Layer description, carbon and nitrogen content and stable isotope record of bulk sedimentary organic matter from Laguna Potrok Aike

An investigation of stable isotope (d13C TOC and d15N TN) and elemental parameters (TOC, TN contents and TOC/TN ratios) of bulk organic matter (<200 µm) from sediment cores recovered from the Patagonian lake Laguna Potrok Aike (Argentina) in the framework of the ICDP deep drilling project PASADO provided insights into past changes in lake primary productivity and environmental conditions in South Patagonia throughout the last Glacial-Interglacial transition. Stratigraphically constrained cluster analyses of all proxy parameters suggest four main phases. From ca 26,100 to 17,300 cal. years BP, lacustrine phytoplankton was presumably the predominant organic matter source in an aquatic environment with low primary productivity rates. At around 17,300 cal. years BP, abrupt and distinct shifts of isotopic and elemental values indicate that the lacustrine system underwent a rapid reorganization. Lake primary productivity (phytoplankton and aquatic macrophytes) shows higher levels albeit with large variations during most of the deglaciation until 13,000 cal. years BP. The main causes for this development can be seen in improved growing conditions for primary producers because of deglacial warming in combination with expedient availability of nutrients and likely calm wind conditions. After 13,000 cal. years BP, decreased d13C TOC values, TOC, TN contents and TOC/TN ratios indicate that the lake approached a new state with reduced primary productivity probably induced by unfavourable growing conditions for primary producers like strengthened winds and reduced nutrient availability. The steady increase in d15N TN values presumably suggests limitation of nitrate supply for growth of primary producers resulting from a nutrient shortage after the preceding phase with high productivity. Nitrate limitation and consequent decreased lacustrine primary productivity continued into the early Holocene (10,970-8400 cal. years BP) as reflected by isotopic and elemental values.

Organic geochemistry at DSDP Leg 80 Holes

The four sites drilled on the Irish continental margin (Goban Spur) yielded sediments ranging in age from Holocene to Barremian. Most of the sediments were deposited in well oxygenated waters, and the small amounts of organic matter they contain are highly oxidized. During a few time intervals from the Cenomanian to earliest Turonian, however, the oxygen content of the bottom waters reached very low levels, resulting in the deposition of homogeneous or laminated black sediments containing from 0.5 to 11% total organic carbon (TOC). The original organic matter was of mixed marine and terrestrial origin. The oxidizing-reducing cycles represented by interbedded black and light sediments are probably a result of changes in both circulation and productivity. The black sediments at Sites 550, 551, and 549 were probably deposited near the lower end, middle, and upper end, respectively, of an expanded oxygen-minimum layer. The oil and gas source potential of the laminated black sediments is very good to excellent. The organic-carbon-lean sediments deposited under oxidizing conditions have no oil or gas source potential. The thermal maturity of all sediments is low.

Technical assistance document for sampling and analysis of toxic organic compounds in ambient air /

Mode of access: Internet.

Organic compounds in organophosporus pesticide manufacturing wastewaters /

Issued Sept. 1978.

Determination of octanol/water distribution coefficients, water solubilities, and sediment/water partition coefficients for hydrophobic organic pollutants /

Mode of access: Internet.

Pressure and vacuum sewer demonstration project, Bend, Oregon /

Mode of access: Internet.

Investigations of biodegradability and toxicity of organic compounds /

Mode of access: Internet.

Results of a joint U.S.A./U.S.S.R. hydrodynamic and transport modeling project /

"February 1979."

Adsorption of energy-related organic pollutants : a literature review /

Mode of access: Internet.

Bibliography of aquatic ecosystems effects, analytical methods and treatment technologies for organic compounds in advanced fossil-fuel processing effluents /

Mode of access: Internet.

Treatability of carcinogenic and other hazardous organic compounds/

Mode of access: Internet.

Potentially toxic and hazardous substances in the industrial organic chemicals and organic dyes and pigments industries /

Mode of access: Internet.

Preliminary analysis of cancer rates in organic chemical-producing counties /

"June 1979."

Group treatment of multicompany wastes : the Taunton silver project /

Mode of access: Internet.

Houston-Galveston Navigation Channels, Texas Project.

"July 1995."