Centennial-to-millennial hydrologic trends and variability along the North Atlantic Coast, USA, during the Holocene

Author Posting. © American Geophysical Union, 2014. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 41 (2014): 4300–4307, doi:10.1002/2014GL060183.Geophysical and sedimentary records from five lakes in Massachusetts reveal regionally coherent hydrologic variability during the Holocene. All of the lakes have risen since ~9.0 ka, but multicentury droughts after 5.6 ka repeatedly lowered their water levels. Quantified water level histories from the three best-studied lakes share >70% of their reconstructed variance. Four prominent low-water phases at 4.9–4.6, 4.2–3.9, 2.9–2.1, and 1.3–1.2 ka were synchronous across coastal lakes, even after accounting for age uncertainties. The droughts also affected sites up to ~200 km inland, but water level changes at 5.6–4.9 ka appear out of phase between inland and coastal lakes. During the enhanced multicentury variability after ~5.6 ka, droughts coincided with cooling in Greenland and may indicate circulation changes across the North Atlantic region. Overall, the records demonstrate that current water levels are exceptionally high and confirm the sensitivity of water resources in the northeast U.S. to climate change.The National Science Foundation (EAR-0602408, EAR- 1036191, and DEB-0816731 to Shuman; EAR-0602380 to Donnelly) and the Woods Hole Oceanographic Institution, Ocean and Climate Change Institute (Donnelly) funded this research.2014-12-2

Repeated century-scale droughts over the past 13,000 yr near the Hudson River watershed, USA

Author Posting. © The Author(s), 2009. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Quaternary Research 75 (2011): 523-530, doi:10.1016/j.yqres.2011.01.006.Sediment and ground-penetrating radar data from Davis Pond near the Hudson River valley reveal past droughts in a historically humid region that presently supplies water to millions of people in and around New York City. A minimum of eleven sandy paleoshoreline deposits in the lake date from 13.4-0.6 cal ka BP. The deposits span 1500 to 200 years between bracketing radiocarbon dates, and intrude into lacustrine silts up to 9.0 m below the modern lake surface in a transect of six cores. Three lowstands, ca. 13.4-10.9, 9.2 and 8.2 cal ka BP indicate low regional moisture balance when low temperatures affected the North Atlantic region. Consistent with insolation trends, water levels rose from ca. 8.0 cal ka BP to present, but five low stands interrupted the rise and are likely associated with ocean-atmosphere interactions. Similar to evidence from other studies, the data from Davis Pond indicate repeated multi-century periods of prolonged or frequent droughts super-imposed on long-term regional trends toward high water levels. The patterns indicate that water supplies in this heavily populated region have continuously varied at multiple time scales, and confirm that humid regions such as the northeastern USA are more prone to severe drought than historically expected.We thank The Ocean and Climate Change Institute at Woods Hole Oceanographic Institution and NSF Earth System History program grants (EAR-0602380 to J. Donnelly and EAR-0602408 to B. Shuman) for supporting this research

Coupling instrumental and geological records of sea-level change : evidence from southern New England of an increase in the rate of sea-level rise in the late 19th century

Author Posting. © American Geophysical Union, 2004. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 31 (2004): L05203, doi:10.1029/2003GL018933.We construct a high-resolution relative sea-level record for the past 700 years by dating basal salt-marsh peat samples above a glacial erratic in an eastern Connecticut salt marsh, to test whether or not the apparent recent acceleration in the rate of sea-level rise (SLR) is coeval with climate warming. The data reveal an average SLR rate of 1.0 ± 0.2 mm/year from about 1300 to 1850 A.D. Coupling of the regional tide-gauge data (1856 to present) with this marsh-based record indicates that the nearly three-fold increase in the regional rate of SLR to modern levels likely occurred in the later half of the 19th century. Thus the timing of the observed SLR rate increase is coincident with the onset of climate warming, indicating a possible link between historic SLR increases and recent temperature increases.A Research Initiative Grant from the NOSAMS facility at WHOI funded the C-14 analysis. The Postdoctoral Scholar Program at WHOI (with funding provided by the U.S.G.S.), The John E. and Anne W. Sawyer Endowed Fund, and The J. Lamar Worzel Assistant Scientist Fund provided support to J. Donnelly

