The potential of the coral species Porites astreoides as a paleoclimate archive for the Tropical South Atlantic Ocean
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The potential of the coral species Porites astreoides as a paleoclimate archive for the Tropical South Atlantic Ocean. / Pereira, Natan S.; Sial, Alcides N.; Frei, Robert; Ullmann, Clemens Vinzenz; Korte, Christoph; Kikuchi, Ruy K.P. ; Ferreira, Valderez P.; Kilbourne, K. H.
I: Journal of South American Earth Sciences, Bind 77, 2017, s. 276-285.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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T1 - The potential of the coral species Porites astreoides as a paleoclimate archive for the Tropical South Atlantic Ocean
AU - Pereira, Natan S.
AU - Sial, Alcides N.
AU - Frei, Robert
AU - Ullmann, Clemens Vinzenz
AU - Korte, Christoph
AU - Kikuchi, Ruy K.P.
AU - Ferreira, Valderez P.
AU - Kilbourne, K. H.
PY - 2017
Y1 - 2017
N2 - The aragonitic skeletons of corals are unique archives of geochemical tracers that can be used as proxies for environmental conditions with high fidelity and sub-annual resolution. Such records have been extensively used for reconstruction of climatic conditions in the Pacific and Indian Oceans, Red Sea and Caribbean, but lack for the Equatorial South Atlantic. Here we present coral-based records of Sr/Ca, δ18O and δ13C and the first δ18O–SST calibration for the scleractinian coral species Porites astreoides from the Rocas Atoll, Equatorial South Atlantic. The investigated geochemical proxies for P. astreoides presented a very well-developed seasonal cyclicity in all proxies. We use the monthly means of δ18O and SST from the period of 2001–2013 to propose a calibration for a paleothermometer based on Porites, which gives T(°C) = −8.69(±0.79)* δ18O −7.05(±3.14), and yielded a SST δ18O–depended reconstruction with fidelity better than 0.5 °C for most of the record. Biases of up to 2 °C might be associated with reduced growth rate periods of the coral record. The Sr/Ca data show systematic, annual fluctuations but analyses are too imprecise to propose a Sr/Ca-SST calibration. The δ13C values are found to vary in phase with δ18O and Sr/Ca and are interpreted to be controlled by solar irradiation-modulated photosynthetic activity on the annual level. Our findings extend the global data base of coral records, contributing to further investigations using coral skeleton as environmental archives. In particular, the present study helps to better understand the climate variability of the South Atlantic tropical ocean-atmosphere system.
AB - The aragonitic skeletons of corals are unique archives of geochemical tracers that can be used as proxies for environmental conditions with high fidelity and sub-annual resolution. Such records have been extensively used for reconstruction of climatic conditions in the Pacific and Indian Oceans, Red Sea and Caribbean, but lack for the Equatorial South Atlantic. Here we present coral-based records of Sr/Ca, δ18O and δ13C and the first δ18O–SST calibration for the scleractinian coral species Porites astreoides from the Rocas Atoll, Equatorial South Atlantic. The investigated geochemical proxies for P. astreoides presented a very well-developed seasonal cyclicity in all proxies. We use the monthly means of δ18O and SST from the period of 2001–2013 to propose a calibration for a paleothermometer based on Porites, which gives T(°C) = −8.69(±0.79)* δ18O −7.05(±3.14), and yielded a SST δ18O–depended reconstruction with fidelity better than 0.5 °C for most of the record. Biases of up to 2 °C might be associated with reduced growth rate periods of the coral record. The Sr/Ca data show systematic, annual fluctuations but analyses are too imprecise to propose a Sr/Ca-SST calibration. The δ13C values are found to vary in phase with δ18O and Sr/Ca and are interpreted to be controlled by solar irradiation-modulated photosynthetic activity on the annual level. Our findings extend the global data base of coral records, contributing to further investigations using coral skeleton as environmental archives. In particular, the present study helps to better understand the climate variability of the South Atlantic tropical ocean-atmosphere system.
KW - Climate variability
KW - Coral geochemistry
KW - Coral-based archive
KW - Rocas Atoll
U2 - 10.1016/j.jsames.2017.05.008
DO - 10.1016/j.jsames.2017.05.008
M3 - Journal article
AN - SCOPUS:85020270433
VL - 77
SP - 276
EP - 285
JO - Journal of South American Earth Sciences
JF - Journal of South American Earth Sciences
SN - 0895-9811
ER -
ID: 180967886