Monaco aco, , March 29 29, , 2011. International Symposium on Isotopes in Hydrology, Marine Ecosystems, and Climate Change Studies 210 Pb-derived reconstruction of environmental changes in Amatique Bay, Guatemala Ruiz-Fernández AC, Solares Cortez N, Martínez VM, Sanchez-Cabeza JA, Alonso-Hernández C, Pérez-Bernal LH, Ontiveros-Cuadras JF
The Wider Caribbean Region A A=Havana Bay, B=Coatzacoalcos River, C=Amatique Bay, D=Cortés Harbor, E=Bluefields Bay, F=Portete Bay, K L B J G=Almirante Bay, H=Cartagena Bay, C D I=Cariaco Gulf, J=Kingston Bay, K=Prince Harbor, L=Haina Bay E H I F G MAR Sampling site Core Latitud N Longitud W Depth (m) C org (%) C/N (g cm -2 y -1 ) Havana Bay, CUB BI 23° 08' 82° 20' 8.00 0.06-0.43 1.35-8.07 21-50 Port-au-Prince Bay, HAI AI 18° 33' 72° 21' 14.00 0.03-0.44 1.06-2.72 14-32 Bluefields Bay, NIC AI 11 53' 83 45' 1.50 0.10-0.63 0.94-2.22 13-24 Cortes Bay, HON BI 15º 48' 87º 58' 9.00 n.a. 1.44-2.07 13-20 Cartagena Bay, COL EI 10° 21' 75° 31' 10.00 0.50-1.09 1.81-3.78 11-17 Almirante Bay, PAN CI 9 17' 82° 23' 6.00 0.04-0.23 1.80-5.95 7-17 Kingston Bay, JAM AI 17 58' 76° 46' 14.00 n.a. 1.74-4.33 10-15 Amatique Bay, GUA BI 15º 54' 88° 42' 20.00 0.03-0.21 0.90-1.70 8-15 Coatzacoalcos River, MEX AIII 18 14' 94° 27' 25.00 0.69-0.79 0.18-0.70 6-15 Cariaco Gulf, VEN AI 10° 28' 63° 41' 12.00 0.04-0.39 3.65-4.81 11-13
Sampling and sample preparation methods Amatique Bay Carib ibbea ean Sea GUATEMA EMALA Sampling date 6 May 2009 Core selection: LOI – (550 ° C, 4 h) (OBIMAR-GUA)
Nuclear techniques to support coastal management Dating of recent sediments: 210 Pb - a -spectrometry (ICMyL-MEX); 137 Cs - g -spectrometry (CEAC-CUBA) Trace elements : XR-fluorescense (MONACO) Nutrients: C org , N org – CHN analyzer (ICMyL-MEX)
Amatique Bay (core RLA7012-B1) LOI (%) LOI (%) LOI (%) 8 9 10 11 12 13 14 8 9 10 11 12 13 14 8 9 10 11 12 13 14 0 0 0 2 AI 2 BI 2 CI 4 4 4 6 6 6 8 8 8 R² = 0.6076 10 10 10 12 12 12 14 14 14 16 16 16 Depth (cm) Depth (cm) Depth (cm) 18 18 18 20 20 20 22 22 22 24 24 24 26 26 26 28 28 28 30 30 30 32 32 32 34 34 34 36 36 36 38 38 38 40 40 40 42 42 42 44 44 44 46 46 46
Amatique Bay (core RLA7012-B1) 210 Pb exc (Bq kg -1 ) 137 Cs (Bq kg -1 ) 0 2 4 6 8 10 0 30 60 90 0 0 2009 2 2 2007 4 4 2002 6 6 1997 8 8 1991 10 10 1985 Depth (cm) Depth (cm) 12 12 1978 14 14 1971 16 16 1962 18 18 1951 20 20 1932 22 22 1903 <100 y y = 36.794e -0.029x 24 24 R² = 0.6494 26 26
Amatique Bay (core RLA7012-B1) MAR (cm yr -1 ) SAR (cm yr -1 ) 0.0 0.5 1.0 1.5 0.00 0.05 0.10 0.15 0.20 0.25 0 2009 0 2009 2 2007 2007 2 2002 2002 4 4 1997 1997 6 6 1991 8 1991 8 1985 10 1985 10 Depth (cm) Depth (cm) 1978 12 12 1978 1971 14 14 1971 1962 16 1962 16 1951 18 1951 18 1932 20 1932 20 22 22 1903 1903 <100 y <100 y 24 24 26 26
Amatique Bay (core RLA7012-B1) N org (%) C/N C org (%) 0.0 0.1 0.2 0.3 0.0 0.5 1.0 1.5 2.0 0 1 2 3 4 5 6 7 8 9 10 11 12 0 2009 2007 2 2002 4 1997 6 1991 8 1985 10 Depth (cm) 1978 12 1971 14 16 1962 18 1951 20 1932 22 1903 <100 y 24 26 Significant correlation between C org and N org
Amatique Bay (core RLA7012-B1) Al (%), Ti (µg g -1 ) Al/Ti Ni, Zn (µg g -1 ) 0 1 2 0 1 2 3 4 5 6 0 25 50 75 100 125 150 175 0 0 0 2009 2 2 2 2007 4 4 4 2002 6 6 6 1997 8 8 8 1991 10 10 10 Depth (cm) 1985 12 12 12 1978 14 14 14 1971 16 16 16 1962 18 18 18 1951 20 20 20 1932 Ti Zn 22 22 22 1903 <100 y Ni 24 Al 24 24 26 26 26 Zn and Ni are significantly correlated with Ti (P<0.05)
Amatique Bay (core RLA7012-B1) Hg (ng g -1 ) As (µg g -1 ) Pb (µg g -1 ) 0 10 20 30 40 50 60 70 0 5 10 15 0 5 10 15 20 0 0 0 2009 2 2 2 2007 4 4 4 2002 6 6 6 1997 8 8 8 1991 Depth (cm) Depth (cm) Depth (cm) 10 10 10 1985 12 12 12 1978 1971 14 14 14 16 16 16 1962 18 18 18 1951 20 20 20 1932 22 22 22 1903 <100 y 24 24 24 26 26 26
Amatique Bay (core RLA7012-B1) Hg excess flux (ng cm -2 a -1 ) Hg flux ratio 0 1 2 3 0 1 2 3 4 5 6 7 8 9 10 2009 0 0 2007 2 2 2002 4 4 1997 6 6 1991 8 8 1985 10 10 Depth (cm) 1978 12 12 1971 14 14 16 1962 16 1951 18 18 20 20 1932 1903 22 22 <100 y 24 24 26 26
Conclusions 1. Amatique Bay sediment record showed signs of increasing sediment accumulation rates, starting from the decade of 1920s, and more conspicuously after year 2000, most likely as a result of the urban growth in the surroundings of the bay, fostered by the development of the commercial and tourism activities at Livingston, Santo Tomas Barrios. 2. Geochemical indexes (such as C/N and Al/Ti ratios) have indicated that the sediment source is stable; with organic carbon showing terrigenous pulses and that most trace metals are the result of terrigenous contribution. 3. As, Hg and Pb have cannot be related to terrigenous supply and further analysis are still ongoing to elucidate their origin.
In the name of the RLA/7/012 family, many thanks for your attention!
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