Identification of organic matter sources in sulfidic late Holocene Antarctic fjord sediments from fossil rDNA sequence analysis
Coolen, Marco J. L.
Volkman, John K.
Sinninghe Damste, Jaap S.
MetadataShow full item record
The 18S ribosomal DNA (rDNA) isolated from sulfidic Holocene sediments and particulate organic matter in the water column of the stratified Small Meromictic Basin (SMB) in Ellis Fjord (eastern Antarctica) was analyzed to identify possible biological sources of organic matter. Previous work had shown that the sediments contained numerous diatom frustules and high contents of a highly branched isoprenoid (HBI) C25:2 alkene (which is a specific biomarker of certain species of the diatom genera Navicula, Haslea, Pleurosigma, or Rhizosolenia), so we focused our search on preserved fossil 18S rDNA of diatoms using sensitive polymerase chain reaction (PCR) approaches. We did not find diatom-derived fossil 18S rDNA using general eukaryotic primers, and even when we used primers selective for diatom 18S rDNA, we only identified a Chaetoceros phylotype, which is known to form cysts in the SMB but is not a likely source of the C25:2 HBI. When we used PCR/denaturing gradient gel electrophoresis methods specific to phylotypes within the HBI-biosynthesizing genera, we were able to identify three phylotypes in the sediments related to HBI-producing strains of the genera Haslea and Navicula. The ancient DNA data thus provided a limited, but valuable, view of the diversity of late Holocene primary producers with a particular bias to specific components of the biota that were better preserved such as the Chaetoceros cysts. This use of paleogenetics also revealed unexpected possible sources of organic matter such as novel stramenopiles for which no specific lipid biomarkers are known and thus would not have been identified based on traditional lipid stratigraphy alone.
Author Posting. © American Geophysical Union, 2007. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Paleoceanography 22 (2007): PA2211, doi:10.1029/2006PA001309.
Showing items related by title, author, creator and subject.
Jackson, Rebecca H.; Straneo, Fiamma (American Meteorological Society, 2016-09-01)In Greenland’s glacial fjords, heat and freshwater are exchanged between glaciers and the ocean. Submarine melting of glaciers has been implicated as a potential trigger for recent glacier acceleration, and observations ...
Late Holocene sea-surface temperature and precipitation variability in northern Patagonia, Chile (Jacaf Fjord, 44°S) Sepulveda, Julio; Pantoja, Silvio; Hughen, Konrad A.; Bertrand, Sebastien; Figueroa, Dante; Leon, Tania; Drenzek, Nicholas J.; Lange, Carina B. (2009-06-12)A high-resolution multi-proxy study including the elemental and isotopic composition of bulk organic matter, land plant-derived biomarkers, and alkenone-based sea surface temperature (SST) from a marine sedimentary record ...
Rapid sulfurisation of highly branched isoprenoid (HBI) alkenes in sulfidic Holocene sediments from Ellis Fjord, Antarctica Sinninghe Damste, Jaap S.; Rijpstra, W. Irene C.; Coolen, Marco J. L.; Schouten, Stefan; Volkman, John K. (2006-04-03)Samples of particulate organic matter from the water column and anoxic Holocene sediment layers from the Small Meromictic Basin (SMB) in Ellis Fjord (eastern Antarctica) were analyzed to study the early incorporation of ...