216 



P.J. Webber et al. 



Original terrestrial community in equilibrium 



Crude oil 

 spillage 



Surface penetration 



(fast) 



High plant 

 mortality 



(slow) 



Depressed 

 plant growth 



Increased 



winter 



mortality 



Carbon source 

 for microbes 



Nutrient 



immobilization 



by microbes 



Foliar contact 

 only 



Death of vascular 



leaves, mosses, 



lichens 



Hydrophobic 

 soil surface 



Impeded water 



and nutrient 



movement 



Slow plant recovery 



> 



•D 



C 



o 



Lf) 



I 



00 



5-20 years 

 on wet sites 



Little recovery 

 on dry sites 



New terrestrial communities in equilibrium 



FIGURE 6-12. Impact of crude oil upon the coastal tun- 

 dra at Barrow. Recovery times are estimated from obser- 

 vations by Wein and Bliss (1973), Deneke et al. (1975), 

 Hutchinson et al. (1976), and Walker et al. (1978). 



lively retard nutrient cycling and decrease nutrient availability in an eco- 

 system that is already nutrient-poor and highly dependent upon internal 

 recycling of nutrients. Oil is hydrophobic and once within the soil greatly 

 reduces water movement both into the soil and from the bulk soil to 

 plant roots (Raisbeck and Mohtadi 1974, Everett 1978). Because nutrient 



