@article {26, title = {Sediment flux and recent paleoclimate in JordanBasin, Gulf of Maine}, journal = {Continental Shelf Research}, volume = {96}, year = {2015}, note = {PT: J; TC: 0; UT: WOS:000351249700005}, pages = {45-55}, abstract = {We report planktonic foraminiferal fluxes (accumulation rates) and oxygen isotopes (5180) from a nine-month sediment trap deployment, and 8180 from three sediment cores in Jordan Basin, Gulf of Maine. The sediment trap was deployed at 150 m, about halfway to the basin floor, and samples were collected every three weeks between August 2010 and May 2011. The planktonic foraminiferal fauna in the trap is dominated by Neogloboquadrina incompta that reached a maximum flux in the second half of October. Oxygen isotope ratios on that species indicate that on average during the collecting period it lived in the surface mixed layer, when compared to predicted values based on data from a nearby hydrographic buoy from the same period. New large diameter piston cores from Jordan Basin are 25 and 28 m long. Marine hemipelagic sediments are 25 m thick, and the sharp contact with underlying red deglacial sediments is bracketed by two radiocarbon dates on bivalves that indicate ice-free conditions began 16,900 calibrated years ago. Radiocarbon dating of foraminifera indicates that the basin floor sediments (270-290 m) accumulated at > 3 m/kyr during the Holocene, whereas rates were about one tenth that on the basin slope (230 m). In principle, Jordan Basin sediments have the potential to provide time series with interannual resolution. Our results indicate the Holocene is marked by similar to 2 degrees C variability in SST, and the coldest events of the 20th century, during the mid 1960s and mid 1920s, appear to be recorded in the uppermost 50 cm of the seafloor. (C) 2015 Elsevier Ltd. All rights reserved.}, issn = {0278-4343}, doi = {10.1016/j.csr.2015.01.008}, author = {Keigwin, Lloyd D. and Pilskaln, Cynthia H.} } @article {101, title = {Molecular and isotopic insights into particulate organic carbon sources and dynamics in Jordan Basin, Gulf of Maine}, journal = {Continental Shelf Research}, volume = {68}, year = {2013}, pages = {15-22}, abstract = {The carbon isotope and lipid biomarker composition of suspended particles and surface sediment was measured to examine the impact of sediment supply, redistribution and post-depositional alteration processes on organic matter cycling in the Gulf of Maine, a semi-enclosed shelf sea in the northwest Atlantic. A beam attenuation profile revealed a >50 m-thick benthic nepheloid layer (BNL) in the Jordan Basin at the time of sampling (April 2006). The relatively low radiocarbon content of suspended particulate organic carbon (POC) in the BNL indicates that up to 82\% of the POC in this layer was supplied from resuspension of sediment. The concentration of alkenones normalized to POC increased with increasing depth in the water column and was highest in the surface sediment. In contrast to these markers of surface ocean photoautotrophy, the vertical profiles for the concentration and composition of short-chain (C14{\textendash}C18) n-alkanoic acids provided evidence for enhanced heterotrophic processes near the top of the BNL. Suspended POC samples from two depths within the BNL exhibited marked differences in radiocarbon content and fatty acid composition, suggesting that biological activity and associated processes within the BNL are vertically heterogeneous.}, issn = {0278-4343}, doi = {10.1016/j.csr.2013.08.005}, url = {http://www.sciencedirect.com/science/article/pii/S0278434313002653}, author = {Hwang, Jeomshik and Montlu{\c c}on, Daniel B. and Pilskaln, Cynthia H. and Eglinton, Timothy I.} }