Little Bahama Bank Modern Benthic Foraminifera Element/Temperature Calibration Data ----------------------------------------------------------------------- World Data Center for Paleoclimatology, Boulder and NOAA Paleoclimatology Program ----------------------------------------------------------------------- NOTE: PLEASE CITE CONTRIBUTORS WHEN USING THIS DATA!!!!! NAME OF DATA SET: Little Bahama Bank Modern Benthic Foraminifera Element/Temperature Calibration Data LAST UPDATE: 2/2004 (Original Receipt by WDC Paleo) CONTRIBUTORS: Yair Rosenthal, Rutgers, The State University IGBP PAGES/WDCA CONTRIBUTION SERIES NUMBER: 2004-008. SUGGESTED DATA CITATION: Rosenthal, Y., et al., 2004, Little Bahama Bank Modern Benthic Foraminifera Element/Temperature Calibration Data, IGBP PAGES/World Data Center for Paleoclimatology Data Contribution Series # 2004-008. NOAA/NGDC Paleoclimatology Program, Boulder CO, USA. ORIGINAL REFERENCE: Rosenthal, Y., E.A. Boyle, and N. Slowey. 1997. Temperature control on the incorporation of magnesium, strontium, fluorine, and cadmium into benthic foraminiferal shells from Little Bahama Bank: Prospects for thermocline paleoceanography. Geochimica et Cosmochimica Acta, Volume 61, Issue 17, Pages 3633-3643. GEOGRAPHIC REGION: Little Bahama Bank, tropical west Atlantic PERIOD OF RECORD: Modern surface sediments ABSTRACT: Surface sediments from Little Bahama Bank (LBB), intersecting the subtropical thermocline, were used to assess the influence of temperature on the incorporation of Mg, Sr, F, and Cd into shells of benthic foraminifera. Samples were obtained from twelve box cores along the southern slope of LBB, covering a temperature range of 18-4.5°C between 301 and 1585 m. We studied the composition of ten calcitic and one aragonitic species, which are often used in paleochemical reconstructions. Mg/Ca ratios decrease with increasing water depth in all benthic species, both with calcitic and aragonitic mineralogy, showing a strong correlation with water temperature. Similar decrease is seen in Sr/Ca but with no correlation with temperature. None of the benthic species studied here exhibits a depth or temperature related change in F/Ca. Similar trends are observed when using an ocean-wide dataset, which includes shallow and deep core tops (300–5000 m). We suggest that temperature is the primary control on the Mg content of benthic foraminifera. Based on inorganic precipitation experiments and thermodynamic considerations, presented here, a 30–40% decrease in the Mg distribution coefficient in calcite may be expected as a result of a temperature change from 25°C to 5°C, which is about half the observed change in LBB. A calibration curve applied to C. pachyderma data from core tops along the slope of Little Bahama Bank suggests that water temperature may be inferred from Mg/Ca ratios with an uncertainty of about ±0.8°C. Therefore, the Mg content of benthic foraminifera may provide a new, independent temperature proxy for studying shallow waters paleoceanography. The linear decrease in Sr/Ca with increasing depth is not correlated with temperature; the trend is constant from the ocean surface down to 5 km, suggesting that pressure related effects on the calcification process are a more likely explanation than post-depositional dissolution. Mg/Ca ratios in aragonitic shells of H. elegans covary with temperature, in accord with recent observations from corals. In contrast, the Sr and F chemistry of H. elegans is very different than that of corals and inorganically precipitated aragonites. The disparities between the elemental composition of biogenic and inorganic phases and the large intergeneric and interspecific differences observed both in planktonic and benthic foraminifera implicate temperature related physiological processes in regulating the coprecipitation of elements in foraminiferal shells. Our work demonstrates that Cd/Ca ratios of shallow calcitic species reflect the vertical distribution of nutrients; no significant influence of temperature on the partitioning of Cd into the shells was found. Our data extend the previous deep water calibration (Boyle, 1992), thereby allowing for the reconstruction of the nutrient chemistry