Award: OCE-1535203

Global climate change is now the leading cause of coral-reef degradation, but the extent to which mesoscale oceanography overprints climatic forcing is poorly understood. Previous studies in Pacific Panamá showed that reef ecosystems collapsed from ~4100 to 1600 years ago. The primary cause of the 2500-year hiatus in Panamá was increased variability of the El Niño–Southern Oscillation, and the hiatus may have occurred throughout the Pacific. The goal of this study is to determine the influence of contemporary variability in mesoscale oceanography in the eastern tropical Pacific on variability in the condition of local coral populations. Insights from the living populations will be combined with paleoecological and geochemical studies of reef frameworks to infer past conditions that were inimical or beneficial to coral growth and reef accretion. Three primary hypotheses are being tested in Pacific Panamá. H1.Mesoscale oceanography is manifested in gradients of reef condition, coral growth, and coral physiological condition. Physiographic protection from upwelling currents and thermocline shoaling confers positive effects on coral growth rate and physiology. H2.The impacts of mesoscale oceanographic regimes on the growth and condition of reef-corals were felt at least as far back as the mid- to late Holocene. H3.Physiographic protection from upwelling currents and thermocline shoaling conferred positive effects on vertical reef accretion in the past and shortened the late-Holocene hiatus. Specific research approaches to test these hypotheses include: (1) collecting synchronous, high-resolution, oceanographic time series from reefs in the Gulfs of Panamá and Chiriquí to characterize their contemporary environments; (2) collecting ecological and geochemical data on the condition of living coral populations; and (3) extracting cores from the reef frameworks and analyzing the coral assemblages taxonomically, taphonomically, and geochemically to assess spatial patterns of biotic and paleoenvironmental variability. Last Modified: 10/28/2019 Submitted by: James J Leichter