Light hydrocarbons in recent Texas continental shelf and slope sediments
Article first published online: 20 SEP 2012
Copyright 1978 by the American Geophysical Union.
Journal of Geophysical Research: Oceans (1978–2012)
Volume 83, Issue C8, pages 4053–4061, 20 August 1978
How to Cite
1978), Light hydrocarbons in recent Texas continental shelf and slope sediments, J. Geophys. Res., 83(C8), 4053–4061, doi:10.1029/JC083iC08p04053., , and (
- Issue published online: 20 SEP 2012
- Article first published online: 20 SEP 2012
- Manuscript Accepted: 21 FEB 1978
- Manuscript Received: 12 SEP 1977
The distributions of the concentrations of methane, ethene, ethane, propene, and propane in twelve 1-to 2-m-long gravity cores for two transects from nearshore to midslope off the southwest Texas Gulf Coast are reported. Methane profiles exhibit maxima in the top 40 cm of sediment on the shelf, in contrast to downward increasing gradients in the slope region. Nearshore surface methane concentrations ranging from 50 to 400 μl (normal temperature and pressure) per liter pore water are apparently due to microbial production in sulfate-free microenvironments such as fecal pellets in a near-seawater sulfate environment. A decrease in sediment methane levels to less than 5 μl/l pore water in downslope sediments is attributed to reduced microbial activity due to lower organic contents and temperatures. Profiles of the saturated and unsaturated C2 and C3 hydrocarbons suggest that these gases are also microbially produced.