The Proxy Archive Ontology
The geochemical tracers contain in the skeletons of corals provide an unaltered record of the chemical and physical conditions that existed in the surrounding seawater at the time of accretion of its calcium carbonate skeleton [1]. Corals are useful oceanic recorders because they are widely distributed, can be accurately dated, provide an enhanced time resolution (monthly) available from the high growth rate, and are nor subjected to the mixing processes that are present in all toxic sediments (i.e., bioturbation) [1] [2]. Corals are from the order Scleractinian, a group in the subclass Zoantharia. Scleractinians include solitary and colonial species of corals. may of which secrete external skeletons of aragonite [1]. The oldest known scleractinians are shallow water corals from the Middle Triassic [3]. The polyp portion of the coral secretes calcium carbonate (CaCO3) as the mineral aragonite [1]. Massive hermatypic corals (i.e., reef-building corals) are more desirable than the branching varieties for paleoreconstructions. First, massive corals form round, wave-resistant structures that can include hundreds of years of uninterrupted growth. Second, the accretion rate of calcium carbonate is much higher for hermatypic corals that contain symbiotic zooxanthellae than for deep species [1]. Most massive reef corals live at water depths of <40m and grow continuously at rated of 6-20 mm yr-1 [4] ? 1.0 1.1 1.2 1.3 1.4 Druffel, E. R. M. (1997). Geochemistry of corals: Proxies of past ocean chemistry, ocean circulation, and climate. Proceeding of the National Academy of Sciences, 94, 8354-8361. ? Gagan, M. K., Ayliffe, L. K., Beck, J. W., Cole, J. E., Druffel, E. R. M., Dunbar, R. B., & Schrag, D. P. (2000). New views of tropical paleoclimates from corals. Quaternary Science Reviews, 19(1-5), 45-64. doi:10.1016/S0277-3791(99)00054-2 ? Stanley, G. (1981). Early history of scleractinian corals and its geological consequences. Geology, 9, 507-511. ? Knutson, D. W., Buddemeier, R. W., & Smith, S. V. (1972). Coal chronologies: seasonal growth bands in reef corals. Science, 177, 270-272.
Coral
Document
Glacier ice
Hybrid
Lake sediment proxies provide widespread, continuous records of terrestrial environment variability. A variety of sensors are used to indicate past water temperature, physical properties, biology, and chemistry within the lake environment as well as changes in vegetation and precipitation in the catchment area.
Lake sediment
Marine sediments are a type of proxy archives that provide long, continuous records of past ocean variability. The timescales associated with this archive are usually in the order of several tens to millions of years. The resolution of the sedimentary archive varies from annual to multi-century. Paleoceanographic data are derived from many sensors found in deep-sea sediments including trace metal and isotopic composition of foraminifera, alkenones, and TEX86.
Marine sediment
Mollusk shells
Peat
The medium in which the response of a sensor to environmental forcing is recorded. Sensu Evans et al. (2013). Examples of archives include: marine sediments, corals, wood, lake sediments, speleothems, glacier ice, etc.
Proxy archive
Rock
Sclerosponge
Speleothem
The field of dendroclimatology and, to some extent, the field of dendrochronology have played an important role in generating climate reconstructions of the past millennium [1] [2] [3] [4]. In regions with large seasonal variations, trees produce rings of varying color depending on the species. In most cases, the rings shift from a lighter, low density early wood of spring and early summer to a darker, denser band of late wood at the end of the growing season. The growing season generally occurs during the summer month and its length depends on the species, latitude, and altitude. Therefore, trees hold perhaps the greatest potential for reconstructing past terrestrial climates at annual or even sub-annual resolution. The following observations can be made on the wood archive: Tree ring width Wood density Stables isotopes ? Mann, M. E., Bradley, R. S., & Hughes, M. K. (1998). Global-scale temperature patterns and climate forcing over the past six centuries. Nature, 392(6678), 779-787. doi:10.1038/33859 ? Mann, M. E., Bradley, R. S., & Hughes, M. K. (1999). Northern Hemipshere temperatures during the past millennium: Inferences, Uncertainties, and Limitations. Geophysical Research Letters, 26(6), 759. ? Moberg, A., Sonechkin, D. M., Holmgren, K., Datsenko, N. M., & Karlen, W. (2005). Highly variable Northern Hemisphere temperatures reconstructed from low- and high-resolution proxy data. Nature, 433(7026), 613-617. doi:10.1038/nature03265 ? Mann, M. E., Zhang, Z., Rutherford, S., Bradley, R., Hughes, M. K., Shindell, D. T., . . . Ni, F. (2009). Global signatures and dynamical origins of the Little Ice Age and Medieval Climate Anomaly. Science, 326, 1256-1260. dos: 10.1126/science.1177303
Wood