Dispersed and Particulate Petroleum Residues in the Gulf of St. Lawrence

Concentrations of petroleum residues both as material in solution or dispersed through the water column and as fresh oil or tarry particles floating on the surface in the Gulf of St. Lawrence were measured during July–August 1971. Dissolved and dispersed forms were present in concentrations generally less than 5 μg/liter over the southern and western regions while 5–10 μg/liter were encountered in the north and east. A major source of these residues appears to be the Atlantic water that enters through Cabot Strait, and the distribution of these materials is closely related to the circulation of water within the Gulf. Surface oil was present at approximately 50% of the stations occupied in concentrations generally less than 100 μg/m2 but as great as 12,400 μg/m2 in the vicinity of the sunken barge Whale. There is no evidence to indicate an appreciable change in concentrations to those of a year ago.

Fish School Size and Migration

When a group of fish is migrating as a school, the error in navigation should be smaller as the size of the school increases, if the individuals jointly orient to a group mean direction. An approximation of this effect is available from consideration of the properties of the circular normal distribution.

Rhodium-102 Fallout: Variations in Deposition and Concentrations in Precipitation

Rhodium-102 was produced as a tracer for U.S. high-altitude detonations in August 1958 and has been detected and monitored in precipitation since October 1960. Between January and September 1961, when atmospheric tests were resumed, the contribution of this high-altitude debris in fallout increased.