consumed by browsing invertebrates. Oil coats suspended particulate 

 matter and sinks to the bottom, thus becoming an energy source for 

 certain bacteria that are capable of oxidizing the oil. Thin layers 

 of crude oil can be completely decomposed within two or three 

 months. 



The effect of an oil spill on the marsh depends on the size of the 

 spill, the duration of the release, and the type of oil spilled. 

 Prediction of a spill's severity is difficult because of many com- 

 pounding factors. Fate of a spill depends on prevailing winds, 

 water currents, and temperature. Toxicity to the biota depends on 

 the temperature, salinity, and the life form and life stage exposed. 

 Spill coverage of the marsh is a function of the tidal magnitude at 

 that particular time. 



A crude oil spill causes a die-back of marsh vegetation above the 

 oil line within two or three days. Cleanup efforts have similar 

 results. Plant species left with intact root systems and large food 

 reserves recover within one yr; less tolerant species require more 

 time. If large quantities of materials are not rapidly dispersed 

 over wide areas, mobile consumers capable of avoiding contaminating 

 substances leave the area. Less mobile consumers may be coated with 

 oil or other noxious fractions and die. Food and shelter resources 

 become so degraded as to provide only minor benefits to consumer 

 groups which previously utilized the site. Birds, particularly 

 waterfowl and wading species, contaminate their plumage by landing 

 or wading in spilled oil. Bird mortality results from exposure (due 

 to a loss of insulation properties of the plumage) or ingestion of 

 toxic petrochemical compounds (swallowed when the birds attempt to 

 clean oil from soiled feathers). Furbearers and other small mammals 

 within the impacted area may experience similar difficulties. 



Movement of men, marsh buggies, airboats, barges, outboards, and 

 other cleanup equipment over and through aquatic marsh areas disturbs 

 soft sediments, thereby increasing suspended sediments and dissolved 

 nutrient concentrations. Similar movements on firmer substrates 

 cause partial vegetation damage and rearrangement of surface configu- 

 rations. Such alterations occur within, as well as around, the 

 actual spill area. They are considered to be temporary and restricted 

 in nature, and are of little consequence at the ecosystem level of 

 consideration. 



Cleanup techniques involving all or some of the following procedures 

 include: (1) placement of floating booms or containment skirts; (2) 

 dispersal and collection of absorbent/adsorbent materials; (3) burn- 

 ing; (4) excavation and removal of contaminated plants and soils; 

 and (5) application of chemical dispersants or emulsifiers. Boom 

 deployment by boat causes few, if any, environmental alterations. 

 Deployment and subsequent collection of absorbent/adsorbent mate- 

 rials such as hay, straw, or specially manufactured plastic sheets 



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