Mexico Off Research Articles

Observations on the Offshore Benthic Flora in the Gulf of Mexico off Pinellas County, Florida

The Floridian Plateau is that projection of North America which separates the deep water of the Atlantic Ocean from the deep water of the Gulf of Mexico (Vaughan, 1910). According to Cooke (1945) the Plateau includes both the State of Florida and an equally great or greater area that lies submerged in water less than 50 fathoms deep. Gunter (1929) called this submerged portion the Florida Shelf. The shelf width in the vicinity of Pinellas County is approximately 105 miles. The offshore slope is gradual in certain areas and at a distance of 40 miles offshore in the Gulf of Mexico the bottom may be under approximately 100 feet of water. The present report contains a discussion of the benthic algal flora collected 9 20 miles offshore at depths from 35 60 feet. It is not known if attached algae occur to the offshore edge of the shelf, however, the fact that they are found so far offshore is significant. It is probable that algal growth will be found at distances further offshore and in water deeper than investigated at the present. Several papers contain information on the marine algae of the Gulf coast of Florida. These are: Taylor (1928, 1936, 1954, 1954a), Nielsen and Madsen (1949, 1949a), Madsen and Nielsen (1950), Humm (1953), and Earle (1956). Humm (1956) listed algal records from inshore and offshore waters in an unpublished general checklist of the St. Georges Sound-Apalachee Bay region in northwest Florida. Excepting Humm (1956) and Taylor (1928), all the other papers cited here concern work confined to bay and close-shore waters.

Studies on Origin of Petroleum: Occurrence of Hydrocarbons in Recent Sediments

The failure of past investigators to detect liquid hydrocarbons in recent sediments has been used to support the contention that petroleum does not form in sediments at the time of deposition of the organic source material. The preferred viewpoint has visualized the eventual transformation of the original complex organic into hydrocarbons by such agencies as heat, pressure, bacteria, radioactivity, and catalysis by the sediments over indeterminate periods of time. An investigation of the nature of the organic matter deposited in recent sediments has resulted in the discovery of liquid hydrocarbons in a wide variety of salty, brackish, and fresh-water deposits. Paraffinic, naphthenic, and a variety of aromatic components have been detected. The quantity of free hydrocarbons has varied from 9-11,700 parts per million of dried sediment. Extrapolation of data obtained on two cores from the floor of the Gulf of Mexico off Louisiana, and one core from the Santa Cruz Basin off California gives estimates varying from 4,500,000 to 10,400,000 barrels of crude oil per cubic mile of sediments in these areas. The recent origin of these hydrocarbons has been established by carbon-14 analysis. Possible sources of the hydrocarbons are discussed.