@article {1892, title = {Cooling of Northwest Atlantic slope waters during the Holocene}, journal = {Geophysical Research Letters}, volume = {34}, year = {2007}, note = {136deTimes Cited:35 Cited References Count:33 }, month = {Feb 10}, abstract = {[1] Climate of the last 11,000 years, the Holocene, is usually described as warm and stable. Benchmark temperature records from central Greenland ice cores show none of the large, abrupt variations that characterized the prior 100,000 years of glacial climate. Nor do they show any substantial trend, indicating at most 1 degrees-3 degrees C of cooling. Here we show that the slope waters east of the United States and Canada cooled 4 degrees-10 degrees C during the Holocene. Declining insolation, increasing convection in the Labrador Sea, and equatorward shifting of the Gulf Stream path may have caused the cooling.}, keywords = {circulation, deposition, ice, labrador sea, ocean, oscillation, sea-surface, stratigraphy, Temperature, variability}, isbn = {0094-8276}, doi = {10.1029/2006GL028495}, author = {Sachs, J. P.} } @article {1937, title = {Dissolved and particulate organic matter source-age characterization in the upper and lower Chesapeake Bay: A combined isotope and biochemical approach}, journal = {Limnology and Oceanography}, volume = {51}, year = {2006}, note = {045nhTimes Cited:24 Cited References Count:37 }, month = {May}, pages = {1421-1431}, abstract = {In order to characterize the sources and ages of organic matter contributing to river and estuarine outflow waters, the present study investigated Delta C-14 and delta C-13 signatures of the major operationally defined biochemical classes of ultrafiltered dissolved organic matter (UDOM) in conjunction with lipid biomarker and elemental compositions of UDOM and suspended particulate organic matter (POM) in the Chesapeake Bay. Freshwater (Susquehanna River) UDOM was dominated by a molecularly uncharacterized (MUC) fraction, followed by total carbohydrate (TCHO), total hydrolysable amino acid (THAA) and total lipid (TLE) components. In contrast, UDOM at the bay mouth (salinity similar to 22-24) was comprised mainly of TCHO, followed by MUC, THAA, and TLE. The Delta C-14 and delta C-13 signatures of both UDOM and its major biochemical classes indicate that Susquehanna DOM is derived in part from old allochthonous terrestrial sources, whereas young marine sources dominate at the bay mouth. In contrast to the other biochemical classes, lipophilic DOM at both sites was very old (similar to 5,000-7,000 years B.P.). In addition, factor analysis of lipid biomarker compounds revealed unique signatures for the UDOM and POM pools that imply disparate source and/or recycling properties as well as potential influences due to physical partitioning. Lipid biomarker compounds showed that although autochthonous riverine/estuarine sources dominated both the UDOM and POM pools, terrigenous lipids were elevated in the Susquehanna during high flow conditions. The presence of lipid biomarkers diagnostic of "fresh" algal material in UDOM further suggested its greater reactivity than POM. The observed biochemical and lipid biomarker compositions and isotopic signatures of UDOM and POM are consistent with previous findings suggesting that these two major organic matter pools have dissimilar reactivities and cycling times, and they derive from comparatively unique source-age materials in rivers and estuaries.}, keywords = {biomarkers, carbon, delta-c-13, lipid-composition, ocean, radiocarbon, river, san-francisco, sediments, variability}, isbn = {0024-3590}, doi = {10.4319/lo.2006.51.3.1421}, author = {Loh, A. N. and Bauer, J. E. and Canuel, E. A.} } @article {2083, title = {Penetration of anthropogenic carbon into organic particles of the deep ocean}, journal = {Geophysical Research Letters}, volume = {30}, year = {2003}, note = {709dpTimes Cited:12 Cited References Count:29 }, month = {Jul 23}, pages = {1744}, abstract = {[1] In the late 1980s, bomb C-14 was present in suspended particulate organic carbon (POC) from the North Central Pacific (NCP) and Sargasso Sea ( SS) throughout most of the water column, demonstrating that deep POC had exchanged with atmospheric CO2 in the past 30 years. Upon reoccupation of these sites in 1999 and 2000, respectively, we observed that the delta(13)C values of suspended POC were lower than those measured a decade earlier. This demonstrates that anthropogenic CO2 from fossil fuel and biomass burning has penetrated a major organic matter pool in the deep ocean. Delta(14)C measured in the suspended POC showed similar or higher values in the deep Sargasso Sea and decreased values in the deep NCP compared to those measured previously. We use a box model to show that the differences in the radiocarbon results are likely due to the presence of resuspended sediment that is laterally advected from the continental margin to the deep Sargasso Sea.}, keywords = {bomb radiocarbon, C-14, CO2, delta-c-13, MATTER, NORTH PACIFIC-OCEAN, SARGASSO SEA, Sediment, variability, water}, isbn = {0094-8276}, doi = {10.1029/2003GL017423}, author = {Druffel, E. R. M. and Bauer, J. E. and Griffin, S. and Hwang, J.} }