Collaborative Research: BoCP-Implementation: Ancient DNA approaches to reconstruct environmental impacts on coral reefs

Regents Of The University Of Michigan - Ann Arbor, Ann Arbor MI

Investigators

Abstract

Coral reefs nurture fisheries, protect coastlines, and support rich ecological communities. Reef-building corals depend on microbes living in their tissues to keep them healthy and thriving. This community of microbes – the coral's microbiome – includes algae that provide food and bacteria that promote coral health. Changes in reef conditions can affect the makeup of this microbiome. In coastal regions near coral reefs, environmental stresses have intensified, especially over the past several decades. These changes have impacted coral health. Some corals can live for decades or centuries and have survived these changes. The chemistry of a coral's skeleton reflects the conditions under which it grew. Researchers will measure the chemistry of the coral skeleton from its earliest growth to today. These data will provide a history of warm and cool extremes, periods of fast and slow growth, and changes in seawater salinity, nutrients, pollution, and clarity. Coral skeletons also preserve the DNA of the coral and its associated microbiome. Researchers will use the DNA preserved in the skeleton to describe the composition of the entire community. By pairing DNA analysis with histories of reef conditions, this research represents a major breakthrough to understand how corals and their microbes are surviving in a changing ocean. This study will reconstruct the recent environmental and ecological history of massive corals in the Caribbean (Siderastrea siderea) and the Great Barrier Reef (Porites lobata). Using paleoenvironmental and paleometagenomic reconstructions, this research will elucidate how the coral holobiont - the coral and its associated microorganisms - responds to specific changes in the reef environment. The use of corals from different reef locations will highlight how different species and different ecosystems may show distinctive types of responses to environmental stressors. Historical reconstructions that compare holobiont communities from the pre-industrial era (1600-1850’s) to present day will be used to assess and identify microbial taxa that are robust to environmental stressors, as well as gene functions that appear to be adaptive over time to specific environmental conditions. This will be the first research to document how the dynamics of coral holobionts respond to disturbance events at fine temporal scales, applying new ancient DNA techniques to long-lived coral skeletons over decades to centuries. Broader Impacts of this research will facilitate the creation of a Global Coral ancient DNA Paleobiology Network that will include several teams already in possession of coral cores from different oceans, thus expanding the reach of our efforts to planetary scales. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.