Coral Reefs as Climate Archives Completed
USGS scientists use coral reefs as archives for reconstructing climate change during the Holocene (past 10,000 years). Coral reefs provide proxy information about rates of sea level change in the past, and individual coral colonies can be used to reconstruct the annual cycle of temperature and salinity variations for up to three centuries.
Coral Reefs Store Environmental History Records
Coral reefs provide an important record of environmental conditions in the subtropical Atlantic Ocean and Caribbean Sea. Cores taken of the reef substrate or framework reveal information about the history of sea level change, as well as the history of reef growth or degradation over centuries and millennia. The chemical composition of individual coral skeletons reflects changes in environmental factors such as seawater temperature, salinity, and pH (acidity) over time scales of months to centuries. If scientists understand how each environmental factor influences the coral skeleton, they can reconstruct the environment in which the coral grew.
As corals grow, they deposit a hard skeleton made up of the mineral aragonite, a form of calcium carbonate (CaCO3), which supports the softer tissues that comprise the coral polyp. X-rays of coral skeleton slabs show alternating light and dark layers (bands) that are the result of seasonal changes in growth. A couplet of light and dark layers (bands) represents 1 year of growth and can be used to determine the age of the coral by counting back and down the coral from the known year it was sampled.
Below are other science projects associated with this project.
Climate and Environmental Change in the Gulf of Mexico and Caribbean
Paleoclimate Reconstruction from Marine and Lake Sediments
Paleoceanographic Proxy Calibration
- Overview
USGS scientists use coral reefs as archives for reconstructing climate change during the Holocene (past 10,000 years). Coral reefs provide proxy information about rates of sea level change in the past, and individual coral colonies can be used to reconstruct the annual cycle of temperature and salinity variations for up to three centuries.
Coral Reefs Store Environmental History Records
Coral reefs provide an important record of environmental conditions in the subtropical Atlantic Ocean and Caribbean Sea. Cores taken of the reef substrate or framework reveal information about the history of sea level change, as well as the history of reef growth or degradation over centuries and millennia. The chemical composition of individual coral skeletons reflects changes in environmental factors such as seawater temperature, salinity, and pH (acidity) over time scales of months to centuries. If scientists understand how each environmental factor influences the coral skeleton, they can reconstruct the environment in which the coral grew.
As corals grow, they deposit a hard skeleton made up of the mineral aragonite, a form of calcium carbonate (CaCO3), which supports the softer tissues that comprise the coral polyp. X-rays of coral skeleton slabs show alternating light and dark layers (bands) that are the result of seasonal changes in growth. A couplet of light and dark layers (bands) represents 1 year of growth and can be used to determine the age of the coral by counting back and down the coral from the known year it was sampled.
- Science
Below are other science projects associated with this project.
Climate and Environmental Change in the Gulf of Mexico and Caribbean
This project documents paleoceanographic, climatic, and environmental changes in the Gulf of Mexico and adjacent land areas over the last 10,000 years. The paleoenvironmental data is used to determine rates of change in the past, and to better understand both the natural and anthropogenic factors that contribute to climate variability on inter-annual to millennial timescales.Paleoclimate Reconstruction from Marine and Lake Sediments
Instrumental measurements of climate variables (e.g., precipitation, temperature, ocean circulation, etc.) are only available over the past century or less. In order to quantify the rate and magnitude of natural climate variability going back in time beyond the 20th century, scientists rely on paleoclimate reconstructions.Paleoceanographic Proxy Calibration
A sediment trap time series in the northern Gulf of Mexico is used to better assess the control of environmental variables (e.g., temperature and salinity) on the flux of both microfossils and molecular fossils to the sediments. The information gained from sediment trap studies is used to develop better proxy-based estimates of past oceanographic conditions from analyses of microfossils and...