Humic acids in bottom sediments of the Western Pacific

Elemental composition, functional groups, and molecular mass distribution were determined in humic acids from the Western Pacific abyssal and coastal bottom sediments. Humic acid structure was studied by oxidative degradation with alkaline nitrobenzene and potassium permanganate, p-coumaric, guaiacilic, and syringilic structural units typical for lignin of terrestrial plants were identified in humic acids by chromatographic analysis of oxidation products. Polysubstituted and polycondensed aromatic systems with minor proportion of aliphatic structures were basic structural units of humic acids in abyssal sediments.

Estimates of %NCW bathing deep North Atlantic (IODP Site 306-U1313) over the past ~3.3 Ma

The circulation and internal structure of the oceans exert a strong influence on Earth's climate because they control latitudinal heat transport and the segregation of carbon between the atmosphere and the abyss (Sigman et al., 2010, doi:10.1038/nature09149). Circulation change, particularly in the Atlantic Ocean, is widely suggested (Bartoli et al., 2005, doi:10.1016/j.epsl.2005.06.020; Haug and Tiedemann, 1998, doi:10.1038/31447; Woodard et al., 2014, doi:10.1126/science.1255586; McKay et al., 2012, doi:10.1073/pnas.1112248109) to have been instrumental in the intensification of Northern Hemisphere glaciation when large ice sheets first developed on North America and Eurasia during the late Pliocene, approximately 2.7 million years ago (Bailey et al., 2013, doi:10.1016/j.quascirev.2013.06.004). Yet the mechanistic link and cause/effect relationship between ocean circulation and glaciation are debated. Here we present new records of North Atlantic Ocean structure using the carbon and neodymium isotopic composition of marine sediments recording deep water for both the Last Glacial to Holocene (35-5 thousand years ago) and the late Pliocene to earliest Pleistocene (3.3-2.4 million years ago). Our data show no secular change. Instead we document major southern-sourced water incursions into the deep North Atlantic during prominent glacials from 2.7 million years ago. Our results suggest that Atlantic circulation acts as a positive feedback rather than as an underlying cause of late Pliocene Northern Hemisphere glaciation. We propose that, once surface Southern Ocean stratification (Sigman, et al., 2004, doi:10.1038/nature02357) and/or extensive sea-ice cover (McKay et al., 2012, doi:10.1073/pnas.1112248109) was established, cold-stage expansions of southern-sourced water such as those documented here enhanced carbon dioxide storage in the deep ocean, helping to increase the amplitude of glacial cycles.

Operator, organizational, field, and depot maintenance manual : roller, motorized, gasoline engine, 3 wheel, 10 ton, with scarifier and sprinkler (Huber-Warco model E1012M), FSN 3895-952-5840).

"March 1964."

Operator, organizational, direct and general support and depot maintenance manual : air conditioner, floor mounting, air cooled, 6 HP, AC 208/416 V, 3 phase, 60 cycle, 60,000 BTU (Keco model F-60), FSN 4120-926-1159.

"December 1967."

Operator, organizational, direct and general support, and depot maintenance manual : generator set, self-powered, diesel engine driven, 30 KW, AC, 3 phase, 120/208V, 240/416V, 60 hertz, convertible to 25 KW, 50 hertz, skid mounted (military design model SF-30-MD/CIED), FSN 6115-935-5111.

"January 1969."

Technical manual, operator and organizational maintenance manual : truck, lift, fork, electric, solid rubber tires, Army model MHE 218, 4,000 lbs. capacity, 100 in. lift, Drexel Dynamics model FL-40-EE-6550, FSN 3930-403-5661, 4,000 lbs. capacity, 180 in. lift, Drexel Dynamics model FL-40-EE-6250, FSN 3930-403-5662.

"April 1971."

Hydrogen generator ML-303/TM and hydrogen generator set AN/TMQ-3.

"August 1956."

Combined operation and maintenance instructions : organizational and intermediate : radio terminal set AN/TRC-17017(V)3, part number 951100-5, NSN 5820-01-148-3976.

"1 August 1985."

Mesoionic 1,3-oxazinium olates. Rearrangement to acylketenes and 3-azabicyclo[3.1.1]heptanetriones

Metastable but isolable mesoionic 1,3-oxazinium 4-olates 9d-f undergo ring opening to acylketenes 10 at or near room temperature. The ketenes undergo intramolecular criss-cross [2 + 2] cycloaddition to afford 3-azabicyclo[3.1.1]heptanetriones 12. The structure of 12d was established by X-ray crystallography.