SclerochronologyThis project was archived in August of 2014 when its principal investigator, Dr. Kevin P. Helmle, left CHAMP to accept a position as a chemistry teacher at a local college preparatory school.  We at CHAMP wish him all the best in his new position!

From Encyclopedia of Modern Coral Reefs:

Sclerochronology: The term sclerochronology is derived from the Greek words sklero, meaning 'hard', and chronos, meaning 'time.'


The field of sclerochronology is the study of periodicities stored in accreted hard parts and skeletons of various extant and extinct organisms. The periodicity can range from daily to annual scales and compose chronologies which span years to centuries, thus providing potentially long records of historical variations. Annual periodicity provides a chronology for determining age, growth rates, and reconstructions of environmental influences. Along with the recorded growth chronologies, the chemical composition of the skeleton also contains temporal records based on isotopic ratios and trace elemental concentrations which can be used to reconstruct proxy paleoenvironmental and paleoclimatic records. Studies of skeletal growth and geochemical records have been used within the broader fields of ecology, physiology, and paleoclimatology. Sclerochronology is akin to the study of annual growth rings in trees, termed dendrochronology.

Current applications of sclerochronology at NOAA/AOML include reconstructing histories of land-based sources of pollution using skeletal geochemistry and the effects on coral growth rates is southeast Florida as well as reconstructing seawater pH and temperature using skeletal geochemistry (with collaborators at USGS and UM/RSMAS) and assessing coral growth histories in Puerto Rico and south Florida in relation to climate change and ocean acidification.