Organic matter dynamics were studied in five streams at Coweeta Hydrologic Laboratory. Three of these streams drained logged watersheds, and two drained reference deciduous forest watersheds. Litter inputs to the streams draining disturbed watersheds were significantly lower than to reference streams. Additionally, while undisturbed litterfall consisted primarily of relatively refractory leaf s...

Carbon release due to permafrost thaw represents a potentially major positive climate change feedback. The magnitude of carbon loss and the proportion lost as methane (CH4) vs. carbon dioxide (CO2) depend on factors including temperature, mobilization of previously frozen carbon, hydrology, and changes in organic matter chemistry associated with environmental responses to thaw. While the first ...

Abstraet The amount and type of organic matter present in an exceptionally complete upper Aptian to lower Cenomanian sequence of sediments from ODP site 763 on the Exmouth Plateau has been determined. Organic carbon concentrations average 0.2~o. Organic matter is marine in origin, and its production and preservation was low over the ca. 20-million-year interval recorded by this sequence. Becaus...

High resolution (<10 nm) transmission electron microscopy (TEM), energy-®ltering TEM (EFTEM), and electron energy loss spectroscopy (EELS) have been used for the direct microstructural imaging and analysis of clay-organic matter aggregates in ®ne-grained aquatic sediments from Jourdan River Estuary, MS, USA. EFTEM and EELS allow rapid, high-resolution spatial mapping and analysis of light eleme...

I. Sheep fitted with rumen cannulas were fed at hourly intervals by an automatic feeder in a controlled environment and the contents of the reticulo-rumen were removed at intervals of 6 h, 30 min after the previous feed. 2. No diurnal variation was found in the total contents or in the quantity of dry matter, organic matter and nitrogen. 3. Nine dried pasture herbages containing 0.79-3‘69 yo N ...

The effect of grape pomace (Vitis vinifera) and in oak leaf (Quercus libani) tannins by three runs of in vitro gas production on the organic matter digestibility (OMD) and in situ dry matter (DM) and crude protein (CP) disappearance were studied in four sheeps. Polyethylene glycol (PEG) was used to deactivate the tannins. In vitro gas production was recorded at 2, 4, 6, 8, 12, 48, 72, 96 and 12...

soil organic matter is an indicator of soil, agriculture and environmental quality, playing important roles in soil strength and sound environmental functions. size and chemical fractionation of soil organic matter are long-standing approaches in clarifying their key role in soil processes. twenty seven surface samples (0-20 cm) and 6 pedons from different landform units were sampled and descri...

In order to provide support for the discussion of the fate of organic matter in estuaries, a laboratory simulation was performed by changing freshwater ionic strength, pH and organic matter content. The change in spectroscopic characteristics caused by variations in salinity, pH and organic matter concentration in the filtered samples was observed by UV-Vis and fluorescence spectroscopy. The in...

Variation of hydrochemical conditions, with special reference to adequacy of waters as fish habitats, was traced based on selected hydrochemical parameters obtained during the studies conducted from February 2013 till February 2014 year. The results were compared with earlier studies. The sources of organic pollution were identified, and the effect of biogenic substances on the biomass, as well...

We report here a test of the hypothesis that the extent of organic matter preservation in continental margin sediments is controlled by the average period accumulating particles reside in oxic porewater immediately beneath the water/sediment interface. Oxygen penetration depths, organic element compositions, and mineral surface areas were determined for 16 sediment cores collected along an offs...