Abrupt climate change as an important agent of ecological change in the Northeast U.S. throughout the past 15,000 years

Author Posting. © The Author(s), 2009. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Quaternary Science Reviews 28 (2009): 1693-1709, doi:10.1016/j.quascirev.2009.04.005.We use a series of tests to evaluate two competing hypotheses about the association of climate and vegetation trends in the northeastern United States over the past 15 kyrs. First, that abrupt climate changes on the scale of centuries had little influence on long-term vegetation trends, and second, that abrupt climate changes interacted with slower climate trends to determine the regional sequence of vegetation phases. Our results support the second. Large dissimilarity between temporally-close fossil pollen samples indicates large vegetation changes within 500 years across >4° of latitude at ca. 13.25-12.75, 12.0-11.5, 10.5, 8.25, and 5.25 ka. The evidence of vegetation change coincides with independent isotopic and sedimentary indicators of rapid shifts in temperature and moisture balance. In several cases, abrupt changes reversed long-term vegetation trends, such as when spruce (Picea) and pine (Pinus) pollen percentages rapidly declined to the north and increased to the south at ca. 13.25-12.75 and 8.25 ka respectively. Abrupt events accelerated other long‐term trends, such as a regional increase in beech (Fagus) pollen percentages at 8.5-8.0 ka. The regional hemlock (Tsuga) decline at ca. 5.25 ka is unique among the abrupt events, and may have been induced by high climatic variability (i.e., repeated severe droughts from 5.7-2.0 ka); autoregressive ecological and evolutionary processes could have maintained low hemlock abundance until ca. 2.0 ka. Delayed increases in chestnut (Castanea) pollen abundance after 5.8 and 2.5 ka also illustrate the potential for multi-century climate variability to influence species’ recruitment as well as mortality. Future climate changes will probably also rapidly initiate persistent vegetation change, particularly by acting as broad, regional-scale disturbances.This work was supported by NSF grants to B. Shuman (EAR‐0602408; DEB‐0816731) and J. Donnelly (EAR‐0602380)

Small business owners’ success criteria, a values approach to personal differences

This study of 150 Dutch small business owners, identified through business/ network directories, investigated relationships between owners’ understanding of success and their personal values. Business owners ranked 10 success criteria. Per- sonal satisfaction, profitability, and satisfied stakeholders ranked highest. Multidi- mensional scaling techniques revealed two dimensions underlying the rank order of success criteria: person-oriented (personal satisfaction versus business growth) and business-oriented (profitability versus contributing back to society). Furthermore, business growth, profitability, and innovativeness were guided by self-enhancing value orientations (power and achievement). Softer success criteria, such as having satisfied stakeholders and a good work–life balance, were guided by self-transcendent value orientations (benevolence and universalism)

A Gelatin-Filtration Headend for Fuel Reprocessing Solutions From Silicon- Containing Aluminum Alloys

A laboratory study of a gelatin headend process for feed from silicon- containing aluminum fuels and plant salvage solutions is described. The optimum conditions for the gelatin treatment of fuel solutions were to boil a 0.1 to 0.5N nitric acid solution with 100 milligrams of gelatin per liter for 30 minutes. This treatment improved filtration rates and decreased the surface activity of the filtrate for TBP extraction. A number of possible flowsheets for fuel solutions are presented using gelatin treatment and filtration. An adequate treatment was not found for salvage solutions of unknown composition because a gelatin dosage which was satisfactory for all solutions could not be selected. The optimum treatment for a salvage solution which was grossly contaminated with zirconium, soluble and colloidal silica, and dibutyl phosphate was to boil a 1N acid deficient solution with 600 milligrams of gelatin per liter, filter, and use a Hexone extraction system. A silicic colloid in fuel processing solutions was characterized as a surface active material by this study. (auth