNMP sites from 9 times stemming from Nov. 2007-April 2011. Analyses reveal no pH changes in these shallow 12.2m waters over the duration of the study. pH colorimetric averages were 8.0-8.5 for both April/May and Nov/ Dec collections, and pH litmus 8.0 for all sites, all seasons. Temperature, salinity and turbidity at site-specific locations were recorded and differences in cation and anion water chemistry were evaluated. Results revealed values for environmental means from all collection data are in general range of global averages, but phosphates, nitrites and nitrates are enhanced at specific sites. After accounting for differences in surface area between barrels and blocks, the most common corals in the zone of the former acroporiids are Agaricia sp. (100 occurrences), Diploria labrynthiformis (94.6 occurrences), Porites asteroides (36.3 occurrences), Dichocoenia stokesi (22.6 occurrences) and Diploria strigosa (20.8 occurrences). Coral recruits total 33.6 occurrences and are more abundant in April 2011 than in any previous collection date. These exploratory analyses will be used to focus future research on survivability of specific coral species under experimental conditions using IPCC climate change scenarios, and on reef resiliency through an ecological basis for genetic investigations.