Sclerochronology

 ( Subfields Of Paleontology ) 

Sclerochronology is the study of periodic physical and chemical features in the hard tissues of animals that grow by accretion, including and coralline red algae, and the temporal context in which they formed. It is particularly useful in the study of marine paleoclimatology. The term was coined in 1974 Buddemeier, R. W., Maragos, J. E., and Knutson, D. W. 1974. Radiographic studies of reef coral exoskeletons: Rates and patterns of coral growth. Journal of Experimental Marine Biology and Ecology 14, 179-199. following pioneering work on nuclear test atolls by Knutson and BuddemeierKnutson, D. W., Buddemeier, R. W., and Smith, S. V. 1972. Coral Chronometers: Seasonal Growth Bands in Reef Corals. Science 177, 270-272. and comes from the three Greek language words skleros (hard), chronos (time) and logos (science), which together refer to the use of the hard parts of living organisms to order events in time. It is, therefore, a form of stratigraphy. Sclerochronology focuses primarily upon growth patterns reflecting annual, monthly, fortnightly, tidal, daily, and sub-daily (ultradian) of time.

The regular time increments are controlled by Circadian rhythm, which, in turn, are caused by environmental and astronomical pacemakers.

Familiar examples include:

• annual bandings in coral reef
• annual, fortnightly, daily and ultradian growth increments in mollusk shells
• annual bandings in the ear bones of fish, called .

Sclerochronology is analogous to dendrochronology, the study of tree ring, and equally seeks to deduce organismal life history traits as well as to reconstruct records of environmental and climatic change through space and time.

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Use in paleoclimatic study science of sclerochronology as applied to hard parts of various organism groups is now routinely used for paleoceanographic and paleoclimate reconstructions.Schöne, B.R., Oschmann, W., Kröncke, I., Dreyer, W., Janssen, R., Rumohr, H., Houk, S.D., Freyre Castro, A.D., Dunca, E. and Rössler, J. (2003). North Atlantic Oscillation dynamics recorded in shells of a long-lived bivalve mollusk. Geology 31, 1237–1240.Wanamaker, A.D. Jr., Kreutz, K.J., Schöne, B.R., Pettigrew, N., Borns, H.W., Introne, D.S., Belknap, D., Maasch, K.A. and Feindel, S. 2008. Coupled North Atlantic slopewater forcing on Gulf of Maine temperatures over the past millennium. Climate Dynamics 31, 183-194.Corrège, T., Gagan, M.K., Beck, J.W., Burr, G.S., Cabioch, G & Le Cornec, F. 2004. Interdecadal variation in the extent of South Pacific tropical waters during the Younger Dryas event. Nature 428, 927-929.Halfar, J., Steneck, R.S., Joachimski, M, Kronz, A. & Wanamaker A.D. Jr. 2008. Coralline red algae as high-resolution climate recorders. Geology, 36, 463-466.Black, B.A., Copenheaver, C.A., Frank, D.C., Stuckey, M.J. and Kormanyos, R.E. 2009. Multi-proxy reconstructions of northeastern Pacific sea surface temperature data from trees and Pacific geoduck. Palaeogeography, Palaeoclimatology, Palaeoecology 278, 40–47. The study includes isotopic and elemental proxies, sometimes termed sclerochemistry.Gröcke D. R. and D. P. Gillikin, (2008). Advances in mollusc sclerochronology and sclerochemistry: tools for understanding climate and environment. Geo-Marine Letters 28: 265-268.

Improvements in imaging techniques have now realised the potential to decipher coral banding at daily resolution,Gill, I. P., Dickson, J. A. D., and Hubbard, D. K. 2006. Daily banding in corals: Implications for paleoclimatic reconstruction and skeletonization. Journal of Sedimentary Research 76, 683-688. although biological 'vital' effects may blur the climate signal at such a high resolution.Juillet-Leclerc, A., Reynaud, S., Rollion-Bard, C., Cuif, J. P., Dauphin, Y., Blamart, D., Ferrier-Pagès, C., and Allemand, D. 2009. Oxygen isotopic signature of the skeletal microstructures in cultured corals: Identification of vital effects. Geochimica et Cosmochimica Acta 73, 5320-5332.

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See also

• Paleoceanography
• Paleothermometer

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External links

• Coral Clocks

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