of shallow thermocline waters. DESCRIPTION: Elemental ratio data on benthic foraminifera from surface sediments (box cores) from Little Bahama Bank, tropical west Atlantic. The data were used to assess the influence of water temperature on the incorporation of Mg, Sr, F, and Cd into shells of benthic foraminifera. Samples were obtained from twelve box cores along the southern slope of LBB, covering a temperature range of 18-4.5°C between 301 and 1585 m. DATA: core Depth Temp. species Mg/Ca Sr/Ca EN66.010 3527 2.46 C. kulenbergi 1.61 1.15 EN66.010 3540 2.46 C. wuellerstorfi 1.26 EN66.016 3152 2.62 C. wuellerstorfi 1.33 EN66.021 3995 2.42 C. kulenbergi 1.17 EN66.021 3995 2.42 C. wuellerstorfi 1.27 EN66.026 4745 2.27 C. wuellerstorfi 1.17 EN66.029 5104 2.2 C. kulenbergi 1.22 EN66.029 5104 2.2 C. wuellerstorfi 1.12 EN66.029 5104 2.2 C. wuellerstorfi 1.53 1.25 EN66.029 5104 2.2 C. wuellerstorfi 1.29 1.21 EN66.032 5003 2.19 C. wuellerstorfi 1.16 EN66.044 3428 2.53 C. kulenbergi 1.83 1.13 EN66.044 3428 2.53 C. wuellerstorfi 1.61 1.27 ERDC 112 Bx 2168 2.09 C. wuellerstorfi 1.36 ERDC 113 P 2163 2.1 C. wuellerstorfi 1.42 ERDC 120 Bx 2247 2.03 C. wuellerstorfi 2.07 1.34 ERDC 123 BX 2948 1.74 C. wuellerstorfi 1.41 ERDC 125 Bx 3368 1.58 C. wuellerstorfi 1.24 ERDC 128 BX 3732 1.46 C. pachyderma 1.2 ERDC 128 BX 3732 1.46 C. wuellerstorfi 1.18 ERDC 77 Bx 3585 1.51 C. wuellerstorfi 1.24 ERDC 79 Bx 2767 1.79 C. wuellerstorfi 1.33 ERDC 83 Bx 2342 1.98 C. wuellerstorfi 1.43 1.36 ERDC 88 Bx 1924 2.3 C. wuellerstorfi 1.1 1.36 ERDC 92 BX 1598 2.71 C. kulenbergi 1.35 ERDC 92 BX 1598 2.71 C. wuellerstorfi 1.35 ERDC 92 Bx 1598 2.71 C. wuellerstorfi 1.66 1.44 KNR 110.084 BC 2947 2.75 C. kulenbergi 1.28 KNR 110.084 BC 2947 2.8 C. wuellerstorfi 2.25 KNR 110.086 BC 3320 2.56 C. wuellerstorfi 1.63 1.2 KNR 110.086 BC 3320 2.56 C. wuellerstorfi 1.86 1.2 KNR 110.086 BC 3320 2.56 C. wuellerstorfi 1.37 1.31 KNR 110.086 BC 3320 2.56 C. wuellerstorfi 1.92 1.31 KNR 110.088 BC 2952 2.75 C. wuellerstorfi 2.04 1.15 KNR 110.090 BC 3654 2.45 C. kulenbergi 1.63 1.34 KNR 110.090 BC 3654 2.45 C. wuellerstorfi 1.61 1.31 KNR 110.090 BC 3654 2.45 C. wuellerstorfi 1.77 1.31 KNR 110.092 BC 3882 2.4 C. wuellerstorfi 1.54 1.27 KNR 110.092 BC 3882 2.4 C. wuellerstorfi 1.62 1.27 KNR 110.092 BC 3882 2.4 C. wuellerstorfi 1.46 1.23 KNR 110.092 BC 3882 2.4 C. wuellerstorfi 1.23 KNR 110.094 BC 4107 1.52 C. wuellerstorfi 1.32 Knr 110.094 BC 4107 1.52 C. wuellerstorfi 1.32 1.26 KNR 110.096 BC 4427 0.91 C. wuellerstorfi 1.32 KNR 110.096 BC 4427 0.91 C. wuellerstorfi 1.56 1.2 KNR 110.099 BC 4643 1.05 C. wuellerstorfi 1.19 1.22 KNR 110.099 BC 4643 1.05 C. wuellerstorfi 1.2 KNR64.0051 3047 3.7 C. kulenbergi 2.01 1.11 KNR64.0051 3047 3.7 C. kulenbergi 1.98 1.2 Mackensen 2073-1 4692 0.92 C. wuellerstorfi 1.13 Mackensen 2081-1 4794 0.67 C. wuellerstorfi 1.1 1.12 Mackensen 2108-1 4920 0.4 C. wuellerstorfi 1.2 1.08 OC205-2 BC48 580 13.31 C. pachyderma 4.68 1.5 OC205-2 BC48 580 13.31 C. pachyderma 5.94 1.52 OC205-2 BC48 580 13.31 C. pachyderma 4.49 1.44 OC205-2 BC48 580 13.31 C. pachyderma 5.45 1.44 OC205-2 BC48 580 13.31 C. pachyderma 4.34 1.41 OC205-2 BC48 580 13.31 C. pachyderma 5.56 1.42 OC205-2 BC51 830 8.2 C. pachyderma 3.42 1.32 OC205-2 BC52 668 11.49 C. pachyderma 3.71 1.41 OC205-2 BC52 668 11.49 C. pachyderma 3.95 1.46 OC205-2 BC52 668 11.49 C. pachyderma 1.39 OC205-2 BC54 1043 5.34 C. pachyderma 2.5 1.47 OC205-2 BC57 1243 4.5 C. pachyderma 2.17 1.44 OC205-2 BC57 1243 4.5 C. wuellerstorfi 2.67 1.43 OC205-2 BC59 1477 4.5 C. wuellerstorfi 2.2 1.4 OC205-2 BC69 735 9.86 C. pachyderma 3.39 1.43 OC205-2 BC76 529 14.2 C. pachyderma 6.51 1.56 OC205-2 BC76 529 14.2 C. pachyderma 7.03 1.59 OC205-2 BC77 433 16.55 C. pachyderma 6.09 1.57 OC205-2 BC79 301 18.38 C. pachyderma 1.58 OC205-2 BC79 301 18.38 C. pachyderma 8.28 1.44 OC205-2 BC79 301 18.38 C. pachyderma 9.64 1.63 OC205-2 BC79 301 18.38 C. pachyderma 7.68 1.55 OC205-2 BC79 301 18.38 C. pachyderma 8.85 1.64 OC205-2 BC79 301 18.38 C. pachyderma 10.24 1.64 PLDS 66 Bx 3496 1.48 C. wuellerstorfi 1.2 PLDS 72 Bx 3626 1.42 C. wuellerstorfi 1.2 PLDS 77 Bx 4366 1.47 C. wuellerstorfi 1.14 PLDS 79 Bx 4542 1.49 C. wuellerstorfi 1.16 PLDS 89 Bx 4407 1.48 C. wuellerstorfi 1.16