2.2 Loss of consumers from the affected area 



2.3 Increase in soil toxicants from petrochemicals and brine 



2.4 Loss of soil structure due to excavation and other earthmoving 

 activities or because of petrochemical cohesion of soil particles 



2.5 Possible loss of soil nutrients due to soil extraction 



2.6 Possible increase in available nutrients due to burning of contam- 

 inated vegetation 



Attribute alterations 



Plant assemblages are removed or altered by: (1) the toxic effects of 

 brine or hydrocarbons; (2) the cleanup procedures; or (3) modifications 

 of the soil's microenvironmental regime. Areal extent is a function of 

 the spill size. If large quantities of the material are not dispersed 

 rapidly over wide areas, mobile terrestrial consumers capable of avoiding 

 contaminating substances leave the area. Less mobile consumers may be 

 coated with oil or other noxious effluents and die; food and shelter 

 resources become so degraded as to provide minor benefits to all con- 

 sumers which previously utilized the site. Discharge of brine effluent 

 alters or removes plants because of physiological stresses produced by 

 osmotic water losses. Loss of plant cover, either through immediate 

 direct means such as cutting and burning, or through slower acting 

 mechanisms such as brine increasing soil salinity, means locally 

 increased soil heat, soil moisture evaporation, and surface-water runoff. 

 The magnitude and subsequent implications for the biotic systems depends 

 upon too many unknown variables (spill size, vegetation type, cleanup 

 method, extent of plant removal, site use, etc.) to warrant further con- 

 sideration. 



Cleanup of residual oil or oil quantities too small to efficiently remove 

 with conventional collection techniques is accomplished by burning the 

 contan;inated site. Producers, and consumers which do not abandon the 

 site, are removed. Fire accelerates biomass decomposition, thereby in- 

 creasing the availability of soil nutrients which enhances plant reestab- 

 lishment. 



Excavation and removal of soils impregnated with oil, brine, or other 

 deleterious substances alters soil structure and soil nutrient reserves. 

 Loss of available nutrients impoverishes the site, slowing down later 

 plant recovery. The consequence of soil structure alterations is more 

 important, as this physical feature regulates several important aspects 

 of later plant establishment and growth. Chief among these are soil 



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