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Fellowship and Incentive Funds Project – Coral records of southern Caribbean climate during the demise of the Maya civilization
H. Wu*, T. Felis
(*MARUM Postdoctoral Fellow since 9/2010, collaborators: D. Scholz, C. Giry, S. Scheffers)
Researchers have hypothesized on the many causes of the demise of the Classic Maya civilization during the Terminal Classic Period (TCP; ~AD 750 to 1050) in the lowlands of the Yucatán Peninsula. Explanations ranged from foreign invasion to social turmoil but recent evidence suggests severe climate change such as prolonged dry cycles as the primary influence.
High-resolution records from ocean/lake sediments [Hodell et al., 1995, 2005; Haug et al., 2001, 2003], stalagmites [Medina-Elizalde et al., 2010], and dendrochronology [Stahle et al., 2011] studies have all indicated significant influence of abrupt climate and precipitation changes of sustained droughts within the late Holocene coinciding with the time period of Classic Maya civilization collapse.
Recently collected fossil coral colonies from Bonaire in the southern Caribbean region that grew during the TCP are currently being analyzed for Sr/Ca and δ18O at bimonthly resolution as proxies of sea surface temperature (SST), sea surface salinity (SSS), and hydrological changes. These proxy records show distinct seasonal variability and trends in both SST and SSS indicating possible deviations in the hydrological cycle in which increased evaporation or decreased precipitation yielded more saline surface ocean conditions during the TCP, which might have led to the collapse of the Classic Maya Civilization.
Figure 1: (left) Paleoclimatic records from the central American/Caribbean region that indicate drought during the Terminal Classic Period. (top) Map showing the locations of previous paleoclimatic research, as well as of our study site Bonaire in the southern Caribbean Sea.
Figure 2: The 5 fossil colonies from Bonaire in the southern Caribbean Sea sampled for this study and their centered calibrated 14C ages converted to years A.D. The X-radiographs of each sampled fossil colony are shown with each colony’s total usable length of growth.
Figure 3: Bimonthly resolved coral d18O and Sr/Ca records of a fossil Montastraea sp. colony from Bonaire in the southern Caribbean Sea that grew around AD 860. Unmistakable seasonal cycles of δ18O and Sr/Ca between the annual density bandings are recorded. These preliminary results support the immense potential of these corals to produce seasonal, interannual, and decadal variability archives for the Terminal Classic Period from this region.