Table XXX. Limnology of the Cape Simpson oil seep ponds. 



B-l B-2 B-3 D-1 D-2 



At seep D two ponds were observed. D-1 apparently is a thermokarst pit lying in old, partially 

 revegetated water-asphalt emulsion. A few chunks of emulsion containing gas bubbles were floating 

 on the surface of the pond. D-2 is a shallow, perhaps ephemeral, pond actively receiving a small 

 asphalt flow. This pond has a continuous oil slick and blobs of floating oil around the margins. 

 D-2 was surrounded by a ring of dead or oil-damaged Carex aquatilis, presumably related to a higher 

 pond water level earlier in the season. The somewhat incomplete analytical data for these ponds 

 are listed in Table XXX, together with the pond dimensions and a subjective estimate of the degree 

 of potential oil stress, which is based primarily on the abundance of light fraction hydrocarbons in 

 contact with the pond water. 



In addition to these ponds a large number of other ponds and pools on the asphalt flows were 

 measured for conductivity. The results indicate that in aU cases the total ionic concentration is 

 moderate to low, no brines being present in association with the oil seeps. The pH and alkalinity 

 also range to quite low values. With the exception of B-2 all of these ponds appear to some degree 

 impacted by the oil seeps. Faunal diversity decreased noticeably with increasing potential oil 

 stress, although zooplankton and aquatic insect abundances were reasonably high in all except 

 the most highly impacted pond (D-2). The "C plankton primary productivities ranged well above 

 those of undisturbed tundra ponds, although this would not be predicted from the chlaophyU a 

 concentrations, which were quite low. 



Future studies 



Although the studies this year were only exploratory in scope, some general comments about 

 the impact of oil pollution on the arctic terrestrial systems can be made. The presence of toxic 

 levels of oil in the Barrow soils did not produce immediate severe damage to the vegetation. How- 

 ever, the shortness of the growing season and the cool temperatures may delay the effects of oil 

 pollution, and thus necessitate studies extending over several growing seasons. 



85 



