102 



BIOLOGICAL REPORT 31 



for, that may represent a significant unquantified 

 source to bay waters (SAIC 1991). 



Our understanding of the effects of oil spills on 

 coastal marine systems has been significantly in- 

 creased through two of the oil spills in Buzzards 

 Bay, which provided experimental sites for investi- 

 gation of long-term ecological impacts. The chronic 

 impacts of these oil spills (both occurring within the 

 relatively short time frame of 5 years) have been 

 monitored by researchers since their original oc- 

 currence and provide some of the only long-term 

 data sets available on the persistence of aromatic 

 hydrocarbons, the major constituents of oil and the 

 compounds considered most damaging in the 

 coastal environment. 



On 1 6 September 1 969, the barge Florida ran 

 aground on a rocky shoal just west of Fassett's 

 Point, West Falmouth, Massachusetts. Roughly 

 675,000 L of Number 2 fuel oil leaked into Buz- 

 zards Bay and were driven on-shore by strong 

 south-southwest winds into the Wild Harbor River 

 in North Falmouth. The oil spread over more than 

 400 ha, including 6.4 km of coastline, contaminat- 

 ing intertidal and subtidal bay areas and causing the 

 death of many marine and salt marsh organisms. 

 Much of the oil settled along a few meter band in 

 the Wild Harbor Marsh, resulting in significant losses 

 of benthic infauna and marsh grass, primarily 

 Spartina alterniflora. Blumer et al. ( 1 975) reported 

 up to 95% of the benthic bay animals were dead or 

 dying in heavily oiled areas 8 days after the spill; 1 6 

 months after the spill, areas with more than 1 -2 mg 

 oil/g sediment contained no living higher plants. Most 

 of the fuel oil entering the marsh was sorbed into 

 the anoxic marsh sediments with long-term chronic 

 effects. Even in high marsh areas dominated by 

 Spartina patens, oil was found to have penetrated 

 at least 1 1 5 cm below the surface. In less contami- 

 nated areas where Spartina had nonetheless been 

 killed, some regrowth of Salicornia europaea was 

 evident (Salicornia sp. germinate well from seed 

 and often recolonize damaged wetland areas until 

 outcompeted by Spartina, which grows primarily 

 from roots and rhizomes; Burns and Teal 1 979). 

 The abundant green algae (Enteromorpha 

 clathrata) was highly contaminated, as was the less 



abundant red algae (Polysiphonia fibrillosa). 

 These algae, along with Spartina and Salicornia, 

 are the major sources of plant material to detritivores 

 in these marshes. All of the organisms in the imme- 

 diate area of the spill had oil incorporated into their 

 tissues, including the fiddler crab {Uca pagnax), 

 the marsh killifish (Fundulus conjluentus), the 

 ribbed mussel, and the herring gull. Fiddler crabs 

 obtained most of their oil through feeding on mud, 

 detritus, and algae; mussels and fish were probably 

 contaminated through the processing of contami- 

 nated water; and the gulls were contaminated pri- 

 marily from food. The effect of the spill on these 

 organisms, although still evident, had lessened after 

 4 years. Although over 90% of the heavily oiled 

 areas were considered "recovered" within 6 years, 

 oil was still detectable in a subtidal mud core at 1 0- 

 1 5 cm, and fuel oil hydrocarbons were present in 

 some organisms near the contaminated salt marsh 

 sites 20 years after the spill (Teal et al. 1 992). 



The greater recovery 5-20 years after contami- 

 nation in subtidal areas versus marsh was due to 

 offshore stations being affected by physical and bio- 

 logical processes that stir and weather the sedi- 

 ments, increasing physical removal and degrada- 

 tion of sorbed oil. The highly organic and reduced 

 nature of marsh sediments and their low-energy 

 environment limit physical removal and oxidation of 

 introduced hydrocarbons. Twenty years later there 

 was only limited evidence for oil hydrocarbons in 

 existing marsh species, and that residue appeared 

 to be a result from oil in less than 1% of the con- 

 taminated marsh area. Crabs, which burrow in the 

 sediments and feed on detritus and algae, showed 

 the greatest concentration of hydrocarbons in their 

 tissues. Although present in only trace concentra- 

 tions, these hydrocarbons still appear to be impact- 

 ing the biota. 



The other monitored spill that affected Buzzards 

 Bay waters occurred on 9 October 1974, when 

 the barge Bouchard No. 65 hit a submerged ob- 

 ject while travelling northeast into Buzzards Bay 

 (Hampson and Moul 1 978). The barge was towed 

 to the west entrance of the Cape Cod Canal and 

 anchored, leaking an undetermined portion of the 

 original 1 1 ,604,8 1 L of Number 2 fuel oil into the 



