HR: 1340h
AN: PP43B-1254 [Abstracts]
TI: A Fossil DNA Based High Resolution Record of Holocene Planktonic Taxa and Environmental
Change in the Black Sea
AU: * Coolen, M J
EM: mcoolen@whoi.edu
AF: Woods Hole Oceanographic Institution, 360 Woods Hole Road, Woods Hole, MA 02543,
AU: Saenz, J P
EM: jsaenz@whoi.edu
AF: Woods Hole Oceanographic Institution, 360 Woods Hole Road, Woods Hole, MA 02543,
AU: Trowbridge, N
AF: Woods Hole Oceanographic Institution, 360 Woods Hole Road, Woods Hole, MA 02543,
AU: Eglinton, T
EM: teglinton@whoi.edu
AF: Woods Hole Oceanographic Institution, 360 Woods Hole Road, Woods Hole, MA 02543,
AB:
A standard approach to study past planktonic taxa which carry information about past environments and climate
variability is the microscopic determination and enumeration of microfossils. However, most planktonic taxa are
soft-bodied and in cases where microfossils are absent or difficult to identify, chemical fossils (lipid biomarkers)
can be used as paleoecological tools. Nevertheless, most lipids are not very specific, multiple sources are
possible, or their biological source remains unknown. Recently, we and others have shown that under excellent
preservation conditions, the analysis of preserved genetic signatures (fossil DNA) offers great potential to study
past planktonic communities, including soft-bodied species, at the unprecedented species- and even strain-level
(this work). Given the dramatic shifts in hydrography and the present anoxia that permeates most of the water
column which promotes preservation of cellular materials, the Black Sea is an excellent setting to study the
ancient species composition based on fossil DNA.
We developed a high temporal resolution (50-100 yr) fossil DNA and lipid biomarker based stratigraphic record of
planktonic community structure in the Black Sea spanning the complete Holocene development from the first
post-glacial input of Mediterranean waters in the paleo-lacustrine Black Sea to the present. Preserved genetic
markers for microbial communities dwelling at the surface (algal primary producers and zooplankton), the
suboxic layer (marine Crenarchaeota), and the sulfidic chemocline (green sulfur bacteria) were targeted to
provide information on past environmental change in the Black Sea. Specifically, we targeted markers that
contributed to our understanding of past surface water temperature, salinity and stratification. Where possible, a
side-by-side phylogenetic and lipid biomarker analyses was performed in order to carefully assess the validity of
utilizing the former as proxies of a given biological input. As the corollary to this, we will also assess the influence
of species changes in the putative biological precursors on both the distribution and isotopic composition of
corresponding lipid biomarkers for which we plan to present data as well.
DE: 0404 Anoxic and hypoxic environments (4802, 4834)
DE: 0424 Biosignatures and proxies
DE: 0473 Paleoclimatology and paleoceanography (3344, 4900)
DE: 4950 Paleoecology
DE: 4954 Sea surface temperature
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2007 Fall Meeting