National Coral Reef Monitoring Program: Bioerosion monitoring unit (BMU) data from BMUs deployed at coral reef sites in Dry Tortugas National Park, Puerto Rico and St. Croix from 2014-05-26 to 2018-07-11 (NCEI Accession 0209107)

The erosion rates provided in this data set were collected from bioerosion monitoring units (BMUs) retrieved at existing long-term monitoring sites during NOAA Atlantic Oceanographic and Meteorological Laboratory (AOML), Acidification, Climate, and Coral Reef Ecosystems Team (ACCRETE) led NCRMP missions in Dry Tortugas National Park, La Parguera, Puerto Rico and Salt River, St. Croix.

This archive package contains BMU data from permanent long-term monitoring sites in the Dry Tortugas National Park, La Parguera, Puerto Rico and Salt River, St. Croix that were analyzed at NOAA’s Atlantic Oceanographic and Meteorological Laboratory (AOML), as part of the NOAA National Coral Reef Monitoring Program (NCRMP). BMUs are constructed from clean coral skeletons and left on the reef for a period of 3 years.

BMUs are CT scanned for changes in density, volume and mass in which rates of bioerosion can be assessed using Amira analysis software (FEI). Annual erosion and accretion rates can be determined from these data in terms of loss of reef structure volume as well as mass in grams of calcium carbonate. Accretion rates given in this data set were determined by finding the volume of non-original carbonate material found on the external surface of the BMUs divided by the number of years the BMU was deployed on the reef. These rates can detect accretion signals when calcifying organisms, such as corals or algae, have grown on their exteriors. Rates of macroboring were determined by changes in the internal volume of the BMUs (e.g., that removed by bore holes) divided by the number of years the BMU was deployed on the reef. Macroboring can occur from eroders such as, clionaid sponges, annelids and other macroboring fauna. BMU protocols have evolved over the years and due to this, a subset of these BMUs from St. Croix do not have initial data.

This set of data follows earlier BMU data produced during what was a testing phase of best practices, and as such, the protocols used at the time were amended in order to give a more thorough picture of bioerosion rates. PreCTDensity measurements are not provided for the St. Croix BMUs as they were not available due to differences in earlier methodologies utilizing a 3D scanner for the pre-scans. La Parguera and Dry Tortugas were initially scanned using a Bruker Skyscan 1174 microCT.